A Study of Urodynamic Parameters at Different Bladder Filling Stages for Predicting Upper Urinary Tract Dilatation.

PURPOSE: To identify more accurate predictors of upper urinary tract dilatation (UUTD) in neurogenic bladder (NB) children, we studied the relationship among urodynamic parameters at different bladder filling stages, detrusor leak point pressure (DLPP) and UUTD. METHODS: A total of 158 children (3-16 years) with NB were included and then divided into 2 groups according to whether their NB diagnosis was complicated with UUTD: the UUTD group (39 patients) and those without UUTD group (control group, 119 patients). The bladder filling phase was divided into 3 equal parts: the early, middle, and end filling stages. The bladder compliance (BC) and detrusor pressure (△Pdet) at each phase and DLPP at the end filling stage were recorded. RESULTS: A BC<8 mL/cm H2O both in the middle and end stages is more specific than a BC<9 mL/cm H2O in the end stage (72%, 73%, vs. 66%), and △Pdet >8 cm H2O in the early stage, 20 cm H2O in the middle stage and 25 cm H2O in the end stage are more sensitive than △Pdet >40 cm H2O in the end stage (82%, 85%, 85%, vs. 49%). A DLPP cutoff value of 20 cm H2O showed higher sensitivity for predicting UUTD than 40 cm H2O. CONCLUSION: Low BC and a high △Pdet in the middle and end filling stages are more accurate factors than classic indicators for predicting UUTD. In addition, a DLPP value of >20 cm H2O in the end bladder filling stage shows high sensitivity.

Changes in bladder function with time following cystostomy in rats.

AIMS: To investigate bladder function patterns following cystostomy and determine the best time window for cystometric evaluation of bladder function in conscious rats. MATERIALS AND METHODS: Cystostomy was performed in rats of the first seven groups; thereafter, cystometry was performed in the designed time interval. Noncystostomy rats of group 8 voided freely as control. Basal bladder pressure (Pves.basal ), maximum bladder pressure (Pves.max ), bladder threshold pressure (Pves.thre ), voiding interval (VI), bladder contraction duration (CD), bladder compliance (ΔC), voided volume (VV), postvoiding residual urine (PVR), and bladder capacity (BC) were recorded and compared with cystostomy groups, with VV, PVR, BC compared with the control values. Bladders were collected after the urodynamic study for weighing, hematoxylin-eosin, and Masson staining to investigate pathological changes. RESULTS: Pves.basal , Pves.max , and Pves.thre trended downward, while BC, VI, VV, and ΔC trended upward on days 1 to 5 postcystostomy. BC and VV significantly decreased on days 1 to 3 postcystostomy compared with control values; on days 5 to 15 postcystostomy, Pves.basal , Pves.max , Pves.thre , VI, VV, BC, and PVR were stable, and BC, VV, and PVR showed no significant differences from the control values. However, on day 21 postcystostomy, BC increased significantly compared with the controls. Bladder weight increased in the cystostomy groups compared with the controls. Pathological analysis showed severe acute bladder inflammation on days 1 to 3, mild inflammation on days 5 to 15, and increased collagen deposition in bladder tissue on day 21 postcystostomy. CONCLUSION: Cystometric evaluation of bladder function in conscious rats is best performed on days 5 to 15 postcystostomy.