Continuous non-invasive measurement of bladder voiding pressure using an experimental constant low-flow test.

Purpose We developed a prototype device using an automatically controlled inflatable penile cuff to measure bladder voiding pressure continuously and non-invasively in men. The purpose of this study was to validate the pressure measurements made by this device by comparison to those during simultaneous invasive PFS. Methods A device was developed to automatically modulate flow rate by controlling pressure in a penile cuff. Men undergoing conventional urodynamics studies were recruited to have an additional fill-void cycle whilst using the new device. We report on 40 men using a standardized protocol. Pressure measured by this device was compared with simultaneous vesical pressure by evaluating maximum pressure during voiding, and calculating the root mean square (RMS) difference between p_cuff and p_ves. Results We recruited 80 men of whom 18 were excluded, 22 were involved in initial development phase and 40 in the standard protocol. Mean (SD) difference between maxima of p_cuff and p_ves (1.3 (15.6) cmH₂O) was not significant. In 20 (50%) men, agreement between p_cuff and p_ves throughout the void was moderate or good (RMS difference <20 cmH₂O). Causes of unsuccessful measurements were identified. Conclusions Although a prototype device, this technique appears to be promising for continuous non-invasive bladder pressure measurement. From the results of this study a number of improvements have been recommended and implemented. The next generation of this technique will allow assessment of clinical application. Neurourol. Urodynam. 31:557-563, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]