BACKGROUND: Low-dose dopamine (2 (mg/kg/min) has long been used in the ICU setting in an attempt to preserve renal function in critically ill patients who are at significant risk for renal failure. This practice is based on evidence in healthy patients that low-dose dopamine increases renal blood flow, induces natriuresis and diuresis, and may prevent acute renal failure.
POPULATION STUDIED: A total of 324 patients from 23 ICUs in Australia and New Zealand who had a central venous catheter, had 2 or more changes of the systemic inflammatory syndrome (SIRS), and had at least one marker of early renal dysfunction (decreased urine output, elevated serum creatinine, or rapidly increasing serum creatinine). SIRS is a common response to a variety of severe clinical insults and is a marker of impending sepsis. One operational definition is 2 or more of the following: temperature greater than 38Þ C or less than 36Þ C, heart rate greater than 90, tachypnea (respiratory rate greater than 20), or hyperventilation (partial pressure of carbon dioxide in the arterial blood <32 mm Hg), WBC greater than 12,000 or less than 4,000 or greater than 10% immature neutrophils (bands), where these alterations represent an acute alteration from baseline without other known causes for such abnormalities.
STUDY DESIGN AND VALIDITY: This was a randomized double-blind study comparing the use of low-dose dopamine (n=161) with placebo (n=163) in patients with renal dysfunction. The patients were randomized to receive dopamine or placebo. ICU nurses, staff, and physicians were blinded to the randomization results. There was concealed allocation. The patients were followed until they died, their renal dysfunction resolved for 24 hours, or they were discharged from the ICU.
OUTCOMES MEASURED: The primary outcome was peak serum creatinine level. The secondary outcomes included duration of mechanical ventilation, length of ICU and hospital stay, and survival to hospital discharge.
RESULTS: After randomization, the 2 groups were similar in all characteristics measured (age, illness severity score, blood pressure, central venous pressure, urinary output, and serum creatinine). The dopamine group had a peak serum creatinine concentration of 245 micromols per L, compared with 249 micromols per L in the placebo group. This difference was not statistically or clinically significant. Survival to hospital discharge, survival to ICU discharge, and all other secondary outcomes were not significantly different. The trial drug and placebo were stopped at the same rate for suspected adverse effects.
Low-dose dopamine does not prevent renal failure in critically ill patients in the ICU. This study does not have enough statistical power to detect small changes in clinical outcomes, such as death or length of hospital stay. The study also does not address the use of low-dose dopamine as a prophylactic agent before the development of renal dysfunction.