Figure 2

Curve fit of the mean intra-bladder pressures (IBPs) on the X-axis versus the instilled bladder volume (Y-axis) from all patients. The 'inflation' (right-hand side) and 'deflation' (left hand side) pressure volume (PV) curve is plotted as a curve fit of the means of the 30 measurements. Hysteresis can be seen, as with respiratory PV curves. No clear lower inflection point can be identified; via extrapolation, an upper inflection point was found at a bladder volume of 150 ml to 175 ml on the inflation limb. Error bars show 95% confidence intervals.