Physiologic Effect of Topical Nitroglycerin on Microcirculation Capacity in Patients With Circulatory Shock.

Trial of a Topical Nitroglycerin Challenge to Detect Reversible Microcirculatory Dysfunction in Patients With Circulatory Shock.

This is an open-label, single center, trial that will enroll up to 25 participants with circulatory shock after cardiac surgery. Participants will be administered a topical sublingual nitroglycerin solution and assessed for changes microcirculatory blood flow using incident dark field microscopy.

Inclusion Criteria:

• Adult patients receiving elective CABG or valvular surgery requiring cardiopulmonary bypass
• Receiving postoperative catecholamine therapy to maintain a MAP > 65mmHg, cardiac index > 2 despite initial fluid resuscitation
• Invasive hemodynamic monitoring

Exclusion Criteria:

• Surgical hemorrhage
• Unable to tolerate sublingual microcirculatory flow imaging
• Known intolerance or allergy to nitroglycerin
• Inadequate microcirculation imaging (based on Massey Score)