Summary Diuretic therapy in acute renal failure is mainly done with loop diuretics, foremost furosemide. Torasemide has a longer duration of action and does not accumulate in renal failure. In renal failure both diuretics have been effectively applied, with a more pronounced diuretic effect for torasemide. However, the use of diuretics in acute renal failure is controversially discussed, mainly because of the missing positive outcome regarding renal recovery, requirement for dialysis and death. In this study, the effects of torasemide versus furosemide on renal function in cardiac surgery patients recovering from acute renal failure after renal replacement therapy were studied. Twenty-nine patients admitted to an intensive care unit at a university teaching hospital after cardiac surgery were included in this prospective, randomized clinical trial. Torasemide and furosemide dosage was adjusted with the target urine output being 0.8–1.5 ml/kg/h. Hemodynamic data, urine output, volume balance, creatinine clearance, electrolytes, blood urea nitrogen, serum creatinine, renin and aldosterone concentrations were measured. A dosage of 29 (0–160) mg torasemide and a dosage of 60 (0–240) mg furosemide were given every 6 h in each group, respectively. Urine output, 24 h balance, serum creatinine clearance, renin and aldosterone concentrations did not differ significantly between groups. Urine output decreased in both groups, mostly dose-dependent in the torasemide group. The intra-group comparison of the first time-interval after inclusion with the last time-interval showed a significant increase in serum creatinine and blood urea nitrogen in the furosemide group. However, 4 patients had to be reinitiated in renal replacement therapy in the torasemide group versus 2 patients in the furosemide group.
Conclusion Torasemide and furosemide were effective in increasing urine output in cardiac surgery patients. Torasemide might show a better dose-dependent diuretic effect in acute renal failure patients after renal replacement therapy treatment. Serum creatinine and blood urea nitrogen elimination were comparable between diuretic groups.