SeaStar Medical Holding (ICU) S-1 8 Sep 23 IPO registration Financial data

Cover Page

Cover Page	6 Months Ended
	Jun. 30, 2023
Document Information [Line Items]
Document Type	S-1
Amendment Flag	false
Entity Registrant Name	SeaStar Medical Holding Corporation
Entity Central Index Key	0001831868
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3681132
Entity Address, Address Line One	3513 Brighton Blvd
Entity Address, Address Line Two	Suite 410
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80216
City Area Code	844
Local Phone Number	427-8100
Entity Primary SIC Number	6770
Business Contact [Member]
Document Information [Line Items]
Entity Address, Address Line One	3513 Brighton Blvd
Entity Address, Address Line Two	Suite 410
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80216
Contact Personnel Name	Eric Schlorff

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Jun. 30, 2023		Dec. 31, 2022		Dec. 31, 2021
Current assets
Cash		$ 13		$ 47		$ 510
Other receivables		0		12		58
Prepaid expenses		2,319		2,977		33
Total current assets		2,332		3,036		601
Forward option-prepaid forward contracts, net		0		1,729		0
Other assets		2		2		2
Total assets		2,334		4,767		603
Current liabilities
Accounts payable		4,355		1,927		85
Accrued expenses		1,095		2,245		186
Contingent upfront payment for license agreement		100		0
Notes payable		5,907		1,178		0
Convertible notes - related party, net of discount				0		2,378
Convertible notes		2,230		0
Warrants liability		95		0
Convertible notes derivative liability				0		471
Total current liabilities		13,782		5,350		3,120
Notes payable		0		7,652		0
Convertible notes - related party, net of discount, net of current portion				0		181
Government loans				0		63
Convertible notes derivative liability, net of current portion				0		55
Total liabilities		13,782		13,002		3,419
Commitments and contingencies (see Note 13)
Stockholders' deficit
Common stock	[1]	2		1
Additional paid-in capital		96,806	[1]	91,089	[2]	73,495	[2]
Accumulated deficit		(108,256)	[1]	(99,325)	[2]	(76,312)	[2]
Total stockholders' deficit		(11,448)	[1]	(8,235)	[2]	(2,816)	[2]
Total liabilities, convertible preferred stock and stockholders' deficit		$ 2,334		4,767		603
Class A Common Stock [Member]
Stockholders' deficit
Common stock	[2]			$ 1		$ 1
[1] Retroactively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	18,121,238	12,699,668
Common stock, shares outstanding	18,121,238	12,699,668
Common Class A [Member]
Common stock, par value		$ 0.0001	$ 0.0001
Common stock, shares authorized		100,000,000	100,000,000
Common stock, shares issued		12,699,668	7,238,767
Common stock, shares outstanding		12,699,668	7,238,767

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2023		Jun. 30, 2022		Jun. 30, 2023		Jun. 30, 2022		Dec. 31, 2022		Dec. 31, 2021
Operating expenses
Research and development	$ 2,007		$ 596		$ 3,791		$ 951		$ 2,819		$ 2,766
General and administrative	1,743		716		4,540		1,173		6,600		1,683
Origination cost of prepaid forward contracts									2,190		0
Total operating expenses	3,750		1,312		8,331		2,124		11,609		4,449
Loss from operations	(3,750)		(1,312)		(8,331)		(2,124)		(11,609)		(4,449)
Other income (expense), net
Interest expense	(225)		(191)		(658)		(360)		(630)		(212)
Change in fair value of convertible notes	(100)
Other income											91
Change in fair value of warrants liability	480				480		0		(602)		(27)
Change in fair value of notes payable derivative liability			601				578
Change in fair value of forward option-prepaid forward contracts	(69)				(1,723)				(10,170)		0
(Loss)/gain on sale of recycled shares					1,306		0		(1)		0
Total other expense, net	86		410		(595)		218		(11,403)		(148)
Loss before income tax provision (benefit)	(3,664)		(902)		(8,926)		(1,906)		(23,012)		(4,597)
Income tax provision (benefit)	5				5				1		(1)
Net loss	$ (3,669)		$ (902)		$ (8,931)		$ (1,906)		$ (23,013)		$ (4,596)
Net loss per share:
Net loss per share of common stock, basic	$ (0.25)		$ (0.12)		$ (0.64)		$ (0.26)		$ (2.8)		$ (0.63)
Diluted net loss per share	$ (0.25)		$ (0.12)		$ (0.64)		$ (0.26)		$ (2.8)		$ (0.63)
Weighted-average shares outstanding - basic	14,932,866	[1]	7,238,767	[1]	13,984,625	[1]	7,238,767	[1]	8,211,256	[2]	7,238,767	[2]
Weighted-average shares outstanding - diluted	14,932,866	[1]	7,238,767	[1]	13,984,625	[1]	7,238,767	[1]	8,211,256	[2]	7,238,767	[2]
[1] Retrospectively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Consolidated Statements of Chan

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands		Total		Previously Reported [Member]	Retroactive Application of Recapitalization [Member]	PIPE Financing [Member]	Series B Preferred Stock [Member] Previously Reported [Member]	Series B Preferred Stock [Member] Retroactive Application of Recapitalization [Member]	Series A-1 Preferred Stock [Member] Previously Reported [Member]	Series A-1 Preferred Stock [Member] Retroactive Application of Recapitalization [Member]	Series A-2 Preferred Stock [Member] Previously Reported [Member]	Series A-2 Preferred Stock [Member] Retroactive Application of Recapitalization [Member]	Convertible Preferred Stock [Member] Previously Reported [Member]	Convertible Preferred Stock [Member] Retroactive Application of Recapitalization [Member]	Common Stock [Member]	Common Stock [Member] Retroactive Application of Recapitalization [Member]	Common Stock [Member] PIPE Financing [Member]	Additional Paid In Capital [Member]	Additional Paid In Capital [Member] Previously Reported [Member]	Additional Paid In Capital [Member] Retroactive Application of Recapitalization [Member]	Additional Paid In Capital [Member] PIPE Financing [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Previously Reported [Member]
Beginning Balance at Dec. 31, 2020							$ 5,270	$ (5,270)	$ 19,451	$ (19,451)	$ 48,628	$ (48,628)	$ 73,349	$ (73,349)
Beginning Balances (in shares) at Dec. 31, 2020	[1]						426,977	(426,977)	1,576,154	(1,576,154)	784,511	(784,511)
Beginning Balance at Dec. 31, 2020		$ 1,766		$ (71,583)	$ 73,349										$ 1	$ 1		$ 73,481	$ 133	$ 73,348		$ (71,716)	$ (71,716)
Beginning Balances (in shares) at Dec. 31, 2020	[1]														7,238,767	7,238,767
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		14																14
Stock-based compensation		14																14
Net loss		(4,596)																				(4,596)
Ending Balance at Dec. 31, 2021		(2,816)	[2]												$ 1			73,495				(76,312)
Ending Balances (in shares) at Dec. 31, 2021	[1],[3]														7,238,767
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		4																4
Stock-based compensation		4																4
Net loss		(1,004)																				(1,004)
Ending Balance at Mar. 31, 2022		(3,816)													$ 1			73,499				(77,316)
Ending Balances (in shares) at Mar. 31, 2022	[3]														7,238,767
Beginning Balance at Dec. 31, 2021		(2,816)	[2]												$ 1			73,495				(76,312)
Beginning Balances (in shares) at Dec. 31, 2021	[1],[3]														7,238,767
Net loss		(1,906)
Ending Balance at Jun. 30, 2022		(4,373)													$ 1			73,844				(78,218)
Ending Balances (in shares) at Jun. 30, 2022	[3]														7,238,767
Beginning Balance at Dec. 31, 2021		(2,816)	[2]												$ 1			73,495				(76,312)
Beginning Balances (in shares) at Dec. 31, 2021	[1],[3]														7,238,767
Conversion of Convertible Notes to Class A common shares, Shares	[1]														598,861
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		1,311																1,311
Conversion of Convertible Notes to Class A common shares		5,989																5,989
PIPE financing, Shares	[1]																700,000
PIPE financing						$ 7,000															$ 7,000
Stock-based compensation		1,311																1,311
Net loss		(23,013)																				(23,013)
Ending Balance at Dec. 31, 2022		(8,235)	[2]												$ 1			91,089				(99,325)
Ending Balances (in shares) at Dec. 31, 2022	[1],[3]														12,699,668
Beginning Balance at Mar. 31, 2022		(3,816)													$ 1			73,499				(77,316)
Beginning Balances (in shares) at Mar. 31, 2022	[3]														7,238,767
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		345																345
Stock-based compensation		345																345
Net loss		(902)																				(902)
Ending Balance at Jun. 30, 2022		(4,373)													$ 1			73,844				(78,218)
Ending Balances (in shares) at Jun. 30, 2022	[3]														7,238,767
Beginning Balance at Dec. 31, 2022		(8,235)	[2]												$ 1			91,089				(99,325)
Beginning Balances (in shares) at Dec. 31, 2022	[1],[3]														12,699,668
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		505																505
Issuance of shares - equity line of credit, Shares	[3]														378,006
Issuance of shares - equity line of credit		1,108																1,108
Issuance of shares - commitment fee for equity line, Shares	[3]														218,842
Issuance of shares - commitment fee for equity line		1,000																1,000
Stock-based compensation		505																505
Net loss		(5,262)																				(5,262)
Ending Balance at Mar. 31, 2023		(10,884)													$ 1			93,702				(104,587)
Ending Balances (in shares) at Mar. 31, 2023	[3]														13,296,516
Beginning Balance at Dec. 31, 2022		(8,235)	[2]												$ 1			91,089				(99,325)
Beginning Balances (in shares) at Dec. 31, 2022	[1],[3]														12,699,668
Issuance of shares - commitment fee for equity line, Shares															218,842
Net loss		(8,931)
Ending Balance at Jun. 30, 2023		(11,448)	[4]												$ 2			96,806				(108,256)
Ending Balances (in shares) at Jun. 30, 2023	[3]														18,121,238
Beginning Balance at Mar. 31, 2023		(10,884)													$ 1			93,702				(104,587)
Beginning Balances (in shares) at Mar. 31, 2023	[3]														13,296,516
Conversion of Convertible Notes to Class A common shares, Shares	[3]														3,088,167
Issuance of shares - vesting of RSU's	[3]														153,405
Issuance of shares - prepaid forward contracts, Shares	[3]														1,096,972
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition		555													$ 555
Stock-based compensation, Shares	[3]														459,185
Issuance of shares - prepaid forward contracts		558																558
Conversion of Convertible Notes to Class A common shares															$ 1
Issuance of shares - conversion of convertible notes		1,937													$ 1,936
Issuance of shares - equity line of credit, Shares	[3]														26,993
Issuance of shares - equity line of credit		55																55
Stock-based compensation		555													$ 555
Net loss		(3,669)																				(3,669)
Ending Balance at Jun. 30, 2023		$ (11,448)	[4]												$ 2			$ 96,806				$ (108,256)
Ending Balances (in shares) at Jun. 30, 2023	[3]														18,121,238
[1] Retroactively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization (1) Retroactively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (8,931)	$ (1,906)	$ (23,013)	$ (4,596)
Adjustments to reconcile net loss to net cash used in operating activities
Amortization of discount on convertible notes	0	208	242	140
Amortization of deferred financing costs	23	0
Non-cash accrued interest related to notes payable	0	151
Non-cash conversion of accrued expenses into notes payable	0	96
Non-cash fair value of discount on issuance of notes payable	0	(52)
Non-cash fair value of derivative liability on issuance of notes payable	0	52
Change in fair value of notes payable derivative liability	0	(578)
Non-cash accrued interest related to convertible notes			341	72
Change in fair value of warrants liability	(480)	0	602	27
Change in fair value of forward option - prepaid forward contracts	1,723	0	10,170	0
Gain on sale of recycled shares	(1,306)	0	1	0
Stock-based compensation	1,060	349
PPP loan forgiveness			0	(91)
Stock-based compensation	1,060	349	1,311	14
Changes in operating assets and liabilities
Other receivables	12	0	4	0
Inventory			0	55
Prepaid expenses	658	(777)	(1,073)	12
Accounts payable	2,428	584	1,548	(297)
Accrued expenses	350	295
Accrued expenses and other current liabilities			2,073	(450)
Net cash used in operating activities	(4,463)	(1,578)	(7,794)	(5,114)
Cash flows from financing activities
Proceeds from issuance of convertible notes	5,000	0	1,681	2,746
Payment of convertible notes	(258)	0
Proceeds from issuance of shares	1,163	0
Payment of commitment fee - equity line of credit	(500)	0
Proceeds from recapitalization			9,961	0
Payment of recapitalization transaction costs			(1,211)	0
Proceeds from PIPE investors			7,000	0
Payment for forward contracts			(11,940)	0
Proceeds from sale of recycled shares	1,870	0	40	0
Proceeds from notes payable	100	1,681	1,878	0
Payment of notes payable	(2,946)	0	(15)
Proceeds from PPP loan			0	91
Repayment of Government loans			(63)	0
Repayment of PPP loan			0	(20)
Net cash provided by financing activities	4,429	1,681	7,331	2,817
Net increase (decrease) in cash	(34)	103	(463)	(2,297)
Cash, beginning of period	47	510	510	2,807
Cash, end of period	13	613	47	510
Supplemental disclosure of cash flow information
Cash paid for income taxes			1	0
Cash paid for interest	675	0	6	0
Supplemental disclosure of noncash financing activities
Conversion of Series A-2 Preferred stock into Series B Preferred stock			2,400	151
Shares issued as payment of convertible notes	1,937	0
Shares issued to settle forward option-prepaid forward contracts	558	0
Issuance of convertible note warrants	$ 575	$ 0
Conversion of Preferred stock to common stock			73,349	0
Conversion of convertible notes to common stock			5,989	0
Recapitalization transaction costs in accounts payable			294	0
Recapitalization transaction costs in notes payable			2,209	0
Value of derivative liability on issuance of convertible notes			52	499
Non-cash conversion of accrued expenses into convertible notes			96	114
Other receivables of cash in transit for convertible notes			$ 0	$ 58

