Urorectodynamic evaluation of healthy volunteers

Twelve female and 8 male healthy volunteers underwent urorectodynamic evaluation. Mean bladder capacity was 594 ml. and mean maximal vesical pressure 12.5 cm. water (H2O). Maximal bladder pressure correlated significantly with maximal mural tension (r = 0.96) but did not correlate well with bladder capacity (r = 0.20). Mean bladder volume at first desire to void was 32 per cent of mean bladder capacity. The bladder volume at the first desire did not correlate significantly with the capacity. Mean bladder pressure at 100 ml. volume was 2.9 +/- 0.4 cm. H2O (X +/- SEM). After bethanechol injection, the bladder pressure at 100 ml. volume increased by 8.8 +/- 1.2 cm. H2O (X +/- SEM) at twenty minutes. In only 1 subject did bladder pressure rise higher than 15 cm. H2O (5 per cent). Rectal pressure increased from 1.4 +/- 0.3 to 14.1 +/- 2 cm. H2O (X +/- SEM) at sixteen minutes. Electromyogram (EMG) of the external and sphincter did not follow regular pattern with vesical filling or attempt of voiding. The data obtained in these normal subjects may serve as a basis for comparison in the interpretation of data obtained in patients.