Pressure (ICP) Monitoring:
patient's ICP has increased, but is not responding to drainage. What could
cause this problem?
The stopcock could be open to pressure monitoring but closed to drainage.
2. The drainage unit
could be positioned higher than the pressure in the patient's head.
all stopcocks. Ensure that all stopcocks are open to both the drainage
unit and to the patient catheter (the system is open in any direction where
one of the stopcock "prongs" are pointed).
3. The catheter
may be blocked.
that the "0" on the drainage unit panel is positioned at the external auditory
canal, and the arrow on the drainage collecting chamber is positioned at
the correct position above the head.
that drainage will only occur if a) the system is open, and b) the ICP
exceeds the level of the drainage unit. For example, if the unit
is positioned at 10 cmH20 above the patient's head (which is equal to 7.4
mmHg), the ICP must be higher than 10 cmH20 (or higher than 7.4 mmHg on
the bedside monitor) before drainage will occur.
To ensure that the ICP measurement obtained is accurate, the ICP reading
should be taken when the stopcock is closed to drainage and open between
the pressure system and the patient catheter. Pressure measurements
that are obtained when the stopcock is opened to both drainage and monitoring
can be inaccurate (they would reflect a blended pressure from both the
patient catheter AND the drainage bag versus an ICP from the patient catheter
4. The ICP elevation
may be the result of severe brain swelling, but the ventricles are either
empty or collapsed.
check for catheter patency, lower the drainage chamber below the patient's
head (ensuring that the drainage system remains vertical). If the
catheter is patent, CSF drainage should occur.
the ICP waveform.
that an appropriate scale is selected to ensure good visibility of the
the catheter is patent, a crisp waveform should be present; the waveform
should demonstrate pressure changes that correspond to the heart rhythm.
waveform suggests that the catheter is not patent. Note that if the ICP
increases significantly, brain edema could obstruct the catheter tip and
impair waveform transmission.
- To confirm
that an increase in the ICP accurately reflects raised intracranial
pressure, observe the patient for other findings that support the
ICP reading such as: bradycardia, hypertension,
pupillary dilation, any other neurological deterioration or a reduction
in the SjO2.
the cause of the problem is either #3 or #4, the problem requires medical
intervention (i.e. catheter flushing or medical intervention to treat the
Clinical Educator, CCTC
May 12, 2001