Cystometry1 embraces more than bladder pressure, more than vesical volume pressure. It is a sensory, vesical volume pressure with sphincter control diagnostic procedure. As the bladder immediately accommodates itself to incoming fluid, it is necessary to use a two-way catheter to provide a fluid intake as well as a recording compartment for the instantaneous return pressure to obtain a complete graph in the process of filling. This means, as nearly as possible, an uninterrupted tracing of muscle contraction and relaxation of the bladder wall on which line sphincteric reactions, sensations of temperature, the first desire to void, and degrees of overdistention can be noted. The relationship of volume pressure to sensation and sphincter control is often abnormal and is of more value in cystometric diagnosis than any one factor alone.
The clinical value of this procedure lies chiefly in its identifying the bladder to clinicians as an organ of
ROSE DK. THE PRESENT STATUS OF CYSTOMETRY. JAMA. 1936;107(19):1534–1537. doi:10.1001/jama.1936.02770450018005