Accuracy of methods for urinary detection in women with stress urinary incontinence

We assessed the accuracy of urinary detection by visualization compared with a method using the urethral channel of a transurethral, three-channel urodynamic catheter.

This was a case series of 52 patients presenting with stress urinary incontinence over 2 years. Patients underwent video-urodynamic studies in both the supine and the erect positions by use of two techniques for measuring leak point pressure (LPP) by one examiner. LPP was determined as the intravesical pressure simultaneous to the starting point of urethral pressure changes through the urethral channel of a urodynamic catheter (LPP-ure) and then by visualization (LPP-vis) during different events. We also measured the time related to the provocations and the time to mark the leakage on the urodynamic machine by the examiner.

The LPP-ure values (cough supine: 42.1+/-18.7, cough erect: 42.1+/-21.8, Valsalva supine: 42.2+/-23.3, Valsalva erect: 41.0+/-22.6 cmH(2)O) were significantly lower than the LPP-vis values (89.9+/-29.4, 97.4+/-30.4, 70.6+/-25.2, and 74.4+/-32.6 cmH(2)O, respectively, all p<0.001). Whereas the actual leakages happened during the pressure increases, urodynamic recording by visualization was done after those increases had finished.

The use of visualization as a urinary detection method entails potential errors that cannot be adjusted for on that time scale. Our results emphasize the need to standardize the methodologies used for urinary leakage detection, because this measurement is closely related to the accuracy of measurement of leak point pressure.