Description of Business

Description of Business	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Note 1. Descrip tion of Business Organization and description of business SeaStar Medical, Inc. was incorporated as a Delaware corporation in June 2007, and it is headquartered in Denver, Colorado. The Company is principally engaged in the research, development, and commercialization of a platform medical device technology designed to modulate inflammation in various patient populations. The primary target of this technology is for the treatment of acute kidney injuries. SeaStar Medical, Inc. is in the pre-revenue stage focused on product development. On October 28, 2022, LMF Merger Sub, Inc., a wholly-owned subsidiary of LMF Acquisition Opportunities, Inc., (“LMAO”) merged with and into SeaStar Medical, Inc. (the "Business Combination"), with SeaStar Medical, Inc. surviving the Business Combination as a wholly-owned subsidiary of LMAO. Following the consummation of the Business Combination, LMAO was renamed to "SeaStar Medical Holding Corporation" ("the Company", "we", "SeaStar Medical"). Basis of presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules and regulations, certain notes or other financial information normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The interim unaudited condensed consolidated financial statements have been prepared on the same basis as the annual condensed consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal, recurring adjustments that are necessary to present fairly the Company’s results for the interim periods presented. The results from operations for the three and six months ended June 30, 2023, are not necessarily indicative of the results to be expected for the year ended December 31, 2023, or for any future annual or interim period. The accompanying interim unaudited condensed consolidated financial statements should be read in conjunction with the annual condensed consolidated financial statements and the related notes for the year ended December 31, 2022. There have been no material changes in our significant accounting policies as described in our Annual Report on Form 10-K for the year ended December 31, 2022. The interim unaudited condensed consolidated financial statements include the consolidated accounts of the Company's wholly-owned subsidiary, SeaStar Medical, Inc. All significant intercompany transactions have been eliminated in consolidation. Segment information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein. Liquidity and Going Concern As of June 30, 2023, the Company has an accumulated deficit of $ 108,256 and cash of $ 13 . We do not believe that will be sufficient to enable us to fund our operations, including clinical trial expenses and capital expenditure requirements for at least 12 months from the issuance of these unaudited condensed consolidated financial statements. We believe that these conditions raise substantial doubt about our ability to continue as a going concern. Our need for additional capital will depend in part on the scope and costs of our development activities. To date, we have not generated any revenue from the sales of commercialized products. Our ability to generate product revenue will depend on the successful development and eventual commercialization of our product. Until such time, if ever, we expect to finance our operations through the sale of equity or debt, borrowing under credit facilities, or through potential collaborations, other strategic transactions or government and other grants. Adequate capital may not be available to us when needed or on acceptable terms. If we are unable to raise capital, we could be forced to delay, reduce, suspend, or cease our research and development programs or any future commercialization efforts, which would have a negative impact on our business, prospects, operating results and financial condition. The accompanying unaudited condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern and do not include adjustments that might result from the outcome of this uncertainty. This basis of accounting contemplates the recovery of the Company’s assets and the satisfaction of liabilities in the normal course of business. Risks and uncertainties The Company is subject to risks common to early-stage companies in the medical technology industry including, but not limited to, new medical and technological innovations, regulatory approval requirement, lack of funding and capital resources, protection of proprietary technology, and product liability. There can be no assurance that the Company's products or services will be accepted in the marketplace, nor can there be any assurance that any future products or services can be developed or deployed at an acceptable cost and with appropriate performance characteristics, or that such products or services will be successfully marketed, if at all. These factors could have a materially adverse effect on the Company's future financial resul ts, financial position, and cash flows.	Note 1. D e scription of Business Organization and description of business SeaStar Medical, Inc. was incorporated as a Delaware corporation in June 2007, and it is headquartered in Denver, Colorado. The Company is principally engaged in the research, development, and commercialization of a platform medical device technology designed to modulate inflammation in various patient populations. The primary target of this technology is for the treatment of acute kidney injuries. SeaStar Medical, Inc. is in the pre-revenue stage focused on product development. On October 28, 2022, LMF Merger Sub, Inc., a wholly-owned subsidiary of LMF Acquisition Opportunities, Inc., (“LMAO”) merged with and into SeaStar Medical, Inc. (the "Business Combination"), with SeaStar Medical, Inc. surviving the Business Combination as a wholly-owned subsidiary of LMAO (see Note 3). Following the consummation of the Business Combination, LMAO was renamed to "SeaStar Medical Holding Corporation" ("the Company", "we", "SeaStar Medical"). Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC"). The consolidated financial statements include the consolidated accounts of the Company's wholly-owned subsidiary, SeaStar Medical, Inc. All significant intercompany transactions have been eliminated in consolidation. Segment information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein. Liquidity and Going Concern As of December 31, 2022, the Company has an accumulated deficit of $ 99,325 and cash of $ 47 . We do not believe that will be sufficient to enable us to fund our operations, including clinical trial expenses and capital expenditure requirements for at least 12 months from the issuance of these consolidated financial statements. We believe that this raises substantial doubt about our ability to continue as a going concern. Our need for additional capital will depend in part on the scope and costs of our development activities. To date, we have not generated any significant revenue from the sales of commercialized products. Our ability to generate product revenue will depend on the successful development and eventual commercialization of our product. Until such time, if ever, we expect to finance our operations through the sale of equity or debt, borrowing under credit facilities, or through potential collaborations, other strategic transactions or government and other grants. Adequate capital may not be available to us when needed or on acceptable terms. If we are unable to raise capital, we could be forced to delay, reduce, suspend, or cease our research and development programs or any future commercialization efforts, which would have a negative impact on our business, prospects, operating results and financial condition. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern and do not include adjustments that might result from the outcome of this uncertainty. This basis of accounting contemplates the recovery of the Company’s assets and the satisfaction of liabilities in the normal course of business. Risks and uncertainties The Company is subject to risks common to early-stage companies in the medical technology industry including, but not limited to, new medical and technological innovations, dependence on key personnel, protection of proprietary technology, and product liability. There can be no assurance that the Company's products or services will be accepted in the marketplace, nor can there be any assurance that any future products or services can be developed or deployed at an acceptable cost and with appropriate performance characteristics, or that such products or services will be successfully marketed, if at all. These factors could have a materially adverse effect on the Company's future financial results, financial position and cash flows. The Company cannot at this time predict the specific extent, duration, or full impact that a future pandemic will have on its financial condition and operations. A future pandemic may affect our ability to initiate and complete preclinical studies, delay our clinical trials or future clinical trials, disrupt regulatory activities, or have other adverse effects on our business and operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and reported amounts of revenues and expenses during the period. Significant estimates include the valuation of the forward option on prepaid forward contracts, derivative liability, warrants, provision for income taxes, convertible debt measured at fair value, and the amount of stock-based compensation expense. Although actual results could differ from those estimates, such estimates are developed based on the best information available to management and management's best judgments at the time. Concentrations of credit risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist primarily of cash. Periodically, the Company may maintain deposits in financial institutions in excess of government insured limits. The Company has not experienced any losses on deposits since inception. Fair value option of accounting Generally, when financial instruments are first acquired and are not required to be recorded at fair value, ASC 825, Financial Instruments (“ASC 825”), allows an entity to elect the fair value option (“FVO”). The FVO may be elected on an instrument-by-instrument basis only at the time of acquisition and once elected is irrevocable. The FVO allows an entity to account for the entire financial instrument at fair value with subsequent changes in fair value recognized in earnings through the condensed consolidated statements of operations at each reporting date. A financial instrument is generally eligible for the FVO if, amongst other factors, no part of the financial instrument is classified in stockholders’ equity. Based on the eligibility assessment discussed above, the Company concluded that its convertible notes (see Note 7) were eligible for the FVO and accordingly elected the FVO for those debt instruments. This election was made because of operational efficiencies in valuing and reporting for these debt instruments at fair value in their entirety at each reporting date. The convertible notes contain certain embedded derivatives that otherwise would require bifurcation and separate accounting at fair value. The convertible notes, inclusive of their respective accrued interest at the stated interest rates (collectively referred to as the “FVO debt instruments”) were initially recorded at fair value as liabilities on the condensed consolidated balance sheets and subsequently re-measured at fair value at the end of each reporting period presented within the condensed consolidated financial statements. The changes in fair value of the FVO debt instruments are recorded in changes in fair value of convertible notes, included as a component of other income (expense), net, in the condensed consolidated statements of operations. Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Inputs used to measure fair value are classified into the following hierarchy: Level 1 – quoted prices in active markets for identical assets and liabilities. Level 2 – other significant observable inputs (including quoted prices for similar assets and liabilities, interest rate, credit risk, etc.). Level 3 – significant unobservable inputs (including the Company’s own assumptions in determining the fair value of assets and liabilities). The fair value of the forward option on prepaid forward contracts, convertible notes, and the warrants liability, are classified as Level 3 in the fair value hierarchy. The following table presents the changes in the forward option-prepaid forward contracts, convertible notes measured at fair value, warrants liability, and the notes derivative liability for the six months ended June 30, 2023 and 2022 (in thousands): Forward Option- Prepaid Notes Payable Level 3 Rollforward Forward Contracts Convertible Notes Warrants Liability Derivative Liability Balance January 1, 2022 $ — $ — $ — $ ( 526 ) Additions — — — ( 52 ) Changes in fair value — — — 578 Balance June 30, 2022 $ — $ — $ — $ — Balance January 1, 2023 $ 1,729 $ — $ — $ — Additions — 4,425 575 — Sale of recycled shares ( 564 ) — — — Payments — ( 258 ) — — Shares issued as payments — ( 1,937 ) — — Changes in fair value ( 1,723 ) — ( 480 ) — Shares issued as maturity consideration 558 — — — Balance June 30, 2023 $ — $ 2,230 $ 95 $ — The convertible notes are recorded as liabilities and are recorded at fair value based on Level 3 measurements. The estimated fair values of the convertible notes are each determined based on the aggregated, probability-weighted average of the outcomes of certain possible scenarios. The combined value of the probability-weighted average of those outcomes is then discounted back to each reporting period in which the convertible notes are outstanding, in each case, based on a risk-adjusted discount rate estimated based on the implied interest rate using the changes in observed interest rates of corporate rate debt that the Company believes is appropriate for those probability-adjusted cash flows. The estimated fair value of prepaid expenses, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these instruments. Emerging growth company status The Company is an “emerging growth company”, as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they would apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company or (2) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act.	Note 2. Summary of Significant Accounting Policies Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the period. Significant estimates include the valuation of the forward option on prepaid forward contracts, derivative liability, warrants, tax provision, and the amount of share-based compensation expense. Although actual results could differ from those estimates, such estimates are developed based on the best information available to management and management's best judgments at the time. Cash The Company maintains its cash in commercial banks in the United States ("U.S.") which are insured by the Federal Deposit Insurance Corporation up to $ 250 . Concentrations of credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash. Periodically, the Company may maintain deposits in financial institutions in excess of government insured limits. The Company has not experienced any losses on deposits since inception. Income taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statement carrying amounts and the tax bases of assets and liabilities using enacted tax rates expected to apply to taxable income in the periods in which such differences are expected to reverse. A valuation allowance is provided when the realization of net deferred tax assets is not deemed more likely than not. The Company complies with the provisions of "Accounting Standards Codification ("ASC") 740, Income Taxes, which provides a comprehensive model for the recognition, measurement, and disclosure in consolidated financial statements of uncertain income tax positions that a company has taken or expects to take on a tax return. Under this guidance, a company can recognize the benefit of an income tax position only if it is more likely than not (greater than 50 %) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position; otherwise, no benefit can be recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50 % likelihood of being realized upon ultimate settlement. Additionally, the Company accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. Interest and penalties are classified as income tax expense in the consolidated financial statements. Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Inputs used to measure fair value are classified into the following hierarchy: Level 1 – quoted prices in active markets for identical assets and liabilities. Level 2 – other significant observable inputs (including quoted prices for similar assets and liabilities, interest rate, credit risk, etc.). Level 3 – significant unobservable inputs (including the Company’s own assumptions in determining the fair value of assets and liabilities). The fair value of the forward option on prepaid forward contracts and the convertible notes derivative liability are classified as Level 3 in the fair value hierarchy. The following table presents the changes in the forward option and the convertible notes derivative liability for the years ended December 31, 2022 and 2021 (in thousands): Forward Option Convertible Notes On Prepaid Derivative Level 3 Rollforward Forward Contracts Liability Balance December 31, 2020 $ — $ — Additions — ( 499 ) Changes in fair value — ( 27 ) Balance December 31, 2021 — ( 526 ) Additions 11,940 ( 52 ) Sale of recycled shares ( 41 ) — Changes in fair value ( 10,170 ) ( 602 ) Reclassified to additional paid-in capital — 1,180 Balance December 31, 2022 $ 1,729 $ — The forward option in the amount of $ 11,940 was recorded on October 28, 2022, for the forward option in the forward purchase agreements (see Note 4). The forward option is remeasured each reporting period using a Monte-Carlo Simulation in a risk-neutral framework (a special case of the Income Approach). Specifically, the future stock price is simulated assuming a Geometric Brownian Motion (“GBM”). For each simulated path, the forward purchase value is calculated based on the contractual terms and then discounted at the term-matched risk-free rate. Finally, the value of the forward is calculated as the average present value over all simulated paths. Convertible notes derivative liabilities in the amounts of $ 4 , $ 0 , $ 35 and $ 13 , were recorded on January 31, 2022, February 28, 2022, March 16, 2022 and March 31, 2022, respectively, for the issuance of convertible notes along with a corresponding debt discount (see Note 8). The convertible notes liabilities are remeasured each reporting period using a probability-weighted model and assumption related to the conversion price and timing of conversion. The put option liability was valued based on the calculated returns as a result of the various discounts included in the Company’s convertible notes and the related probability assessments of the various settlement scenarios. The convertible notes derivative liability was extinguished as of the c losing of the Business Combination (the "Closing"), as a result of the conversion of the convertible notes. On October 28, 2022, the put option liability was settled upon the Closing and reclassified to additional paid-in capital. Derivative liabilities in the amounts of $ 80 , $ 364 , and $ 55 were recorded on June 10, 2021, September 10, 2021 and December 31, 2021, respectively, for the issuance of convertible notes along with a corresponding debt discount. The change in fair value of the derivative liabilities were recorded in change in fair value of convertible notes derivative liability in the consolidated statements of operations. The estimated fair value of prepaid expenses, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these instruments. Stock-based compensation In accordance with ASC Topic 718, Compensation – Stock Compensation, the Company recognizes compensation expense for all stock-based awards issued to employees based on the estimated grant-date fair value, which is recognized as expense on a graded vesting approach over the requisite service period. The Company has elected to recognize forfeitures as they occur. The fair value of stock options is determined using the Black-Scholes option-pricing model. The determination of fair value for stock options on the date of grant using an option-pricing model requires management to make certain assumptions including expected volatility, expected term, risk-free interest rate and expected dividends in addition to the Company’s Common Stock valuation. The determination of fair value of restricted stock units is valued based on the value of the Company's Common Stock on the grant date (see Note 12). Prior to the Business Combination, due to the absence of an active market for the Company’s Common Stock, the Company utilized methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants Audit and Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation to estimate the fair value of its Common Stock. In determining the exercise prices for options granted, the Company considered the fair value of the Company as of the grant date. The fair value of the Company was determined based upon a variety of factors, including the Company’s financial position, historical performance and operating results, the Company’s stage of development, the progress of the Company’s research and development programs, the prices at which the Company sold its convertible preferred stock, the superior rights, preferences and privileges of the Company’s convertible preferred stock relative to its Common Stock, external market conditions affecting the biotechnology industry, the lack of marketability of the Company’s Common Stock and the prospects of a liquidity event and the analysis of initial public offering and market performance of similar companies as well as recently completed mergers and acquisition of peer companies. Significant changes to the key assumptions underlying the factors used could result in different fair values of the Company at each valuation date. Research and development expenses Expenditures made for research and development are charged to expense as incurred. External costs consist primarily of payments for laboratory supplies purchased in connection with the company’s discovery and preclinical activities, and process development and clinical development activities. Internal costs consist primarily of employee-related costs, consultants fees and costs related to compliance with regulatory requirements. Nonrefundable advance payments for goods and services that will be used in future research and development activities are capitalized and recorded as expense in the period that the Company receives the goods or when services are performed. The Company records expenses related to external research and development services based on services received and efforts expended pursuant to invoices and contracts with consultants that supply, conduct, and manage preclinical studies and clinical trials on its behalf. Emerging growth company status The Company is an “emerging growth company”, as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they would apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company or (2) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. Net loss per share attributable to Common Stockholders The Company’s basic net loss per share attributable to Common Stockholders is calculated by dividing the net loss attributable to Common Stockholders by the weighted-average number of shares of Common Stock outstanding for the period. The diluted net loss per share attributable to Common Stockholders is computed by giving effect to all potential dilutive Common Stock equivalents outstanding for the period. The dilutive effect of these potential common shares is reflected in diluted earnings per share by application of the treasury stock method. Recently issued accounting standards not yet adopted In August 2020, the Financial Accounting Standards Board ("FASB") issued Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity ("ASU 2020-06"). ASU 2020-06 addresses issues identified as a result of the complexity associated with applying US GAAP for certain financial instruments with characteristics of liabilities and equity. In addressing the complexity, ASU 2020-06 focused on amending the guidance on convertible instruments and the guidance on the derivatives scope exception for contracts in an entity’s own equity. The amendments in this Update are effective for public business entities that meet the definition of a Securities and Exchange Commission ("SEC") filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted. In accordance with the JOBS Act, the Company has delayed adoption of ASU 2020-06. As a result, these consolidated financial statements may not be comparable to those companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Business Combination and Recapi

Business Combination and Recapitalization	12 Months Ended
	Dec. 31, 2022
Business Combination And Recapitalization [Abstract]
Business Combination and Recapitalization	Note 3. Business Combination and Recapitalization On October 28, 2022, LMAO consummated a series of transactions that resulted in the combination of LMF Merger Sub, Inc. and SeaStar Medical, Inc. pursuant to an Agreement and Plan of Merger, as described in Note 1. The Business Combination was accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting LMAO was treated as the acquired company for financial reporting purposes. This determination is primarily based on the fact that subsequent to the Business Combination, SeaStar Medical, Inc.'s stockholders have the majority of the voting power of the combined entity, SeaStar Medical, Inc. comprised all of the ongoing operations of the combined entity, SeaStar Medical, Inc. comprised a majority of the governing body of the combined entity, and SeaStar Medical, Inc.’s senior management comprised all of the senior management of the combined entity. Accordingly, for accounting purposes, the Business Combination was treated as the equivalent of SeaStar Medical, Inc. issuing shares for the net assets of LMAO, accompanied by a recapitalization. The net assets of LMAO were stated at historical costs. No goodwill or intangibles were recorded. Operations prior to the Business Combination are those of SeaStar Medical, Inc. The aggregate consideration to the stockholders of SeaStar Medical, Inc. at the closing of the Business Combination was $ 85,406 , which consisted of shares of the Company's Class A Common Stock, par value $ 0.0001 per share, valued at $ 10.00 per share, resulting in the issuance of 8,540,552 shares. Upon the Closing, each of SeaStar Medical, Inc.’s outstanding convertible notes, in the amount of $ 4,636 , and related accrued interest totaling $ 341 less $ 168 in unamortized discounts converted into 598,861 shares of SeaStar Medical Holding Corporation Class A Common Stock valued at $ 10.00 per share. The excess fair value of shares transferred for convertible note conversion of $ 1,180 is recorded in the consolidated statement of operations for the year ended December 31, 2022. Also, upon the Closing, 633,697 shares of Series B Preferred stock, 1,576,154 shares of Series A-1 Preferred stock, and 577,791 shares of Series A-2 Preferred stock of SeaStar Medical, Inc. converted into 7,238,767 shares of SeaStar Medical Holding Corporation Class A Common Stock. SeaStar Medical, Inc.’s 57,942 outstanding warrants were assumed by LMAO and converted into 69,714 warrants to purchase SeaStar Medical Holding Corporation Class A Common Stock. SeaStar Medical, Inc.’s 271,280 outstanding options were assumed by LMAO and converted into 326,399 options to purchase SeaStar Medical Holding Corporation Class A Common Stock. SeaStar Medical, Inc.’s 255,000 outstanding restricted stock unit awards were assumed by LMAO and converted into 306,811 SeaStar Medical Holding Corporation restricted stock units. The increase in the number of stock-based awards was accounted for as a modification (see Note 12). As part of the Business Combination, $ 92,137 was paid to redeem Class A shares from LMAO existing shareholders. 4,162,040 Class A shares remained unredeemed at the time of the Business Combination. LMAO had 10,350,000 public warrants and 5,738,000 private placement warrants at the time of the Business Combination. The public warrants and the private placement warrants are classified as equity. The Company received net cash consideration of $ 9,961 and net liabilities of LMAO of $ 10,882 . The net liabilities of LMAO were as follows (in thousands): Other receivables $ 16 Prepaid expenses 1,871 Accrued expenses ( 82 ) Public warrants liability ( 1,241 ) Private placement warrants liability ( 6,688 ) LMFAO note payable ( 2,785 ) Maxim note payable ( 1,973 ) $ ( 10,882 ) The table below summarizes the shares of Class A Common Stock issued immediately after the Closing as well as the impact of the transaction on the consolidated statements of changes in convertible preferred stock and stockholders' deficit as of October 28, 2022. Common Shares Additional ($ in thousands) Shares Amount Paid-In Capital SPAC financing 4,162,040 $ — $ ( 921 ) Public warrants liability reclassified to equity — — 1,241 Private Placement warrants liability reclassified to equity — — 6,688 Transaction costs — — ( 3,714 ) Reverse recapitalization on October 28, 2022 4,162,040 $ — $ 3,294

Forward Purchase Agreements

Forward Purchase Agreements	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Prepaid Forward Purchase Agreements [Abstract]
Forward Purchase Agreements	Note 3. Forward Purchase Agreements During the six months ended June 30, 2023, 374,005 recycled shares were sold by Forward Purchase Agreement Sellers ("FPA Sellers"). The Company received $ 1,870 for the shares sold and recognized a gain of $ 1,306 on the sale. Losses on remeasurement of $ 69 and $ 1,723 were recorded in Change in fair value of forward option-prepaid forward contracts on the unaudited condensed consolidated statements of operations for the three and six months ended June 30, 2023, respectively. In March 2023, the price of the Company stock was below $ 3.00 for more than 20 trading days and the FPA Sellers at their discretion had the ability to specify the maturity dates f or the FPA. During the three months ended June 30, 2023, the FPA Sellers specified the maturity dates and the FPAs matured and were settled by transferring 1,096,972 shares to the FPA Sellers, with a fair value of $ 558 . As the FPAs were classified as a liability at fair value, upon settlement, the FPAs were marked to their fair value at the settlement dates and the liability was settled.	Note 4. Forward Purchase Agreements In October 2022, LMAO, SeaStar Medical, Inc. entered into a Forward Purchase Agreements ("FPAs") with Vellar Opportunity Fund SPV LLC – Series 4 and HB Strategies LLC (“FPA Sellers"), whereby, prior to the Business Combination, the FPA Sellers purchased 1,151,400 LMF Class A Shares from redeeming holders (the “Recycled Shares”), and an additional 200,000 LMF Class A Shares constituting share consideration, each at an average price per share of $ 10.37 . Pursuant to the FPA, the FPA Sellers waived their redemption rights under the governing documents of LMF Merger Sub, Inc. in connection with the Business Combination. At the Closing, LMAO paid to Vellar, out of funds held in the LMAO trust account, aggregate amounts of $ 14,358 , an amount equal to 1,173,400 LMF Class A Shares ("Recycled Shares"), multiplied by $ 10.37 , the redemption price, $ 2,074 for the purpose of repayment of the FPA Sellers having purchased 200,000 shares from third parties in the open market, and reimbursement of legal expenses and a commission fee in the amount of $ 116 . The FPA Sellers may, at their discretion, sell Recycled Shares, ("Terminated Shares"). The Company is entitled to proceeds from such sales of Terminated Shares equal to the number of Terminated Shares multiplied by the reset price (the "Reset Price"). The Reset Price is initially the per-share redemption price, but will be adjusted on a monthly basis to the lower of (a) the then-current Reset Price, (b) $ 10.00 and (c) the volume weighted average price ("VWAP") price of the last ten trading days of the prior calendar month, but not lower than $ 5.00 ; provided, however, that if we offer and sell Class A Common Stock, or currently outstanding or future issued securities are exercised or converted, at a price lower than then then-current Reset Price, then the Reset Price shall be modified to equal such reduced price. In the event that the VWAP Price is less than $ 3.00 per share for 20 trading days during any 30 trading-day-period, then the FPA Sellers may accelerate the maturity date ("Maturity Date"), which otherwise will be the third anniversary of the Closing. Upon the occurrence of the Maturity Date, we are obligated to pay to the FPA Sellers an amount equal to the number of unsold Recycled Shares, multiplied by $ 2.50 (the "Maturity Consideration"). The Maturity Consideration shall be payable by the Company in cash, or at the Company’s option, as equity, issued in Class A Common Stock, with a per share issue price based on the average daily VWAP Price over 30 scheduled trading days. FPA Sellers will deliver to the Company the number of unsold Recycled Shares. During the year ended December 31, 2022, 3,995 recycled shares were sold by FPA Sellers. There were 1,147,405 recycled shares remaining at December 31,2022. In accordance with ASC 815, Derivatives and Hedging, the Company has determined that the forward option within the Forward Purchase Agreements (i) is a freestanding financial instrument (ii) does not meet the definition of a derivative, (iii) is indexed to the Company's own stock, and (iv) does not meet the requirements for equity classification. The fair value of the option is recorded as an asset or a liability on the Consolidated Balance Sheets as forward option-prepaid forward contracts. The Company has performed fair value measurements for the forward option within the FPAs as of the Closing and as of December 31, 2022, which is described in Note 2. The Company remeasures the fair value of the forward option each reporting period. The initial value of the Forward option-prepaid forward contracts was $ 11,940 at Closing. Recycled Shares with a value of $ 41 were sold by the FPA Sellers. A loss on remeasurement of $ 10,170 was recorded in Change in fair value of forward option on the consolidated statements of operations for the year ended December 31, 2022. On December 31, 2022, the value of the forward option within the FPAs was $ 1,729 and recorded as Forward option-prepaid forward contracts on the consolidated balance sheets.

