external ventricular drain

Department of Neurosurgery, Hospital Sultanah Aminah

1 August 2007

Outline

• Introduction• Indications• Types of EVD system• Insertion of external ventricular drainage• Drain management• Pitfalls• Complication• Rules and facts• Conclusion

Introduction

• An External Ventricular Drainage (EVD) is the temporary drainage of cerebrospinal fluid (CSF) from the fluid filled cavities of the brain (lateral ventricles) to a closed collection system outside the body.

CSF Diversion

Outline


Indications

• To relieve raised intracranial pressure (ICP).

• To divert infected CSF• To divert bloodstained CSF

following neurosurgery / haemorrhage.

• To divert the flow of CSF• For ICP monitoring• For Irrigation?

Copyright ©2003 American Academy of Pediatrics

The direction of irrigation and drainage of the ventricular system

Outline


Types of EVD system

• New ventricular catheter– New catheter placed into the ventricle through a

small hole (burr hole) made in the skull – The new catheter is tunnelled under the scalp,

and connects to an external drainage system – This system does not have a pressure valve so

drainage depends upon gravity.

• Externalisation of existing shunt system– Externalised at the distal end and connected to

an external drainage system. – This shunt system will contain a pressure valve,

which controls the amount of drainage from the ventricles.

External drainage system

• The system has several components:

•A self-sealing sampling & injection port.

•To provide access to the catheter.

•An anti reflux drip/collection chamber.

•To observe CSF drainage.

•A drainage bag. •To enable on-going collection of CSF.

•A pressure scale mounting panel or a tape measure.

•To facilitate accurate positioning.

External drainage system

Types of ventricular catheter

• Ventricular Catheter 8F

• Antiseptic EVD-Catheters

Equipment

Outline


INSERTION OF EXTERNAL VENTRICULAR DRAINAGE

Outline


Drain Management: Positioning of Drain

• The system must be positioned accurately, to ensure desired amount of CSF

1. The level of the ventricles must be estimated:

2. The midpoint of this line is the zero point for the EVD system.

The difference in height between the patient’s ventricles and the drip chamber creates both a pressure gradient and a safety valve.

The height of the drip chamber equates to the pressure inside of the head or intracranial pressure (ICP).

This pressure must be reached before any CSF will drain into the drip chamber

Drain Management: Positioning of Drain

• Neurosurgeons will specify and prescribe a drain height post-operatively and that the drain height is to be either: – Maintained OR – Altered, to drain a certain amount

of CSF an hour. The flow chamber of the EVD system must be aligned at the cm mark prescribed by the neurosurgeon (initially this is generally 10cm).

Position of EVD System

The position of drain should be indicated on the patient’s fluid chart

Drain Management: Drainage

• Once the drain is connected and positioned an initial assessment of CSF drainage should be made. (To ensure CSF is draining at the correct rate.)

• Subsequently hourly checks should be made of: – Amount of drainage.

• To ensure CSF drainage rate is as prescribed. • A sudden increase in drainage may result from

inaccurate zeroing of the drain or could signify a rise in ICP.

• A decrease in drainage could also indicate inaccurate zeroing of the drain or that the tubing may be kinked, blocked, disconnected or the ports are closed


• Subsequently hourly checks should be made of: – Colour of CSF - should be

colourless. • Bloodstained CSF could indicate blood

in the ventricles • Cloudy CSF may indicate the

presence of an infection

– Exit site. • To ensure CSF is not leaking.


• An approximate guide to CSF drainage

• CSF drainage must be observed regularly (having the flow chamber facing the nurse at the bedside will ensure regular observation), and recorded hourly on the ICU chart.

CSF is produced continuously by the choroid plexus of the two lateral ventricles at a rate of approximately 20-25ml per hour, or 500mls per day (Hickey, 1997)


• Drainage of more than 50mls/hour is considered excessive, however this may be acceptable in patients with gross hydrocephalus

• The presence of blood may indicate haemorrhage.

• The sudden presence of blood in the EVD must be reported to a neurosurgeon immediately


• Description the colour of CSF– 1. Clear and colourless– 2. Xanthocromic – discoloured CSF

usually yellow, orange or brown due to the breakdown of RBC’s from previous haemmorhage

– 3. Blood stained – as a result of recent haemmorhage or surgery

CSF may also be described as turbid (cloudy) which occurs due to the presence of increased WBC’s as a result of CNS infection e.g. Meningitis.


• The drainage tubing must be checked for patency at the beginning of each shift and again at regular intervals thereafter.

• Observe the tubing to establish whether or not the level of CSF in the tube is oscillating

• If the level is not oscillating the flow chamber may be dropped to below the foramen of Monro for a brief period only to check whether CSF drains into the chamber.

• Once this has been observed the flow chamber must be re-aligned to prevent over-drainage of CSF.

