What are the guidelines for intraoperative use of furosemide (Lasix)?

Intraoperative Use of Furosemide

For intraoperative management, furosemide should be reserved for specific clinical scenarios rather than routine use, with initial IV dosing of 20-40 mg administered slowly over 1-2 minutes when indicated for acute volume overload or pulmonary edema. 1

Primary Indications for Intraoperative Furosemide

Acute Pulmonary Edema

• Administer furosemide 20-80 mg IV shortly after diagnosis of acute cardiogenic pulmonary edema is established 2
• The FDA-approved initial dose for acute pulmonary edema is 40 mg IV given slowly over 1-2 minutes, with potential escalation to 80 mg if inadequate response within 1 hour 1
• Furosemide should be given in combination with nitrate therapy rather than as monotherapy for moderate-to-severe pulmonary edema 2

Critical Dosing Considerations

• All IV doses must be administered slowly over 1-2 minutes to prevent ototoxicity 1
• For patients already on chronic oral diuretics, the initial IV dose should equal or exceed their oral maintenance dose 3
• Maximum infusion rate should not exceed 4 mg/min when using continuous infusion 1

Important Contraindications and Cautions

When to Avoid Furosemide

• Do not administer if signs of hypovolemia are present (prolonged capillary refill, hypotension, oliguria without volume overload) 2
• Avoid in patients with right ventricular infarction who require preload maintenance 2
• Exercise extreme caution when systolic blood pressure is <100 mmHg or >30 mmHg below baseline 2
• Stop immediately if anuria develops 2

Hemodynamic Concerns

• Furosemide can transiently worsen hemodynamics for 1-2 hours after administration by increasing systemic vascular resistance and left ventricular filling pressures while decreasing stroke volume 2
• This paradoxical effect makes combination therapy with vasodilators (nitrates) superior to furosemide monotherapy 2

Monitoring Requirements During Perioperative Use

Essential Parameters

• Continuous blood pressure monitoring during and after administration 2
• Urine output measurement (target response: prompt diuresis within hours) 1
• Electrolyte monitoring, particularly potassium and sodium 2
• Renal function assessment (creatinine, BUN) as worsening renal function correlates with increased mortality 2

Dose Adjustment Algorithm

• If inadequate response after initial 20-40 mg dose, increase by 20 mg increments no sooner than 2 hours after previous dose 1
• Continue titration until desired diuretic effect achieved, then maintain with that individually determined dose 1
• For high-dose therapy (>6 mg/kg/day), limit duration to <1 week and administer over 5-30 minutes to prevent ototoxicity 2

Special Populations

Pediatric Patients

• Initial dose: 1 mg/kg IV given slowly under close supervision 1
• May increase by 1 mg/kg increments (not sooner than 2 hours) if response inadequate 1
• Maximum dose: 6 mg/kg; for premature infants, do not exceed 1 mg/kg/day 1
• Continuous infusion (0.1 mg/kg/hr) produces more stable hemodynamics than intermittent boluses in critically ill infants post-cardiac surgery 4

Geriatric Patients

• Start at the low end of dosing range with cautious titration 1
• Increased risk of electrolyte disturbances and volume depletion 1

Practical Pitfalls to Avoid

• Never administer furosemide concurrently with acidic solutions (labetalol, ciprofloxacin, amrinone, milrinone) as precipitation will occur 1
• Avoid aggressive diuretic monotherapy in acute pulmonary edema—it is less effective than nitrate-based therapy and may increase intubation rates 2
• Do not rely on serum albumin levels alone to guide therapy; use clinical indicators of volume status 2
• Recognize that diuretic resistance develops over time, requiring dose escalation or addition of hypertonic saline 5