Accrued Expenses

Accrued Expenses	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Accrued Expenses	Note 4. Accrued Expenses Accrued expenses consisted of the following: ($ in thousands) June 30, December 31, Accrued commitment fee, equity line of credit $ — $ 1,500 Accrued bonus 502 450 Accrued director remuneration 244 61 Accrued settlement 150 — Accrued interest 72 112 Accrued legal 51 80 Accrued research and development 19 18 Other 57 24 Total accrued expenses $ 1,095 $ 2,245	Note 5. Accrued Expenses Accrued expenses consisted of the following amounts as of December 31, 2022 and 2021: ($ in thousands) 2022 2021 Accrued commitment fee, equity line of credit $ 1,500 $ — Accrued bonus 450 — Accrued interest 112 72 Accrued legal 80 27 Accrued director remuneration 61 — Accrued research and development 18 58 Accrued other 24 29 Total accrued expenses $ 2,245 $ 186

Equity Line of Credit

Equity Line of Credit	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Equity [Abstract]
Equity Line of Credit	Note 5. Equity Line of Credit T he Company paid previously accrued commitment fees of $ 1,500 during the six months ended June 30, 2023, of which $ 1,000 was paid in 218,842 shares of Common Stock and $ 500 was paid in cash. During the three and six months ended June 30, 2023, the Company sold 26,993 and 404,999 shares of Common Stock to Tumim Stone Capital LLC for proceeds of $ 55 and $ 1,162 , respectively, as part of the equity line financing arrangement. As of June 30, 2023, $ 98,837 was available to draw.	Note 6. Equity Line of Credit In August 2022, SeaStar Medical, Inc., LMAO, and Tumim Stone Capital LLC ("Tumim") entered into an equity line financing arrangement through a common Stock Purchase Agreement providing the right to sell Tumim up to $ 100,000 worth of shares of Common Stock. The Common Stock Purchase Agreement is subject to certain limitations and conditions and provided for a $ 2,500 commitment fee payable to Tumim. The Company paid $ 1,000 of the commitment fee in cash on the closing date of the Business Combination. The Company has recorded an accrued expense for the remaining $ 1,500 of the commitment fee as of December 31, 2022, of which $ 1,000 will be paid in newly issued shares of Common Stock. The $ 2,500 commitment fee was recorded in general and administrative expenses in the consolidated statements of operations for the year ended December 31, 2022.

Notes Payable

Notes Payable	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Notes Payable [Abstract]
Notes Payable	Note 6. Notes Payable Notes payable consisted of the following: ($ in thousands) June 30, December 31, LMFA notes payable $ 438 $ 968 LMFAO note payable 1,757 2,785 Maxim note payable 3,590 4,167 Insurance financing 199 910 Unamortized deferred financing costs ( 77 ) — 5,907 8,830 Less current portion ( 5,907 ) ( 1,178 ) $ — $ 7,652 Future maturities of principal repayment of the notes payable as of June 30, 2023 are as follows: ($ in thousands) Years ended December 31: 2023 (remaining) $ — 2024 5,907 $ 5,907 On March 15, 2023, the Company amended its LMFA notes, LMFAO note, and Maxim note, extending their maturity dates to June 15, 2024 . In consideration for such extension, the Company agreed to pay the noteholders an aggregate amount of $ 100 in cash upon receipt of proceeds from the issuance of the note at the second closing under the Securities Purchase Agreement (see Note 7). The $ 100 consideration for the modification was capitalized as a deferred financing cost. The Company amortized $ 20 and $ 23 of the deferred financing cost during the three and six months ended June 30, 2023, respectively. LMFA Notes Payable During the six months ended June 30, 2023, the maturity date was extended to June 15, 2024 . The balance due was $ 438 and $ 968 as of June 30, 2023 and December 31, 2022, respectively. The balance at December 31, 2022 consisted of a $ 700 interest bearing note and a $ 268 noninterest bearing note. The Company recorded interest expense of $ 7 and $ 19 for the three and six months ended June 30, 2023, respectively, on the interest-bearing note. The noninterest bearing note was paid i n full in January 2023. The mandatory repayment provisions of the LMFA note were waived for the second senior unsecured convertible note drawn on May 12, 2023 (see Note 7). LMFAO Note Payable During the six months ended June 30, 2023, the maturity date was extended to June 15, 2024 . The mandatory repayment provisions of the LMFA note were waived for the second senior unsecured convertible note drawn on May 12, 2023 (see Note 7). The balance due was $ 1,757 and $ 2,785 on June 30, 2023 and December 31, 2022, respectively. The Company recorded interest expense of $ 31 and $ 74 for the three and six months ended June 30, 2023, respectively. Maxim Note Payable During the six months ended June 30, 2023, the maturity date was extended to June 15, 2024 . The mandatory repayment provisions of the Maxim note were waived for the first senior unsecured convertible note drawn on March 15, 2023 (see Note 7). The balance of the Maxim note was $ 3,590 and $ 4,167 as of June 30, 2023 and December 31, 2022, respectively. The Company recorded interest expense of $ 63 and $ 130 for the six months ended June 30, 2023. Insurance Financing The balance due was $ 199 and $ 910 on June 30, 2023 and December 31, 2022, respectively. As of June 30, 2023, two monthly installments of $ 101 , consisting of principal and interest remain . The Company recorded interest expense of $ 6 and $ 17 for the thre e and six months ended June 30, 2023. Notes Payable Amortization of the debt discounts related to the Dow, Union Carbide, IBT and investor notes for the three and six months ended June 30, 2022 was $ 99 and $ 208 , respectively.	Note 7. Notes Payable Notes payable consisted of the following on December 31: ($ in thousands) 2022 2021 LMFA notes payable $ 968 $ — LMFAO note payable 2,785 — Maxim note payable 4,167 — Insurance financing 910 — Total notes payable $ 8,830 $ — LMFA Notes Payable On September 9, 2022, SeaStar Medical, Inc. entered into a Credit Agreement (“LMFA Note”) with LM Funding America, Inc. (“LMFA”) whereby LMFA agreed to make advances to SeaStar Medical, Inc. of up to $ 700 for general corporate purposes at an interest rate of 15 % per annum. All advances made to SeaStar Medical, Inc. under the LMFA Note and accrued interest were due and payable to LMFA on the maturity date. The maturity date of the loan was the earlier of (a) October 25, 2022, (b) the consummation of the Business Combination, and (c) the termination of the Merger agreement. On October 28, 2022, SeaStar Medical Holding Corporation and LMFA entered into the First Amendment to Credit Agreement, dated September 9, 2022 between LMFA and SeaStar Medical, Inc. whereby (i) the maturity date of the loan under the LMFA Note was extended to October 30, 2023 ; (ii) the Company is required to use 5.0 % of the gross cash proceeds received from any future debt and equity financing to pay outstanding balance of LMFA Note, provided that such repayment is not required for the first $ 500 of cash proceeds; (iii) the interest rate of the LMFA Note is reduced from 15 % to 7 % per annum; and (iv) the default interest rate is reduced from 18 % to 15 %. Subsequent to December 31, 2022, the maturity date was extended to June 15, 2024 (Note 16). As such, the Company has classified the LMFA Note as long-term in the consolidated balance sheets as of December 31, 2022. The LMFA Note contains customary representations and warranties, affirmative and negative covenants, and events of default. The balance due was $ 700 as of December 31, 2022. The Company recorded interest expense of $ 19 for the year ended December 31, 2022. In addition, on October 28, 2022, the parties entered into a security agreement, pursuant to which SeaStar Medical Holding Corporation granted LMFA a security interest in substantially all of the assets and property of the Company, subject to certain exceptions, as collateral under the amended LMFA Note. In addition, the Company entered into a guaranty, dated October 28, 2022, whereby SeaStar Medical Holding Corporation unconditionally guarantees and promises to pay to LMFA the outstanding principal amount under the LMFA Note. On November 2, 2022, The Company entered into an additional promissory note in the amount of $ 268 with LMFA. The promissory note is noninterest bearing and is due on demand at any time on or after March 31, 2023. The note was paid in full in January 2023. LMFAO Note Payable On October 28, 2022, the Company entered into a consolidated amended and restated promissory note with LMFAO Sponsor, LLC, LMAO’s sponsor and the sole holder of founding shares (the “Sponsor”) as the lender, for an aggregate principal amount of $ 2,785 (the “LMFAO Note”) to amend and restate in its entirety (i) the promissory note, dated July 29, 2022, for $ 1,035 in aggregate principal amount issued by LMAO to the Sponsor and (ii) the Amended and Restated Promissory Note, dated July 28, 2022, for $ 1,750 in aggregate principal amount, issued by LMAO to the Sponsor (collectively, the “Original Notes”). The LMFAO Note amended the Original Notes to: (i) extend maturity dates of the Original Notes to October 30, 2023 ; (ii) permit outstanding amount due under the LMFAO Note to be prepaid without premium or penalty; and (iii) require the Company to use 20.0 % of the gross cash proceeds received from any future debt and equity financing to pay outstanding balance of LMFAO Note, provided that such repayment is not required for the first $ 500 of cash proceeds. Subsequent to December 31, 2022, the maturity date was extended to June 15, 2024 (Note 16). As such, the Company has classified the LMFAO Note as long-term in the consolidated balance sheets as of December 31, 2022. The LMFAO Note carries an interest rate of 7 % per annum and contains customary representations and warranties and affirmative and negative covenants. The LMFAO Note is subject to events of default, which may result in the LMFAO Note becoming immediately due and payable, with interest of 15.0 % per annum. In addition, on October 28, 2022, the parties entered into a security agreement whereby the Company granted the Sponsor a security interest in substantially all of the assets and property of the Company, subject to certain exceptions, as collateral to secure the Company’s obligations under the LMFAO Note. The balance due was $ 2,785 as of December 31, 2022. The Company recorded interest expense of $ 35 for the year ended December 31, 2022. Maxim Note Payable Pursuant to an engagement letter between the Company and Maxim dated October 28, 2022, the Company was required to pay Maxim, as its financial advisor, an amount equal to $ 4,182 in cash as professional fees ($ 1,973 assumed from LMAO and $ 2,209 related to professional fees of the Company). Upon the Closing, the parties agreed that such amount would be paid in the form of a promissory note. Accordingly, on October 28, 2022, the Company entered into a promissory note with Maxim as the lender, for an aggregate principal amount of $ 4,182 (the “Maxim Note”). The Maxim Note had a maturity date of October 30, 2023 and outstanding amounts may be prepaid without premium or penalty. Subsequent to December 31, 2022, the maturity date was extended to June 15, 2024 (Note 16). As such, the Company has classified the Maxim Note as long-term in the consolidated balance sheets as of December 31, 2022. If the Company receives any cash proceeds from a debt or equity financing transaction prior to the maturity date, then the Company is required to prepay the indebtedness equal to 25.0 % of the gross amount of the cash proceeds, provided that such repayment obligation shall not apply to the first $ 500 of the cash proceeds received by the Company. Interest on the Maxim Note is due at 7.0 % per annum. The Maxim Note contains customary representations and warranties, and affirmative and negative covenants. The Maxim Note is subject to events of default, which may result in the Maxim Note becoming immediately due and payable, with interest of 15.0 % per annum. The balance of the Maxim Note was $ 4,167 as of December 31, 2022. The Company recorded interest expense of $ 51 for the year ended December 31, 2022. Insurance Financing In October 2022, the Company entered into a financing agreement with a lender to finance a portion of the annual premium of an insurance policy in the amount of $ 910 . Interest on the financing agreement is due at 7.35 % per annum. The balance due was $ 910 as of December 31, 2022. The Company made payments of principal and interest of $ 135 and $ 101 , in January 2023 and February 2023, respectively. Seven additional monthly installments of principal and interest of $ 101 will be made during the year ended December 31, 2023. The Company recorded interest expense of $ 7 for the year ended December 31, 2022.

Convertible Notes

Convertible Notes	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Convertible Notes	Note 7. Convertible Notes 3i Notes On March 15, 2023, the Company entered into a Securities Purchase Agreement with 3i LP ("3i") an institutional investor, whereby the Company has the ability to issue a series of four senior unsecured convertible notes (collectively the "Convertible Notes"), with principal amounts totaling up to $ 9,000 , and warrants to purchase shares of the Company’s Common Stock. On March 15, 2023, the Company issued a note (the "First Convertible Note"), convertible into 1,207,729 shares of Common Stock at an initial conversion price of $ 2.70 , in a principal amount of $ 3,261 , and a warrant to purchase up to 328,352 shares of Common Stock. The First Convertible Note was issued at an 8.0 % discount, bears interest at 7.0 % per annum, matures on June 15, 2024 , and requires monthly installments of principal and interest. On May 12, 2023, the Company issued a note (the "Second Convertible Note"), convertible into 805,153 shares of Common Stock at an initial conversion price of $ 2.70 , in a principal amount of $ 2,174 , and a warrant to purchase up to 218,901 shares of Common Stock. The Second Convertible Note was issued at an 8.0 % discount, bears interest at 7.0 % per annum, matures on August 12, 2024 , and requires monthly installments of principal and interest. The Company concluded that the transactions include two legally detachable and separately exercisable freestanding financial instruments: the Convertible Notes and the warrants. The Company concluded that the warrants should be recorded as a liability (see Note 8). The Company determined the Convertible Notes are liability instruments under ASC 480, Distinguishing Liabilities from Equity . The Convertible Notes were then evaluated in accordance with the requirements of ASC 825, and it was concluded that the Company was not precluded from electing the FVO for the Convertible Notes. As such, the Convertible Notes are carried at fair value in the condensed consolidated balance sheets. The Convertible Notes are measured at fair value each reporting date with changes in fair value recognized in the condensed consolidated statements of operations, unless the change is concluded to be related to the changes in the Company’s credit rating, in which case the change will be recognized as a component of accumulated other comprehensive income in the condensed consolidated balance sheets. During the six months ended June 30, 2023, the Company made cash payments of principal and interest of $ 238 and $ 20 , respectively, on the First Convertible Note. The Company also made additional principal and interest payments, which included accelerated payments through equity conversions. In accordance and pursuant to the First Convertible Note, 3i elected to convert the conversion amount (as defined in the First Convertible Note) into shares of Common Stock of the Company. The Company converted principal and interest into 1,879,688 shares of Common Stock with a fair value of $ 1,291 . During the six months ended June 30, 2023, the Company made principal and interest payments on the Second Convertible Note, which included accelerated payments, though equity conversions. In accordance and pursuant to the Second Convertible Note, 3i elected to convert the conversion amount (as defined in the Second Convertible Note) of principal and interest into shares of Common Stock of the Company. The Company converted principal and interest into 1,208,479 shares of Common Stock with a fair value of $ 646 . Future maturities of principal repayment of the Convertible Notes as of June 30, 2023 are as follows: ($ in thousands) Years ended December 31: 2023 (remaining) $ 2,609 2024 1,009 $ 3,618	Note 8. Convertible Notes Dow Notes The Company had issued convertible note agreements to the Dow Employee’s Pension Plan Trust (Dow Notes) in the following amounts (in thousands): Issue Maturity Date Amount Date June 2021 $ 300 December 2022 September 2021 840 December 2024 October 2021 240 December 2024 November 2021 240 December 2024 March 2022 120 March 2024 April 2022 480 April 2025 April 2022 120 April 2025 $ 2,340 Interest on the unpaid balances accrued at the rate of eight percent per year. At each issuance, the fair value of the conversion features was separated from the convertible notes and reported as a debt discount and derivative liability as discussed in Note 2, Recurring fair value measurements. Upon the occurrence of the Business Combination, the principal plus accrued interest was converted into shares of Common Stock. Union Carbide Notes The Company had issued convertible note agreements to the Union Carbide Employee Pension Plan Trust (Union Carbide Notes) in the following amounts (in thousands): Issue Maturity Date Amount Date June 2021 $ 200 December 2022 September 2021 560 December 2024 October 2021 160 December 2024 November 2021 160 December 2024 March 2022 80 March 2024 April 2022 320 April 2025 April 2022 80 April 2025 $ 1,560 Interest on the unpaid balances accrued at the rate of eight percent per year. At each issuance, the fair value of the conversion features was separated from the convertible notes and reported as a debt discount and derivative liability as discussed in Note 2, Recurring fair value measurements. Upon the occurrence of the Business Combination, the principal plus accrued interest was converted into shares of Common Stock. IBT Notes During the years ended December 31, 2022 and 2021, the Company converted unpaid invoices in the amounts of $ 96 and $ 114 , respectively, into convertible note agreements with IBT and David Humes (collectively the “IBT Notes”). Interest on the unpaid balances accrued at the rate of eight percent per year. At each issuance, the fair value of the conversion features was separated from the convertible notes and reported as a debt discount and derivative liability as discussed in Note 2, Recurring fair value measurements. Upon the occurrence of the Business Combination, the principal plus accrued interest was converted into shares of Common Stock. Investor Notes During the years ended December 31, 2022 and 2021, the Company issued convertible notes to investors for $ 422 and $ 104 , respectively (collectively the “Investor Notes”). Interest on the unpaid balances accrued at the rate of eight percent per year. At each issuance, the fair value of the conversion features was separated from the convertible notes and reported as a debt discount and derivative liability as discussed in Note 2, Recurring fair value measurements. Upon the occurrence of the Business Combination, the principal plus accrued interest was converted into shares of Common Stock. The discounts recorded at the time of the above issuances were amortized to interest expense over the life of the convertible notes using the effective interest method. Amortization of the debt discounts for the years ended December 31, 2022 and 2021 was $ 242 and $ 140 , respectively. The convertible notes and debt discounts consisted of the following on December 31, 2021: December 31, ($ in thousands) 2021 Dow Notes $ 1,620 Union Carbide Notes 1,080 IBT & David Humes Notes 114 Investor Notes 104 Unamortized debt discount ( 359 ) 2,559 Less current portion ( 2,378 ) $ 181 As part of the Business Combination, the Company converted all convertible notes with a principal amount of $ 4,636 , accrued interest of $ 341 , and unamortized discount of $ 168 into 598,861 shares of Common Stock. The fair value of the Common Stock issued was $ 5,989 and the Company has recognized a loss on conversion of convertible notes of $ 1,180 in the consolidated statements of operations for the year ended December 31, 2022. The following notes were converted: ($ in thousands) Dow Notes $ 2,340 Union Carbide Notes 1,560 IBT & David Humes Notes 210 Investor Notes 526 $ 4,636

Government Loans and PPP Loans

Government Loans and PPP Loans	12 Months Ended
	Dec. 31, 2022
Government Loans and PPP Loans [Abstract]
Government Loans and PPP Loans	Note 9. Government Loans and PPP Loans Government Loans In June 2020, SeaStar Medical, Inc. received a loan in the amount of $ 63 from the U.S. Small Business Administration ("SBA") under the Economic Injury Disaster Loan assistance program established as part of the CARES Act. The loan called for monthly payments in the amount of $ 0.3 until maturity in May 2050 . The loan accrued interest at 3.75 %. On October 17, 2022, the Company pre-paid the full balance to the SBA in the amount of $ 63 principal and $ 6 accrued interest. Interest expense was $ 2 and $ 3 for the years ended December 31, 2022 and 2021, respectively. PPP Loans On April 2, 2021, the Company received loan proceeds of $ 91 from a promissory note issued by Silicon Valley Bank, under the Paycheck Protection Program (“PPP”) which was established under the CARES Act. The original term on the loan was two years and the annual interest rate was 1 %. Payments of principal and interest were deferred for the first six months of the loan. Under the terms of the CARES Act, PPP loan recipients can apply for and be granted forgiveness for all or a portion of the loan proceeds. Such forgiveness is determined based on the use of the loan proceeds for payroll costs, rent and utility expenses and the maintenance of workforce and compensation levels with certain limitations. During the year ended December 31, 2021, the Company was granted forgiveness for the entire PPP loan. The Company recorded $ 91 to other income. In April 2020, the Company had received loan proceeds of $ 104 from a promissory note issued by Silicon Valley Bank, under the PPP. During the year ended December 31, 2020, the Company recorded $ 84 to other income for loan forgiveness and during the year ended December 31, 2021, the Company paid $ 20 for the unforgiven remaining balance of a PPP loan.

