Large Voided Volume Suggestive of Abnormal Uroflow Pattern and Elevated Post-Void Residual Urine

Aim: To report the cut-off value for large voided volume (LVV) suggestive of abnormal uroflow pattern or elevated post-void residual urine (PVR) in healthy kindergarteners. Methods: From 2003 through 2008, we enrolled 417 healthy kindergarten children for evaluation of uroflowmetry tests and PVR. The uroflowmetry curves were interpreted if voided volumes (VV) were > 50 ml, and categorized as bell-shaped, staccato, plateau, and interrupted. Only bell-shaped curves were categorized as normal. After 2006, PVR was assessed within 5min after each voiding with a VV > 50 ml. A PVR > 20 ml is regarded as elevated. Receiver operative characteristic (ROC) curves were constructed to evaluate the cut-off value of VV/expected bladder capacity (EBC) with regard to nonbell-shaped uroflowmetry curves, and/or elevated PVR. Results: Of 385 children (mean age: 4.85 +/- 0.96 years), 699 uroflowmetry, and 556 PVR data were eligible for analysis. There were 502 (71.8%) bell-shaped, 76 (10.9%) plateau, 102 (14.6%) staccato, and 19 (2.7%) interrupted curves. Mean and median PVR were 12.4 +/- 21.2 and 5.5 ml, respectively. Of 556 PVRs, 96 (17.3%) were > 20 ml. Based on the ROC curve for the nonbell-shaped curves and/or elevated PVR, VV > 100% EBC was best defined as LVV. There were statistically more elevated PVR, and more nonbell-shaped curves in the voidings with than without LVV. There is a trend that peak flow rate decreased when VV was > 150% EBC. Conclusions: VV of more than 100% EBC can be defined as LVV which was associated with higher rates of abnormal uroflow pattern and/or elevated PVR. Neurourol. Urodynam. 30: 58-61, 2011. (C) 2010 Wiley-Liss, Inc.