Carbon dioxide urethral pressure profile.

In an evaluation of patients with lower urinary tract symptoms, particularly incontinence, the role played by the urethra is crucial. One of the most important methods of evaluation of urethral dysfunction is the urethral pressure profile. From among the many simple and more sophisticated methods of urethral pressure profile measurements we have chosen to describe a simple office procedure and a reliable method of urethral pressure profile evaluation, using the carbon dioxide cystometer. Slow withdrawal of the special catheter connected to the carbon dioxide cystometer allows the determination of the resistance of the urehtral wall at sequential centimeter levels along the entire length of the urethra. Carbon dioxide urethral pressure profile is a safe office procedure that is easy to perform for immediate recording and interpretation of results. The cystometer is easy to calibrate. We have had no complications in 450 consecutive urethral pressure profile determinations. The shortcoming of the procedure is the compressibility of the gas (carbon dioxide), giving a lag in the register's response to pressure differential. The use of carbon dioxide urethral pressure profile is demonstrated in male incontinence, in female incontinence and in patients with neurogenic bladder dysfunction, and the results are discussed.