In this section
The cranial vault contains brain tissue, blood and cerebrospinal fluid (CSF). 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 there 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 monitor) 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 anterior horn of a lateral ventricle.
The ventricular system produces CSF at approximately 25ml/hr (estimated at 0.35mls/kg/hr 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. The normal range of ICP is 0-15mmHg with the upper limit being 20mmHg.
This guideline is aimed at RCH staff involved in the use and management of EVD and ICP monitoring.
Indications for an EVD or ICP monitor can include hydrocephalus, haemorrhage, tumour, meningitis or traumatic brain injury.
An EVD / ICP monitor is contraindicated in the following circumstances:
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 Clinical Practice Guideline for more information.
Increased ICP is usually referred to as above 15mmHg. Common clinical signs of early intracranial hypertension include: vomiting, irritability, headache, seizures, photophobia, lethargy, nystagmus, and diplopia.
With severe intracranial hypertension, consciousness is 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 pre-morbid 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.
Management of raised ICP may include drainage of CSF if an EVD is in place. Other management may include urgent surgical decompression, administration of an osmotic agent (e.g., mannitol), diuretic, temporary mechanical hyperventilation (which lowers CO2 tension in blood and causes cerebral vasoconstriction), serum sodium maintained at 140-145, sedation and muscle relaxation (PICU/NICU only), and therapeutic hypothermia.
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 Anesthetic Observations Clinical Practice Guideline.
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, CNF 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:
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, 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 releveled.
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 AUM.
Under no circumstances is a sample to be obtained via aspiration, as the risk of aspirating brain parenchyma exists.
See: 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 Neurosurgical 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.
Sterile Dressing Pack and extra Gauze, Chlorhexadine 0.5 % in Alcohol 70%, Sterile Gloves, 2 Sterile Integra Stopcock Protection Boxes (External reference number 901400), Medtronic Exacta EVD Kit (Stores Number 309634), 0.9 % Normal Saline, 10ml and 20ml Syringes, Drawing Up Needle, Betadine Solution, Forceps
Link: Aseptic Technique Policy & Procedure (RCH access only)
If the patient with a Medtronic Exacta EVD requires ICP monitoring, attach and prime with 0.9% Normal Saline, via sterile procedure, attach the ICP transducer (Stores Number 7291) to the Medtronic Exacta EVD system at the three way tap parallel to the burette.
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, eg subdural space) but it may be placed within the brain (parenchymal position) or within the CSF.
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, Codman and via an EVD. A Codman 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 a large Phillips Screen.
It is essential when monitoring ICP that the transducer is calibrated to the monitor at a minimum of once a shift (preferably the commencement of a shift). If this is not performed strictly, the variation in ICP reading can be up to +/- 2mmHg outside of the true ICP.
Codman monitor should be connected to Phillips monitor via ICP monitor cable into transducer
* NB the reference range will be documented on the inpatient notes or in the patient’s post-operative orders.
Intracranial Pressure is the pressure exerted by the CSF, which circulates from the ventricles around the brain and spinal cord. The normal range of ICP is 0-15mmHg; increased ICP is usually referred to as 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.Cerebral perfusion pressure (CPP=Mean arterial pressure-ICP) is also measured in patients whilst admitted to PICU with an ICP monitor. Adequate CPP is required to ensure the brain is being well perfused therefore receiving oxygen and important substrates. Inadequate CPP should be reported to the PICU consultant and AUM. Inadequate CPP may be due to elevated ICP, low BP or a combination of both and should be managed according to the underlying problem.
Normal range for CPP is age dependant:
Dressings of the ICP site need to be observed hourly and this documented 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 Codman 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.
When patient with an EVD is being transported off the ward, the patient MUST be accompanied by an accredited RN. This RN must stay with patient at all times until handed over to another accredited person.
** Parents are not to be taught how to clamp the EVD, an accredited RN or doctor are only to handle the EVD.
External Ventricular Drains and Intracranial Pressure Monitoring evidence table.
Nursing Competency Workbook- External Ventricular Drains and Intracranial Pressure Monitoring
Medtronic: Exacta- external drainage and monitoring system- quick reference guide
Aseptic Technique Procedure
RCH Clinical Practice Nursing Guideline: Nursing Assessment
RCH Clinical Practice Nursing Guideline: Routine Post Anesthetic Observations
Please remember to read the disclaimer.
development of this nursing guideline was coordinated by Sinead O'Flaherty, RN, Michelle Taverna, ANUM & Jess Ellis, Clinical Nurse Facilitator, all of Cockatoo Ward,
and approved by the Nursing Clinical Effectiveness Committee. Updated April 2016.