In this section
The cranial vault contains brain tissue, blood and cerebrospinal fluid (CSF). After closure of a child’s sutures, the cranial vault is similar to a rigid box. As the volume of the three components within the skull (brain matter, blood and CSF) must remain equal, an increase in one component must be accompanied by a decrease in another component. If there is not, an increase in intracranial pressure (ICP) will occur.
ICP can be monitored via a fibre optic monitor (Codman™ microsensor) which is placed on the surface of the brain or in the brain or an external ventricular drain (EVD) system which is a closed sterile system allowing drainage of CSF via a silastic catheter tip which rests in the ventricle.
The ventricular system produces CSF at approximately 20mL/hr (estimated at 0.35mL/min in children) by the choroid plexus in the lateral ventricles. The CSF circulates around the brain and spinal cord and is then reabsorbed via the arachnoid villi.
This guideline is aimed at RCH staff involved in the use and management of EVD and ICP monitoring.
An EVD may be used:
An ICP monitoring probe may be placed either at the same time as an EVD or separately, in patients where monitoring ICP is vital. ICP monitoring may be used in patients with:
A lumbar CSF drain may be used for treatment of CSF leak as part of post-operative care, or in some circumstances, if a ventricular drain is contraindicated.
An EVD/ICP monitor is contraindicated in the following patients:
A lumbar catheter for drainage and monitoring of CSF is contraindicated in the following patients:
Physical assessment including completing ABCD and neurological assessment on the paediatric patient with an EVD/ICP monitor and documenting is required at the beginning of each shift and PRN in relation to the patient’s condition. See
Nursing Assessment guideline for more information.
Increased ICP is usually defined as sustained rises above 15mmHg. Common clinical signs of early intracranial hypertension include; headache, vomiting, irritability, seizures, photophobia, lethargy, nystagmus, and diplopia.
With severe intracranial hypertension, consciousness becomes depressed, tone and reflexes of the limbs are altered, pupils enlarge, papillary reaction to light is sluggish and spontaneous movement of the limbs is decreased. Signs may be unilateral or bilateral depending on the cause of the intracranial hypertension.
At a critically high level of ICP, spontaneous respiration is depressed, hypertension occurs, and heart rate is slowed, this is known as Cushing’s triad. Infants who have non-fused suture lines with open fontanel’s have a degree of compensation before signs of increased ICP are evident, such as macrocephaly.
Management of raised ICP may include drainage of CSF if an EVD is in place. Other management may include:
When an ICP monitor has been inserted in the operating theatre, upon admission to the recovery room or return to the PICU, NICU or Cockatoo ward, it is imperative that the patient be monitored closely with routine post anaesthetic observations as per operation notes and neurological assessment. See
Routine post anaesthetic observation Clinical Guidelines (Nursing).
Patients will usually arrive on the unit from the operating theatre with the EVD insitu, if the EVD is not set up; seek advice from the AUM, CSN or CNS.
At the beginning of each shift it is the responsibility of the nurse RN caring for a patient with an EVD to complete the following mandatory safety checks:
It is imperative that the management of the drain is documented hourly.
Hourly documentation must include:
When a patient with an EVD is being transported off the ward, the patient MUST be accompanied by a competent RN. This RN must stay with the patient at all times until handed over to another accredited person.
** Parents and carers are not to be taught how
to clamp the EVD, a proficient RN or Doctor only, should handle the EVD.
The pressure transducer of the EVD must be maintained at the same horizontal level as the ventricles to ensure reliable interpretation of its value. The laser level device should be in line with the patient's Foramen of Monro (FOM). If the patient is supine with their
head neutral, level the EVD system to the tragus of the ear. If the patient is lateral, level the EVD to the mid sagittal line (between the eyebrows). Every time the patient moves the EVD must be
CSF sampling must be conducted using standard aseptic technique every 24 hours (preferably in the AM) unless otherwise indicated by the Neurosurgeon. The procedure will require 1 – 2 registered nurses who are competent and confident with this procedure, having previously completed their EVD and CVAD competencies.
N.B. If patient has minimal drainage: consider clamping EVD 10-15 minutes prior to sampling to assist with collection of CSF as the patients ICP will increase, enabling a sample to be obtained more easily. To maintain patient safety, ensure this is discussed with the AUM.
** Under no circumstance is a sample to be obtained via aspiration, as the risk of aspirating brain parenchyma exists.
** If emptying CSF collection bag – require collection jug and one extra red cap
RCH Aseptic Technique Policy (RCH access only)
Dressings of the EVD site need to be observed hourly and this documented to ensure a leak has not occurred. If a leak is identified, place pressure combine/dressing and notify the AUM and Neurosurgical team. Dressings should be changed using sterile technique when soiled or otherwise directed by the Neurosurgical Medical team.
The entire system needs to be changed using sterile technique every 7 days. The procedure will require 2 registered nurses who are competent and confident with this procedure.
Aseptic Technique Policy & Procedure (RCH access only)
Patients with an EVD are losing CSF, which the body would normally reabsorb. With Neurosurgeon direction, CSF losses may be replaced mL for mL with 0.9% Normal Saline. Patients with an EVD may require daily full blood count and urea and electrolyte measurements to ensure electrolyte stability.
For neonates on Butterfly Ward, if the CSF volume drained reaches 20mL/kg within a 24-hour period, then it must be replaced mL for mL. The previous 4 hours of losses, and subsequent losses should be replaced mL for mL with 0.9% Normal Saline IV over the following 4 hours until the CSF loss is less than 20ml/kg
within a 24-hour period. The 24-hour measurement period is midday to midday, and volumes are measured 4-hourly.
