Accuracy of a Portable Bladder Scanner to Measure Post-Void Residual Urine Volume in Women with Pelvic Organ Prolapse

Introduction Lower urinary tract evaluation in women with pelvic organ prolapse commonly includes measurement of the post-void residual urine volume. Portable bladder scanners may not accurately measure post-void residual urine volume in women with pelvic organ prolapse as the bladder is no longer in its normal anatomical position. In this study we investigated the accuracy of the BladderScan® BVI 9400 to measure post-void residual urine volume in women with prolapse. Methods We conducted a prospective observational study of 31 women with pelvic organ prolapse being evaluated in the outpatient setting. Women underwent 3 post-void residual urine volume measurements, including 1) portable bladder scan with prolapse not reduced, 2) portable bladder scan with prolapse reduced and 3) straight catheterization. Student's t-test, Pearson's correlation and Bland-Altman analysis were used to compare the 3 measurements. Results There were no differences in absolute errors among the 3 methods of measurement (all p >0.05). All 3 measurements were strongly correlated (all r >0.85 and all p <0.001). The bladder scan measurements obtained during prolapse reduction did not appear to agree more with the catheterized volume than the bladder scan measurements obtained when prolapse was not reduced. Bladder scan error was not related to obesity (p=0.46) or prior hysterectomy (p=0.81). Conclusions Pelvic organ prolapse did not affect post-void residual urine volume measurement error using a portable bladder scanner. Thus, it may be unnecessary to reduce stage 2-3 pelvic organ prolapse before obtaining a post-void residual urine volume measurement.