FIGURE 2. Pressure-flow/-volume analyses of a voiding.
(A) A representative cystometry of a SUI patient. Arrows on the top indicate coughs. Pves: vesical pressure, Pabd: abdominal pressure, Pdet: detrusor pressure, Flow: urethral flow, Vvod: voided volume, Vinf: infused volume, and Vive: intra-vesical volume. (B) A pressure-volume analysis established by plotting the Pdet against Vive. The trajectory of pressure-volume data moves counterclockwise and shapes an enclosed loop representing a voiding cycle. Four phases are identified in the pressure-volume loop, namely (1) Filling (F), (2) Iso-volumic contraction (IVC), (3) Emission (E), and (4) Iso-volumic relaxation (IVR). Although coughs induce marked fluctuations in the vesical and abdominal pressure in the cystometry, they exhibit trivial influence on the pressure-volume trajectory.