• If at any time an EVD appears to be blocked, a neurosurgeon must be contacted immediately as it may be necessary to flush the system

Drain Management: Clamping The EVD

• It may be necessary to clamp the system for short periods.

• An example of such an occasion is during the moving and handling or repositioning of patients.

• It must be clamped for no more than 30 minutes at a time.

• Following administration of the drug (intrathecal antibiotics) the EVD must be clamped for 60 minutes to allow for absorption of the drug

When moving or repositioning the patient

• Clamp drain

• Re-zero drain

• Unclamp drain immediately

Drain Management

• In children, to clamp the drain if:

– Moving their child

– If their child is crying excessively.

• To prevent over drainage of CSF.

• The drain should not be clamped for longer than 1 hour.

• This to minimise risk of blocked catheter and to prevent raised intracranial pressure.

Drain Management: Intracranial Pressure

• It is possible to monitor intracranial pressure through the ventricular catheter using a continuous closed monitoring system with a non-flush transducer device.

• Careful technique and handling is essential to prevent infection.

Drain Management: To obtain a CSF specimen

• Clean injection port on EVD system • Insert syringe into port • Slowly withdraw 2 mls of CSF,

remove syringe & discard • Insert second syringe into port • Slowly withdraw 2 mls of CSF • Place CSF into each universal

specimen container • Open clamps on drainage system

close to injection port

Drain Management: To administer intrathecal

antibiotics: • Prepare drugs using aseptic non-touch technique • Clean injection port on EVD system • Slowly withdraw 2 mls of CSF, remove syringe &

discard • Insert syringe containing the antibiotic into injection

port • Inject antibiotic according to manufacturer’s

guidelines • Remove syringe • Insert syringe containing 0.9% sodium chloride into

port & gently flush catheter with 2mls 0.9% sodium chloride

• Remove syringe • Keep drainage system clamped for one hour only

Drain Management: Exit Site Care

• If exit site is dry it should be dressed with a sterile dressing.

• Change the dressing weekly unless contaminated.

• The dressing should be changed if it becomes contaminated with CSF or blood.

• If the exit site is oozing it should be dressed with sterile gauze pads and surgical tape.

• A microbiological swab may need to be taken for culture & sensitivity.

• Check exit site hourly for: – Redness – Inflammation– Oozing of blood– Leakage of CSF

• Loop catheter once at exit site under dressing.

Drain Management: CSF Sampling

• CSF samples should be taken: – Every 24 hours, according to

microbiological advice, until the CSF is sterile/infection free

– Every 72 hours for infection free CSF

Drain Management: Removal of the Drain

• Once the patients’ clinical condition and neurological status has stabilised, instructions may be given to raise or clamp the EVD prior to removal.

• The patient’ neurological status must be closely monitored during the period when the drain is clamped or raised

• The EVD is removed by a neurosurgeon using strict aseptic technique. The skin must be sutured at the insertion site and an occlusive dressing applied.

• The catheter tip must be sent for culture.• On removal of the EVD the patients’ neurological

observations must be monitored closely. • It is recommendation of the people reviewing these

guidelines that neuro observations be recorded hourly for 4 hours, then reduced once the patients’ condition is stable.

Drain Management: Removal of the Drain

• The EVD should remain in situ for no longer than 10 days.

• After this time the entire system should be removed or changed in theatre??

• Pre-operatively the nurse may be asked to clamp the drain for a specified time prior to surgery.

• If the patient’s condition deteriorates due to clamping pre-operatively, unclamp the drain and contact the neurosurgical team.

• Post operatively assess the patient and dress the exit site.

Fluid and Electrolyte Balance

• Cerebrospinal fluid (CSF) losses should be replaced ml/ml unless otherwise indicated.

• The losses are usually replaced with intravenous 0.9% sodium chloride.

• Oral sodium chloride can be used. • Cerebrospinal Fluid (CSF) losses and

intravenous fluid replacement should be recorded hourly on a fluid balance chart and reviewed every shift by the nurse in charge.

Outline


If there is no CSF in chamber:

• Observe for movement of CSF in system

• Ensure system is not clamped or kinked

• Lower chamber momentarily below head level

• Call doctor, may need to aspirate the system.

If a catheter becomes disconnected:

• Clamp catheter close to patient • Place end in sterile

wrapping/container • Lie patient down • Thoroughly clean exposed tip using a

sterile alcohol impregnated swab & connect a new system aseptically

• Record event in patient’s health care records & inform the doctor

To repair a split catheter: • Put on apron and perform a ward aseptic

procedures hand wash • Open new drainage system and put on sterile gloves • Assemble new drainage set closing clamps • Remove last 3-way tap on drainage set • cleans the exposed catheter end • Using sterile scissors cut just above the split • Insert EVD connector into the catheter lumen • Connect new system • Check connections • Position system as prescribed by the neurosurgeon • Release clamps on new system & those close to the

patient

If a catheter appears to be blocked:

• Exclude damage to the EVD system

• Lower drain & observe for CSF movement

• Change EVD

• The EVD to be aspirated. – *All EVD’s may be aspirated

including those with a valve.

