Hemodynamic performance and histamine levels after desmopressin acetate administration following cardiopulmonary bypass in adult patients.

Sixteen patients undergoing cardiac surgical procedures were prospectively randomized into two groups to study the hemodynamic and histamine-releasing effects of desmopressin acetate (DDAVP) administration after cardiopulmonary bypass. Ten minutes after administration of protamine for reversal of heparin, DDAVP, 0.3 microgram/kg, was infused intravenously over 5 seconds in group 1, and the same dose of DDAVP was administered over 5 minutes as an infusion in group 2. There were no statistical differences between baseline values in groups 1 and 2. DDAVP decreased mean arterial pressure by 30% and 25% in groups 1 and 2 (69 +/- 5 mm Hg to 52 +/- 8 mm Hg, P less than 0.005, and 79 +/- 20 mm Hg to 55 +/- 8 mm Hg, P less than 0.005), respectively. The hypotension in both groups was related to decreases in systemic vascular resistance (1,616 +/- 262 dyne.s.cm-5 to 1,073 +/- 199 dyne.s.cm-5, P less than 0.005, and 1,850 +/- 541 dyne.s.cm-5 to 1,144 +/- 214 dyne.s.cm-5, P less than 0.005). Phenylephrine infusion successfully treated the DDAVP-induced hypotension in all patients. Arterial histamine levels at 3 and 5 minutes after infusion of DDAVP did not differ significantly from baseline values. It is concluded that DDAVP at 0.3 microgram/kg is a potent vasodilator when administered intravenously and that histamine is not involved in producing its hypotensive effects.