Cystometrogram
A cystometrogram (commonly referred to as a CMG) is an electronically
recorded measurement of the bladder pressure, bladder activity, and the degree
of sensation present during bladder filling. It may also be used to test the
ability to initiate (start) and and inhibit (stop) bladder contractions. The
test is performed by the urodynamics nurse.
Preparing for the test
- The test should not be done if your child has a bladder infection unless
specifically ordered by your doctor.
- Some medications interfere with the test so stop them (such as Ditropan,
Detrol, or Tofranil) one to two days before the test — unless specifically
instructed to stay on them for the test. If in doubt, check with your doctor
or call the nurse in urodynamics at 773.327.1840. However, do NOT discontinue
antibiotic therapy.
- The child can eat and drink before the test.
- Please feel free to ask questions before, during and after the tests. It
is very important that the child feels relaxed and comfotable to get valid
results.
Procedure
- A urinary catheter (small hollow flexible tube) is inserted into the
bladder (if not already in place) in order to fill the bladder with water.
- The catheter is attached to a monitor that will measure the pressure
inside the bladder while it is being filled.
- A small catheter (rectal tube) with a balloon tip is placed just inside
the rectum to monitor straining or movement which creates artifact(s) during
monitoring of bladder function.
- When starting to fill the bladder, the monitor is turned on (no pain is
involved) and the recording of the child's bladder activity starts. While this
is occurring, the child is asked to tell the nurse:
- When he first feels something in his bladder
- When he feels full
- When he feels like he/she has to urinate (or cath) and cannot hold it
anymore.
Note: The test will be stopped if at any point the child becomes too
uncomfortable.