| Document and Entity Information | Feb. 09, 2023 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | SeaStar Medical Holding Corp |
| Entity Address, State or Province | CO |
| Amendment Flag | false |
| Entity Central Index Key | 0001831868 |
| Document Type | 8-K |
| Document Period End Date | Feb. 09, 2023 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39927 |
| 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, Postal Zip Code | 80216 |
| City Area Code | (813) |
| Local Phone Number | 222-8996 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Common Stock 0.0001 Par Value [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $0.0001 par value |
| Trading Symbol | ICU |
| Security Exchange Name | NASDAQ |
| Warrants Each Whole Warrant Exercisable For One Share Of Common Stock For 11.50 Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Warrants, each whole warrant exercisable for one share of Common Stock for $11.50 per share |
| Trading Symbol | ICUCW |
| Security Exchange Name | NASDAQ |
