The use of intravenous hydroxocobalamin as a rescue in methylene blue-resistant vasoplegic syndrome in cardiac surgery.

Vasoplegic syndrome is a well-recognized complication during cardiopulmonary bypass (CPB) and is associated with increased morbidity and mortality, especially when refractory to conventional vasoconstrictor therapy. This is the first reported case of vasoplegia on CPB unresponsive to methylene blue whereas responsive to hydroxocobalamin, which indicates that the effect of hydroxocobalamin outside of the nitric oxide system is significant or that the two drugs have a synergistic effect in one or multiple mechanisms.