Randomized comparison of vaginal and rectal measurement of intra-abdominal pressure during subtracted dual-channel cystometry

Objectives. To compare the rectal (P-rec) and vaginal (P-vag) measurement of intra-abdominal pressure during cystometry in women by assessment of patient acceptability and cystometrogram quality control. Methods. Of 136 consecutive women undergoing cystometrography, 100 were randomized to measurement Of P-rec or P-vag. The patients' experience was measured using visual analogue scales of anticipated and actual discomfort and embarrassment before and after the procedure. The setup time was recorded, and quality control was assessed by the number of catheter events (pressure lines failing out, requiring flushing, or repositioning), and quality of the cough signal. Results. A total of 136 consecutive patients were approached. Of those eligible, 50 were randomized to Prec and 50 to P-vag; 23 women declined randomization because of preference for a vaginal line. Overall, 81 line events occurred in 29 women with a vaginal line and 1 17 occurred in 34 women with a rectal line. No difference was found in patient acceptability nor in trace quality for the two routes. Despite catheter repositioning and flushing, only 13% of traces showed optimum trace quality throughout the entire investigation; the cough signal quality was worse after provocation, during voiding, and in women with prolapse. Conclusions. A significant proportion of patients undergoing cystometry expressed a preference for the vaginal line. The quality of output from cystometry was limited by the conditions of the investigation rather than the method of intra-abdominal pressure measurement.