On Call: Oliguria & Urinary Retention

Oliguria (Low Urine Output)

Definitions

  • Oliguria – Decreased Urine Output
  • Anuria – No Urine Output
  • Urinary Retention – Inability to Completely Empty the Bladder

Causes

  • Hypovolemia & Fluid Under-Resuscitation – Most Common Cause of Postoperative Oliguria
  • Any Cause of Acute Kidney Injury (AKI) Can Cause Oliguria

Goal Urine Output (UOP)

  • Infant (< 1 Year): ≥ 2.0 cc/kg/hr
  • Peds: 1.0-2.0 cc/kg/hr
  • Adult: 0.5-1.0 cc/kg/hr

Risk Factors for Postoperative Urinary Retention (POUR)

  • Elderly
  • Male
  • History of Urinary Retention
  • Neurologic Diseases
  • Prior Pelvic Surgery
  • Hernia Repair
  • Prolonged Anesthesia
  • Medications:
    • Opioids
    • Anticholinergic Medication
    • Beta-Blockers

Management

Evaluation

  • Initial First Step: Bladder Scan (US)
    • Differentiate Urinary Retention from Other Causes
    • If Scan Unavailable, “In-and-Out” Catheterization to Both Drain & Measure Fluid in the Bladder is an Option (More Invasive)
  • If Concerned for Acute Kidney Injury (AKI):
    • Renal Function Panel/Basic Metabolic Panel
    • Fractional Excretion of Sodium (FENa)
    • Urinalysis

Postoperative Urinary Retention (POUR)

  • Prevention: Early Ambulation & Limited Narcotic Use
  • Catheter to Decompress if Volume > 400-600 cc on Bladder Scan (US)
  • Treatment Options: Debated
    • Clean Intermittent Catheterization (Straight Cath)
      • Lower Risk of Bacteriuria & Infection
      • Potential Risk of Long-Lasting Detrusor Decompensation with Bladder Overdistention
      • Consider a “3-Strike Rule” – If Patient Fails to Void 3-Times Sequentially, Leave an Indwelling Foley Catheter
    • Indwelling Foley Catheter
      • Wait 1-5 Days for Repeat Voiding Attempt
      • Does Not Mandate Hospitalization & Can Be Managed Outpatient

Oliguria/Anuria

  • Start with a Bolus of Crystalloid Fluid – 1 Liter Lactated Ringer
    • Consider Smaller Boluses (500 cc) in CHF
  • Postoperative Patient May Require Multiple Fluid Boluses if Under-Resuscitated in the OR
  • Ongoing Management Should Be Directed Based on the Cause