What is the approach for a trial of void in patients with urinary retention?

Trial of Void Protocol for Patients with Urinary Retention

For patients with urinary retention, a trial of void should be conducted after catheter removal with concomitant alpha blocker administration (such as tamsulosin 0.4mg daily) started prior to catheter removal to improve success rates, followed by post-void residual measurement to determine if the trial was successful. 1

Preparation for Trial of Void

1. Alpha Blocker Administration

   • Start alpha blocker therapy (e.g., tamsulosin 0.4mg or alfuzosin) prior to catheter removal
   • Contraindications: prior alpha blocker side effects, unstable medical comorbidities (orthostatic hypotension, cerebrovascular disease) 1

2. Timing of Catheter Removal

   • For post-surgical patients, consider removing the catheter approximately 6 hours postoperatively 2
   • For non-surgical retention, catheter should typically remain in place for 3-5 days before attempting trial of void

Trial of Void Techniques

Back Fill Technique (Preferred)

• Fill the bladder with 300cc saline before removing the Foley catheter
• This technique shows better correlation with successful voiding trials (κ = 0.91) compared to auto fill (κ = 0.56) 3

Auto Fill Technique

• Remove catheter and allow bladder to fill spontaneously
• Less predictive of adequate postoperative bladder emptying 3

Assessment of Successful Trial

1. Post-Void Residual (PVR) Measurement

   • Perform bladder scan after first void
   • Successful trial: voiding at least two-thirds of total bladder volume 3
   • Failed trial: PVR >150ml 2

2. Risk Factors for Failed Trial of Void

   • High baseline PVR (particularly >200ml) 4
   • Advanced age 2
   • Use of medications with anticholinergic properties 2
   • Pre-existing urinary dysfunction 2

Management Based on Trial Results

Successful Trial

• Remove catheter permanently
• Continue alpha blocker therapy if retention was related to BPH 1
• Consider follow-up evaluation of underlying cause

Failed Trial

• Replace urethral catheter or consider suprapubic catheterization
  • Suprapubic catheterization may be superior for short-term management 5
  • Silver alloy-impregnated urethral catheters reduce urinary tract infection risk 5
• Extend catheterization period (typically additional 7-14 days) 4
• Consider urodynamic studies for persistent retention 1
• Consider cystoscopy if anatomical obstruction is suspected 1

Special Considerations

• For patients with detrusor underactivity, implement double voiding technique (several toilet visits in close succession) 1
• For chronic urinary retention from neurogenic bladder, consider clean intermittent self-catheterization with low-friction catheters 5
• Monitor for complications such as urinary tract infections, which occur more frequently in patients who fail trial of void (20.0% vs 4.7%) 4

Evaluation of Underlying Cause

• For persistent retention, conduct further evaluation:
  • Urodynamic studies 1
  • Cystoscopy for suspected anatomical obstruction 1
  • Address potential causes: BPH, prostatitis, cystitis, urethritis, medication effects, neurological conditions 5, 6