IntroductionThe 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. Show
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. AimThis guideline is aimed at RCH staff involved in the use and management of EVD and ICP monitoring. Definition of terms
IndicationsAn 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. ContraindicationsAn EVD/ICP monitor is contraindicated in the following patients:
A lumbar catheter for drainage and monitoring of CSF is contraindicated in the following patients:
AssessmentPhysical 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. ManagementManagement 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). External ventricular drains (EVD)Setting UpPatients 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. Mandatory Checks (Treatment Orders)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:
DocumentationIt is imperative that the management of the drain is documented hourly.
TransportationWhen 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. Levelling the EVD systemThe 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 re-levelled. Errors in positioning the transducer
Procedure
** Parents and untrained staff are NOT to alter the EVD including clamping or unclamping. CSF Sampling from the EVDIntroductionCSF 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. ** Under no circumstance is a sample to be obtained via aspiration, as the
risk of aspirating brain parenchyma exists. Equipment Required
** If emptying CSF collection bag – require collection jug and one extra red cap Procedure
Dressing changesDressings 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. Changing the EVD system setThe 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. Equipment
ProcedureLink: Aseptic Technique Policy & Procedure (RCH access only)
Complications of EVD’S
Removal of EVD
ICP monitoring
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. Mandatory checks (treatment orders)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:
Documentation of ICP
Setting up the ICP monitorThere 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.
ZeroingPlease note; the Codman™ microsensor ICP transducer is calibrated in theatre prior to insertion and must not be zeroed post this to avoid erroneous readings.
Reading ICPReading with an EVD
Normal ranges/reportable limitsThe normal range of ICP is 0-15mmHg; increased ICP is usually referred to as sustained above 15mmHg (refer to assessment section for clinical signs). * NB refer to the Traumatic Brain Injury Guideline (RCH access only) for more information on Cerebral Perfusion Pressure (CPP). Dressing changesDressings 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.
Removal of ICP monitor lineWhen 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 drainage devicesLumbar 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. References
Evidence tableExternal Ventricular Drains and Intracranial Pressure Monitoring evidence table. Companion Documents
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. |