The effect of changing detrusor power or urethral resistance on the pressure flow plot. A patient was voiding well, then asked to voluntarily interrupt the flow. Detrusor pressure rises at the same time as flow decreases. The pressure flow plot then effectively plots out the Bladder output relation.
Thus the phenomenon of high pressure voiding happens in the normal bladder when urethral resistance increases. It is NOT the result of a so called "compensated bladder" - an erroneous concept whereby the detrusor was thought to hypertrophy and generate nore power because of the need to void past an obstruction. if anythin the long term obstructed detrusor is weaker.