Recently, hydroxocobalamin has also been revealed to inhibit the NO system and was successfully utilized for one case of CPB-associated refractory vasoplegia without attempting MBfirst. However, there have yet been randomized control trials of MB that indicate optimum dosage, timing of administration, or target population, leaving the possibility that MB may not be effective for all patients. Thus, treatment of CPB-associated refractory vasoplegia has been successful with inhibitors of the NO system.Ĭonventionally, methylene blue (MB) has been the treatment of choice due to its inhibition of cGMP and has been shown to be effective as both a preventive and rescue therapy. During times of physiological stress, however, an inducible form of NOS can be activated by inflammatory cytokines, resulting in the continually activated NO system postulated to be the cause of refractory vasoplegia seen in CPB. Under normal physiological conditions, NO is activated by NO synthase (NOS) in the cardiomyocyte and acts through the cyclic guanosine monophosphate (cGMP) mechanism to decrease vascular tone. The cause of refractory vasoplegia is in part due to an inappropriately activated nitric oxide (NO) system. s/cm 5), and normal or increased filling pressures.In such cases, refractory vasoplegia manifests itself as systemic hypotension (mean arterial pressure 2.5 L/min/m 2), low systemic vascular resistance (SVR) (<800 dynes Vasoplegic syndrome is a well-recognized complication during cardiopulmonary bypass (CPB) occurring in up to 25% of patients and is associated with increased morbidity and mortality, especially in the 5% nonresponsive to conventional vasoconstrictor therapy.

Hydroxocobalamin cyanokit