Methylene Blue and Endocarditis

Infectious endocarditis is a life-threatening condition that occasionally requires emergency valve replacement. Patients with an ongoing systemic inflammatory response because of infective endocarditis (IE) and those who need cardiopulmonary bypass (CPB) for emergency valve replacement may demonstrate resistant hypotension related to vasoplegia. It presents a spectrum of clinical presentation and is associated with a systemic inflammatory response and the release of endothelial nitric oxide (NO). Hemodynamically it is characterized by arterial vasodilation, high cardiac output despite myocardial depression, and decreased sensitivity of the heart and peripheral vessels to sympathomimetic agents. These observations led us to propose a protocol with the use of MB in cases of emergency surgery in patients with vasoplegic syndrome: (1) 3 mg.Kg−1 bolus infusion right after anesthetic induction (perhaps even earlier); (2) infusion of 1 mg.Kg−1 (intravenous (IV) or in the oxygenator) if blood pressure maintenance is not possible due to high perfusion flow and high doses of norepinephrine, and (3) repeat the infusion in bolus (or continuous if the patient is stable) after CPB discontinuity.