Ambulatory monitoring of bladder pressures in patients with low compliance as a result of neurogenic bladder dysfunction.

A group of 28 patients with neurogenic bladder dysfunction and low bladder compliance was studied using medium fill cystometry (CMG) and ambulatory monitoring (AM) during natural bladder filling. The aims of the study were to compare the 2 techniques and to determine if ambulatory monitoring might be useful in predicting upper tract dilatation. AM demonstrated significantly lower end filling pressures compared with CMG. Phasic detrusor contractions were found more commonly during AM and the frequency of phasic detrusor contractions during AM was associated significantly with poor compliance identified during CMG. Patients with upper tract dilatation had significantly greater residual urine volumes, higher pressure rises during CMG and higher frequencies of phasic detrusor contractions compared with those patients with normal upper tracts. The high pressures seen at the end of a medium fill CMG were not found during AM and therefore are unlikely to be the underlying explanation of upper tract dilatation in such patients.