Effects of anesthesia on urodynamic studies in the primate model

To elucidate the effect of anesthesia on bladder function and urodynamic studies by performing controlled comparisons of the effects of 2 anesthetics on urodynamics in a primate model.

Cystometrograms were performed in 4 awake adult female Rhesus monkeys (Macaca mulatta) via implantable transducer for continuous monitoring and compared with cystometrograms obtained under anesthetic agents. A total of 183 cystometric studies was performed (48 in the awake group, 74 under ketamine anesthesia and 61 under flurane anesthesia.

Maximum detrusor contraction pressure [Pdet(max)] was significantly lower under flurane than under ketamine anesthesia (33.1 +/- 2.5 versus 49.1 +/- 8.1 cm.H2O). In the awake state Pdet(max) (47.7 +/- 25.2 cm.H2O) was equal to that obtained under ketamine anesthesia. Cystometric bladder capacity was significantly larger under flurane (101.5 +/- 81.8 ml.) than under ketamine (70.3 +/- 56.1 ml.) anesthesia. It was only (32.9 +/- 15.9 ml.) in the awake state. Cystometric bladder capacity under both anesthetics was larger than the mean voided volume (43.3 +/- 6.3 ml.), but was comparable to the largest voided volume (102.3 +/- 31 ml.). Cystometric reflex contractions with bladder filling occurred more frequently with ketamine (96%) than with flurane anesthesia (66%).

These findings show that anesthesia has profound effects on the bladder, and careful interpretation of urodynamic data is suggested. These findings also suggest that ketamine is a suitable anesthetic for urodynamic studies in the subhuman primate.