Hydrodynamics of micturition in healthy females: pressure and flow at different micturition volumes.

A new urodynamic technique, in which detrusor and bladder pressures are recorded with suprapubic percutaneous catheters, was used for investigation of 19 healthy female volunteers to obtain urodynamic reference values. The investigation was made in parous as well as in nulliparous women of varying ages. Apart from a significantly elevated premicturition pressure in the elderly women, neither age nor parity seemed to change urodynamic parameters. Voidings with three different, defined bladder volumes in each volunteer indicated that flow increased with a larger volume up to a certain limit (400 ml) but further increase of volume did not raise the flow. All total bladder pressures, maximum detrusor pressures, and detrusor pressures at maximum flow at micturitions were independent of bladder volumes. Micturitions were made as detrusor micturitions as all volunteers were requested not to strain at voiding. It is considered that detrusor micturitions must be the best way to obtain comparable parameters from different urodynamic investigations.