Author: James A. Russell, A.B., M.D.
Anesthesiology 1 2017, Vol.126, 9-11.
HAJJAR et al designed, conducted, and now report in this issue an elegant randomized double-blind controlled trial of vasopressin (0.01 to 0.06 U/min) versus norepinephrine (10 to 60 μg/min) post cardiac surgery with vasodilatory shock (Vasopressin versusNorepinephrine in Patients with Vasoplegic Shock After Cardiac Surgery [VANCS] trial). Open-label norepinephrine was added if there was an inadequate response to blinded study drug. Vasodilatory shock was defined by hypotension requiring vasopressors and a cardiac index greater than 2.2 l · min · m-2. The primary endpoint was a composite: “mortality or severe complications.” Patents with vasodilatory shock within 48 h post cardiopulmonary bypass weaning were eligible. Three hundred patients were included, and there was a highly significant decrease in the primary endpoint in the vasopressin compared to the norepinephrine group (absolute risk reduction 17%, number needed to treat 6). There was also a significantly lower rate of atrial fibrillation in the vasopressin versus norepinephrine group (perhaps expected because of lack of β1-adrenergic stimulation with vasopressin). The vasopressin group also had sparing of norepinephrine (shorter duration), shorter duration of study drug infusion, shorter intensive care unit stay, shorter duration of dobutamine, less acute kidney injury, less need for renal replacement therapy, and lower sepsis-related organ failure assessment scores than the norepinephrine group. The authors conclude that vasopressin is superior to norepinephrine in vasodilatory shock after cardiac surgery. There was no difference in 28-day mortality in the composite—the vasopressin signal was driven by severe complications and not by mortality in the mortality or severe complications composite.