Comparison of bladder voiding efficiency in women when calculated from a free flow versus an intubated flow

OBJECTIVES: To assess the reproducibility of bladder voiding efficiency (BVE, Void%) between free flow (FF) and intubated flow (IF) and to correlate BVE measurements with urinary incontinence (UI) complaints and urodynamic (UDS) findings in women. METHODS: UDS recordings of women referred for LUTD evaluation to our UDS center were reviewed. Each file included FF at arrival, filling cystometry, and IF. Post-void residual volumes (PVR) were measured by catheterization after FF and IF. Women unable to void during the study or who expelled the catheter during IF, as well as studies with voided volume < 100 ml were excluded. Data was sub-analyzed according to 3 age categories, and UI complaints and UDS findings. RESULTS: Over the past 3 years, 237 UDS studies for FF and IF met all criteria. There was significant difference between voided volumes (232 vs. 335 ml) and PVR (24 vs. 71 ml) respectively (P < 0.0001). For the whole population, BVE IF (79.8 ± 28.6) was significantly lower than BVE FF (90.7 ± 15.9) (P < 0.0001). A significant decrease of BVE during IF was only noted for UI. BVE IF was significantly different in women in the peri-menopause and older groups. PVR IF increased with age and was significantly higher than PVR FF for women older than 45 years (P < 0.0001). CONCLUSIONS: BVE measurement in women has a role, but is most reliable from a FF. BVE is influenced by age and urinary incontinence complaints as well as UDS findings.