Warrants

Warrants	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Warrants and Rights Note Disclosure [Abstract]
Warrants	Note 8. Warrants On March 15, 2023, as part of the issuance of the First Convertible Note (see Note 7) 328,352 warrants (“Convertible Note Warrants”) were issued with an exercise price of $ 2.97 per share. On May 12, 2023, as part of the issuance of the Second Convertible Note (see Note 7) 218,901 Convertible Note Warrants were issued with an exercise price of $ 2.97 per share. The Convertible Note Warrants expire five years from their issuance date and contain cashless exercise provisions. The Company does not have the ability to redeem the Convertible Note Warrants. The Convertible Note Warrants for the First Convertible Note were valued at $ 500 at issuance. The Convertible Note Warrants for the Second Convertible Note were valued at $ 75 at issuance. In accordance with ASC 815-40, Derivatives and Hedging-Contracts in and Entity’s own Equity , the Company has determined that the Convertible Note Warrants do not meet the conditions for equity classification, due to potential cash settlement under the exchange cap provision of the Securities Purchase Agreement, and should be carried on the condensed consolidated balance sheets as a liability measured at fair value, with subsequent changes in fair value recorded in the condensed consolidated statements of operations as change in fair value of warrants liability. The fair value of the Convertible Note Warrants was determined using a Black-Scholes option pricing model, which considers variables such as estimated volatility, time to maturity, and the risk-free interest rate. The risk-free interest rate is the U.S. Treasury rate at the date of issuance, and the time to maturity is based on the contractual life at the date of issuance, which is five years . The Company has the following warrants outstanding: June 30, December 31, 2023 2022 Public Stockholders' Warrants 10,350,000 10,350,000 Private Placement Warrants 5,738,000 5,738,000 PIPE Investor Warrants 700,000 700,000 Convertible Note Warrants 547,253 — SeaStar Warrants 69,714 69,714 17,404,967 16,857,714	Note 10. Warrants Prior to the Business Combination, SeaStar Medical, Inc. had outstanding warrants to purchase shares of SeaStar Medical, Inc.’s preferred stock which had been issued in conjunction with various debt financings. Upon effectiveness of the Business Combination, 57,942 outstanding warrants were converted into 69,714 warrants to purchase Common Stock of SeaStar Medical Holding Corporation (“Legacy SeaStar Warrants”) at their previous exercise prices. On December 31, 2022, there were 69,714 Legacy SeaStar Warrants outstanding, which are accounted for as equity. As part of LMAO’s initial public offering, under the Warrant Agreement dated as of January 25, 2021 and, prior to the effectiveness of the Business Combination, LMAO issued 10,350,000 warrants each of which entitled the holder to purchase one share of Common Stock at an exercise price of $ 11.50 per share (“Public Stockholders’ Warrants”). Simultaneously with the closing of the Initial Public Offering, LMAO completed the private sale of 5,738,000 million warrants each of which entitled the holder to purchase one share of Common Stock at an exercise price of $ 11.50 per share, to LMAO’s sponsor (“Private Placement Warrants”). Upon the effectiveness of the Business Combination, the outstanding Public Stockholders’ Warrants and Private Placement Warrants automatically converted into warrants of SeaStar Medical Holding Corporation. The Company has reviewed the terms of the warrants to determine whether the warrants should be classified as liabilities or stockholders' deficit in its consolidated balance sheets. In order for a warrant to be classified in stockholders' deficit, the warrant must be (a) indexed to the Company's equity and (b) meet the conditions for equity classification in ASC 815-40, Derivatives and Hedging-Contracts in an Entity's own Equity . If a warrant does not meet the conditions for equity classification, it is carried on the consolidated balance sheets as a warrant liability measured at fair value, with subsequent changes in the fair value of the warrant recorded in the consolidated statements of operations as change in fair value of warrants. The Company determined that the warrants are required to be classified as stockholders' deficit as of the date of the Business Combination. The Company has the ability to redeem outstanding Public Shareholders' Warrants at any time after they become exercisable and prior to their expiration, at a price of $ 0.01 per warrant, provided that the last reported sales price of our Common Stock equals or exceeds $ 18.00 per share (as adjusted for stock splits , stock dividends, reorganizations, and the like) for any 20 trading days within a 30 day trading-day period. The Company does not have the ability to redeem the Private Placement Warrants. The Private Placement Warrants were valued a t $ 6,688 at t he date of the Business Combination date. On December 31, 2022, there were 10,350,000 Public Shareholders' Warrants outstanding and 5,738 Private placement Warrants outstanding. On October 28, 2022, the Company entered into a Private Investment in Public Equity (“PIPE”) Agreement, pursuant to which the PIPE investors purchased an aggregate of 700,000 shares of Common Stock at $ 10.00 per share and received 700,000 PIPE Investor Warrants, which entitled the holder to purchase one share of Common Stock of SeaStar Medical Holding Corporation at $ 11.50 per share, for an aggregate purchase price of $ 7,000 . At December 31, 2022, there were 700,000 PIPE Investor Warrants outstanding, which are accounted for as equity. The Company has the following warrants outstanding on December 31, 2022 and 2021: December 31, December 31, 2022 2021 Public Stockholders' Warrants 10,350,000 — Private Placement Warrants 5,738,000 — PIPE Investor Warrants 700,000 — SeaStar Warrants 69,714 69,714 16,857,714 69,714

Common Stock and Stock-Based Co

Common Stock and Stock-Based Compensation	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Common Stock and Stock-Based Compensation	Note 9. Common Stock and Stock-Based Compensation During the six months ended June 30, 2023, the Company issued 459,185 shares of Common Stock for management bonuses and 153,405 shares of Common Stock for vested restricted stock units. The Company also granted 351,029 options and 234,019 restricted stock units during the six months ended June 30, 2023. For options granted during the six months ended June 30, 2023, the weighted-average grant date fair value was $ 1.20 per share and the options vest one year from the grant date. For RSUs granted during the six months ended June 30, 2023, the weighted-average grant date fair value was $ 1.47 per share and the RSUs vest one year from the grant date. The following represents stock-based compensation expense in the company’s unaudited condensed consolidated statements of operations: ($ in thousands) Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development $ 96 $ 90 $ 135 $ 90 General and administrative 459 255 925 259 Total $ 555 $ 345 $ 1,060 $ 349

Convertible Preferred Stock, Co

Convertible Preferred Stock, Common Stock And Preferred Stock	12 Months Ended
	Dec. 31, 2022
Convertible Preferred Stock, Common Stock and Preferred Stock [Abstract]
Convertible Preferred Stock, Common Stock and Preferred Stock	Note 11. Convertible Preferred Stock, Common Stock and Preferred Stock During the years ended December 31, 2022 and 2021, SeaStar Medical, Inc. converted 194,494 and 12,226 shares of Series A-2 Preferred stock, respectively, to Series B Preferred stock. Immediately prior to the Business Combination, SeaStar Medical, Inc. converted 633,697 shares of Series B Preferred stock, 1,576,154 shares of Series A-1 Preferred stock and 577,791 shares of Series A-2 Preferred stock to 7,238,767 shares of Common Stock. Also, during the year ended December 31, 2022, SeaStar Medical, Inc. converted Convertible Notes with a principal amount of $ 4,636 , a discount amount of $ 168 and accrued interest of $ 341 to 598,861 shares of Common Stock. SeaStar Medical, Inc.’s convertible preferred stock was classified as temporary equity in the accompanying consolidated balance sheets given the voting interest held by convertible preferred stockholders which could cause certain events to occur that were outside of SeaStar Medical, Inc.’s control whereby SeaStar Medical, Inc. could have been obligated to redeem the convertible preferred stock. SeaStar Medical, Inc. did not adjust the carrying values of the convertible preferred stock to the respective liquidation preferences of such shares as the instruments were not yet redeemable, and SeaStar Medical, Inc. believed it was not probable that the instruments would become redeemable. Subsequent to the Business Combination, the Company is authorized to issue 110,000,000 shares, consisting of (a) 100,000,000 shares of Common Stock and (b) 10,000,000 shares of preferred stock (the “Preferred Stock”). Common stock The charter of the Company (the "Charter") provides the following with respect to the rights, powers, preferences, and privileges of the Common Stock. Voting power Except as otherwise required by law or as otherwise provided in any certificate of designation for any series of preferred stock, the holders of Common Stock possess all voting power for the election of the Company’s directors and all other matters requiring stockholder action. Holders of Common Stock are entitled to one voter per share on matters to be voted on by stockholders. The Charter does not provide for cumulative voting rights. Dividends Subject to the rights, if any, of the holders of any outstanding shares of preferred stock, under the Charter, holders of Common Stock will be entitled to receive such dividends, if any, as may be declared from time to time by the Board in its discretion out of funds legally available therefor. Liquidation, dissolution and winding up In the event of the Company’s voluntary or involuntary liquidation, dissolution, distribution of assets or winding-up, the holders of the Common Stock will be entitled to receive an equal amount per share of all of the Company’s assets of whatever kind available for distribution to stockholders, after the rights of the holders of the Preferred Stock have been satisfied and after payment or provision for payment of the Company’s debts. Preemptive or other rights There are no preemptive rights or sinking fund provisions applicable to the shares of the Company’s Common Stock. Preferred Stock The Charter provides that shares of preferred stock may be issued from time to time in one or more series. Our Board is authorized to fix the voting rights, if any, designations, powers, preferences, the relative, participating, optional, or other special rights and any qualifications, limitations, and restrictions thereof, applicable to the shares of each series. We have no preferred stock outstanding at December 31, 2022.

Stock-Based Compensation Awards

Stock-Based Compensation Awards	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation Awards	Note 12. Stock-Based Compensation Awards Equity incentive plan - stock options The Company’s board of directors adopted the SeaStar Medical, Inc.’s 2019 Stock Incentive Plan (the "Stock Incentive Plan") on February 25, 2019 to provide long-term incentive for its key employees and non-employee service providers. As of December 31, 2022 and 2021, 547,717 shares were reserved for the issuance of stock options to key employees and non-employee service providers for the purchase of SeaStar Medical, Inc.’s Common Stock. The vesting of stock options is stated in each individual grant agreement, which is generally four years . Options granted expire 10 years after the date of grant. There were 260,355 shares available for future grant as of December 31, 2021. Upon the Closing, the Stock Incentive Plan was terminated, and the Company will not grant any further awards under such plan. However, the outstanding awards under the Stock Incentive Plan will be assumed and continued in connection with the Business Combination. Each SeaStar Medical, Inc. Option to purchase shares of SeaStar Medical, Inc. Common Stock or SeaStar Medical, Inc. Preferred Stock (“SeaStar Option”) that was outstanding and unexercised immediately prior to the Business Combination converted into an option to purchase Common Stock, par value $ 0.0001 per share, of SeaStar Medical Holding Corporation in accordance with its terms. The increase in the number of stock options was accounted for as a modification. The incremental fair value from the stock option modification increased stock-based compensation expense by $ 134 for the year ended December 31, 2022, and increased unrecognized stock-based compensation cost by $ 223 as of December 31, 2022. The Company's Board of Directors adopted, and the shareholders approved SeaStar Medical, Inc.'s 2022 Omnibus Incentive Plan (the "Equity Incentive Plan") to provide long-term incentive for its key employees and non-employee service providers. As of December 31, 2022, 1,270,000 shares were reserved for the issuance of stock options to key employees and non-employee service providers for the purchase of the Company’s Common Stock. The vesting of stock options is stated in each individual grant agreement, which is generally four years . Options granted expire 10 years after the date of grant. There were 743,720 options available for future grant as of December 31, 2022. Option activity for the years ended December 31, 2022 and 2021, are as follows: Weighted Weighted Average Average Total Remaining Exercise Intrinsic Contractual ($ in thousands) Options Price Value Life (Years) Outstanding as of December 31, 2020 141,851 $ 5.34 Granted 153,504 $ 0.55 Forfeited ( 7,973 ) $ 10.00 Outstanding as of December 31, 2021 287,382 $ 2.65 $ — 8.61 Forfeited prior to merger conversion ( 83,928 ) $ 4.63 Additional options issued in merger conversion 41,338 $ 1.84 Outstanding as of December 31, 2022 244,792 $ 1.84 $ 751,851 7.65 Options exercisable as of December 31, 2022 145,365 $ 2.46 $ 412,681 7.48 The Company recognized $ 148 and $ 14 in stock-based compensation expense in connection with the Equity Incentive Plan for the years ended December 31, 2022 and 2021. As of December 31, 2022, there was unrecognized stock-based compensation cost of $ 246 , which is expected to be recognized over a term of three years . There were no options exercised during the years ended December 31, 2022 and 2021. For options granted during the year ended December 31, 2021, the weighted-average grant date fair value was $ 0.40 per share. No options were granted during the year ended December 31, 2022, other than the additional options issued in the Business Combination. Stock-based compensation expense for options included in the consolidated statements of operations is as follows: ($ in thousands) 2022 2021 Research and development $ 7 $ 1 General and administrative 141 13 Total $ 148 $ 14 Equity incentive plan - restricted stock units In April 2022, the board of directors granted employees and members of the board restricted stock units ("RSUs"), under which the holders have the right to receive an aggregate of 255,000 shares of Common Stock. The majority of the RSUs granted vest 50 % on the first anniversary of the grant date, with the remaining 50 % of the awards vesting monthly over a 12 -to- 24 month period following the first anniversary of the grant date . At grant date, the fair market value of an RSU was $ 8.00 per share. Each SeaStar Medical, Inc. RSU that was outstanding immediately prior to the Business Combination converted into an RSU to receive Common Stock, par value $ 0.0001 per share, of SeaStar Medical Holding Corporation in accordance with its terms. The increase in the number of RSUs was accounted for as a modification. The incremental fair value from the modification increased stock-based compensation expense increased by $ 130 for the year ended December 31, 2022, and increased unrecognized stock-based compensation cost by $ 373 as of December 31, 2022. RSU activity for the year ended December 31, 2022, was as follows: Outstanding as of December 31, 2021 — Granted 255,000 Forfeited prior to merger conversion ( 7,000 ) Additional RSUs issued in merger conversion 50,389 Outstanding as of December 31, 2022 298,389 Vested as of December 31, 2022 — Shares subject to repurchase as of December 31, 2022 298,389 The Company recognized $ 1,163 in stock-based compensation expense in connection with the RSUs for the year ended December 31, 2022. As of December 31, 2022, there was unrecognized stock-based compensation cost of $ 1,353 , which is expected to be recognized over a term of 2.2 years . For RSUs granted during the year ended December 31, 2022, the weighted-average grant date fair value was $ 8.00 per share. The weighted-average fair value of the additional RSUs issued in the Business Combination conversion was $ 10.00 per share. Stock-based compensation expense for RSUs included in the consolidated statements of operations is as follows: ($ in thousands) 2022 2021 Research and development $ 89 $ — General and administrative 1,074 — Total $ 1,163 $ —

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10. Commitments and Contingencies License and distribution agreement On December 27, 2022, the Company entered into a license and distribution agreement with a distributor, appointing the distributor as the exclusive distributor to promote, advertise, market, distribute and sell the Selective Cytopheretic Device (“SCD”) in the United States. The Company received an upfront payment of $ 100 on January 3, 2023. If the Company does not receive written authorization to market the SCD, prior to the first anniversary of the effective date, the Company will repay the $ 100 . The Company has recorded the $ 100 upfront payment as a liability in the unaudited condensed consolidated balance sheets as of June 30, 2023. The Company shall also receive milestone payments in the amounts of $ 450 and $ 350 for obtaining approval from the Food and Drug Administration and for selling the first sixty units to any third parties. The term of the agreement is three years . Lease agreements The Company is part of a membership agreement for shared office space and can cancel at any time. Rent expense was $ 8 and $ 16 for the three and six months ended June 30, 2023 and 2022, respectively. Litigation Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. From time to time, the Company may become involved in legal proceedings arising in the ordinary course of business. In connection with the Business Combination, LMAO proposed, for stockholder approval, various amendments to its Amended and Restated Certificate of Incorporation, which included among other things a proposal to increase the authorized shares of Common Stock. A purported stockholder sent a Stockholder Litigation Demand letter (the “Demand”) to the Board of Directors of LMAO alleging that the Delaware General Corporation Law required a separate class vote of the Class A Common Stockholders to increase the authorized shares of Common Stock. Following receipt of the Demand, the Company canceled and withdrew the proposal to increase the authorized shares of Common Stock. The stockholder’s counsel thereafter demanded that the Company pay counsel fees for the purported benefit conferred upon the Company’s shareholders by causing the Company to withdraw the allegedly invalid proposal to increase the authorized shares of Common Stock. The Com pany recorded $ 150 for a legal settlement in accrued expenses as of June 30, 2023. The settlement will be paid in three installments of $ 50 in August 2023, September 2023, and November 2023. The Company was not subject to any other material legal proceedings during the three and six months ended June 30, 2023, and no material legal proceedings are currently pending or threatened.	Note 13. Commitments and Contingencies License and distribution agreement On December 27, 2022, the Company entered into a license and distribution agreement (“License Agreement”) with a distributor, appointing the distributor as the exclusive distributor to promote, advertise, market, distribute and sell the Selective Cytopheretic Device (“SCD”) in the United States. The Company received an upfront payment of $ 100 on January 3, 2023. If the Company does not receive written authorization to market the SCD, prior to the first anniversary of the effective date, the Company will repay the $ 100 . The Company shall also receive milestone payments in the amounts of $ 450 and $ 350 for obtaining FDA approval and for selling the first sixty units to any third parties. The term of the agreement is three years . Lease agreements The Company is part of a membership agreement for shared office space and can cancel at any time. Rent expense was $ 32 for the years ended December 31, 2022 and 2021. Litigation Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. From time to time, the Company may become involved in legal proceedings arising in the ordinary course of business. The Company was not subject to any material legal proceedings during the years ended December 31, 2022 and 2021 and no material legal proceedings are currently pending or threatened.

