Early Use of Vasopressin in Post-Fontan Management

Subjects will be started on a blinded continuous infusion of study drug/placebo in the OR, immediately following the completion of the MUF at 0.3 mU/kg/min. All caregivers will be blinded to the arm assignment. The infusion will run for 20 hours, at which time it will be weaned off at 0.1 mU/hr, over 3 hours.During the active study period, the care team will treat subjects per SOC, using any preferred medication to correct low cardiac output; there is no restriction on using open-label vasopressin during the active study treatment period.

Subjects will be started on a blinded continuous infusion of study drug/placebo in the OR, immediately following the completion of the MUF at 0.3 mU/kg/min. All caregivers will be blinded to the arm assignment. The infusion will run for 20 hours, at which time it will be weaned off at 0.1 mU/hr, over 3 hours.During the active study period, the care team will treat subjects per SOC, using any preferred medication to correct low cardiac output; there is no restriction on using open-label vasopressin during the active study treatment period.