Effects of methylene blue on oxygen availability and regional blood flow during endotoxic shock

Abstract

Low and moderate doses of methylene blue can significantly increase arterial blood pressure but not cardiac index during endotoxic shock. Methylene blue infusion may selectively increase mesenteric blood flow. High doses of methylene blue can worsen systemic hypotension, myocardial depression, and pulmonary hypertension after endotoxemia.

Methylene blue for vasoplegic syndrome treatment in heart surgery: fifteen years of questions, answers, doubts and certainties

“…The security perception is fully grounded in data set in studies in healthy animals that received the MB in vivo. Although ischemic events were not evidenced in the ECG monitoring, the normal vascular reactivity, endothelium dependent and independent, was determined by in vitro studies [21]. With a wide safety range, these data support the assumption that, unlike the NO (LNAME) synthesis inhibition, the injection in vivo does not cause endothelial dysfunction.…”

Blockade of the action of nitric oxide in human septic shock increases systemic vascular resistance and has detrimental effects on pulmonary function after a short infusion of methylene blue

“…The different effects of inhibitors of nitric oxide production and methylene blue on cardiac output may be due to a more intense vasoconstriction induced by the former than by the latter, but the cause is not known (32). However, methylene blue may act not only by inhibiting activation of guanylate cyclase (33), but also by inhibiting nitric oxide synthesis (25,(34)(35)(36). Although cardiac output did not increase significantly, the increase in left ventricular stroke work in the presence of unchanged filling pressures, despite an increase in systemic vascular resistance, suggests an improvement in myocardial function following methylene blue administration.…”

“…We may speculate that methylene blue possibly influenced the redistribution of blood flow among different organs. The effects of methylene blue on regional blood flow may be different (25) from those of nitric oxide synthase inhibitors (5,32,(38)(39)(40). In endotoxemic dogs, low doses of methylene blue have been shown to increase splanchnic blood flow (25).…”

“…The effects of methylene blue on regional blood flow may be different (25) from those of nitric oxide synthase inhibitors (5,32,(38)(39)(40). In endotoxemic dogs, low doses of methylene blue have been shown to increase splanchnic blood flow (25). However, several investigators reported that nitric oxide synthase inhibitors caused a dosedependent reduction in mesenteric and renal blood flow, exarcebating organ vasoconstric-tion and ischemia and increasing mortality rate (5,6,32,38,39).…”

“…On the other hand, methylene blue, an inhibitor of soluble guanylate cyclase, may be a safer option by suppressing the action of nitric oxide without major side effects. In experimental studies, methylene blue attenuated vasodilation and myocardial dysfunction and increased mesenteric blood flow (11,14,25). Three studies on septic shock patients have reported an increase in blood pressure and in myocardial function after a bolus infusion of methylene blue without acute toxicity (26)(27)(28).…”