Income Taxes

Income Taxes	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Note 11. Income Taxes In accordance with U.S. GAAP, a valuation allowance should be provided if it is more likely than not that some or all of the Company’s deferred tax assets will not be realized. The Company’s ability to realize the benefit of its deferred tax assets will depend on the generation of future taxable income. Due to the uncertainty of future profitable operations and taxable income, the Company has recorded a full valuation allowance against its net deferred tax assets. The Company believes its tax filing position and deductions related to tax periods subject to examination will be sustained under audit and, therefore, has no reserve for uncertain tax positions.	Note 14. Income Taxes The Company recorded $ 1 of current income tax expense and $ 1 of current income tax benefit for the years ended December 31, 2022 and 2021, respectively. The effective income tax rate of the Company’s provision for income taxes differed from the federal statutory rate as follows: 2022 2021 Federal tax at statutory rate 21.0 % 21.0 % State income tax 4.4 % 3.6 % Interest on convertible notes ( 0.6 )% 0.0 % Change in fair value of convertible notes derivative liability ( 0.7 )% 0.0 % Other 0.3 % ( 0.8 )% Change in valuation allowance ( 24.4 )% ( 23.8 )% Total effective income tax rate ( 0.0 )% ( 0.0 )% Significant components of deferred tax assets for federal and state income taxes were as follows: December 31, December 31, ($ in thousands) 2022 2021 Deferred tax assets: Net operating losses $ 18,627 $ 17,538 Forward option-prepaid forward contracts, net 2,585 — Finance charges and origination fees 1,028 — Accrued compensation 130 — Stock-based compensation 311 3 Section 174 research and development capitalization 434 — Tax credits 715 648 Total deferred tax assets 23,830 18,189 Valuation allowance ( 23,830 ) ( 18,189 ) Net deferred tax assets $ — $ — In accordance with U.S. GAAP, a valuation allowance should be provided if it is more likely than not that some or all of the Company’s deferred tax assets will not be realized. The Company’s ability to realize the benefit of its deferred tax assets will depend on the generation of future taxable income. Due to the uncertainty of future profitable operations and taxable income, the Company has recorded a full valuation allowance against its net deferred tax assets. For the years ended December 31, 2022 and 2021, the net increase in the valuation allowance was $ 5,641 and $ 869 , respectively. As of December 31, 2022 and 2021, the Company had federal net operating loss carryforwards of $ 82,265 and $ 78,127 , respectively, of which $ 29,425 of federal net operating loss carryforwards post 2017 will be carried forward indefinitely. The remaining $ 52,840 of federal net operating loss carryforwards begin expiring in 2027 . The Company also had $ 28,896 of state (Colorado, California, and Florida) net operating loss carryforwards, which will begin expiring in 2039 . The Company has not used any net operating loss carryforwards to date. The Company had federal energy credit carryforwards of $ 647 as of December 31, 2022 and 2021, which will expire starting in 2027 if not utilized. The Company has federal research and development credit carryforwards of $ 68 as of December 31, 2022, which will expire starting in 2042 if not utilized. Pursuant to Internal Revenue Code (IRC) Sections 382 and 383, the Company's ability to use NOL and research tax credit carry forwards to offset future taxable income may be limited if the Company experiences a cumulative change in ownership of more than 50 % within a three-year testing period. The Company has not completed an ownership change analysis pursuant to IRC Section 382. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of NOL and research tax credit carryforwards available to offset future taxable income and income tax liabilities in future years may be significantly restricted or eliminated. Further, deferred tax assets associated with such NOLs, and research tax credits could be significantly reduced upon realization of an ownership change within the meaning of IRC Section 382. The Company files U.S. federal and state tax returns with varying statutes of limitations. Due to net operating loss and credit carryforwards, the 2019 to 2022 tax years remain subject to examination by the U.S. federal and some state authorities. The actual amount of any taxes due could vary significantly depending on the ultimate timing and nature of any settlement. Uncertain Tax Benefits The Company uses the “more likely than not” criterion for recognizing the income tax benefit of uncertain income tax positions and establishing measurement criteria for income tax benefits. The Company had no uncertain tax benefits as of December 31, 2022 and 2021. The Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months as of December 31, 2022.

Net Loss Per Share

Net Loss Per Share	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	Note 12. Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, including vested restricted stock units for which common shares have not yet been issued, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, the warrants, Common Stock options, and unvested restricted stock units are considered to be potentially dilutive securities. As the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for all periods. The following weighted-average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Public Stockholders' warrants 10,350,000 — 10,350,000 — Private Placement warrants 5,738,000 — 5,738,000 — PIPE Investor warrants 700,000 — 700,000 — Convertible Note warrants 448,627 — 256,393 — SeaStar warrants 69,714 69,714 69,714 69,714 Options to purchase common stock 576,534 332,544 411,579 335,102 Unvested restricted stock units 129,640 296,696 213,548 149,168 Total 18,012,515 698,954 17,739,234 553,984 Net loss per share is calculated using the shares in connection with the Business Combination and related transactions, assuming the shares were outstanding since January 1, 2022. As the Business Combination and related transactions are being reflected as if they had occurred at the beginning of the period presented, the calculation of weighted average shares outstanding for basic and diluted net loss per share assumes that the shares issued in connection with the Business Combination have been outstanding for the entire period presented. The calculation of weighted average shares outstanding for basic and diluted net loss per share for the three and six months ended June 30, 2022 has been retroactively restated to give effect to the Business Combination. Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Net loss $ ( 3,669 ) $ ( 902 ) $ ( 8,931 ) $ ( 1,906 ) Weighted average shares outstanding - basic and diluted 14,932,866 7,238,767 13,984,625 7,238,767 Basic and diluted net loss per share $ ( 0.25 ) $ ( 0.12 ) $ ( 0.64 ) $ ( 0.26 )	Note 15. Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, the convertible preferred stock and Common Stock options are considered to be potentially dilutive securities. Basic and diluted net loss per share is presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security. The Company’s participating securities do not have contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to Common Stockholders. As the Company has reported net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. The following weighted-average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: 2022 2021 Public Stockholders' warrants 10,350,000 — Private Placement warrants 5,738,000 — PIPE Investor warrants 700,000 — SeaStar warrants 69,714 69,714 Options to purchase common stock 244,792 345,773 Restricted stock units 298,389 — Total 17,400,895 415,487 Net loss per share is calculated using the shares in connection with the Business Combination and related transactions, assuming the shares were outstanding since January 1, 2021. As the Business Combination and related transactions are being reflected as if they had occurred at the beginning of the period presented, the calculation of weighted average shares outstanding for basic and diluted net loss per share assumes that the shares issued in connection with the Business Combination have been outstanding for the entire period presented. Year Ended December 31: 2022 2021 Net loss $ ( 23,013 ) $ ( 4,596 ) Weighted average shares outstanding - basic 8,211,256 7,238,767 Basic net loss per share $ ( 2.80 ) $ ( 0.63 ) Weighted average shares outstanding - diluted 8,211,256 7,238,767 Diluted net loss per share $ ( 2.80 ) $ ( 0.63 )

Subsequent Events

Subsequent Events	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Note 13. Subsequent Events In July 2023, the Company sold 234,579 shares of Common Stock to Tumim Stone Capital LLC for proceeds of $ 120 , as part of the equity line financing arrangement (see Note 5). In July and August 2023, the Company made principal and interest payments on the Second Convertible Note, which included accelerated payments, through equity conversions. In accordance and pursuant to the Second Convertible Note, 3i elected to convert the conversion amount (as defined in the Second Convertible Note) into shares of Common Stock of the Company. The Company converted principal and interest into 590,154 shares of Common Stock with a fair value of $ 283 . On August 7, 2023, the Company entered into an amendment to the Securities Purchase Agreement with 3i, whereby the VWAP price will be $ 0.20 for all future conversions and the provisions of the third closing have been amended. 3i will have the discretion to purchase additional shares of the Company Common Stock in an aggregate principal amount of $ 2,000 , provided that 3i will purchase additional shares of the Company Common Stock in an aggregate principal amount of $ 1,000 in two tranches no later than September 5, 2023. On August 7, 2023, the Company issued a note (the "Third Convertible Note") in a principal amount of $ 543 , convertible into shares of Common Stock at an initial conversion price of $ 0.20 , and a warrant to purchase up to 738,791 shares of Common Stock. The Third Convertible Note was issued at an 8.0 % discount, bears interest at 7.0 % per annum, matures on November 6, 2024 , and requires monthly installments of principal and interest. In connection with the amendment to the Securities Purchase Agreement with 3i, the Company entered into a letter agreement with 3i, providing for (i) certain adjustment mechanisms for the conversion price of the First and Second Convertible Notes and additional notes issued or to be issued under the Securities Purchase Agreement, as amended, (ii) a six month waiver period of any cash payment obligations of the Company under each existing note, and (iii) the issuance of an additional warrant to purchase an aggregate of 4,765,620 shares of Common Stock. Also on August 7, 2023, the Company entered into certain amendments and waivers for the Maxim Note, LMFA Note, and LMFAO Note. The lenders waved their rights to receive any mandatory prepayments for proceeds received by the Company from the convertible note financings and agreed to extend the maturity dates to 91 days after the last maturity date applicable to any of the notes issued pursuant to the amended Securities Purchase Agreement with 3i.	Note 16. Subsequent Events On January 3, 2023, the Company received an upfront payment of $ 100 as part of its License Agreement (Note 13). On March 13, 2023, the Company entered into a $ 100 promissory note with LM Funding America Inc. with an interest rate of 7.0 % per annum. The promissory note was payable on demand at any time after April 13, 2023 and had no prepayment penalty. The Company repaid the loan on March 24, 2023 . On March 15, 2023, the Company entered into a Securities Purchase Agreement with an institutional investor, whereby the Company will issue a series of four senior unsecured convertible notes, with principal amounts totaling up to $ 9,800 , and warrants to purchase shares of the Company’s Common Stock. On March 15, 2023, the Company issued a note, convertible into 1,207,729 shares of Common Stock at an initial conversion price of $ 2.70 , in a principal amount of $ 3,261 , and a warrant to purchase up to 328,352 shares of Common Stock. The senior unsecured convertible note was issued at an 8.0 % discount, bears interest at 7.0 % per annum, and matures on June 15, 2024 . The senior unsecured convertible notes are redeemable, in whole or in part, at any time at the discretion of the Company. The warrants have an initial exercise price of $ 2.97 per share of Common Stock, expire five years from their issuance date, and contain cashless exercise provisions. On March 15, 2023, the Company amended its LMFA notes, LMFAO note and Maxim note, extending their maturity dates to June 15, 2024 . In consideration for such extension, the Company agrees to pay the note holders an aggregate amount of $ 0.1 million in cash upon receipt of proceeds from the issuance of the notes at the second closing under the Securities Purchase Agreement. In March 2023, a VWAP trigger event occurred, and the Forward Purchase Agreements could mature on the date specified by the FPA Sellers at the FPA Sellers’ discretion. The FPA Sellers have not specified the Maturity Date of the Forward Purchase Agreements as of the issuance of these consolidated financial statements. During the period from January 1, 2023 through March 30, 2023 , the Company made payments of $ 2,701 on notes payable that were outstanding as of December 31, 2022.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Basis of presentation	Basis of presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules and regulations, certain notes or other financial information normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The interim unaudited condensed consolidated financial statements have been prepared on the same basis as the annual condensed consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal, recurring adjustments that are necessary to present fairly the Company’s results for the interim periods presented. The results from operations for the three and six months ended June 30, 2023, are not necessarily indicative of the results to be expected for the year ended December 31, 2023, or for any future annual or interim period. The accompanying interim unaudited condensed consolidated financial statements should be read in conjunction with the annual condensed consolidated financial statements and the related notes for the year ended December 31, 2022. There have been no material changes in our significant accounting policies as described in our Annual Report on Form 10-K for the year ended December 31, 2022. The interim unaudited condensed consolidated financial statements include the consolidated accounts of the Company's wholly-owned subsidiary, SeaStar Medical, Inc. All significant intercompany transactions have been eliminated in consolidation.	Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC"). The consolidated financial statements include the consolidated accounts of the Company's wholly-owned subsidiary, SeaStar Medical, Inc. All significant intercompany transactions have been eliminated in consolidation.
Segment information	Segment information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein.	Segment information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein.
Use of Estimates	Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and reported amounts of revenues and expenses during the period. Significant estimates include the valuation of the forward option on prepaid forward contracts, derivative liability, warrants, provision for income taxes, convertible debt measured at fair value, and the amount of stock-based compensation expense. Although actual results could differ from those estimates, such estimates are developed based on the best information available to management and management's best judgments at the time.	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the period. Significant estimates include the valuation of the forward option on prepaid forward contracts, derivative liability, warrants, tax provision, and the amount of share-based compensation expense. Although actual results could differ from those estimates, such estimates are developed based on the best information available to management and management's best judgments at the time.
Cash		Cash The Company maintains its cash in commercial banks in the United States ("U.S.") which are insured by the Federal Deposit Insurance Corporation up to $ 250 .
Concentrations of credit risk	Concentrations of credit risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist primarily of cash. Periodically, the Company may maintain deposits in financial institutions in excess of government insured limits. The Company has not experienced any losses on deposits since inception.	Concentrations of credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash. Periodically, the Company may maintain deposits in financial institutions in excess of government insured limits. The Company has not experienced any losses on deposits since inception.
Income taxes		Income taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statement carrying amounts and the tax bases of assets and liabilities using enacted tax rates expected to apply to taxable income in the periods in which such differences are expected to reverse. A valuation allowance is provided when the realization of net deferred tax assets is not deemed more likely than not. The Company complies with the provisions of "Accounting Standards Codification ("ASC") 740, Income Taxes, which provides a comprehensive model for the recognition, measurement, and disclosure in consolidated financial statements of uncertain income tax positions that a company has taken or expects to take on a tax return. Under this guidance, a company can recognize the benefit of an income tax position only if it is more likely than not (greater than 50 %) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position; otherwise, no benefit can be recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50 % likelihood of being realized upon ultimate settlement. Additionally, the Company accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. Interest and penalties are classified as income tax expense in the consolidated financial statements.
Fair value option of accounting	Fair value option of accounting Generally, when financial instruments are first acquired and are not required to be recorded at fair value, ASC 825, Financial Instruments (“ASC 825”), allows an entity to elect the fair value option (“FVO”). The FVO may be elected on an instrument-by-instrument basis only at the time of acquisition and once elected is irrevocable. The FVO allows an entity to account for the entire financial instrument at fair value with subsequent changes in fair value recognized in earnings through the condensed consolidated statements of operations at each reporting date. A financial instrument is generally eligible for the FVO if, amongst other factors, no part of the financial instrument is classified in stockholders’ equity. Based on the eligibility assessment discussed above, the Company concluded that its convertible notes (see Note 7) were eligible for the FVO and accordingly elected the FVO for those debt instruments. This election was made because of operational efficiencies in valuing and reporting for these debt instruments at fair value in their entirety at each reporting date. The convertible notes contain certain embedded derivatives that otherwise would require bifurcation and separate accounting at fair value. The convertible notes, inclusive of their respective accrued interest at the stated interest rates (collectively referred to as the “FVO debt instruments”) were initially recorded at fair value as liabilities on the condensed consolidated balance sheets and subsequently re-measured at fair value at the end of each reporting period presented within the condensed consolidated financial statements. The changes in fair value of the FVO debt instruments are recorded in changes in fair value of convertible notes, included as a component of other income (expense), net, in the condensed consolidated statements of operations.
Fair value measurements	Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Inputs used to measure fair value are classified into the following hierarchy: Level 1 – quoted prices in active markets for identical assets and liabilities. Level 2 – other significant observable inputs (including quoted prices for similar assets and liabilities, interest rate, credit risk, etc.). Level 3 – significant unobservable inputs (including the Company’s own assumptions in determining the fair value of assets and liabilities). The fair value of the forward option on prepaid forward contracts, convertible notes, and the warrants liability, are classified as Level 3 in the fair value hierarchy. The following table presents the changes in the forward option-prepaid forward contracts, convertible notes measured at fair value, warrants liability, and the notes derivative liability for the six months ended June 30, 2023 and 2022 (in thousands): Forward Option- Prepaid Notes Payable Level 3 Rollforward Forward Contracts Convertible Notes Warrants Liability Derivative Liability Balance January 1, 2022 $ — $ — $ — $ ( 526 ) Additions — — — ( 52 ) Changes in fair value — — — 578 Balance June 30, 2022 $ — $ — $ — $ — Balance January 1, 2023 $ 1,729 $ — $ — $ — Additions — 4,425 575 — Sale of recycled shares ( 564 ) — — — Payments — ( 258 ) — — Shares issued as payments — ( 1,937 ) — — Changes in fair value ( 1,723 ) — ( 480 ) — Shares issued as maturity consideration 558 — — — Balance June 30, 2023 $ — $ 2,230 $ 95 $ — The convertible notes are recorded as liabilities and are recorded at fair value based on Level 3 measurements. The estimated fair values of the convertible notes are each determined based on the aggregated, probability-weighted average of the outcomes of certain possible scenarios. The combined value of the probability-weighted average of those outcomes is then discounted back to each reporting period in which the convertible notes are outstanding, in each case, based on a risk-adjusted discount rate estimated based on the implied interest rate using the changes in observed interest rates of corporate rate debt that the Company believes is appropriate for those probability-adjusted cash flows. The estimated fair value of prepaid expenses, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these instruments.	Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Inputs used to measure fair value are classified into the following hierarchy: Level 1 – quoted prices in active markets for identical assets and liabilities. Level 2 – other significant observable inputs (including quoted prices for similar assets and liabilities, interest rate, credit risk, etc.). Level 3 – significant unobservable inputs (including the Company’s own assumptions in determining the fair value of assets and liabilities). The fair value of the forward option on prepaid forward contracts and the convertible notes derivative liability are classified as Level 3 in the fair value hierarchy. The following table presents the changes in the forward option and the convertible notes derivative liability for the years ended December 31, 2022 and 2021 (in thousands): Forward Option Convertible Notes On Prepaid Derivative Level 3 Rollforward Forward Contracts Liability Balance December 31, 2020 $ — $ — Additions — ( 499 ) Changes in fair value — ( 27 ) Balance December 31, 2021 — ( 526 ) Additions 11,940 ( 52 ) Sale of recycled shares ( 41 ) — Changes in fair value ( 10,170 ) ( 602 ) Reclassified to additional paid-in capital — 1,180 Balance December 31, 2022 $ 1,729 $ — The forward option in the amount of $ 11,940 was recorded on October 28, 2022, for the forward option in the forward purchase agreements (see Note 4). The forward option is remeasured each reporting period using a Monte-Carlo Simulation in a risk-neutral framework (a special case of the Income Approach). Specifically, the future stock price is simulated assuming a Geometric Brownian Motion (“GBM”). For each simulated path, the forward purchase value is calculated based on the contractual terms and then discounted at the term-matched risk-free rate. Finally, the value of the forward is calculated as the average present value over all simulated paths. Convertible notes derivative liabilities in the amounts of $ 4 , $ 0 , $ 35 and $ 13 , were recorded on January 31, 2022, February 28, 2022, March 16, 2022 and March 31, 2022, respectively, for the issuance of convertible notes along with a corresponding debt discount (see Note 8). The convertible notes liabilities are remeasured each reporting period using a probability-weighted model and assumption related to the conversion price and timing of conversion. The put option liability was valued based on the calculated returns as a result of the various discounts included in the Company’s convertible notes and the related probability assessments of the various settlement scenarios. The convertible notes derivative liability was extinguished as of the c losing of the Business Combination (the "Closing"), as a result of the conversion of the convertible notes. On October 28, 2022, the put option liability was settled upon the Closing and reclassified to additional paid-in capital. Derivative liabilities in the amounts of $ 80 , $ 364 , and $ 55 were recorded on June 10, 2021, September 10, 2021 and December 31, 2021, respectively, for the issuance of convertible notes along with a corresponding debt discount. The change in fair value of the derivative liabilities were recorded in change in fair value of convertible notes derivative liability in the consolidated statements of operations. The estimated fair value of prepaid expenses, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these instruments.
Stock-based compensation		Stock-based compensation In accordance with ASC Topic 718, Compensation – Stock Compensation, the Company recognizes compensation expense for all stock-based awards issued to employees based on the estimated grant-date fair value, which is recognized as expense on a graded vesting approach over the requisite service period. The Company has elected to recognize forfeitures as they occur. The fair value of stock options is determined using the Black-Scholes option-pricing model. The determination of fair value for stock options on the date of grant using an option-pricing model requires management to make certain assumptions including expected volatility, expected term, risk-free interest rate and expected dividends in addition to the Company’s Common Stock valuation. The determination of fair value of restricted stock units is valued based on the value of the Company's Common Stock on the grant date (see Note 12). Prior to the Business Combination, due to the absence of an active market for the Company’s Common Stock, the Company utilized methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants Audit and Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation to estimate the fair value of its Common Stock. In determining the exercise prices for options granted, the Company considered the fair value of the Company as of the grant date. The fair value of the Company was determined based upon a variety of factors, including the Company’s financial position, historical performance and operating results, the Company’s stage of development, the progress of the Company’s research and development programs, the prices at which the Company sold its convertible preferred stock, the superior rights, preferences and privileges of the Company’s convertible preferred stock relative to its Common Stock, external market conditions affecting the biotechnology industry, the lack of marketability of the Company’s Common Stock and the prospects of a liquidity event and the analysis of initial public offering and market performance of similar companies as well as recently completed mergers and acquisition of peer companies. Significant changes to the key assumptions underlying the factors used could result in different fair values of the Company at each valuation date.
Research and development expenses		Research and development expenses Expenditures made for research and development are charged to expense as incurred. External costs consist primarily of payments for laboratory supplies purchased in connection with the company’s discovery and preclinical activities, and process development and clinical development activities. Internal costs consist primarily of employee-related costs, consultants fees and costs related to compliance with regulatory requirements. Nonrefundable advance payments for goods and services that will be used in future research and development activities are capitalized and recorded as expense in the period that the Company receives the goods or when services are performed. The Company records expenses related to external research and development services based on services received and efforts expended pursuant to invoices and contracts with consultants that supply, conduct, and manage preclinical studies and clinical trials on its behalf.
Emerging growth company status	Emerging growth company status The Company is an “emerging growth company”, as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they would apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company or (2) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act.	Emerging growth company status The Company is an “emerging growth company”, as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they would apply to private companies. The Company has elected to use this extended transition period for complying with certain new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (1) no longer an emerging growth company or (2) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act.
Net loss per share attributable to common stockholders		Net loss per share attributable to Common Stockholders The Company’s basic net loss per share attributable to Common Stockholders is calculated by dividing the net loss attributable to Common Stockholders by the weighted-average number of shares of Common Stock outstanding for the period. The diluted net loss per share attributable to Common Stockholders is computed by giving effect to all potential dilutive Common Stock equivalents outstanding for the period. The dilutive effect of these potential common shares is reflected in diluted earnings per share by application of the treasury stock method.
Recently issued accounting standards not yet adopted		Recently issued accounting standards not yet adopted In August 2020, the Financial Accounting Standards Board ("FASB") issued Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity ("ASU 2020-06"). ASU 2020-06 addresses issues identified as a result of the complexity associated with applying US GAAP for certain financial instruments with characteristics of liabilities and equity. In addressing the complexity, ASU 2020-06 focused on amending the guidance on convertible instruments and the guidance on the derivatives scope exception for contracts in an entity’s own equity. The amendments in this Update are effective for public business entities that meet the definition of a Securities and Exchange Commission ("SEC") filer, excluding entities eligible to be smaller reporting companies as defined by the SEC, for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted. In accordance with the JOBS Act, the Company has delayed adoption of ASU 2020-06. As a result, these consolidated financial statements may not be comparable to those companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Changes in Forward Option and Convertible Notes Derivative Liability	The following table presents the changes in the forward option-prepaid forward contracts, convertible notes measured at fair value, warrants liability, and the notes derivative liability for the six months ended June 30, 2023 and 2022 (in thousands): Forward Option- Prepaid Notes Payable Level 3 Rollforward Forward Contracts Convertible Notes Warrants Liability Derivative Liability Balance January 1, 2022 $ — $ — $ — $ ( 526 ) Additions — — — ( 52 ) Changes in fair value — — — 578 Balance June 30, 2022 $ — $ — $ — $ — Balance January 1, 2023 $ 1,729 $ — $ — $ — Additions — 4,425 575 — Sale of recycled shares ( 564 ) — — — Payments — ( 258 ) — — Shares issued as payments — ( 1,937 ) — — Changes in fair value ( 1,723 ) — ( 480 ) — Shares issued as maturity consideration 558 — — — Balance June 30, 2023 $ — $ 2,230 $ 95 $ —	The following table presents the changes in the forward option and the convertible notes derivative liability for the years ended December 31, 2022 and 2021 (in thousands): Forward Option Convertible Notes On Prepaid Derivative Level 3 Rollforward Forward Contracts Liability Balance December 31, 2020 $ — $ — Additions — ( 499 ) Changes in fair value — ( 27 ) Balance December 31, 2021 — ( 526 ) Additions 11,940 ( 52 ) Sale of recycled shares ( 41 ) — Changes in fair value ( 10,170 ) ( 602 ) Reclassified to additional paid-in capital — 1,180 Balance December 31, 2022 $ 1,729 $ —

