Reproducibility of pressure transmission ratios in stress incontinent women

Pressure transmission ratios (PTR) are obtained during cough pressure profiles (delta urethral pressure/delta bladder pressure x 100) and have been extensively used in pre and post operative evaluation of patients with stress urinary incontinence. Sixteen patients with genuine stress were studied to assess the magnitude of PTR variance in incontinent women and how changes in bladder pressure impact on PTR. A marked variation in PTR was seen in individual patients with the coefficient of variation averaging 19.8%. Using linear regression analysis, 5 patients demonstrated a statistically significant relationship between bladder pressure and PTR. Only one of the five patients showed a decrease in pressure transmission with increased cough strength. The differences seen in PTR within individual patients make comparisons of single recordings at different times difficult to interpret.