BACKGROUND Acute renal failure occurring in the postoperative period, requiring dialysis after cardiac surgery is an important risk factor for an early mortality, and the overall mortality of this complication is as high as 40% to 60%. Dialysis in the early postoperative period is often complicated by acute hemodynamic, metabolic, and hematologic effects that adversely affect cardiopulmonary function in patients stabilizing from recent surgery. The purpose of this study was to avoid the need for dialysis by infusion of the solution of mannitol, furosemide, and dopamine in the early postoperative period in oliguric renal failure. METHODS One hundred patients with postoperative oliguric or anuric renal failure despite adequate postoperative cardiac output and hemodynamic function were randomized. Forty patients (group A) were given intermittent doses of diuretics (furosemide, bumetadine, and ethracrynic acid) and fluids. Sixty patients (group B) were given continuous infusion of the solution of mannitol, furosemide, and dopamine; the infusion was started within 6 hours (mean 3.5 hours) in subgroup B1 (n = 30), and later than 6 hours (mean 7.5 hours) in subgroup B2 (n = 30) after the onset of renal failure. RESULTS Diuresis occurred in 93.3% of group B (n = 56) versus 10% in group A (n = 4; patients with preop normal renal function). Ninety percent of group A (n = 36) required dialysis versus only 6.7% of group B (n = 4; patients with preexisting renal disease of subgroup B2). Renal function returned to preoperative normal (serum creatinine 0.9 +/- 0.05, p < 0.0001) or baseline value (serum creatinine 2.5 +/- 0.01, p < 0.0001) after first postoperative week in subgroup B1 and third postoperative week in subgroup B2. CONCLUSIONS Infusion of solution of mannitol, furosemide, and dopamine promoted diuresis in patients with acute postoperative renal failure with adequate postoperative cardiac output and had decreased the need for dialysis in the majority of patients. Early administration of this solution in acute renal failure caused early restoration of renal function to normal or baseline status. It remains to be determined whether routine administration of this solution in the early postoperative period for oliguric renal failure influences the long-term mortality and morbidity in those patients who do require dialysis.