Accuracy of Post-Void Residual Urine Volume Measurement Using an Ultrasound Bladder Scanner among Postoperative Radical Hysterectomy Patients.

Background: Postoperative urinary retention occurs in 17 to 42% of Radical hysterectomy (RH) cases. The gold standard assessment of post-void residual urine volume (PVR) is bladder catheterization. The use of the 3D portable ultrasound device (VerathonBladderScan BVI 9400) to evaluate PVR is quick, safe, non-invasive, painless, and comfortable for patients as well as being easy to use.

Objective: To compare the accuracy of ultrasound bladder scanner with that of urethral catheterization in the assessment of post-void residual urine volume (PVR).

Material and Method: This was a prospective study. After removal of Foley’s catheter in postoperative radical hysterectomy(RH) patients, the voiding care schedule consisted of voids after six hours or earlier if the patient had the urge. Promptly after voiding, PVR was measured using the BladderScan (Scan volume). Immediately after the procedure, urethral catheterization was performed to obtain the actual PVR (Catheter volume). The process was repeated in subsequent voids, and correlations between scan volume and catheter volume were analyzed.

Results: Seventy patients (140 measurements) were included. A high correlation was found between the scan volume and the catheter volume (r = 0.89, p<0.001). A 91.0% specificity and 93.1% negative predictive value(NPV) were obtained using the scan volume in predicting a catheter volume of <100 ml. The difference in measurements between the two methods was not related to age, body mass index, parity, co-existing illness, type of surgical incision or duration of indwelling catheter. When catheter volume >100 ml was the cutoff for determining the need for re-catheterization, the scan volume returned 90.0% accuracy. Repetition of ultrasound scan in patients who had a first scan volume of <100 ml yielded a 97.2% specificity and 100% NPV in predicting catheter volume of <100 ml.

Conclusion: The Bladder Scan provides good correlation together with high rates of specificity and NPV, and it could be an alternative modality to catheterization for the measurement of PVR in postoperative RH patients.