of the Week: March
absence of drainage.
intraventricular drainage unit is positioned at 15 cm above the external
auditory canal. The bedside monitor reveals a pressure of 35 mmHg,
however, there is no drainage of CSF from the catheter. Identify
2 possible reasons for the absence of drainage.
The catheter may be blocked.
The ventricles do not have CSF to drain; the cause for the elevated ICP
is cerebral edema.
check for catheter patency, lower the drainage chamber below the patient's
head. If the catheter is patent, CSF drainage should occur.
the ICP waveform. Ensure that an appropriate scale is selected to
ensure good visibiltiy of the waveform. If the catheter is
patent, a crisp waveform should be present; the waveform should demonstrate
pressure changes that correspond to the heart rhythm.
evaluating the intracranial pressure, be sure to have the system open to
the intraventricular catheter and closed to the drainage unit. Pressure
measurements that are obtained with the stopcock opened to both the patient
catheter and drainage unit can produce inaccurate readings (reflecting
a blended pressure from the patient catheter AND the drainage bag versus
exclusively from the patient catheter alone).
intervention is needed in either situation.
March 24, 2000