We report the successful use of a low-dose vasopressin (VP) infusion to recover a hypotensive crisis in patients who suffered persistent hypotension after prolonged hemorrhage during general anesthesia. VP was infused in two posthemorrhagic vasodilatory shock patients when they remained persistently hypotensive despite adequate fluid resuscitation and infusions of pharmacological doses of catecholamines. On administration of VP at 0.04 U x min(-1), systemic vascular resistance, systolic arterial pressure, and urine output were immediately increased (as compared with the values obtained just before VP), and infusion of catecholamine could be decreased. No adverse cardiac effects were observed during VP infusions in these patients. During vasodilatory shock after prolonged and severe hemorrhage, VP seems to be effective in reversing hypotension and decreasing the need for exogenous cathecholamines while preserving cardiac function and critical organ blood flow.

Because three phosphodiesterase-3 inhibitors (milrinone, olprinone, and amrinone) differed in their vasodilator potencies (against the contractile response to either norepinephrine or a thromboxane A2 analog) among human arteries removed from different parts of the body, their vascular relaxation profiles should be considered before they are used clinically.