Methylene Blue to Treat Vasoplegia Due to a Severe Protamine Reaction: A Case Report

Protamine sulfate is used during coronary artery bypass graft surgery to reverse the anticoagulating effects of heparin. Vasoplegic syndrome is a state of endothelial dysregulation that produces profound vasodilatation that is refractory to vasopressors. This syndrome leads to systemic hypoperfusion and may progress to death. Up to 27% of patients after cardiac bypass may experience vasoplegia. Symptoms of vasoplegia may also be present in many different clinical settings. This case report describes a 57-year-old woman who after cardiac bypass experienced a severe protamine reaction with profound hypotension, which was unresponsive to volume resuscitation and vasopressor therapy. A dramatic increase in blood pressure resulted almost immediately after administration of methylene blue. This patient had no prior risk factors for a protamine reaction other than her current cardiac surgery. A review of the pathophysiologic characteristics associated with vasoplegia and the pharmacodynamics of methylene blue will potentially enable anesthesia providers to utilize this lifesaving drug when needed.