After Aquablation, a male patient with pre‑operative post‑void residuals of 150 mL and 260 mL voided only 250 mL at 48 hours; does this meet the criteria for a successful voiding trial and what is the appropriate next step?

Post-Aquablation Voiding Trial at 48 Hours: Assessment and Management

Initial Assessment

A voided volume of 250 mL at 48 hours after Aquablation does NOT definitively meet criteria for a successful voiding trial and requires post-void residual (PVR) measurement before making any catheter management decisions. 1, 2

The critical issue is that you only know half the picture—the voided volume tells you nothing about retention without measuring what remains in the bladder.

Evidence-Based Voiding Trial Algorithm

Interpretation Framework

Based on validated void trial protocols, the following thresholds apply 2:

• Voided volume ≥200 mL: Likely successful, but PVR measurement still recommended to confirm PVR <100-150 mL 1, 2
• Voided volume 100-199 mL: Indeterminate—PVR measurement mandatory 2
• Voided volume <100 mL: Likely failed—expect need for re-catheterization 2

Your patient's 250 mL void falls into the favorable range, but you must measure PVR before declaring success. 1, 2

Specific Next Steps

Measure post-void residual immediately using bladder ultrasound or catheterization. 3, 1

If PVR ≤100 mL:

• Void trial is successful—remove catheter permanently 1, 2
• Discharge with standard post-Aquablation instructions 1
• Schedule follow-up within 1-2 weeks 1

If PVR 100-150 mL:

• Borderline zone—clinical judgment required 3, 1
• Consider patient symptoms: if voiding comfortably without straining, can attempt catheter-free trial with close monitoring 1
• If symptomatic (incomplete emptying sensation, straining), proceed to re-catheterization 1

If PVR >150 mL:

• Void trial has failed—re-insert transurethral catheter 1
• Repeat void trial in 24-48 hours (NOT 7 days—shorter intervals are appropriate for post-prostatectomy patients) 1, 4
• Alternative: initiate intermittent catheterization every 4-6 hours if patient is capable and willing 1

Critical Context for Post-Aquablation Patients

Expected Retention Rates

Men with pre-operative urinary retention have significantly higher rates of failed initial void trials (40% in acute retention, 12.5% in chronic retention with PVR >300 mL) compared to those without retention (7.2%). 4

Your patient's pre-operative PVRs of 150 and 260 mL place him in the chronic retention category, making initial void trial failure more likely. 4

Reassuring Long-Term Data

Even if this void trial fails, 98% of men with pre-operative urinary retention achieve spontaneous voiding after Aquablation by 5-month follow-up. 4 This should guide your counseling—temporary catheter dependence does not predict long-term failure.

Common Pitfalls to Avoid

Pitfall #1: Assuming Voided Volume Alone Defines Success

Never discharge a patient based solely on voided volume without measuring PVR. 1, 2 A patient can void 250 mL yet retain 400 mL, representing incomplete emptying and high risk for urinary tract infection, bladder decompensation, or acute retention after discharge. 3, 1

Pitfall #2: Waiting Too Long for Repeat Trial

If this void trial fails, do not leave the catheter in for 7 days. 1, 4 Post-prostate surgery patients benefit from earlier repeat trials (24-48 hours), unlike the 7-day protocols used after vaginal reconstructive surgery. 5 Men in acute retention may benefit from slightly delayed trials, but 48-72 hours is appropriate. 4

Pitfall #3: Ignoring Pre-Operative Retention History

This patient's baseline PVRs of 150-260 mL indicate chronic incomplete emptying. 4 Set expectations that temporary post-operative retention is common in this population and does not indicate surgical failure. 4

Pitfall #4: Overlooking Medication Effects

Avoid or use extreme caution with anticholinergics for bladder spasm in patients with borderline voiding function. 3, 1 Anti-muscarinics should be used cautiously when PVR exceeds 250-300 mL. 3 Opioid analgesics also impair detrusor function—prioritize multimodal analgesia with acetaminophen and NSAIDs. 1

Warning Signs Requiring Urgent Re-Evaluation

Monitor for 1:

• Inability to void at all after catheter removal
• Severe suprapubic pain or distension suggesting acute retention
• Fever >38.5°C suggesting urinary tract infection
• Heavy bleeding with clots requiring irrigation or re-operation

Summary Algorithm

1. Measure PVR now (bladder scan or catheterization) 1, 2
2. PVR ≤100 mL: Success—discharge with 1-2 week follow-up 1, 2
3. PVR 100-150 mL: Assess symptoms; if comfortable, trial without catheter with close monitoring 3, 1
4. PVR >150 mL: Re-catheterize and repeat trial in 24-48 hours 1, 4
5. Counsel patient: Temporary retention is common with his pre-operative retention history, and 98% achieve spontaneous voiding long-term 4