Checking the catheter response for the method of Brown and Wickham

Occluding the measuring holes of the catheter produces a sharp pressure rise. The gradient of the rise tells whether the combined measuring system has a sharp enough response for urethral pressure profile measurement. In this case the gradient is 31.6 cm water per second. Brown and Wickham specify that a figure of 200 cm H2O per second is adequate at a profile withdrawal rate of 1 cm per second. Therefore with this combination of catheter and connecting tube, the withdrawal rate needs to be one sixth of 1 cm per second or just less than 2 mm per second