Infusion of low-dose vasopressin improves left ventricular function during separation from cardiopulmonary bypass: a double-blind randomized study.

We aimed to investigate whether low-dose vasopressin administered to patients undergoing coronary artery bypass grafting (CABG) surgery with preexisting mild to moderate systolic dysfunction can produce sustained improvement in cardiac function. This double-blind randomized study was conducted in a hospital where a single anesthetic and surgical team performed elective CABG. Twenty patients aged 32-61 years who underwent elective CABG between January 2007 and December 2007 were enrolled in this study. The patients randomly received either vasopressin 0.03 IU/min (Group A) or normal saline (Group B) in equal volume for 60 min after cardiopulmonary bypass (CPB). The cardiac output, cardiac index, stroke volume index, fractional area of contraction and systemic vascular resistance index were significantly higher in Group A than in Group B. Adrenaline (mean dose: 0.06 μg/kg x min-1) was required in seven patients from Group B but in none of the Group A patients on initial separation from CPB (P< 0.05). Of the 10 patients in Group B, five required phenylepherine to maintain the mean arterial pressure (MAP) >65 mmHg, whereas none of the Group A patients required phenylephrine for MAP regulation (P< 0.05). We conclude that Infusion of low-dose vasopressin for patients with mild to moderate left ventricular systolic dysfunction during separation from CPB is beneficial for the postoperative hemodynamic profile, reduces the catecholamine doses required and improves left ventricular systolic function.