(1549) Using Continuous Hydroxocobalamin for Refractory Vasogenic Shock in Setting of Acute Graft Failure

Introduction: Vasodilatory shock, also known as vasoplegia, is a condition of refractory hypotension with normal to elevated cardiac index and decreased systemic vascular resistance, and often reduced response to vasopressor agents. This can develop in many settings including cardiopulmonary bypass, liver transplantation, and sepsis.

Description: This is a case of a 47-year-old male with a complicated past medical history including heart failure with reduced ejection fracture of 15-20% admitted for cardiogenic shock. He was placed on extracorporeal membrane oxygenation as a bridge to transplantation and received a heart-liver transplant and then a kidney transplant one day later. His course was complicated by rising liver enzymes and findings consistent with primary acute graft failure of his liver transplant. In the next few days, the patient required multiple vasopressor agents to sustain his blood pressure. An initial dose of 5,000 milligrams (mg) of hydroxocobalamin was given over 10 minutes for free radical scavenging to reduce vasodilation. In the next 30 minutes, it was possible to lower the norepinephrine infusion to 0.04 micrograms per kilogram per minute (mcg/kg/min) while maintaining the goal mean arterial pressure (MAP). This did not last, and the norepinephrine was increased back to its prior dose. Given the initial effectiveness but transient nature of the hydroxocobalamin bolus, a hydroxocobalamin infusion was started at 10 milliliters an hour over 20 hours for a total dose of 5,000 mg. After 4 hours, it was possible to wean the patient’s vasopressors slightly while still maintaining the MAP goal, and after 20 hours, the patient’s vasoactive infusions were greatly reduced (e.g., epinephrine at 0.12 mcg/kg/min to 0.05 mcg/kg/min and halving the dose of norepinephrine).

Discussion: Hydroxocobalamin has been reported in literature as a potential treatment for vasoplegia. However, the dosing of this is described as a bolus over 10-15 minutes. While there are a few scant reports of its use as an infusion, it has not been described as an infusion in the setting of acute graft failure. Many descriptions of its use typically discuss its effect as impact on MAP, as opposed to a more clinically significant outcome, such as weaning of vasopressors, which we describe in our case report.