Reexamination of the intraurethral pressure determination using CO2 perfusion: its monitoring mechanism, standardization, and employment for the determination of the urethral constitutive property.

Urethral closure pressure profile is intended to provide an index of urethral resistance to bladder output, enable an assessment of urinary continence, provide distinction between a distensible and fibrotic sphincter urethral segment, and contribute information to enable characterization of detrusor-sphincter dyssynergia. However, the intraurethral pressure is a function of the catheter size, the hole size through which fluid is perfused, the fluid perfusion rate and the distensibility of the urethral sphincter segment; for want of standardization, it is difficult to functionally interpret the value of the peak urethral pressure taken with a certain catheter at a given perfusion rate. We have catered to this lacunae by developing (i) the urethral closing pressure, as the peak intraurethral pressure for theoretical limiting cases of zero perfusion rate and urethral diameter, and (ii) the urethral stiffness as a relation between its wall tension and tensile strain. Their detailed analyses and clinical interpretations are provided.