Pharmacological studies of the uninhibited neurogenic bladder. I. The influence of repeated filling and various filling rates on the cystometrogram of neurological patients with normal and uninhibited neurogenic bladder.

The influence on the cystometrogram of repeated filling and varying filling rates was studied in two groups of neurological patients, one with normal and one with uninhibited neurogenic bladder. A technique which permits an even bladder filling and a continuous recording of the intravesical pressure was used. The effect of repeated bladder filling without interval at a rate of 50 ml per min resulted in the following findings: In the normal bladder the intravesical pressure decreased at the second filling in three of the five patients. The bladder capacity remained unchanged in four of the five patients. In the uninhibited bladder, only a slight tendency to pressure decrease could be observed at the second filling in the 14 patients studied. The bladder capacity increased significantly (14 patients), while the amplitude of the uninhibited contraction was reduced (17 patients). These changes of the cystometric parameters cold be avoided in both groups when an interval of 20 min was interposed between the fillings. Varying filling rates (range 10 to 90 ml per min) resulted in the following findings: The normal bladder responded to higher filling rates partly with pressure increase (3 out of 6 patients), partly with pressure decrease (2 patients) or with unchanged pressure (1 patient). The capacity was independent of the filling rate. In the uninhibited neurogenic bladder, the pressure response to higher filling rates was either unchanged (11 out of 16 patients), higher pressure (3 patients) or a reduced pressure (2 patients). The capacity of the uninhibited bladder was not influenced by the filling rate in 10 out of 16 patients. The capacity increased at higher filling rates in four patients, and decreased in one. The amplitude of the uninhibited detrusor contraction was not influenced by the filling rate in nine out of 18 patients. The amplitude increased in five and decreased in four patients at higher filling rates. The present results show that an interval of at least 20 min has to be interposed between the fillings when cystometry with high and non-physiological filling rates is used for pharmacological studies. Otherwise, non-specific results will frequently be obtained. The influence of the rate of filling is of less importance as long as one and the same rate is used in the same experiments.