Business Combination and Reca_2

Business Combination and Recapitalization (Tables)	12 Months Ended
	Dec. 31, 2022
Business Combination And Recapitalization [Abstract]
Schedule of Net Liabilities of LMAO	Other receivables $ 16 Prepaid expenses 1,871 Accrued expenses ( 82 ) Public warrants liability ( 1,241 ) Private placement warrants liability ( 6,688 ) LMFAO note payable ( 2,785 ) Maxim note payable ( 1,973 ) $ ( 10,882 )
Summary of Changes in Convertible Preferred Stock and Stockholders' Deficit	The table below summarizes the shares of Class A Common Stock issued immediately after the Closing as well as the impact of the transaction on the consolidated statements of changes in convertible preferred stock and stockholders' deficit as of October 28, 2022. Common Shares Additional ($ in thousands) Shares Amount Paid-In Capital SPAC financing 4,162,040 $ — $ ( 921 ) Public warrants liability reclassified to equity — — 1,241 Private Placement warrants liability reclassified to equity — — 6,688 Transaction costs — — ( 3,714 ) Reverse recapitalization on October 28, 2022 4,162,040 $ — $ 3,294

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Summary of Accrued Expenses	Accrued expenses consisted of the following: ($ in thousands) June 30, December 31, Accrued commitment fee, equity line of credit $ — $ 1,500 Accrued bonus 502 450 Accrued director remuneration 244 61 Accrued settlement 150 — Accrued interest 72 112 Accrued legal 51 80 Accrued research and development 19 18 Other 57 24 Total accrued expenses $ 1,095 $ 2,245	Accrued expenses consisted of the following amounts as of December 31, 2022 and 2021: ($ in thousands) 2022 2021 Accrued commitment fee, equity line of credit $ 1,500 $ — Accrued bonus 450 — Accrued interest 112 72 Accrued legal 80 27 Accrued director remuneration 61 — Accrued research and development 18 58 Accrued other 24 29 Total accrued expenses $ 2,245 $ 186

Notes Payable (Tables)

Notes Payable (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Notes Payable [Abstract]
Summary of Notes Payable	Notes payable consisted of the following: ($ in thousands) June 30, December 31, LMFA notes payable $ 438 $ 968 LMFAO note payable 1,757 2,785 Maxim note payable 3,590 4,167 Insurance financing 199 910 Unamortized deferred financing costs ( 77 ) — 5,907 8,830 Less current portion ( 5,907 ) ( 1,178 ) $ — $ 7,652	Notes payable consisted of the following on December 31: ($ in thousands) 2022 2021 LMFA notes payable $ 968 $ — LMFAO note payable 2,785 — Maxim note payable 4,167 — Insurance financing 910 — Total notes payable $ 8,830 $ —
Schedule of Future Maturities of Principal Repayment of Convertible Notes	Future maturities of principal repayment of the notes payable as of June 30, 2023 are as follows: ($ in thousands) Years ended December 31: 2023 (remaining) $ — 2024 5,907 $ 5,907

Convertible Notes (Tables)

Convertible Notes (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Summary of Convertible Notes and Debt Discounts		The convertible notes and debt discounts consisted of the following on December 31, 2021: December 31, ($ in thousands) 2021 Dow Notes $ 1,620 Union Carbide Notes 1,080 IBT & David Humes Notes 114 Investor Notes 104 Unamortized debt discount ( 359 ) 2,559 Less current portion ( 2,378 ) $ 181 The following notes were converted: ($ in thousands) Dow Notes $ 2,340 Union Carbide Notes 1,560 IBT & David Humes Notes 210 Investor Notes 526 $ 4,636
Convertible Notes [Member]
Debt Instrument [Line Items]
Future Maturities of Principal Repayment of Convertible Notes	Future maturities of principal repayment of the Convertible Notes as of June 30, 2023 are as follows: ($ in thousands) Years ended December 31: 2023 (remaining) $ 2,609 2024 1,009 $ 3,618
Dow Notes [Member]
Debt Instrument [Line Items]
Summary of Issued Convertible Note Agreements		The Company had issued convertible note agreements to the Dow Employee’s Pension Plan Trust (Dow Notes) in the following amounts (in thousands): Issue Maturity Date Amount Date June 2021 $ 300 December 2022 September 2021 840 December 2024 October 2021 240 December 2024 November 2021 240 December 2024 March 2022 120 March 2024 April 2022 480 April 2025 April 2022 120 April 2025 $ 2,340
Union Carbide Notes [Member]
Debt Instrument [Line Items]
Summary of Issued Convertible Note Agreements		The Company had issued convertible note agreements to the Union Carbide Employee Pension Plan Trust (Union Carbide Notes) in the following amounts (in thousands): Issue Maturity Date Amount Date June 2021 $ 200 December 2022 September 2021 560 December 2024 October 2021 160 December 2024 November 2021 160 December 2024 March 2022 80 March 2024 April 2022 320 April 2025 April 2022 80 April 2025 $ 1,560

Warrants (Tables)

Warrants (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Warrants and Rights Note Disclosure [Abstract]
Schedule of Warrants Outstanding	The Company has the following warrants outstanding: June 30, December 31, 2023 2022 Public Stockholders' Warrants 10,350,000 10,350,000 Private Placement Warrants 5,738,000 5,738,000 PIPE Investor Warrants 700,000 700,000 Convertible Note Warrants 547,253 — SeaStar Warrants 69,714 69,714 17,404,967 16,857,714	The Company has the following warrants outstanding on December 31, 2022 and 2021: December 31, December 31, 2022 2021 Public Stockholders' Warrants 10,350,000 — Private Placement Warrants 5,738,000 — PIPE Investor Warrants 700,000 — SeaStar Warrants 69,714 69,714 16,857,714 69,714

Common Stock and Stock-Based _2

Common Stock and Stock-Based Compensation (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Stock Based Compensation Expense	The following represents stock-based compensation expense in the company’s unaudited condensed consolidated statements of operations: ($ in thousands) Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development $ 96 $ 90 $ 135 $ 90 General and administrative 459 255 925 259 Total $ 555 $ 345 $ 1,060 $ 349	Stock-based compensation expense for options included in the consolidated statements of operations is as follows: ($ in thousands) 2022 2021 Research and development $ 7 $ 1 General and administrative 141 13 Total $ 148 $ 14

Stock-Based Compensation Awar_2

Stock-Based Compensation Awards (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Option activity		Option activity for the years ended December 31, 2022 and 2021, are as follows: Weighted Weighted Average Average Total Remaining Exercise Intrinsic Contractual ($ in thousands) Options Price Value Life (Years) Outstanding as of December 31, 2020 141,851 $ 5.34 Granted 153,504 $ 0.55 Forfeited ( 7,973 ) $ 10.00 Outstanding as of December 31, 2021 287,382 $ 2.65 $ — 8.61 Forfeited prior to merger conversion ( 83,928 ) $ 4.63 Additional options issued in merger conversion 41,338 $ 1.84 Outstanding as of December 31, 2022 244,792 $ 1.84 $ 751,851 7.65 Options exercisable as of December 31, 2022 145,365 $ 2.46 $ 412,681 7.48
Summary of Stock Based Compensation Expense	The following represents stock-based compensation expense in the company’s unaudited condensed consolidated statements of operations: ($ in thousands) Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development $ 96 $ 90 $ 135 $ 90 General and administrative 459 255 925 259 Total $ 555 $ 345 $ 1,060 $ 349	Stock-based compensation expense for options included in the consolidated statements of operations is as follows: ($ in thousands) 2022 2021 Research and development $ 7 $ 1 General and administrative 141 13 Total $ 148 $ 14
Summary of RSU Activity		RSU activity for the year ended December 31, 2022, was as follows: Outstanding as of December 31, 2021 — Granted 255,000 Forfeited prior to merger conversion ( 7,000 ) Additional RSUs issued in merger conversion 50,389 Outstanding as of December 31, 2022 298,389 Vested as of December 31, 2022 — Shares subject to repurchase as of December 31, 2022 298,389
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Stock Based Compensation Expense		Stock-based compensation expense for RSUs included in the consolidated statements of operations is as follows: ($ in thousands) 2022 2021 Research and development $ 89 $ — General and administrative 1,074 — Total $ 1,163 $ —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The effective income tax rate of the Company’s provision for income taxes differed from the federal statutory rate as follows: 2022 2021 Federal tax at statutory rate 21.0 % 21.0 % State income tax 4.4 % 3.6 % Interest on convertible notes ( 0.6 )% 0.0 % Change in fair value of convertible notes derivative liability ( 0.7 )% 0.0 % Other 0.3 % ( 0.8 )% Change in valuation allowance ( 24.4 )% ( 23.8 )% Total effective income tax rate ( 0.0 )% ( 0.0 )%
Schedule of Net Deferred Tax Assets	Significant components of deferred tax assets for federal and state income taxes were as follows: December 31, December 31, ($ in thousands) 2022 2021 Deferred tax assets: Net operating losses $ 18,627 $ 17,538 Forward option-prepaid forward contracts, net 2,585 — Finance charges and origination fees 1,028 — Accrued compensation 130 — Stock-based compensation 311 3 Section 174 research and development capitalization 434 — Tax credits 715 648 Total deferred tax assets 23,830 18,189 Valuation allowance ( 23,830 ) ( 18,189 ) Net deferred tax assets $ — $ —

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Summary of Weighted-Average Outstanding Shares	The following weighted-average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Public Stockholders' warrants 10,350,000 — 10,350,000 — Private Placement warrants 5,738,000 — 5,738,000 — PIPE Investor warrants 700,000 — 700,000 — Convertible Note warrants 448,627 — 256,393 — SeaStar warrants 69,714 69,714 69,714 69,714 Options to purchase common stock 576,534 332,544 411,579 335,102 Unvested restricted stock units 129,640 296,696 213,548 149,168 Total 18,012,515 698,954 17,739,234 553,984	The following weighted-average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: 2022 2021 Public Stockholders' warrants 10,350,000 — Private Placement warrants 5,738,000 — PIPE Investor warrants 700,000 — SeaStar warrants 69,714 69,714 Options to purchase common stock 244,792 345,773 Restricted stock units 298,389 — Total 17,400,895 415,487
Summary of Weighted Average Shares Outstanding for Basic and Diluted Net Loss Per Share	As the Business Combination and related transactions are being reflected as if they had occurred at the beginning of the period presented, the calculation of weighted average shares outstanding for basic and diluted net loss per share assumes that the shares issued in connection with the Business Combination have been outstanding for the entire period presented. The calculation of weighted average shares outstanding for basic and diluted net loss per share for the three and six months ended June 30, 2022 has been retroactively restated to give effect to the Business Combination. Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Net loss $ ( 3,669 ) $ ( 902 ) $ ( 8,931 ) $ ( 1,906 ) Weighted average shares outstanding - basic and diluted 14,932,866 7,238,767 13,984,625 7,238,767 Basic and diluted net loss per share $ ( 0.25 ) $ ( 0.12 ) $ ( 0.64 ) $ ( 0.26 )	As the Business Combination and related transactions are being reflected as if they had occurred at the beginning of the period presented, the calculation of weighted average shares outstanding for basic and diluted net loss per share assumes that the shares issued in connection with the Business Combination have been outstanding for the entire period presented. Year Ended December 31: 2022 2021 Net loss $ ( 23,013 ) $ ( 4,596 ) Weighted average shares outstanding - basic 8,211,256 7,238,767 Basic net loss per share $ ( 2.80 ) $ ( 0.63 ) Weighted average shares outstanding - diluted 8,211,256 7,238,767 Diluted net loss per share $ ( 2.80 ) $ ( 0.63 )

Description of Business - Addit

Description of Business - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2023		Dec. 31, 2022		Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (108,256)	[1]	$ (99,325)	[2]	$ (76,312)	[2]
Cash	$ 13		$ 47		$ 510
[1] Retroactively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands									12 Months Ended
	Oct. 28, 2022	Mar. 31, 2022	Mar. 16, 2022	Feb. 28, 2022	Jan. 31, 2022	Dec. 31, 2021	Sep. 10, 2021	Jun. 10, 2021	Dec. 31, 2022
Minimum threshold percentage for recognizing benefit of an uncertain income tax position									50%
Minimum threshold percentage of income tax benefit for settlement with tax authority									50%
Uncertain tax position						$ 0			$ 0
Forward Option Derivatives [Member] | Prepaid Forward Purchase Agreements [Member]
Fair value of liability on issuance of convertible notes	$ 11,940
Discount Derivative Liabilities [Member]
Fair value of liability on issuance of convertible notes		$ 13	$ 35	$ 0	$ 4
Derivative Liabilities [Member]
Fair value of liability on issuance of convertible notes						$ 55	$ 364	$ 80
Maximum [Member]
Cash, FDIC insured amount									$ 250

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Changes in Forward Option and Convertible Notes Derivative Liability (Detail) - USD ($) $ in Thousands								6 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 16, 2022	Feb. 28, 2022	Jan. 31, 2022	Dec. 31, 2021	Sep. 10, 2021	Jun. 10, 2021	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Derivative Financial Instruments, Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Additions					$ 55	$ 364	$ 80
Forward Option Derivatives [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance								$ 1,729	$ 0	$ 0	$ 0
Additions								$ 0	$ 0	$ 11,940	$ 0
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]								Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Sale of recycled shares								$ 564		$ (41)
Payments								0
Shares issued as payments								0
Changes in fair value								(1,723)	$ 0	(10,170)	$ 0
Shares issued as maturity consideration								558
Reclassified to additional paid-in capital										0
Balance					0			0	0	1,729	0
Convertible Notes [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance								0	0	0
Additions								4,425	0
Sale of recycled shares								0
Payments								(258)
Shares issued as payments								(1,937)
Changes in fair value								0	0
Shares issued as maturity consideration								0
Balance					0			2,230	0	0	0
Warrants Liability [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance								0	0	0
Additions								575	0
Sale of recycled shares								0
Payments								0
Shares issued as payments								0
Changes in fair value								(480)	0
Shares issued as maturity consideration								0
Balance					0			95	0	0	0
Discount Derivative Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Additions	$ 13	$ 35	$ 0	$ 4
Discount Derivative Liabilities [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments								0
Balance								0	(526)	(526)	0
Additions								0	52	(52)	(499)
Sale of recycled shares								0		0
Shares issued as payments								0
Changes in fair value								0	578	(602)	(27)
Shares issued as maturity consideration								0
Reclassified to additional paid-in capital										1,180
Balance					$ (526)			$ 0	$ 0	$ 0	$ (526)

