How are the terms used in bladder pressure assessment defined?

Updated: Jan 16, 2020
  • Author: Pamela I Ellsworth, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Abdominal pressure (Pabd): The pressure measurement obtained from a rectal catheter during a urodynamic study

Bladder compliance: The relationship between change in bladder volume and change in detrusor pressure (ΔDV/ΔDP). (The International Continence Society recommends two standard points be used for compliance calculations: (1) the detrusor pressure at the start of bladder filling and the corresponding bladder volume (usually zero) and (2) the detrusor pressure and corresponding bladder volume at cystometric capacity or immediately before the start of a detrusor contraction that causes significant leakage.)

Detrusor leak point pressure (DLPP): The lowest detrusor pressure at which urine leakage occurs in the absence of either a detrusor contraction or increase in abdominal pressure.

Detrusor overactivity: A urodynamic observation characterized by involuntary detrusor contractions during the filling phase, which may be spontaneous or provoked

Detrusor pressure (Pdet): The true bladder pressure. It is calculated by subtracting the abdominal pressure (Pabd), measured with a rectal catheter, from the vesical pressure (Pves), measured with a catheter in the bladder. Pdet = Pves - Pabd

Filling cystometry: The method by which the pressure/volume relationship of the bladder is measured during bladder filling

Intravesical pressure (Pves): The pressure recording from a urodynamic catheter placed inside the bladder

Physiologic filling rate: A filling rate (during cystometry) that is less than the predicted maximum (see definition below)

Predicted maximum: The maximum rate of urine production, calculated using the predicted maximum body weight in kg divided by 4 and expressed as mL/min

Pressure at maximum flow: The lowest pressure recorded at maximum measured flow rate

Pressure/flow study: Measures the detrusor pressure required to void and the flow rate a given bladder pressure generates (The study can be useful in the evaluation of suspected bladder outlet obstruction.)

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