Exhibit 24

                                POWER OF ATTORNEY

        KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and
appoints each of the Chief Executive Officer and the Chief Financial Officer of
SeaStar Medical Holding Corporation (the "Company"), signing singly, as his or
her true and lawful attorney-in-fact to:

                (1)    execute for and on behalf of the undersigned, in the
        undersigned's capacity as an officer or director of the Company, Forms
        3, 4, and 5 in accordance with Section 16(a) of the Securities Exchange
        Act of 1934, as amended, and the rules thereunder and any other forms
        or reports the undersigned may be required to file in connection with
        the undersigned's ownership, acquisition, or disposition of securities
        of the Company;

                (2)    do and perform any and all acts for and on behalf of the
        undersigned which may be necessary or desirable to complete and execute
        any such Form 3, 4, or 5, or other form or report, and timely file such
        form or report with the U.S. Securities and Exchange Commission and any
        stock exchange or similar authority; and

                (3)    take any other action of any type whatsoever in
        connection with the foregoing which, in the opinion of such attorneys-
        in-fact, may be of benefit to, in the best interest of, or legally
        required by, the undersigned, it being understood that the documents
        executed by such attorneys-in-fact on behalf of the undersigned,
        pursuant to this Power of Attorney, shall be in such form and shall
        contain such terms and conditions as such attorneys-in-fact may approve
        in his or her discretion.

        The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform each and every act and thing whatsoever
requisite, necessary, and proper to be done in the exercise of any of the
rights and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorneys-in-fact, or his or her substitute or substitutes, shall lawfully do
or cause to be done by virtue of this Power of Attorney and the rights and
powers herein granted. The undersigned acknowledges that no such attorney-in-
fact, in serving in such capacity at the request of the undersigned, is hereby
assuming any of the undersigned's responsibilities to comply with Section 13
and Section 16 of the Securities Exchange Act of 1934, as amended, and the
rules thereunder.

        This Power of Attorney shall remain in full force and effect until
revoked by the undersigned in a signed writing delivered to the foregoing
attorneys-in-fact.

                             [Signature Page Follows]

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney
to be executed as of this 31st day of October, 2022.

                                   /s/ Rick Barnett
                                   -------------------------------
                                   Rick Barnett