Non-Invasive Bladder Analysis For Men

Frequently Asked Questions

Clinical Specific Information

Isovolumetric pressure is not routinely recorded in urodynamics. Can it be used as a measure of bladder contractility?

There is a sound theoretical basis for using isovolumetric pressure. Also the relationship between isovolumetric pressure and pressure at maximum flow has been assessed so that an allowance can be made in the construction of a specific nomogram for the non-invasive data. (Griffiths DJ. Hydrodynamics and mechanics of the bladder and urethra. In: Mundy AR, Stephenson TP, Wein AJ: Urodynamics: Principles Practice and Application 2nd ed Churchill Livingstone 1994.)

The bladder pressure measured by the cuff machine includes abdominal pressure. Does this cause a problem?

In practice abdominal pressure has a predictable narrow range of 35 ± 9cm water (mean ± SD) for which an allowance can be made in the modified ICS nomagram used to interpret the results. (Neurourol Urodynam, 22:602–605, 2003)

Is cuff pressure transmitted to the urethra & does it show bladder pressure?

During the clinical study, pressure monitoring and video cystometry was carried out which established that the urethral lumen remains open from the cuff to the bladder. This column of fluid transmits the bladder pressure down the urethral lumen. (J Urol, 166: 2549–9, 2001)

Is bladder contraction maintained during cuff inflation?

When the cuff deflates, we take the fact that voiding continues to indicate that the bladder contraction is continuing and if flow does not restart it is practice to discard the test. Specific analysis of the bladder contraction, by simultaneous invasive PFS, provided good evidence that performing the test does not inhibit the detrusor muscle. (Neurourol Urodyn, 20:382–4, 2001 & J Urol, 1003–1006, 2003)

Is bladder contraction inhibited by the interruption?

On release of the cuff pressure after interruption, and on resumption of flow, the bladder pressure returns to the pre interruption pressure, indicating inhibition has not occurred. (J Urol 169, 1003-1006, 2003)

What about straining?

During trials patients were asked not to strain and provided the request was made in terms they understood, most were able to comply. Straining has not been found to be an issue, in practice. (J Urol 172, 1394–1398, 2004)

Can I detect over activity in the bladder?

No because the cuff test does not record information on the filling phase of the bladder.

Can it be used for neurological conditions?

Invasive Urodynamics may be more suitable in this select group of patients. However, the CT3000 could provide initial information on obstruction.

How can I detect if a patient has a stricture?

During the course of the test, when the cuff deflates and allows flow to continue, you will not necessarily see a ‘surge’ of urine as you would normally expect. This can be an indication of a stricture, although further investigations would be recommended.

How repeatable are measurements?

Inter observer agreement on inflation cycles to analyse and measurement reproducibility is good. In keeping with flow rate measurements, a voided volume of 150ml or more produces reliable data. (J Urol 172, 1394-1398, 2004)

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