What are the steps to initiate a voiding trial?

How to Initiate a Voiding Trial

A voiding trial should be initiated on postoperative day 1 after perineal laceration repair or other procedures with risk of urinary retention, using the backfill technique as it is a better predictor of adequate bladder emptying than the autofill technique. 1, 2, 3

Voiding Trial Procedure: Backfill Method

1. Preparation:

   • Ensure patient is comfortable and privacy is maintained
   • Gather necessary supplies: sterile syringe, sterile saline, collection device for measuring output, straight catheter for post-void residual (PVR) measurement

2. Backfill Procedure:

   • Fill the bladder with 300 mL of sterile saline through the existing Foley catheter 2
   • Clamp the catheter for 15-20 minutes to ensure no leakage
   • Remove the Foley catheter completely
   • Ask patient to void when they feel the urge (within 15-30 minutes)

3. Assessment:

   • Measure the voided volume
   • Within 15 minutes of voiding, measure post-void residual (PVR) by straight catheterization 2
   • Calculate voiding efficiency: Voided volume ÷ (Voided volume + PVR) × 100%

4. Success Criteria:

   • Primary criterion: Patient voids at least two-thirds (≥66%) of total bladder volume (voided volume + PVR) 2, 3
   • Alternative criterion: Patient reports force of stream at least 50% of their baseline, which has been shown to correlate well with measured voided volume 4

Management Based on Voiding Trial Results

If Voiding Trial is Successful:

• Remove catheter permanently
• Document successful voiding trial in medical record
• Ensure patient is able to void again before discharge
• Provide instructions on adequate fluid intake and voiding frequency

If Voiding Trial is Unsuccessful:

• Reinsert Foley catheter or teach patient intermittent self-catheterization
• Consider trial of alpha-blocker therapy prior to next catheter removal attempt 1
• Schedule repeat voiding trial in 24-48 hours
• If second attempt fails, consider urologic consultation

Special Considerations

• For obstetrical patients: After repair of perineal lacerations, especially third and fourth-degree tears, a Foley catheter should remain in place until postoperative day 1 when a voiding trial should be performed 1

• For pediatric patients: Voiding trials should include assessment of voiding patterns, proper toilet posture, and may require a more comprehensive approach including urotherapy and treatment of any constipation 5

• For patients with urinary retention: Consider concomitant administration of an alpha-blocker prior to attempted catheter removal, especially if using a non-titratable option like tamsulosin or alfuzosin 1

Common Pitfalls to Avoid

• Autofill method: Research shows this method (removing catheter and allowing bladder to fill naturally) is less reliable than the backfill method 2, 3

• Inadequate volume: Ensuring adequate bladder filling (300 mL) is essential for an accurate assessment of voiding function

• Delayed PVR measurement: Post-void residual should be measured within 15 minutes of voiding for accuracy 2

• Ignoring patient symptoms: Patient's subjective assessment of force of stream correlates well with measured voided volume and can be a reliable indicator of voiding function 4

• Failure to document: Clear documentation of the voiding trial procedure, volumes, and outcomes is essential for continuity of care

By following this structured approach to voiding trials, clinicians can effectively assess bladder emptying function while minimizing patient discomfort and the risk of complications from prolonged catheterization.