The SOAP-II trial: First-line vasopressor for shock management [Classics Series]

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1. There were no significant differences in 28-day, 6-month, or 12-month mortality when comparing dopamine and norepinephrine as first-line vasopressors in managing shock.

2. Dopamine was associated with a significantly higher rate of arrhythmias, as well as severe arrhythmias that required stopping the study drug, when compared to norepinephrine.

Original Date of Publication: March 4, 2010

Study Rundown: The SOAP-II trial demonstrated that there were no significant differences in mortality when comparing dopamine and norepinephrine as first-line vasopressors. Dopamine, however, was associated with a significantly higher rate of arrhythmias, as well as severe arrhythmias that led to withholding of the study drug. Moreover, the study demonstrated significantly increased 28-day mortality with dopamine use in a prespecified subgroup of patients who had cardiogenic shock. These findings challenged the American College of Cardiology-American Heart Association recommendation at the time, which suggested using dopamine as the first-line agent in patients suffering from acute myocardial infarction and hypotension.

Please click to read study in the NEJM (New England Journal of Medicine)

In Depth [randomized, controlled study]: Originally published in 2010 in NEJM, the SOAP-II trial compared the use of norepinephrine and dopamine as first-line agents in treating patients suffering from circulatory shock. At the time, guidelines and recommendations suggested that either agent could be used as the first-line vasopressor. Some studies, however, had suggested that dopamine use was a predictor of mortality in shock. A total of 1,679 patients were enrolled from 8 centres in Belgium, Austria, and Spain. Patients were eligible if they were 18 years of age and required a vasopressor for treatment of shock. Shock was defined as a mean arterial pressure <70 mmHg or systolic blood pressure <100 mmHg, despite adequate fluid resuscitation, and clinical signs of tissue hypoperfusion (e.g., altered mental state, mottled skin, urine output <0.5 mL/kg/hour). The primary outcome was 28-day mortality, while secondary outcomes included mortality in the intensive care unit (ICU), in hospital mortality, 6- and 12-month mortality, and days requiring ICU care or organ support.

There were no significant differences between the two groups in terms of 28-day mortality, or mortality in the ICU, in hospital, at 6- months, or at 12-months. There were no significant differences between the two groups in terms of number of days requiring ICU care or organ support. The study demonstrated a significantly higher incidence of arrhythmias in the dopamine group compared to the norepinephrine group (24.1% vs. 12.4%, P<0.001). The dopamine group also experienced a significantly higher incidence of severe arrhythmia, which necessitated stopping the study drug (6.1% vs. 1.6%, P<0.001). In the prespecified subgroup of patients suffering cardiogenic shock, 28-day mortality was significantly higher in the dopamine group compared to the norepinephrine group (P=0.03).

By Aimee Li, M.D.; Andrew Cheung, M.D.

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