What to do for a patient on Lasix (furosemide) drip with no urination in 12 hours and a low bladder volume of 42 mL?

Management of Oliguria in a Patient on Lasix Drip

For a patient on a Lasix drip who hasn't urinated in 12 hours and has only 42 mL in the bladder, you should immediately discontinue the Lasix drip and evaluate for potential hypovolemia, as this indicates acute kidney injury that may be worsened by continued diuretic therapy.

Initial Assessment

• Verify bladder volume measurement and confirm oliguria (urine output <0.5 mL/kg/hr for 12 hours) 1
• Assess for signs of hypovolemia: hypotension, tachycardia, poor skin turgor, dry mucous membranes 1
• Check vital signs, particularly blood pressure, as hypotension (SBP <90 mmHg) makes patients unlikely to respond to diuretic treatment 1
• Evaluate for signs of peripheral and pulmonary congestion/edema 1
• Obtain immediate laboratory studies: serum electrolytes, BUN, creatinine, and arterial blood gas if hypoxemia is present 1

Immediate Management

• Stop the Lasix (furosemide) drip immediately to prevent further kidney injury 2
• Place a urinary catheter if not already present to accurately monitor urine output 1
• Assess fluid status and hemodynamics:
  • If hypotensive: administer fluid bolus to restore adequate intravascular volume 1
  • If normotensive with signs of volume overload: consider alternative causes of oliguria 1

Diagnostic Workup

• Obtain renal ultrasound to rule out post-renal obstruction 1
• Check for drug-induced nephrotoxicity or other medications that may affect renal function 1
• Consider right heart catheterization if left ventricular filling pressure is uncertain and the patient is refractory to treatment 1
• Evaluate for acute kidney injury using serum creatinine trends 1

Management Algorithm Based on Clinical Scenario

If Hypovolemic:

1. Administer IV fluid bolus (crystalloid) 1
2. Reassess urine output after fluid administration 1
3. If urine output improves, continue careful fluid administration 1
4. If no improvement, consider additional diagnostic studies 1

If Euvolemic or Hypervolemic:

1. Maintain the Lasix discontinuation 2
2. Consider alternative causes of oliguria:
   • Acute tubular necrosis
   • Hepatorenal syndrome (if cirrhotic)
   • Cardiorenal syndrome 1
3. If the patient has pulmonary edema despite oliguria:
   • Consider venovenous ultrafiltration if refractory to other measures 1
   • Consider inotropic support with dobutamine if heart failure is present 1

Monitoring After Intervention

• Monitor urine output hourly 1
• Check electrolytes (particularly potassium, sodium) every 4-6 hours 1
• Reassess volume status frequently 1
• Monitor for signs of worsening renal function 1

Common Pitfalls to Avoid

• Continuing diuretic therapy despite oliguria can worsen kidney injury and lead to electrolyte imbalances 2
• Excessive concern about hypotension and azotemia can lead to undertreatment of volume overload, but in this case of oliguria, diuretic cessation is appropriate 1
• Failure to recognize that inadequate urine output (<100 mL/h over 1-2 hours) is an inadequate response to IV diuretics and requires prompt intervention 1
• Assuming oliguria is always due to hypovolemia; consider other causes including intrinsic renal disease 3

Special Considerations

• If the patient has cirrhosis with ascites, be aware that diuretic resistance is common and may require combination therapy with aldosterone antagonists once renal function improves 1
• In heart failure patients, persistent volume overload not only contributes to symptoms but may also compromise the safety of other drugs used for treatment 1
• The response to diuretics is dependent on the concentration of the drug and the time course of its entry into the urine; patients with kidney injury may have impaired drug delivery to the site of action 4, 5