Diagnosis of voiding dysfunction by pressure-flow study in women

Figure 4 To determine projected isovolumetric pressure 1 the point representing the pressure and flow rate measured during uninterrupted voiding is projected back to the axis with a line of slope -1 cm H₂O/mL per second. (Note that the value of original PIP would be much larger). For this void, the value of PIP1 is about 60 cm H₂O, and the void falls in the band of typical values (unshaded). Values in the regions shaded gray would represent either ST or W contractions than those typical of the subjects in this group. (From Tan et al[30]. Stop test or pressure-flow study? Measuring detrusor contractility in older females. Neurourol Urodyn 2004: 23: 184 with permission). PIP: Projected isovolumetric pressure; ST: Stronger; W: Weaker.