Should Lasix (furosemide) be continued postoperatively?

Should Lasix Be Continued Postoperatively?

Yes, continue Lasix (furosemide) postoperatively in patients with heart failure who have signs or symptoms of congestion, but discontinue it on the day of surgery in patients taking it solely for hypertension. 1, 2

Decision Algorithm Based on Indication

For Heart Failure Patients

Diuretics must be continued throughout the perioperative period in heart failure patients with signs or symptoms of congestion. 1 The European Society of Cardiology explicitly recommends that diuretics be continued up to the day of surgery, resumed intravenously perioperatively, and continued orally when possible in heart failure patients. 1, 2

Key management principles:

• Continue furosemide up to the day of surgery to maintain euvolemic status 1
• Resume intravenously in the immediate postoperative period to control volume overload 1
• Transition back to oral administration as soon as clinically feasible 1, 3
• Monitor volume status carefully, as fluid overload from perioperative fluid administration can cause decompensation of chronic heart failure or development of de novo acute heart failure 1, 3

Critical pitfall: Patients with heart failure are particularly susceptible to fluid overload postoperatively because fluids given during surgery may be mobilized days later, causing hypervolemia and heart failure decompensation. 1 This makes continued diuretic therapy essential rather than optional.

For Hypertension Patients (Without Heart Failure)

Discontinue low-dose diuretics on the day of surgery and resume orally when possible. 1, 2 The European Society of Cardiology guidelines explicitly state that hypertensive patients should discontinue low-dose diuretics on the day of surgery to prevent volume depletion and electrolyte disturbances. 1, 2

Rationale for discontinuation:

• Diuretics cause hypokalemia in up to 34% of surgical patients, which increases risk of ventricular arrhythmias and perioperative mortality 1, 2
• Volume depletion from diuretics increases risk of perioperative hypotension 2
• If blood pressure control is needed before oral therapy can be resumed, other intravenous antihypertensive agents are preferred 1

Electrolyte Management

Correct electrolyte disturbances, especially hypokalemia and hypomagnesemia, before surgery. 1, 2 This is critical because:

• Hypokalemia significantly increases risk of ventricular tachycardia and ventricular fibrillation in cardiac disease 1
• Hypokalemia was independently associated with perioperative mortality in patients with cardiac disease undergoing non-cardiac surgery 1
• Potassium and magnesium homeostasis should be evaluated preoperatively in all patients on diuretics 1

Management strategies include:

• Dietary advice to increase potassium and magnesium intake 1
• Addition of potassium-sparing diuretics (spironolactone or eplerenone) 1
• Direct supplementation when needed 1

Special Postoperative Considerations

Monitor for cardiac decompensation, which occurs in up to 20% of patients after procedures. 1 Preemptive furosemide may be employed to prevent cardiac decompensation in patients at risk. 1

Volume status assessment is paramount postoperatively:

• High-volume infusion is often needed intra- and immediately postoperatively 1
• Third-space fluid reabsorption can occur days after surgery, causing delayed heart failure 1
• Heart failure may develop immediately after surgery (due to prolonged procedure, myocardial ischemia, rapid fluid shift) or days later (due to third-space fluid reabsorption) 1

Common Pitfalls to Avoid

Do not routinely discontinue diuretics in all patients—the indication matters. The distinction between heart failure and hypertension as the indication for furosemide is critical and determines opposite management strategies. 1, 2

Do not delay resumption of diuretics in heart failure patients. Life-saving therapies in stable heart failure patients should be reinstated postoperatively as soon as clinical conditions are satisfactory. 1 Patients with heart failure have significantly higher risk of hospital readmission after surgical procedures, confirming the need for careful discharge planning. 1

Do not ignore signs of hepatic encephalopathy in cirrhotic patients. In patients with hepatic cirrhosis and ascites, furosemide therapy is best initiated in the hospital, and sudden alterations of fluid and electrolyte balance may precipitate hepatic coma. 4 Strict observation is necessary during the period of diuresis. 4