Business Combination and Reca_3

Business Combination and Recapitalization - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		12 Months Ended
	Oct. 29, 2022	Oct. 28, 2022	Jun. 30, 2023		Dec. 31, 2022		Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Common stock, par value			$ 0.0001		$ 0.0001
Outstanding options					244,792		287,382	141,851
Restricted Stock Units [Member]
Business Acquisition [Line Items]
Outstanding restricted stock unit awards					298,389		0
Common Class A [Member]
Business Acquisition [Line Items]
Common stock, par value					$ 0.0001		$ 0.0001
Series B Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted	633,697
Conversion of stock, shares issued					194,494		12,226
Series A-1 Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted	1,576,154
Series A-2 Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted	577,791				194,494		12,226
Common Stock [Member]
Business Acquisition [Line Items]
Conversion of convertible notes to class A common shares, Shares			3,088,167	[1]	598,861	[2]
Common Stock [Member] | Common Class A [Member]
Business Acquisition [Line Items]
Options to purchase shares		4,162,040
SPAC financing, Shares		4,162,040
LMF Merger Sub, Inc [Member]
Business Acquisition [Line Items]
Business combination, consideration transferred		$ 85,406
Debt conversion, original debt amount		4,636
Debt conversion, accrued interest, amount		341
Unamortized debt discount		$ 168
Excess fair value of shares transferred for convertible note conversion					$ 1,180
Outstanding options		271,280
Net cash consideration		$ 9,961
Net liabilities		$ 10,882
LMF Merger Sub, Inc [Member] | Restricted Stock Units [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted		306,811
Outstanding restricted stock unit awards		255,000
LMF Merger Sub, Inc [Member] | Public Stockholders Warrants [Member]
Business Acquisition [Line Items]
Class of warrants of rights, outstanding		10,350,000
LMF Merger Sub, Inc [Member] | Private Placement Warrants [Member]
Business Acquisition [Line Items]
Class of warrants of rights, outstanding		5,738,000
LMF Merger Sub, Inc [Member] | Common Class A [Member]
Business Acquisition [Line Items]
Common stock, par value		$ 0.0001
Conversion of convertible notes to class A common shares, Shares		598,861
Business acquisition share price		$ 10
Conversion of stock, shares issued		7,238,767
Warrants to purchase		69,714
Options to purchase shares		326,399
Business acquisition, equity interest issued or issuable, number of shares		8,540,552
Remained unredeemed recapitalization		4,162,040
Payment to redeem existing shareholders		$ 92,137
SPAC financing, Shares		326,399
LMF Merger Sub, Inc [Member] | Series B Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted		633,697
LMF Merger Sub, Inc [Member] | Series A-1 Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted		1,576,154
LMF Merger Sub, Inc [Member] | Series A-2 Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of stock, shares converted		577,791
LMF Merger Sub, Inc [Member] | Warrant [Member]
Business Acquisition [Line Items]
Class of warrants of rights, outstanding		57,942
SeaStar Medical, Inc. [Member]
Business Acquisition [Line Items]
Class of warrants of rights, outstanding		57,942
[1] (1) Retroactively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Business Combination and Reca_4

Business Combination and Recapitalization - Schedule of Net Liabilities of LMAO (Details) - LMF Merger Sub, Inc [Member] $ in Thousands	Oct. 28, 2022 USD ($)
Business Acquisition [Line Items]
Other receivables	$ 16
Prepaid expenses	1,871
Accrued expenses	(82)
Public warrants liability	(1,241)
Private placement warrants liability	(6,688)
Net liabilities	(10,882)
LMFAO Note [Member]
Business Acquisition [Line Items]
Note payable	(2,785)
Maxim Note Payable [Member]
Business Acquisition [Line Items]
Note payable	$ (1,973)

Business Combination and Reca_5

Business Combination and Recapitalization - Summary of Changes in Convertible Preferred Stock and Stockholders' Deficit (Details) $ in Thousands	Oct. 28, 2022 USD ($) shares
Business Acquisition [Line Items]
Reverse recapitalization on October 28, 2022	$ 3,294
Common Shares [Member]
Business Acquisition [Line Items]
Reverse recapitalization on October 28, 2022, Shares | shares	4,162,040	[1]
Common Shares [Member] | Class A Common Stock [Member]
Business Acquisition [Line Items]
SPAC financing, Shares | shares	4,162,040
Stock issued during period, value	$ 0
Public Warrants Liability Reclassified To Equity
Private Placement Warrants Liability Reclassified To Equity	0
Transaction costs	$ 0
Reverse recapitalization on October 28, 2022, Shares | shares	4,162,040
Reverse recapitalization on October 28, 2022	$ 0
Additional Paid In Capital [Member]
Business Acquisition [Line Items]
Reverse recapitalization on October 28, 2022	3,294
Additional Paid In Capital [Member] | Class A Common Stock [Member]
Business Acquisition [Line Items]
Stock issued during period, value	(921)
Public Warrants Liability Reclassified To Equity	1,241
Private Placement Warrants Liability Reclassified To Equity	6,688
Transaction costs	(3,714)
Reverse recapitalization on October 28, 2022	$ 3,294
[1] Retroactively restated to give effect to the reverse recapitalization

Forward Purchase Agreements - A

Forward Purchase Agreements - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 01, 2023	Oct. 27, 2022	Oct. 31, 2022	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from sale of recycled shares					$ 1,870	$ 0	$ 40	$ 0
Proceeds from gain of recycled shares					1,306
Change in fair value of forward option-prepaid forward contracts				$ (69)	(1,723)		(10,170)	0
Change in fair value of forward option					1,723	$ 0	$ 10,170	$ 0
Forward Purchase Agreements [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
PIPE financing, Shares				1,096,972
Stock issued during period, value				$ 558
Proceeds from sale of recycled shares					1,870
Change in fair value of forward option-prepaid forward contracts				$ (69)	$ (1,723)
Sale of recycled shares					374,005		3,995
Remaining recycled shares							1,147,405
Initial value of forward option prepaid forward contracts							$ 11,940
Sale of recycled shares amount							41
Change in fair value of forward option							10,170
Forward option-prepaid forward contracts							$ 1,729
Forward Purchase Agreements [Member] | Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of consecutive trading days for determining share price			20 days
Volume weighted average price	$ 3		$ 3
Number of trading days for determining share price			30 days
Forward Purchase Agreements [Member] | Minimum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of consecutive trading days for determining share price	20 days
Volume weighted average price			$ 2.5
Common Class A [Member] | Maximum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Share price			10
Common Class A [Member] | Minimum [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Share price			$ 5
Common Class A [Member] | Vellar Prepaid Forward Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares, acquisitions		1,151,400	1,173,400
Stock repurchased during period, shares			200,000
Share price			$ 10.37
Payment out of the trust account			$ 14,358
Stock repurchased during period, value			2,074
Reimbursement of legal expense			$ 116

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Accrued commitment fee, equity line of credit	$ 0	$ 1,500	$ 0
Accrued bonus	502	450	0
Accrued settlement	150	0
Accrued interest	72	112	72
Accrued legal	51	80	27
Accrued director remuneration	244	61	0
Accrued research and development	19	18	58
Other	57	24	29
Total accrued expenses	$ 1,095	$ 2,245	$ 186

Equity Line of Credit - Additio

Equity Line of Credit - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended			6 Months Ended	12 Months Ended
		Aug. 31, 2022	Jun. 30, 2023	Mar. 31, 2023		Jun. 30, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock, value	[1]		$ 2			$ 2	$ 1
Equity line financing arrangement, value of shares sold			55	$ 1,108
Amount available to draw			$ 98,837			98,837
General and Administrative [Member]
Class of Stock [Line Items]
Commitment fee payable amount							2,500
Common Stock [Member]
Class of Stock [Line Items]
Long-term purchase commitment, amount						$ 1,000	1,000
Commitment fee, equity line financing, shares issued				218,842	[2]	218,842
Equity line financing arrangement, shares sold	[2]		26,993	378,006
Accrued Expense [Member]
Class of Stock [Line Items]
Long-term purchase commitment, amount						$ 1,500	$ 1,500
Tumim Stone Capital [Member]
Class of Stock [Line Items]
Long-term purchase commitment, amount		$ 1,000
Equity line financing arrangement, shares sold			26,993			404,999
Equity line financing arrangement, value of shares sold			$ 55			$ 1,162
Common Stock Purchase Agreement [Member] | Tumim Stone Capital [Member]
Class of Stock [Line Items]
Commitment fee payable amount		2,500
Common stock, value		$ 100,000
Cash [Member]
Class of Stock [Line Items]
Long-term purchase commitment, amount						$ 500
[1] Retroactively restated to give effect to the reverse recapitalization (1) Retroactively restated to give effect to the reverse recapitalization

Notes Payable - Summary of Note

Notes Payable - Summary of Notes payable (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Notes Payable [Line Items]
Unamortized deferred financing costs	$ (77)
Total notes payable	5,907	$ 8,830
Less current portion	(5,907)	(1,178)
Total		7,652
LMFA Note Payable [Member]
Notes Payable [Line Items]
Notes payable, gross	438	968
Total notes payable		968
LMFAO Note Payable [Member]
Notes Payable [Line Items]
Notes payable, gross	1,757	2,785
Total notes payable		2,785
Maxim Note Payable [Member]
Notes Payable [Line Items]
Notes payable, gross	3,590	4,167
Total notes payable		4,167
Insurance Financing [Member]
Notes Payable [Line Items]
Notes payable, gross	$ 199	910
Total notes payable		$ 910

Notes Payable - Future Maturiti

Notes Payable - Future Maturities of Principal Repayment of Convertible Notes (Details) $ in Thousands	Jun. 30, 2023 USD ($)
Notes Payable [Abstract]
2023 (remaining)	$ 0
2024	5,907
Total	$ 5,907

Notes Payable - Additional Info

Notes Payable - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 15, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Notes Payable [Line Items]
Debt instrument, face amount						$ 63
Amortization of the debt discounts			$ 99	$ 0	$ 208	$ 242	$ 140
Lmfa Notes, Lmfao Note and Maxim Note [Member]
Notes Payable [Line Items]
Debt instrument extended maturity date	Jun. 15, 2024
Debt instrument, face amount	$ 100
Deferred financing costs	$ 100
Amortization of deferred financing cost		$ 20		$ 23

Notes Payable - LMFA Note Payab

Notes Payable - LMFA Note Payable - Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 15, 2023	Oct. 28, 2022	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Mar. 13, 2023	Nov. 02, 2022	Sep. 09, 2022
Notes Payable [Line Items]
Debt instrument, face amount						$ 63
Debt instrument, interest rate						3.75%
Notes payable current			$ 5,907	$ 5,907		$ 1,178	$ 0
Cash proceeds				100	$ 1,681	1,878	$ 0
Subsequent Event [Member]
Notes Payable [Line Items]
Debt instrument, face amount	$ 3,261
LMFA Note Payable [Member]
Notes Payable [Line Items]
Debt instrument, face amount									$ 268	$ 700
Debt instrument, interest rate										15%
Notes payable current						700
Interest expense			7	$ 19		19
Line of credit facility, expiration date		Oct. 30, 2023		Jun. 15, 2024
Notes payable, gross			$ 438	$ 438		968
Percentage of the gross cash proceeds received from any future debt		5%
Cash proceeds		$ 500
LMFA Note Payable [Member] | Subsequent Event [Member]
Notes Payable [Line Items]
Debt instrument, face amount								$ 100
Debt instrument, interest rate								7%
Line of credit facility, expiration date	Jun. 15, 2024
LMFA Note Payable [Member] | Minimum [Member]
Notes Payable [Line Items]
Line of credit facility, interest rate during period		7%
Line of credit facility, interest rate at period end		15%
LMFA Note Payable [Member] | Maximum [Member]
Notes Payable [Line Items]
Line of credit facility, interest rate during period		15%
Line of credit facility, interest rate at period end		18%
Interest Bearing Note [Member] | LMFA Note Payable [Member]
Notes Payable [Line Items]
Notes payable, gross						700
Noninterest Bearing Note [Member] | LMFA Note Payable [Member]
Notes Payable [Line Items]
Notes payable, gross						$ 268

Notes Payable - LMFAO Note Paya

Notes Payable - LMFAO Note Payable - Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 15, 2023	Oct. 28, 2022	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Jul. 29, 2022	Jul. 28, 2022
Notes Payable [Line Items]
Debt instrument, face amount					$ 63
Debt instrument, interest rate					3.75%
Note payable, balance due			$ 5,907	$ 5,907	$ 8,830
Subsequent Event [Member]
Notes Payable [Line Items]
Debt instrument, face amount	$ 3,261
LMFAO Note Payable [Member]
Notes Payable [Line Items]
Debt instrument, face amount		$ 2,785				$ 1,035	$ 1,750
Debt instrument, maturity date		Oct. 30, 2023		Jun. 15, 2024
Notes payable, gross			1,757	$ 1,757	2,785
Percentage of the gross cash proceeds received from any future debt		20%
Limit of gross cash proceeds exempt from repayment		$ 500
Note payable, balance due					2,785
Interest expense			$ 31	$ 74	$ 35
LMFAO Note Payable [Member] | Subsequent Event [Member]
Notes Payable [Line Items]
Debt instrument, maturity date	Jun. 15, 2024
LMFAO Note Payable [Member] | Minimum [Member]
Notes Payable [Line Items]
Debt instrument, interest rate		15%
LMFAO Note Payable [Member] | Maximum [Member]
Notes Payable [Line Items]
Debt instrument, interest rate		7%

Notes Payable - MAXIM Note Paya

Notes Payable - MAXIM Note Payable - Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 15, 2023	Oct. 28, 2022	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Notes Payable LineItems
Debt instrument, interest rate					3.75%
Note payable, balance due			$ 5,907	$ 5,907	$ 8,830
Maxim Note Payable [Member]
Notes Payable LineItems
Professional fees		$ 4,182
Line of credit facility, expiration date		Oct. 30, 2023		Jun. 15, 2024
Notes payable, gross			3,590	$ 3,590	4,167
Percentage of the gross cash proceeds received from any future debt		25%
Limit of gross cash proceeds exempt from repayment		$ 500
Note payable, balance due					4,167
Interest expense			$ 63	$ 130	$ 51
Maxim Note Payable [Member] | Subsequent Event [Member]
Notes Payable LineItems
Line of credit facility, expiration date	Jun. 15, 2024
Maxim Note Payable [Member] | LMAO [Member]
Notes Payable LineItems
Professional fees		2,209
Maxim note payable		$ 1,973
Maxim Note Payable [Member] | Maximum [Member]
Notes Payable LineItems
Debt instrument, interest rate		7%
Maxim Note Payable [Member] | Minimum [Member]
Notes Payable LineItems
Debt instrument, interest rate		15%

Notes Payable - Insurance Finan

Notes Payable - Insurance Financing - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended
	Feb. 28, 2023	Jan. 31, 2023	Oct. 31, 2022	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Notes Payable [Line Items]
Debt instrument, interest rate							3.75%
Note payable, balance due				$ 5,907	$ 5,907		$ 8,830
Insurance Financing [Member]
Notes Payable [Line Items]
Notes payable, gross				199	199		$ 910
Annual premium of insurance policy amount			$ 910
Debt instrument, interest rate			7.35%
Payments of principal and interest					$ 101
Frequency of principal and interest payments					monthly		monthly
Payment terms					two monthly installments of $101, consisting of principal and interest remain		Seven additional monthly installments of principal and interest of $101 will be made
Note payable, balance due							$ 910
Interest expense				$ 6	$ 17		$ 7
Insurance Financing [Member] | Scenario Forecast [Member]
Notes Payable [Line Items]
Payments of principal and interest						$ 101
Insurance Financing [Member] | Subsequent Event [Member]
Notes Payable [Line Items]
Payments of principal and interest	$ 101	$ 135

Convertible Notes - Summary of

Convertible Notes - Summary of Issued Convertible Note Agreements - Dow Notes & Union Carbide Notes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Dow Notes [Member]
Debt Instrument [Line Items]
Long term debt	$ 2,340
Union Carbide Notes [Member]
Debt Instrument [Line Items]
Long term debt	$ 1,560
June 2021 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	June 2021
Long term debt	$ 300
Maturity Date	December 2022
June 2021 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	June 2021
Long term debt	$ 200
Maturity Date	December 2022
September 2021 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	September 2021
Long term debt	$ 840
Maturity Date	December 2024
September 2021 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	September 2021
Long term debt	$ 560
Maturity Date	December 2024
October 2021 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	October 2021
Long term debt	$ 240
Maturity Date	December 2024
October 2021 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	October 2021
Long term debt	$ 160
Maturity Date	December 2024
November 2021 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	November 2021
Long term debt	$ 240
Maturity Date	December 2024
November 2021 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	November 2021
Long term debt	$ 160
Maturity Date	December 2024
March 2022 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	March 2022
Long term debt	$ 120
Maturity Date	March 2024
March 2022 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	March 2022
Long term debt	$ 80
Maturity Date	March 2024
April 2022 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	April 2022
Long term debt	$ 480
Maturity Date	April 2025
April 2022 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	April 2022
Long term debt	$ 320
Maturity Date	April 2025
April 2022 [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Issue Date	April 2022
Long term debt	$ 120
Maturity Date	April 2025
April 2022 [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Issue Date	April 2022
Long term debt	$ 80
Maturity Date	April 2025

Convertible Notes - Additional

Convertible Notes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended	6 Months Ended		12 Months Ended
	May 12, 2023	Mar. 15, 2023	Oct. 28, 2022	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Debt instrument, face amount							$ 63
Fair vaue of shares issued upon conversion of convetible notes							5,989
Amortization of the debt discounts				$ 99	$ 0	$ 208	242	$ 140
3i Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 3,261
Conversion of stock, shares converted		328,352
3i Notes [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Conversion of stock, shares converted		1,207,729
Debt instrument convertible conversion price		$ 2.7
Convertible Debt [Member]
Debt Instrument [Line Items]
Debt conversion, original debt amount							4,636
Unamortized debt discount							168	359
Debt conversion, accrued interest, amount							$ 341
Convertible Debt [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued							598,861
Convertible Debt [Member] | Investor Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount							$ 422	104
Debt conversion, original debt amount			$ 4,636
Debt conversion, accrued interest, amount			$ 341
Amortization of the debt discounts							242	140
Loss on conversion of convertible notes							(1,180)
Convertible Debt [Member] | Investor Notes [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued			598,861
Fair vaue of shares issued upon conversion of convetible notes							5,989
Convertible Debt [Member] | IBT Notes [Member] | IBT and David Humes Notes [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, amount							$ 96	$ 114
Senior Unsecured Convertible Notes [Member] | 3i Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 9,000
Discount of senior unsecured convertible note issued		8%
Interest rate of senior unsecured convertible note issued		7%
Debt instrument, maturity date		Jun. 15, 2024
First Convertible Note [Member]
Debt Instrument [Line Items]
Principal payment					238
Interest payment					$ 20
First Convertible Note [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued					1,879,688
Fair value of convertible notes					$ 1,291
Second Convertible Note [Member]
Debt Instrument [Line Items]
Debt conversion, original debt amount	$ 2,174
Conversion of stock, shares converted	218,901
Discount of senior unsecured convertible note issued	8%
Interest rate of senior unsecured convertible note issued	7%
Debt instrument, maturity date	Aug. 12, 2024
Second Convertible Note [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued	805,153				1,208,479
Debt instrument convertible conversion price	$ 2.7
Fair value of convertible notes					$ 646

Convertible Notes - Schedule of

Convertible Notes - Schedule of Convertible Notes and Debt Discounts (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Less current portion	$ (2,230)	$ 0
Dow Notes [Member]
Debt Instrument [Line Items]
Long term debt		2,340
Union Carbide Notes [Member]
Debt Instrument [Line Items]
Long term debt		1,560
Convertible Debt [Member]
Debt Instrument [Line Items]
Unamortized debt discount		(168)	$ (359)
Total		4,636	2,559
Less current portion			(2,378)
Long term debt, Non-current			181
Convertible Debt [Member] | Dow Notes [Member]
Debt Instrument [Line Items]
Long term debt		2,340	1,620
Convertible Debt [Member] | Union Carbide Notes [Member]
Debt Instrument [Line Items]
Long term debt		1,560	1,080
Convertible Debt [Member] | IBT & David Humes Notes [Member]
Debt Instrument [Line Items]
Long term debt		210	114
Convertible Debt [Member] | Investor Notes [Member]
Debt Instrument [Line Items]
Long term debt		$ 526	$ 104

