Comparison of dopamine versus norepinephrine in circulatory shock after cardiac surgery: A randomized controlled trial

Background and Aim of the Study: Although dopamine and norepinephrine are recommended as first-line agents in the treatment of shock, it is unclear which is the optimal vasoactive inotropic agent (VIA) to manage postcardiotomy circulatory shock. This single-center, randomized clinical trial aimed to investigate the efficacy and safety of dopamine versus norepinephrine in postcardiotomy circulatory shock. Methods: We randomly assigned the patients with postcardiotomy circulatory shock to receive either dopamine or norepinephrine. When shock persisted despite the dose of 20 μg/kg/min of dopamine or the dose of 0.2 μg/kg/min of norepinephrine, epinephrine or vasopressin could be added. The primary endpoint was new-onset tachyarrhythmic event during drug infusion. Secondary endpoints included requirement of additional VIAs, postoperative complications, and all-cause mortality within 30 days of drug initiation. Results: At the planned interim analysis of 100 patients, the boundary for the benefit of norepinephrine has been crossed, and the study was stopped early. Excluding two patients withdrawing a consent, 48 patients were assigned to dopamine and 50 patients to norepinephrine. New-onset tachyarrhythmic event occurred in 12 (25%) patients in the dopamine and one (2%) patient in the norepinephrine group (p =.009). The requirement for additional VIAs was more common in the dopamine group (p <.001). Other secondary endpoints were similar between groups. Conclusions: Despite the limited study subjects with early determination, in patients with postcardiotomy circulatory shock, dopamine as a first-line vasopressor was associated with higher tachyarrhythmic events and greater need for additional VIAs compared with norepinephrine.