What are the steps for ordering a voiding trial for a patient with urinary retention?

Ordering a Voiding Trial After Urinary Retention

For a voiding trial order, specify: (1) remove Foley catheter after backfilling bladder with 300 mL normal saline, (2) patient voids immediately, (3) measure post-void residual (PVR) by bladder scan or straight catheterization, and (4) pass criteria is voided volume ≥200 mL OR PVR <100 mL. 1, 2, 3

Pre-Trial Considerations

Alpha-blocker administration: Consider starting a non-titratable alpha-blocker (tamsulosin or alfuzosin) prior to catheter removal in patients with benign prostatic hyperplasia, particularly if retention is not precipitated by temporary factors like anesthesia or sympathomimetic medications. 4 Avoid alpha-blockers in patients with prior side effects, orthostatic hypotension, or cerebrovascular disease. 4

Assess likelihood of success: Voiding trials are more likely to succeed when retention is caused by reversible factors such as anesthesia, alpha-adrenergic cold medications, constipation, or inadequate hydration. 4, 1

Voiding Trial Protocol

Backfill Technique (Preferred Method)

The backfill technique is superior to spontaneous bladder filling for predicting successful voiding. 2 This method demonstrated better correlation with successful voiding trials (κ = 0.91) compared to auto-fill technique (κ = 0.56). 2

Order components:

• Fill bladder retrograde through Foley catheter with 300 mL normal saline (or until patient reports urgency to void) 1, 2, 3
• Remove catheter 1, 2, 3
• Instruct patient to void immediately into measured collection device 2, 3
• Measure voided volume 2, 3

Interpretation Algorithm

Use voided volume thresholds to minimize unnecessary PVR measurements: 3

• Voided volume ≥200 mL: Trial is successful; no PVR measurement needed (97% pass rate, positive predictive value 97.4%) 3
• Voided volume 100-199 mL: Indeterminate result; measure PVR by bladder scan or straight catheterization 3
• Voided volume <100 mL: Trial has failed; reinsertion of catheter needed (96.7% failure rate) 3

Alternative PVR-based criteria: If PVR is measured, success is defined as PVR <100 mL, particularly in stroke patients and those with neurogenic bladder. 4, 1 Some protocols use voiding efficiency ≥50% (voided volume/total bladder volume) or ≥68% for 100% prediction of success. 5

Management Based on Trial Outcome

Successful Trial

• Discharge patient without catheter 1, 2, 3
• Instruct patient to monitor for voiding difficulty 1
• No routine follow-up needed if voiding normally 1

Failed Trial

First-line intervention is scheduled intermittent catheterization every 4-6 hours, NOT indwelling catheter reinsertion. 1 This approach reduces infection risk compared to indwelling catheters. 4

Intermittent catheterization protocol:

• Perform catheterization every 4-6 hours to prevent bladder filling beyond 500 mL (prevents detrusor muscle damage) 4, 1
• Measure PVR after each spontaneous voiding attempt 1
• Continue until PVR consistently <100 mL on three consecutive measurements 1
• Monitor for urinary tract infection signs (fever, mental status changes, cloudy urine) 1

Repeat voiding trial: Attempt catheter removal again after addressing reversible causes and optimizing medical management. 4, 1

Red Flags Requiring Urgent Urological Consultation

Seek immediate consultation for: 1

• Signs of upper urinary tract involvement (renal insufficiency, hydronephrosis) 1
• Recurrent gross hematuria 1
• Bladder stones 1
• Recurrent UTIs clearly due to obstruction 1
• Refractory retention after at least one failed catheter removal attempt (surgical intervention indicated) 4, 1

Common Pitfalls

Avoid indwelling catheter as first-line management: Intermittent catheterization is preferred due to lower infection risk and better bladder retraining. 4, 1

Do not allow bladder overdistention: Never permit bladder volume to exceed 500 mL during intermittent catheterization, as this causes detrusor dysfunction and prolongs retention. 4, 1

Recognize high-risk patients: Surgery is indicated for patients with refractory retention who have failed at least one catheter removal attempt, assuming acceptable surgical risk. 4 In non-surgical candidates, long-term intermittent catheterization or indwelling catheter/stent is recommended. 4