A double-blind randomized trial: prophylactic vasopressin reduces hypotension after cardiopulmonary bypass

Background Inhibition of angiotensin-converting enzyme (ACE) predisposes patients to vasodilatory hypotension after cardiopulmonary bypass (CPB). This hypotension has been correlated with arginine vasopressin deficiency and can be corrected by its replacement. In patients receiving ACE inhibition, we investigated whether initiation of vasopressin before CPB would diminish post-CPB hypotension and catecholamine use by avoiding vasopressin deficiency. Methods Cardiac surgical patients on ACE inhibitor therapy were randomized to receive vasopressin (0.03 U/min) (n = 13) or an equal volume of normal saline (n = 14) starting 20 minutes before CPB. Results Vasopressin did not change pre-CPB mean arterial pressure or pulmonary artery pressure. After CPB, the vasopressin group had a lower peak norepinephrine dose than the placebo group (4.6 ± 2.5 versus 7.3 ± 3.5 μg/min, p = 0.03), a shorter period on catecholamines (5 ± 6 versus 11 ± 7 hours, p = 0.03), fewer hypotensive episodes (1 ± 1 versus 4 ± 2, p< 0.01), and a shorter intensive care unit length of stay (1.2 ± 0.4 versus 2.1 ± 1.4 days, p = 0.03). Conclusions In this cohort, prophylactic administration of vasopressin, at a dose without a vasopressor effect pre-CPB, reduced post-CPB hypotension and vasoconstrictor requirements, and was associated with a shorter intensive care unit stay.