What is the clinical significance and management of a small post void residual (PVR)?

From the Guidelines

A small post void residual (PVR) volume, typically less than 50-100 mL, is generally considered clinically insignificant and requires no specific intervention. For patients with small PVR values, reassurance is appropriate as this finding indicates adequate bladder emptying 1. No medications or treatments are needed for isolated small PVR measurements in asymptomatic individuals. However, if a patient has urinary symptoms despite a small PVR, those symptoms should be addressed based on their specific presentation.

Key Considerations

• PVR measurement should be repeated if there are changes in symptoms or to establish a baseline in patients with progressive neurological conditions.
• The clinical significance of PVR lies in its ability to identify incomplete bladder emptying, which when significant can lead to urinary tract infections, bladder stones, or upper urinary tract damage.
• PVR is measured either by bladder ultrasound (non-invasive and preferred) or by catheterization after voiding.
• A single PVR measurement should not be over-interpreted, as values can fluctuate based on fluid status, measurement timing, and patient comfort.
• The finding should always be correlated with the patient's symptoms and other clinical findings, as suggested by guidelines for managing lower urinary tract symptoms 1.

Management Approach

• Monitoring postvoid urine residual (PVR) allows for the identification of patients at an increased risk of acute urinary retention (AUR) 1.
• For asymptomatic patients with small PVR values, routine follow-up without specific intervention for the PVR itself is appropriate.
• Symptoms, if present, should be evaluated and managed according to their etiology, which may involve further diagnostic testing or referral to a specialist.

From the Research

Clinical Significance of Small Post Void Residual (PVR)

• A small PVR is generally considered to be less than 100-150 ml 2, 3
• The clinical significance of a small PVR is that it may indicate adequate bladder emptying and a low risk of urinary tract infection or other complications 3
• However, the definition of a significant residual urine volume is unclear, and there is no universally accepted cutoff value 4

Management of Small Post Void Residual (PVR)

• For patients with overactive bladder symptoms and a low PVR, anticholinergic medication may be used 2
• Measurement of PVR is recommended in guidelines and recommendations on the management of lower urinary tract symptoms (LUTS) and urinary incontinence, but the level of evidence for this measurement is not high 4
• In patients with a small PVR, close medical attention may not be necessary, but it is still important to monitor for signs of urinary retention or other complications 5, 6

Factors Associated with Elevated PVR

• Older age, prior incontinence surgery, history of multiple sclerosis, and vaginal prolapse stage 2 or greater are independent predictors of elevated PVR 2
• Large PVR (>200-300 ml) may indicate marked bladder dysfunction and may predispose to unsatisfactory treatment results 4
• A PVR of 180 ml or greater may be associated with an increased risk of bacteriuria in adult men 3

Measurement of PVR

• Ultrasound bladder volume measurement is preferred to urethral catheterization for measuring PVR 4
• The interval between voiding and PVR measurement should be of short duration 4
• Measurement of PVR may not be necessary in all patients, and clinical judgment should be used to determine when it is indicated 6