SeaStar Medical Holding Corp

This proxy statement (the “Proxy Statement”) is furnished in connection with the solicitation by the Board of Directors of SeaStar Medical Holding Corporation of proxies to be voted at our Annual Meeting of Stockholders to be held on June 17, 2026, at 10:00 a.m. Mountain Time, and at any continuation, postponement, or adjournment of the Annual Meeting. The Annual Meeting will be held virtually via live webcast. You will be able to attend the Annual Meeting online by visitingwww.proxydocs.com/ICU and entering your 12-digit control number included on your proxy card or on the instructions that accompanied your proxy materials. You will be able to vote your shares electronically and submit your written questions prior to and during the meeting through the online website.

Holders of record of our Common Stock, par value $0.0001 per share, as of the close of business on April 24, 2026 (the “Record Date”), will be entitled to notice of and to vote at the Annual Meeting and at any continuation, postponement, or adjournment of the Annual Meeting. As of the Record Date, there were 3,997,002 shares of Common Stock outstanding and entitled to vote at the Annual Meeting. Each share of Common Stock is entitled to one vote on any matter presented to stockholders at the Annual Meeting.

The Company will begin mailing, or otherwise make available to stockholders, this Proxy Statement, Notice of Annual Meeting of Stockholders, and proxy card (the “Proxy Materials”) containing instructions on how to access the Proxy Materials and how to vote and the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (the “2025 Annual Report”) to stockholders on orabout May 1, 2026. In this Proxy Statement, “Company”, “we”, “us”, and “our” refer to SeaStar Medical Holding Corporation.