Effect of body position on intravesical pressure in the anaesthetised bitch

The position adopted by 50 recumbent dogs was recorded while they were sleeping or resting; the commonest orientation of their hindquarters was right lateral recumbency. The intravesical pressure in the urinary bladder of 24 anaesthetised bitches lying in right lateral recumbency was compared with the intravesical pressure recorded when the same bitches were supported in a standing position. The intravesical pressure was significantly higher when the bitches were in right lateral recumbency (P less than 0.001) and the difference was unaffected by whether they were continent or not, and had no significant correlation with bodyweight. These findings help to explain why bitches with an incompetent urethral sphincter mechanism tend to leak predominantly when they are recumbent.