Bladder pressure is measured because the bladder is filled to
capacity with a salt solution (normal saline) at a rate of 10 to 100ml/minute, with
the patient lying down.
The study is usually performed using a urinary catheter passed through the urethra into the bladder.
The catheter contains two channels. One channel is used for filling, and pressure can be recorded through the other. A 'volume versus pressure' graph, which is called a cystometrogram (CMG), is produced.
The cystometrogram is basically performed to evaluate the compliance and stability of the detrusor muscle. Eighty five per cent of all incontinence occurs in women, and three quarters of those suffer with stress incontinence (ie leakage in the absence of over activity).
Compliance is simply the elastic property of the detrusor muscles. An evaluation of compliance is an evaluation of the ability of the bladder to 'stretch' to 'normal' capacity, while maintaining low pressures.
Stability is evaluated by observing the detrusor while filling the bladder to normal capacity. The evaluation determines the presence or absence of detrusor overactivity (or instability).
Vesical pressure is the pressure that's measured inside the bladder, with a catheter that's specifically designed for pressure monitoring in the urinary tract.
This is a combination of the pressure being exerted on the bladder by the abdominal contents, the weight or pressure of any urine in the bladder and the force that the detrusor muscle is exerting on that fluid. The pressure in an empty bladder is usually called resting pressure, which changes with position.
The normal bladder resting pressures vary between 8 and 40cm of water (ie the pressure exerted at the bottom of a column of water 40cm high), depending upon the particular patient and position during study.
Abdominal pressure is measured by placing a special catheter either in the rectum or the vagina. Abdominal pressure information is significant because the bladder is contained in the floor of the abdominal cavity, and it's important to isolate pressures and activities occurring in the bladder itself.
The detrusor pressure is a subtracted pressure that's calculated by subtracting the abdominal pressure from the vesical pressure. In doing so, artefacts from abdominal straining, gas and the weight of the abdominal contents are removed from the information being processed from the catheter in the bladder, thereby representing the actual activities taking place in the bladder during the CMG.
A bladder with normal compliance will demonstrate no greater than 15cm water increase in detrusor pressure because it progresses from empty to capacity during a CMG.
When the bladder is properly positioned in the abdominal cavity, both it and the bladder neck are above the pelvic floor muscles. With aging, or after childbirth, the female pelvic floor can relax, causing the base of the bladder and the bladder neck to fall below the pelvic floor.
For a patient to remain dry, the pressures in the urethra must remain greater than the pressure in the bladder, during filling.
The average urethral closure pressure for a female is 60cmH20 and for a male it is 80cmH20.
The study is usually performed using a urinary catheter passed through the urethra into the bladder.
The catheter contains two channels. One channel is used for filling, and pressure can be recorded through the other. A 'volume versus pressure' graph, which is called a cystometrogram (CMG), is produced.
The cystometrogram is basically performed to evaluate the compliance and stability of the detrusor muscle. Eighty five per cent of all incontinence occurs in women, and three quarters of those suffer with stress incontinence (ie leakage in the absence of over activity).
Compliance is simply the elastic property of the detrusor muscles. An evaluation of compliance is an evaluation of the ability of the bladder to 'stretch' to 'normal' capacity, while maintaining low pressures.
Stability is evaluated by observing the detrusor while filling the bladder to normal capacity. The evaluation determines the presence or absence of detrusor overactivity (or instability).
Vesical pressure is the pressure that's measured inside the bladder, with a catheter that's specifically designed for pressure monitoring in the urinary tract.
This is a combination of the pressure being exerted on the bladder by the abdominal contents, the weight or pressure of any urine in the bladder and the force that the detrusor muscle is exerting on that fluid. The pressure in an empty bladder is usually called resting pressure, which changes with position.
The normal bladder resting pressures vary between 8 and 40cm of water (ie the pressure exerted at the bottom of a column of water 40cm high), depending upon the particular patient and position during study.
Abdominal pressure is measured by placing a special catheter either in the rectum or the vagina. Abdominal pressure information is significant because the bladder is contained in the floor of the abdominal cavity, and it's important to isolate pressures and activities occurring in the bladder itself.
The detrusor pressure is a subtracted pressure that's calculated by subtracting the abdominal pressure from the vesical pressure. In doing so, artefacts from abdominal straining, gas and the weight of the abdominal contents are removed from the information being processed from the catheter in the bladder, thereby representing the actual activities taking place in the bladder during the CMG.
A bladder with normal compliance will demonstrate no greater than 15cm water increase in detrusor pressure because it progresses from empty to capacity during a CMG.
When the bladder is properly positioned in the abdominal cavity, both it and the bladder neck are above the pelvic floor muscles. With aging, or after childbirth, the female pelvic floor can relax, causing the base of the bladder and the bladder neck to fall below the pelvic floor.
For a patient to remain dry, the pressures in the urethra must remain greater than the pressure in the bladder, during filling.
The average urethral closure pressure for a female is 60cmH20 and for a male it is 80cmH20.
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