The Urodynamic traces

The Urodynamics traces used in these pages fall into 2 types. They are either acquired from what might be called conventional urodynamics or from ambulatory urodynamics.

Conventional urodynamics
Those from conventional urodynamics can be either filling cystometry, urethral pressure profiles or voiding pressure flow study.

There is a colour code throughout.

Red rectal pressure P
abd

blue



magenta - detrusor pressure P
det

green -
during


yellow - flow. - during filling volume infused Vinfus

The large numbers in the column to the left of the traces represent the value of the parameter at the position of the cursor filling cystometry



ambulatory urodynamics
Red rectal pressure P
abd
Blue intravesical pressure Pves
Magenta detrusor pressure Pabd
Leakage Vol>



The large numbers in the column to the right of the traces represent the value of the parameter at the position of the cursor


Artefacts

Abdominal pressure must be measured in order to eliminate artefacts. A rectal catheter is usually used, or occasionally a vaginal one. The trace below shows how, by subtracting the rectal pressure from the intravesical, a stable detrusor is demonstrated.

Care must be taken in the interpretation of detrusor pressure, however. The image below shows normal rectal contractions with a stable detrusor, which could be misinterpreted if the detrusor pressure only was analysed.

The image below shows both the above aspects of rectal pressure. There are genuine unstable contractions of the detrusor and some abdominal pressure artefacts which are cleanly cancelled. There are also, however, rectal contractions which lead to a less than ideal detrusor pressure trace.

Index Cystometry Urethral pressures Ambulatory