Codman™ Monitor (ICP express) – is a device which enables measurement of pressure via a pressure transducer and fibre optic cable, but it does not have the ability to drain CSF as an EVD does. The monitor is usually placed in an extra-axial position (surface of the brain, e.g. subdural space) but it may be placed within the brain (parenchymal position) or within the CSF.
If the patient with an EVD requires ICP monitoring, attach and prime with 0.9% Normal Saline, via surgical aseptic procedure, attach the ICP transducer (Stores Number 7291) to the Medtronic Exacta EVD system at the 3-way tap parallel to the burette.
At the beginning of each shift it is the responsibility of the RN caring for a patient with an ICP monitor to complete the following mandatory safety checks:
There are two types of ICP monitoring, a direct ICP monitor (Codman™) or via an EVD. An ICP monitor is utilized when ICP monitoring is needed without the need to drain CSF, e.g. investigation of headache. ICP monitoring can also be conducted via an EVD with the benefit of being able to drain excess CSF when necessary.
To enable printing with an ICP monitor, the ICP needs to be displayed on the bedside Phillips™ monitor which will then output to the printer.
1. Turn monitor on and ensure appropriate ICP cords and transducer box are available
2. Connect ICP cable; either from the ICP monitor (Codman™) or EVD, to the bedside Phillips™ monitor
3. Set appropriate alarm limits (including ICP limits)
4. Load paper for printing of ICP, located at the right-hand side of the monitor
5. On the main screen on the bedside Phillips™ monitor, press the recordings touch screen button
6. Select ‘High Res ICP’ touch screen button
7. Printing should commence at this point
Please note; the Codman™ microsensor ICP transducer is calibrated in theatre prior to insertion and must not be zeroed post this to avoid erroneous readings.
1. The ICP only requires ‘zeroing’ if requested by the Codman™ monitor.
2. Codman™ monitor should be connected to the Phillips™ monitor via the ICP monitor cable into the transducer
3. Turn the Codman™ monitor on and press ‘0’
4. On the Phillips™ monitor, press the ‘Zero’ button
5. Press ‘Menu’ on the Codman™ monitor once zero has been displayed on both the Codman™ and Phillips™ monitor- follow the automatic instructions on the screen
6. Press the ’20’ on the Codman™ monitor and wait until ‘20’ is displayed on both the Codman™ and Phillips™ monitors- follow the automatic instructions on the screen
7. To manually zero the Codman™, enter the 3-digit reference code (found in post-operative notes)
8. On completion press the ‘Menu’ key
9. Check alarm is turned on via main menu
10. Ensure appropriate alarm ICP limits are set, in accordance with postoperative orders/treatment orders
1. ICP transducer must be connected to the monitor via an ICP cable to the bedside Phillips™ monitor
2. Wash your hands and ensure a non-touch technique
3. Turn the 3-way tap on the EVD system off to the rest of the system (leaving the system open to the transducer only)
4. Remove a cap (white or yellow) to open the transducer to the atmosphere
5. There are 2 ways to zero the ICP via the Phillips™ monitor:
Press the ‘Zero’ button on the monitor twice, you should hear a beep- press the ICP scale on the monitor
Press the ‘Zero’ button while the EVD transducer is still open to the atmosphere. Press the button twice and the machine will beep once completed
6. The screen should say ICP zeroed, followed by the time and date
7. The ICP only requires ‘zeroing’ if requested by the Codman™ monitor.
8. Ensure appropriate alarm limits are set
The normal range of ICP is 0-15mmHg; increased ICP is usually referred to as sustained above 15mmHg (refer to assessment section for clinical signs).
It is essential to refer to the reportable limits specific to the patient and notify the AUM / Neurosurgery team if a patient has a sustained increase in ICP or changes are noted during their regular observations.
* NB refer to the
Traumatic Brain Injury Guideline (RCH access only) for more information on Cerebral Perfusion Pressure (CPP).
Dressings of the ICP site need to be observed hourly and documented in EMR flowsheets to enable early detection of any leak. If a leak is identified, place pressure combine/dressing and notify the AUM and Neurosurgical team. Dressings should be changed sterilely as per Neurosurgeon or when soiled.
When it is determined that the patient can have the ICP catheter or device removed, this is performed by a member of the Neurosurgery team on the unit. The procedure is performed in the treatment room, under sterile conditions with appropriate pain relief,
distraction and staff assistance. Ensure the site remains dry and no sign of CSF leak is evident.
* NB. Please clean and return all
equipment (EVD measuring set, pole and ICP monitoring devices) to theatre upon
finishing with patient monitoring.
Lumbar drains can be indicated for insertion to assist with CSF leaks, evaluate the effect of reduced CSF pressure or as a temporary external shunt. As lumbar drains use the same circuits as EVD’s the management remains consistent with that of an EVD. However, the zero-point of lumbar drains is the insertion site, the drain will be most often at mattress level/ bed height therefore level with insertion site, and the patient is required to lay supine (flat on their back) to ensure accurate measuring. The Neurosurgical team will document parameters, drainage height or drainage volume.
External Ventricular Drains and Intracranial Pressure Monitoring evidence table.
Please remember to
read the disclaimer.
The revision of this nursing guideline was coordinated by Lauren Tunstall with the support of Cockatoo Ward. Authorised by Alison Wray, Head of Neurosurgery Department and approved by the Nursing Clinical Effectiveness Committee. Updated December 2020.