| Document And Entity Information | Feb. 21, 2024 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Feb. 21, 2024 |
| Entity Registrant Name | SeaStar Medical Holding Corporation |
| Entity Central Index Key | 0001831868 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-39927 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Series A Preferred Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock par value $0.0001 per share |
| Trading Symbol | ICU |
| Security Exchange Name | NASDAQ |
| Series B Preferred Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one share of Common Stock for $11.50 per share |
| Trading Symbol | ICUCW |
| Security Exchange Name | NASDAQ |
