The purpose of this study is to determine whether continuing or discontinuing furosemide (a
diuretic) on the day of elective noncardiac surgery for those who take furosemide on a
chronic basis, causes more intraoperative hypotension (low blood pressure) during surgery.
Our hypothesis is that the usual practice of continuing furosemide on the day of surgery
would contribute to more hypotension during surgery than discontinuing furosemide.
A significant proportion of patients who undergo surgery take medications on a chronic
basis. Little is known about the effects of these medications on the successful conduct of
anesthesia and surgery. Diuretics like furosemide may contribute to low blood pressure
during surgery, an outcome associated with cardiovascular complications. However, many
patients are recommended to take their diuretics on the day of surgery. We wished to
determine if preoperative administration of furosemide contributes to intraoperative
hypotension compared to placebo.
Comparison: We conducted a randomized, double blind placebo controlled trial to compare the
effect of furosemide with that of placebo on intraoperative hypotension using intraoperative
blood pressure recordings in patients who take furosemide chronically and were undergoing
- All adults referred to preoperative assessment clinics by surgeons for elective
non-cardiac surgery who routinely take furosemide.
- Participants must also be able to give informed consent
- Less than 18 years of age
- Have comorbid conditions with which brief periods of hypotension may be particularly
harmful such as: 1) pregnancy; 2) baseline hypotension (systolic <100 mmHg at the
preoperative assessment clinic); 3) autonomic dysfunction; 4) severe aortic stenosis.
- Patients who take furosemide only on an 'as needed basis' rather than 'regularly'.
- Those patients who take less than 10 mg of furosemide daily
- Those patients who are undergoing local anesthetic only surgical procedures
- Patients who are unwilling or unable to give informed consent.
Norman RC Campbell, MD
University of Calgary, Calgary, Alberta, Canada