Convertible Notes - Future Matu

Convertible Notes - Future Maturities of Principal Repayment of Convertible Notes (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total		$ 7,652
Convertible Notes [Member]
Debt Instrument [Line Items]
2023 (remaining)	$ 2,609
2024	1,009
Total	$ 3,618

Government Loans and PPP Loans

Government Loans and PPP Loans - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 17, 2022	Apr. 02, 2021	Jun. 30, 2020	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Apr. 30, 2020
Schedule of Government Loans and PPP Loans [Line Items]
Debt instrument, face amount								$ 63,000
Debt instrument, interest rate, stated percentage								3.75%
Debt instrument, periodic payment			$ 300
Other income									$ 91,000
Interest expense				$ 225,000	$ 191,000	$ 658,000	$ 360,000	$ 630,000	212,000
PPP loan
Schedule of Government Loans and PPP Loans [Line Items]
Other income									91,000	$ 84,000
Repayments of debt									20,000
Government Loans
Schedule of Government Loans and PPP Loans [Line Items]
Debt instrument, face amount	$ 63,000
Accrued interest	$ 6,000
Interest expense								$ 2,000	$ 3,000
U.S. small business administration
Schedule of Government Loans and PPP Loans [Line Items]
Debt instrument, maturity date, description			May 2050
Silicon valley bank | Notes payable government loans
Schedule of Government Loans and PPP Loans [Line Items]
Debt instrument, face amount		$ 91,000									$ 104,000
Debt instrument, interest rate, stated percentage		1%
Debt instrument, term		2 years

Notes Payable Government Loans

Notes Payable Government Loans (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Schedule of Maturities of LongTerm Debt [Line Items]
Total	$ 7,652

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($)		Jun. 30, 2023	May 12, 2023	Mar. 15, 2023	Dec. 31, 2022	Oct. 28, 2022	Oct. 27, 2022	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Warrants outstanding		$ 17,404,967			$ 16,857,714			$ 69,714
Common stock, shares issued		18,121,238			12,699,668
Common stock, value	[1]	$ 2,000			$ 1,000
Warrant to purchase common stock, par value		$ 0.0001			$ 0.0001
SeaStar Medical, Inc. [Member]
Class of Warrant or Right [Line Items]
Outstanding warrants						57,942
Legacy SeaStar Warrants [Member]
Class of Warrant or Right [Line Items]
Outstanding warrants					69,714
Warrants outstanding					$ 7,000
Warrant to purchase common stock, par value						$ 11.5
SeaStar Medical Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding		$ 69,714			69,714			69,714
Public Stockholders Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding		10,350,000			$ 10,350,000		$ 10,350,000	0
Class of warrant or right exercise price					$ 0.01
Common stock, closing price per share					18
Public Stockholders Warrants [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Class of warrant or right exercise price					$ 11.5
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding		5,738,000			$ 5,738,000	$ 6,688		0
Private Placement Warrants [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Class of warrant or right exercise price					$ 11.5
PIPE Investor Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding		700,000			$ 700,000	$ 700,000		$ 0
Common stock, shares issued						700,000
Warrant to purchase common stock, par value						$ 10
Convertible Note Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding		$ 547,253		$ 328,352	$ 0
Class of warrant or right exercise price				$ 2.97
Warrants expire term				5 years
Issuance of convertible notes				$ 500,000
Second Convertible Note Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding			$ 218,901
Class of warrant or right exercise price			$ 2.97
Issuance of convertible notes			$ 75,000
[1] Retroactively restated to give effect to the reverse recapitalization

Warrants - Schedule of Warrants

Warrants - Schedule of Warrants Outstanding (Details) - USD ($)	Jun. 30, 2023	Mar. 15, 2023	Dec. 31, 2022	Oct. 28, 2022	Oct. 27, 2022	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Warrants outstanding	$ 17,404,967		$ 16,857,714			$ 69,714
SeaStar Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding	69,714		69,714			69,714
Public Stockholders Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding	10,350,000		10,350,000		$ 10,350,000	0
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding	5,738,000		5,738,000	$ 6,688		0
PIPE Investor Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding	700,000		700,000	$ 700,000		$ 0
Convertible Note Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding	$ 547,253	$ 328,352	$ 0

Common Stock and Stock-Based _3

Common Stock and Stock-Based Compensation - Additional Information (Details) - $ / shares	1 Months Ended	6 Months Ended	12 Months Ended
	Apr. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted options				153,504
Common Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock shares issued for management bonuses		459,185
Granted options		351,029
Weighted-average grant date fair value, options granted		$ 1.2
Options [Member] | Common Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period from grant date		1 year
Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vested restricted stock units			0
Granted restricted stock units			255,000
Weighted-average grant date fair value, RSUs granted	$ 8		$ 8
Restricted Stock Units [Member] | Common Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vested restricted stock units		153,405
Granted restricted stock units		234,019
Weighted-average grant date fair value, RSUs granted		$ 1.47
Vesting period from grant date		1 year

Common Stock and Stock-Based _4

Common Stock and Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 555	$ 345	$ 1,060	$ 349	$ 1,311	$ 14
Research and Development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	96	90	135	90
General and Administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 459	$ 255	$ 925	$ 259

Convertible Preferred Stock, _2

Convertible Preferred Stock, Common Stock And Preferred Stock - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Oct. 29, 2022	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2023
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Shares authorized	110,000,000
Common stock, shares authorized	100,000,000	100,000,000		100,000,000
Preferred stock, shares authorized	10,000,000
Common stock, voting rights		Holders of Common Stock are entitled to one voter per share on matters to be voted on by stockholders.
Preferred stock outstanding		$ 0
Convertible Notes [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Debt conversion, original debt amount		4,636
Unamortized debt discount		168	$ 359
Debt conversion, accrued interest, amount		$ 341
Series B Preferred Stock [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Conversion of stock, shares converted	633,697
Conversion of stock, shares issued		194,494	12,226
Series A-1 Preferred Stock [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Conversion of stock, shares converted	1,576,154
Series A-2 Preferred Stock [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Conversion of stock, shares converted	577,791	194,494	12,226
Common Stock [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Conversion of stock, shares issued	7,238,767
Common Stock [Member] | Convertible Notes [Member]
Convertible Preferred Stock, Common Stock and Preferred Stock [Line Items]
Debt conversion, converted instrument, shares issued		598,861

Stock-Based Compensation Awar_3

Stock-Based Compensation Awards - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Option to purchase common stock, par value		$ 0.0001		$ 0.0001		$ 0.0001
Stock-based compensation expense		$ 555	$ 345	$ 1,060	$ 349	$ 1,311	$ 14
Granted options							153,504
Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense						148	$ 14
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options available for future grant	255,000
Stock-based compensation expense						1,163	0
Unrecognized stock-based compensation cost						$ 1,353
Unrecognized stock-based compensation cost, recognition period						2 years 2 months 12 days
Vesting description						The majority of the RSUs granted vest 50% on the first anniversary of the grant date, with the remaining 50% of the awards vesting monthly over a 12-to-24 month period following the first anniversary of the grant date
Weighted-average grant date fair value	$ 8					$ 8
Weighted-average grant date fair value additional RSU issued						$ 10
Granted						255,000
Restricted Stock Units (RSUs) [Member] | LMAO [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Option to purchase common stock, par value						$ 0.0001
Stock-based compensation expense						$ 130
Unrecognized stock-based compensation cost						373
Restricted Stock Units (RSUs) [Member] | Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	50%
Restricted Stock Units (RSUs) [Member] | Tranche Two [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	50%
Restricted Stock Units (RSUs) [Member] | Tranche Two [Member] | Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	24 months
Restricted Stock Units (RSUs) [Member] | Tranche Two [Member] | Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	12 months
Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense						148	$ 14
Unrecognized stock-based compensation cost, options						$ 246
Unrecognized stock-based compensation cost, recognition period						3 years
Options exercised						0	0
Weighted-average grant date fair value							$ 0.4
Granted options						0
2019 Stock Incentive Plan [Member] | Key Employees and Non-Employee Service Providers [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for issuance						547,717	547,717
Options expiration period						10 years
Options available for future grant							260,355
Vesting period						4 years
2019 Stock Incentive Plan [Member] | Key Employees and Non-Employee Service Providers [Member] | LMAO [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Option to purchase common stock, par value						$ 0.0001
Stock-based compensation expense						$ 134
Unrecognized stock-based compensation cost, options						$ 223
2022 Omnibus Incentive Plan [Member] | Key Employees and Non-Employee Service Providers [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares reserved for issuance						1,270,000
Options expiration period						10 years
Options available for future grant						743,720
Vesting period						4 years

Stock-Based Compensation Awar_4

Stock-Based Compensation Awards - Summary of Option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, Outstanding	287,382	141,851
Granted		153,504
Forfeited		(7,973)
Forfeited prior to merger conversion	(83,928)
Additional options issued in merger conversion	41,338
Ending balance, Outstanding	244,792	287,382
Options exercisable as of December 31, 2022	145,365
Weighted Average Exercise Price
Beginning balance, Outstanding	$ 2.65	$ 5.34
Granted		0.55
Forfeited prior to merger conversion	4.63
Additional options issued in merger conversion	1.84
Forfeited		10
Ending balance, Outstanding	1.84	$ 2.65
Options exercisable as of December 31, 2022	$ 2.46
Total Intrinsic Value
Outstanding	$ 751,851	$ 0
Options exercisable as of December 31, 2022	$ 412,681
Weighted Average Remaining Contractual Life (Years)
Outstanding	7 years 7 months 24 days	8 years 7 months 9 days
Options exercisable as of December 31, 2022	7 years 5 months 23 days

Stock-Based Compensation Awar_5

Stock-Based Compensation Awards - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 555	$ 345	$ 1,060	$ 349	$ 1,311	$ 14
Options [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					148	14
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					1,163	0
Research and Development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	96	90	135	90
Research and Development [Member] | Options [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					7	1
Research and Development [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					89	0
General and Administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 459	$ 255	$ 925	$ 259
General and Administrative [Member] | Options [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					141	13
General and Administrative [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense					$ 1,074	$ 0

Stock-Based Compensation Awar_6

Stock-Based Compensation Awards - Summary of RSU Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2022 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Outstanding as of December 31, 2021	0
Granted	255,000
Forfeited prior to merger conversion	(7,000)
Additional RSUs issued in merger conversion	50,389
Outstanding as of December 31, 2022	298,389
Vested as of December 31, 2022	0
Shares subject to repurchase as of December 31, 2022	298,389

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands				1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 14, 2023	Jan. 03, 2023	Dec. 27, 2022	Nov. 30, 2023	Sep. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Legal settlement in accrued expenses						$ 150		$ 150		$ 0
Rent expense						8	$ 8	16	$ 16	32	$ 32
Upfront payment liability						$ 100		$ 100		$ 0
Scenario Forecast [Member]
Loss Contingencies [Line Items]
Litigation settlement expense				$ 50	$ 50
Subsequent Event [Member]
Loss Contingencies [Line Items]
Litigation settlement expense	$ 50
License Agreement [Member]
Loss Contingencies [Line Items]
Proceeds from milestone payment to be received			$ 450
Agreement term			3 years
License Agreement [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Proceeds from upfront payment		$ 100
Nonrefundable upfront payment		100
License and Distribution Agreement [Member]
Loss Contingencies [Line Items]
Proceeds from upfront payment		100
Nonrefundable upfront payment		$ 100
Proceeds from milestone payment to be received			$ 450
Agreement term			3 years
F D A Approval [Member] | License Agreement [Member]
Loss Contingencies [Line Items]
Proceeds from milestone payment to be received			$ 350
F D A Approval [Member] | License and Distribution Agreement [Member]
Loss Contingencies [Line Items]
Proceeds from milestone payment to be received			$ 350

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Current income tax expense benefit	$ 1	$ 1
Valuation allowance, deferred tax asset, increase decrease, amount	$ 5,641	869
Testing period	3 years
Income tax examination, description	The Company files U.S. federal and state tax returns with varying statutes of limitations. Due to net operating loss and credit carryforwards, the 2019 to 2022 tax years remain subject to examination by the U.S. federal and some state authorities. The actual amount of any taxes due could vary significantly depending on the ultimate timing and nature of any settlement.
Uncertain tax benefit	$ 0	0
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Cumulative changes in ownership percentage	50%
Federal [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 82,265	78,127
Tax credit carryforward, amount	$ 647	$ 647
Tax credit carryforward expiration start year	2027
Federal [Member] | Research and Development [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	$ 68
Tax credit carryforward expiration start year	2042
Federal [Member] | Post 2017
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 29,425
Federal [Member] | Expiring in 2027
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 52,840
Operating loss carryforwards, expiration year	2027
State [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 28,896
Operating loss carryforwards, expiration year	2039

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal tax at statutory rate	21%	21%
State income tax	4.40%	3.60%
Interest on convertible notes	(0.60%)	0%
Change in fair value of convertible notes derivative liability	(0.70%)	0%
Other	0.30%	(0.80%)
Change in valuation allowance	(24.40%)	(23.80%)
Total effective income tax rate	(0.00%)	(0.00%)

Income Taxes - Schedule of Net

Income Taxes - Schedule of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Assets, Net [Abstract]
Net operating losses	$ 18,627	$ 17,538
Forward option-prepaid forward contracts, net	2,585	0
Finance charges and origination fees	1,028	0
Accrued compensation	130	0
Stock-based compensation	311	3
Section 174 research and development capitalization	434	0
Tax credits	715	648
Total deferred tax assets	23,830	18,189
Valuation allowance	(23,830)	(18,189)
Net deferred tax assets	$ 0	$ 0

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Weighted-Average Outstanding Shares (Detail) - shares	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	18,012,515	698,954	17,739,234	553,984	17,400,895	415,487
Public Stockholders Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	10,350,000	0	10,350,000	0	10,350,000	0
Private Placement Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	5,738,000	0	5,738,000	0	5,738,000	0
PIPE Investor Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	700,000	0	700,000	0	700,000	0
Convertible Note Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	448,627	0	256,393	0
SeaStar Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	69,714	69,714	69,714	69,714	69,714	69,714
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	576,534	332,544	411,579	335,102	244,792	345,773
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	129,640	296,696	213,548	149,168
Restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total					298,389	0

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Earnings Per Share Basic And Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						6 Months Ended				12 Months Ended
	Jun. 30, 2023		Mar. 31, 2023	Jun. 30, 2022		Mar. 31, 2022	Jun. 30, 2023		Jun. 30, 2022		Dec. 31, 2022		Dec. 31, 2021
Earnings Per Share [Abstract]
Net loss	$ (3,669)		$ (5,262)	$ (902)		$ (1,004)	$ (8,931)		$ (1,906)		$ (23,013)		$ (4,596)
Weighted-average shares outstanding - basic	14,932,866	[1]		7,238,767	[1]		13,984,625	[1]	7,238,767	[1]	8,211,256	[2]	7,238,767	[2]
Basic net loss per share	$ (0.25)			$ (0.12)			$ (0.64)		$ (0.26)		$ (2.8)		$ (0.63)
Weighted-average shares outstanding - diluted	14,932,866	[1]		7,238,767	[1]		13,984,625	[1]	7,238,767	[1]	8,211,256	[2]	7,238,767	[2]
Diluted net loss per share	$ (0.25)			$ (0.12)			$ (0.64)		$ (0.26)		$ (2.8)		$ (0.63)
[1] Retrospectively restated to give effect to the reverse recapitalization Retroactively restated to give effect to the reverse recapitalization

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Aug. 14, 2023

Aug. 07, 2023

May 12, 2023

Mar. 15, 2023

Mar. 13, 2023

Jan. 03, 2023

Jul. 31, 2023

Jun. 30, 2023

Mar. 31, 2023

Mar. 30, 2023

Jun. 30, 2023

Jun. 30, 2022

Dec. 31, 2022

Nov. 02, 2022

Sep. 09, 2022

Subsequent Event [Line Items]

Issuance of shares - equity line of credit

$ 55,000

$ 1,108,000

Debt instrument, face amount

$ 63,000

Debt instrument, interest rate, stated percentage

3.75%

Payment of notes payable

$ (2,946,000)

$ 0

$ (15,000)

Tumim Stone Capital [Member]

Subsequent Event [Line Items]

Issuance of shares - equity line of credit, Shares

26,993

404,999

Issuance of shares - equity line of credit

$ 55,000

$ 1,162,000

Common Stock [Member]

Subsequent Event [Line Items]

Issuance of shares - equity line of credit, Shares

[1]

26,993

378,006

Second Convertible Note [Member]

Subsequent Event [Line Items]

Conversion of stock, shares converted

218,901

Discount of senior unsecured convertible note issued

8%

Interest rate of senior unsecured convertible note issued

7%

Debt Conversion, Original Debt, Amount

$ 2,174,000

Debt instrument, maturity date

Aug. 12, 2024

LMFA Note Payable [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 268,000

$ 700,000

Debt instrument, interest rate, stated percentage

15%

Lmfa Notes, Lmfao Note and Maxim Note [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 100,000

3i Notes [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 3,261,000

Conversion of stock, shares converted

328,352

3i Notes [Member] | Senior Unsecured Convertible Notes [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 9,000,000

Discount of senior unsecured convertible note issued

8%

Interest rate of senior unsecured convertible note issued

7%

Debt instrument, maturity date

Jun. 15, 2024

Subsequent Event [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 3,261,000

Warrant to purchase shares of common stock

328,352

Payment of notes payable

$ (2,701,000)

Subsequent Event [Member] | Tumim Stone Capital [Member]

Subsequent Event [Line Items]

Issuance of shares - equity line of credit, Shares

234,579

Issuance of shares - equity line of credit

$ 120,000

Subsequent Event [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Conversion of stock, shares converted

1,207,729

Debt instrument convertible conversion price

$ 2.7

Subsequent Event [Member] | First And Second Convertible Notes [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Debt conversion, converted instrument, shares issued

4,765,620,000

Subsequent Event [Member] | Second Convertible Note [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Debt conversion, converted instrument, shares issued

590,154

Fair value of convertible notes

$ 283,000

Subsequent Event [Member] | Third Convertible Note [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Debt conversion, converted instrument, shares issued

738,791,000

Debt instrument convertible conversion price

$ 0.2

Debt Conversion, Original Debt, Amount

$ 543,000

Subsequent Event [Member] | Senior Unsecured Convertible Notes [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 9,800,000

Discount of senior unsecured convertible note issued

8%

Interest rate of senior unsecured convertible note issued

7%

Debt instrument, maturity date

Jun. 15, 2024

Warrants initial exercise price

$ 2.97

Warrant expiration period

5 years

Subsequent Event [Member] | LMFA Note Payable [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 100,000

Debt instrument, interest rate, stated percentage

7%

Promissory note prepayment penalty

$ 0

Loan repaid date

Mar. 24, 2023

Subsequent Event [Member] | Lmfa Notes, Lmfao Note and Maxim Note [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 100

Debt instrument extended maturity date

Jun. 15, 2024

Subsequent Event [Member] | 3i Notes [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 2,000,000

Debt instrument convertible conversion price

$ 0.2

Subsequent Event [Member] | 3i Notes [Member] | Common Stock [Member] | Tranche One [Member]

Subsequent Event [Line Items]

Debt instrument, face amount

$ 1,000,000

Subsequent Event [Member] | 3i Notes [Member] | Third Convertible Note [Member]

Subsequent Event [Line Items]

Discount of senior unsecured convertible note issued

8%

Interest rate of senior unsecured convertible note issued

7%

Debt instrument, maturity date

Nov. 06, 2024

Subsequent Event [Member] | License Agreement [Member]

Subsequent Event [Line Items]

Proceeds from upfront payment

$ 100,000

[1] (1) Retroactively restated to give effect to the reverse recapitalization