The rectal pressure responds to any changes of
the abdominal cavity due to straining or stress.
These can then be subtracted from the intravesical
to give the true intrinsic bladder pressure from the detrusor muscle (detrusor
pressure).
Quality control is important during cystometry.
The cancellation from the rectal catheter must be accurate. The examples
below shows several artefacts on t he rectal and vesical traces all of
which are completely removed from the detrusor pressure by subtraction.
This is a stable bladder. All the artefacts in
these traces derive from abdominal pressure. Unfortunately , the rectum
"has a life of its own" and can generate its own pressures.
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| Click
here to see
rectal cancellation working badly |
Click
here to see
rectal cancellation working well but with some rectal pressure contractions which can confuse |
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