What happens to the bladder at night? Overnight urodynamic monitoring in children with neurogenic vesical dysfunction.

摘要

PURPOSE: We assess night and day function of the neuropathic bladder in children with neurogenic vesical dysfunction by overnight urodynamic monitoring and conventional static cystometrogram. Overnight urodynamics as a diagnostic tool was evaluated and its reproducibility analyzed. MATERIALS AND METHODS: In 18 months 3 boys and 3 girls 6 to 14 years old (mean age plus or minus standard deviation 10.3 +/- 3.3) were studied prospectively. Each child was evaluated on 4 separate occasions with 2-daytime cystometrograms at a standard fill rate of 10 ml. per minute and 2 overnight urodynamic studies for 8 hours using a Urolog Recorder. All 6 children were interviewed regarding the acceptability, repeatability and compliance to overnight urodynamics. RESULTS: Bladder capacity was not significantly different during each episode for either of the 2 tests. Mean bladder pressures in 2 children showed stable detrusor activity on cystometry (2 +/- 1.4 cm. H2O) and overnight urodynamics (0.4 +/- 0.5, r = 0.9). Detrusor compliance was not impaired in these 2 children. Four patients had frank detrusor instability with a mean bladder pressure of 50.6 +/- 17.4 cm. H2O on cystometry versus 35.9 +/- 5.2 on overnight urodynamics (r = 0.9). Bladder compliance was severely impaired in these 4 patients. Compliance at potential bladder capacity for patient age was 6.6 +/- 2.1 ml./cm. H2O for cystometry versus 9.2 +/- 3.4 for overnight urodynamics (p = 0.26, r = 0.9). Compliance at actual bladder capacity was 3.4 +/- 1.2 ml./cm. H2O for cystometry versus 3.8 +/- 0.8 for overnight urodynamics (p = 0.28, r = 0.9). There was good correlation between daytime cystometry and overnight urodynamics (p <0.001, Pearson's coefficient correlation 0.92, 95% confidence interval 0.90 to 0.94). A kappa statistical analysis showed good agreement between cystometry and overnight urodynamics for stable bladder and frank detrusor instability (kappa = 0.9). Replicated measurements of the same patient by the same observer had an error of variance of 1.7 cm. H2O with a narrow confidence interval, indicating the measurement error was small and that overnight urodynamics can be reproduced with relative accuracy within an individual. All 6 children preferred overnight urodynamics to cystometry. CONCLUSIONS: There was good correlation between bladder behavior day and night. Overnight urodynamics were accurate in predicting detrusor activity, and well tolerated and less embarrassing for a child with neurogenic vesical dysfunction.