Background: Routine diuretic administration after cardiopulmonary bypass is common despite the lack of evidence for its benefit. We performed a prospective study to evaluate if diuretics assist in weight loss or alter clinical outcome.
Methods: Seventy-nine patients undergoing primary elective coronary bypass surgery were randomized to either diuretic (fusemide and amiloride) or placebo (lactose) postoperatively until preoperative weight was achieved or for 5 days in total. Proportions were compared with chi2 or Fisher's exact test.
Results: Forty patients were randomized to diuretics and 39 to placebo. By day 5, 97% of patients (37 of 38) still in the diuretic arm, and 74% of patients (29 of 39) in the placebo arm, achieved preoperative weight (p = 0.02). There were no differences in clinical outcomes.
Conclusions: Routine diuretics promote an earlier diuresis but no clinical benefits are apparent in low risk patients with normal renal function. Clinicians should reconsider routine diuretic prescription in this setting.