Hemodynamics and renal function during administration of low-dose dopamine in severely ill patients
Abstract
CONTEXT: Although a large number of studies have been performed regarding the renal and hemodynamic effects of the infusion of low-dose dopamine (LDD) in severely ill patients, there is still controversy on this subject. OBJECTIVE: To evaluate the effects of dopamine (2 mug/kg/min) on systemic hemodynamics (lowest mean arterial pressure, MAP, highest heart rate, HR, central venous pressure, CVP), creatinine clearance (CLcr), diuresis and fractional sodium excretion (FENa+). TYPE OF STUDY: A non-randomized, open, prospective clinical trial. SETTING: An intensive care unit in a tertiary university hospital. PARTICIPANTS: 22 patients with hemodynamic stability admitted to the intensive care unit. PROCEDURES: Patients were submitted to three two-hour periods: without dopamine (P1), with dopamine (P2) and without dopamine (P3). MAIN MEASUREMENTS: The abovementioned variables were measured during each period. CLcr was assessed based upon the formula U x V/P, where U is urinary creatinine (mg/dl), V is diuresis in ml/min and P is serum creatinine (mg/dl). FENa+ was calculated based upon the formula: urinary sodium (mEq/l) x P/plasma sodium (mEq/l) x U) x 100. Results were presented as mean and standard deviation. The Student t test was used and results were considered significant if p was less than 0.05. RESULTS: Twelve patients (seven males and five females) were included, with a mean age of 55.45 years. There was no significant variation in MAP, HR, CVP, CLcr or FENa+ with a dopamine dose of 2 mug/kg/min. On the other hand, diuresis significantly increased during P2, from 225.4 to 333.9 ml. CONCLUSION: Infusion of 2 mug/kg/min of dopamine for 2 hours increases diuresis. At the doses studied, dopamine does not induce significant alterations in MAP, HR, CVP, CLcr and FENa+.
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