Risk of Intraoperative Hypotension with Loop Diuretics: A Randomized Controlled Trial

BACKGROUND: There is growing concern regarding the safety of blood pressure-lowering medications administered during the perioperative period. Whether loop diuretics also induce intraoperative hypotension is uncertain. Our objective was to compare the effects of continuing or withholding furosemide on the day of noncardiac elective surgery on intraoperative hypotension among chronic users of furosemide. METHODS: A double blind, randomized, placebo controlled trial was conducted at 3 North American university centers between September 2000 and December 2006. Participants were randomly assigned in a 1: 1 ratio to receive either furosemide or placebo on the day of surgery. The primary outcome was risk of developing intraoperative hypotension. A priori secondary outcomes included risk of heart failure; composite cardiovascular event (myocardial infarction, arrhythmia, stroke or transient ischemic attack, or death); and change in renal function and electrolytes. RESULTS: Of the 212 patients enrolled, 193 patients underwent surgery. There was no significant difference in risk of developing intraoperative hypotension between the furosemide (49%) and placebo (51.9%) groups (relative risk [RR], 0.95; 95% confidence interval [CI], 0.72-1.24; P = .78). The intraoperative administration of vasopressors and fluids were similar between both groups. The risk of developing postoperative cardiovascular events was not significantly different between those randomized to furosemide (4.8%) or placebo (2.8%) (RR, 1.73; 95% CI, 0.42-7.06; P = .49). There was no significant difference in renal function or electrolytes between the 2 groups. CONCLUSION: Among elective, noncardiac surgeries in patients chronically treated with furosemide, the administration of furosemide on the day of surgery did not significantly increase the risk for intraoperative hypotension. (C) 2010 Elsevier Inc. All rights reserved. The American Journal of Medicine (2010) 123, 1059.e1-1059.e8