|The drain is set by the medical staff at a predetermined level usually 10-15cms above the zero anatomical reference markers. This point is the intraventricular foramen of Monro (IFM) the nearest external marker correlating with this is the external auditory meatus.
||These are the nearest external points used to locate the level of the foramen of munro where the lateral ventricles communicate with the third ventricle (Wisinger and Mest-Beck (1990), Bisnaire and Robinson (1997) and Pope (1998))
It is important for accuracy that the zero point is measured with a spirit level not by eye (Woodward et al 2002)
|The unit must hang from a separate dedicated intra-venous pole.||To prevent any confusion and clear
identification of the system.
(National Neuroscience Benchmark
|Re-zero the drain when the patient’s head position is altered, which may affect the drainage||Maintain the prescribed level at all times to prevent excessive drainage or reduced drainage.
Excessive drainage can lead to collapse of the ventricles and rupture of the capillaries around the dura. Poor drainage could lead to hydrocephalus and raised ICP
|Maintain a closed system at all times ensure that only essential breaches occur i.e. when the system is changed or taking CSF samples||Any break in the system increases the risk of infection|
|All patients must be monitoring using the Glasgow Coma scale.
The frequency of the observations will be dependent upon their clinical condition of the patient but at least 4 hourly
|To enable progress (or lack of) to be monitored and evaluated.
To maintain patient safety.
|The CSF is monitored regularly
dependent upon the clinical condition of the patient for:
Protein, glucose, cell count and
|To monitor and evaluate the effectiveness of current treatment regimes|
|Drainage is recorded according to the
patient’s clinical condition on the fluid
balance chart and the External
ventricular drainage record chart.
Recording the following:
• Colour of the CSF
Inform the medical staff /nurse –in charge
of any significant changes in the
drainage amount: i.e.
• An increase in the hourly rate by
more than 10mls
• An increase of volume by 30mls
in one hour
|Normal CSF is colourless. Cloudy CSF may indicate infection whilst blood stained CSF indicates haemorrhage.
CSF drainage is an indication of the Intra cranial pressure (ICP), an increase in CSF drainage will indicate a mounting ICP. ICP can be defined as the pressure exerted within the ventricles by the CSF
The average drainage per hour is 10-15 mls. Excessive drainage may collapse the ventricles pulling the brain away from the dura, which, may rupture bridging blood vessels and result in a sub dural haemorrhage.
|Observe the system for patency if no
drainage occurs look for swinging in the
fluid level in the line.
Observe for blockage, kinks or closed
stopcocks If the drain is blocked contact the medical staff immediately after checking for kinks in the line and that the stopcocks are in the correct position system If the line requires flushing this should be performed by medical personale or a trained competent health care practitioner.
This procedure is requires an aseptic
|If minimal drainage has occurred but the line is patent and chamber is at the correct level then the pressure in the ventricles may be within normal limits If the drain is patent but with no drainage visible in the drainage system the meniscus of the CSF should be seen to swing because of the pulsatile pressure.
Swinging is normal and is recorded on the EVD output chart as `osc`
If there is no swinging in the system then the EVD is blocked and hydrocephalus will develop.
If flushing does not unblock the line then re- insertion may be necessary.
Severe cerebral oedema may result in empty ventricles this requires immediate action
|When transporting the patient the EVD
system must remain switched on and at
the prescribed level not laid in the bed.
With medical staff agreement drain can
be switched off and laid in the bed, but
drip chamber must be emptied first to
avoid backflow into the vent.
|If the system is inverted then the reflux vent will become wet, this filter prevents backward flow of CSF and microbes entering into the system and drainage may become obstructed.|
|The entry site must be dressed with an
aseptic occlusive dressing at all times.
The dressing should be changed when
soiled and/or becomes loose
Any wetness of the dressing must be
reported to the medical staff
Observe for signs of infection; redness
swelling discharge around the entry site
Record the patient’s temperature 4 hrly
report any pyrexia to the medical staff
|As the catheter has direct passage to the brain there is an increased risk of infection meningitis
This may indicate a leakage of CSF at the entry site
Pyrexia can be an indication of infection