Exhibit 5.1

April 11, 2023

SeaStar Medical Holding Corporation

3513 Brighton Blvd., Suite 410

Denver, CO 80216

Re: SeaStar Medical Holding Corporation Registration Statement on Form S-1

Ladies and Gentlemen:

We have acted as counsel to SeaStar Medical Holding Corporation (f/k/a LMF Acquisition Opportunities, Inc.), a Delaware corporation (the “Company”), in connection with its filing on the date hereof of the Registration Statement on Form S-1 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), with the Securities and Exchange Commission (the “SEC”). Capitalized terms used herein and not otherwise defined herein shall have the respective meanings set forth in the Registration Statement.

The Registration Statement relates to the proposed resale by the selling stockholder identified in the Registration Statement (the “Selling Stockholder”), or its permitted transferees, of up to 14,228,567 shares (the “Shares”) of the Company’s common stock, $0.0001 par value per share, which includes: (i) 7,548,310 and 5,032,207 shares, respectively, that may be issued pursuant to the conversion of the principal amount of the Notes issued in connection with the First Closing and the Second Closing, (ii) 660,478 and 440,319 shares, respectively, that may be issued pursuant to the conversion of accrued interest over the term of the Notes issued in connection with the the First Closing and the Second Closing, and (iii) 328,352 and 218,901 shares, respectively, that may be issued pursuant to the Warrants issued in connection with the First Closing and the Second Closing.

In connection with this opinion letter, we have examined the Registration Statement and originals, or copies certified or otherwise identified to our satisfaction, of the Third Amended and Restated Certificate of Incorporation, as amended through the date hereof (the “Certificate”), and the Amended and Restated Bylaws, as in effect on the date hereof (the “Bylaws”), of the Company, certain resolutions of the Company’s Board of Directors relating to the Registration Statement, and such other documents, records and other instruments as we have deemed appropriate for purposes of the opinion set forth herein.

Morgan, Lewis & Bockius LLP
1400 Page Mill Road	+1.650.843.4000 +1.650.843.4001
Palo Alto, CA 94304 United States

April 11, 2023

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We have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of the documents submitted to us as originals, the conformity with the originals of all documents submitted to us as certified, facsimile or photostatic copies and the authenticity of the originals of all documents submitted to us as copies.

Based upon the foregoing and subject to the qualifications and assumptions stated herein, we are of the opinion that the Shares have been duly authorized and, when issued and delivered by the Company in the manner described in the Registration Statement and in accordance with the resolutions adopted by the Board of Directors of the Company, will be validly issued, fully paid and non-assessable.

We do not express any opinion with respect to the effect on the opinions stated herein of any bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer, preference and other similar laws affecting creditors’ rights generally, and the opinions stated herein are limited by such laws and by general principles of equity (regardless of whether enforcement is sought in equity or at law).

The opinions expressed herein are limited to the DGCL and the laws of the State of New York, and we express no opinion with respect to the laws of any other state or jurisdiction.

We hereby consent to the use of this opinion as Exhibit 5.1 to the Registration Statement and to the reference to us under the caption “Legal Matters” in the prospectus included in the Registration Statement. In giving such consent, we do not hereby admit that we are acting within the category of persons whose consent is required under Section 7 of the Securities Act or the rules or regulations of the SEC thereunder.

[Signature Page Follows]

April 11, 2023

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Very truly yours,

/s/ Morgan, Lewis & Bockius LLP