Evaluating routine diuretics after coronary surgery: a prospective randomized controlled trial

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 χ2 or Fisher’s exact test. Results. Forty patients were randomized to diuretics and 39 to placebo. By day 5, 97% of patients (37of 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.