ABSTRACT
Vasodilatory shock requiring treatment with catecholamines occurs in some patients following cardiopulmonary bypass. We investigated the use of vasopressin in the treatment of this syndrome. Forty patients with a left main coronary artery disease and a poor left ventricular function (ejection fraction <30%) were studied. Only those patients (n=12, 30%) in whom difficulty was experienced in maintaining a mean arterial pressure of > 60 mm Hg and a systemic vascular resistance of greater than 900 dynes.sec.cm5 on maximal doses of pharmacological and mechanical support were selected. Patients underwent a standard cardiac anaesthesia protocol. All patients had a Swan-ganz catheter inserted pre-operatively. Arginine vasopressin was administered as a bolus of 0.015 units/kg intravenously followed by an infusion of 0.03 units/kg/hour. This dose increased the mean arterial pressure from 67+/-7 to 95+/-5 mm Hg and the systemic vascular resistance from 860+/-55 to 1502+/-71 dynes.sec.cm-5. It was also associated with a decrease in pharmacological support. All subjects responded to vasopressin administration. Vasopressin is an effective pressor in vasodilatory shock after cardiopulmonary bypass.