To aspirate an EVD: • Clamp catheter close to patient • Lie patient down • Put on apron & perform a clinical hand wash • Open new drainage system and put on sterile gloves • Assemble new drainage set closing clamps • Remove last 3-way tap on drainage set • Cleans the catheter connection • Disconnects the old system & cleans the exposed

catheter end • Insert syringe into end of catheter • Release the clamps close to the patient • Very gently attempt to aspirate CSF • If the aspiration has been unsuccessful the EVD

should be flushed.

To flush the EVD: • The doctor should draw up 1-2mls of 0.9% sodium

chloride into a syringe • Insert syringe into the exposed end of catheter • Release the clamps close to the patient • Gently attempt to inject the sodium chloride • Continue after aspirating and/or flushing by:

– Discard syringe – Connect new system – Check connections – Release clamps on new system & those close to the

patient – Gradually lower system to check for drainage – Position system as instructed by the neurosurgeon

Outline


Complication• Inadequate drainage of CSF may cause the ventricles

to enlarge with subsequent rises in ICP• This may occur if:

– 1. The EVD system is placed too high above the level of the foramen of Monro thus minimising CSF drainage.

– 2. CSF drainage is obstructed. This may occur if the tubing is kinked or inadvertently clamped, the three way tap is turned the wrong way, the drainage bag is full or tissue/thick CSF blocks the system.

• Excessive drainage of CSF may also occur if the system is placed too far below the level of the foramen of Monro.

• This excessive drainage may cause the ventricles to collapse and pull the brain tissue away from the dura. This can cause tearing of the blood vessels and result in a subdural or subarachnoid haemorrhage (Bracke et. Al., 1978).

Complication• Tentorial herniation may be caused by either

excessive or insufficient drainage of CSF. Symptoms include:– • Severe headache– • Lethargy– • Drowsiness– • Irritability– • Apnoea– • Sluggish pupillary responses– • Abnormal reflexes– • Pronator arm drift– • Changes in BP and heart rate

• All of the above signs and symptoms require prompt intervention

Complication

• The symptoms of excessive drainage include:– • Sweating– • Tachycardia– • Headache– • Nausea

• If drainage is insufficient the patient will develop signs of increased intracranial pressure with changes in conscious level.

Complication : INFECTION

• Maintenance of a closed system is essential, and IRRIGATION OF THE EVD SHOULD ONLY BE PERFORMED IF ABSOLUTELY NECESSARY and must encompass a strict aseptic technique

• A three minute preparation of the injection port with a povidone iodine solution (betadine) must be performed prior to withdrawal of CSF for sampling or injection of intrathecal antibiotics

• An occlusive dressing e.g. Primapore, Is applied over the insertion site and changed only when soiled or loose using a strict aseptic technique.

• The site must be observed for signs of infection whenever the dressing is removed.

Complication : INFECTION

• Scalp dressings are often difficult to apply and maintain, and it is essential that the ventricular catheter and EVD tubing are free from traction and kinks.

• Observe the EVD for evidence of CSF leakage.

• Leakage is suspected if the dressing is wet, and a neurosurgeon must be informed.

• It can also occur at any connection ports throughout the system and a routine check of these must be made at least once per shift.

Complication : External ventricular drain malposition.

Narenthiran G, White BD. Department of Neurosurgery, Queen’s Medical

Centre, Nottingham • 1-year period (14 February 2003 - 13

February 2004) • All external ventricular drains (EVD) are

inserted in operating theatre • 84 patients had insertion of EVDs (frontal,

parietal and occipital) and 13 of them had more than one EVD

• 8 of the 13 were for malposition of EVD • 9.5% complication from malposition of EVD

with a minimum complication rate for insertion of EVD being 15.5%.

Outline


Antibiotic Prophylaxis ofVentriculostomyPoon et al. Acta Neurochir 1998;71:146-148.

• 228 patients

• Randomized to single-dose or prolonged prophylaxis (ampicillin-sulbactam)

• Lower rate of extracranial and intracranial infections after prolonged prophylaxis

Cefepime vs. Ampicillin/Sulbactam and Aztreonam as antibiotic prophylaxis in

neurosurgical patients with external ventricular drain: result of a prospective

randomized controlled clinical trial

• 255 eligible patients • Group A employed Cefepime 2G 12 hourly and Group B

employed dual antibiotics as Ampicillin/Sulbactam 3 g 8 hourly and Aztrenam 2 g 8 hourly

• There was no statistically significant difference in cerebrospinal fluid (CSF) infection rate with 14 patients (11·5%) in group A (Cefepime prophylaxis) and eight patients (6·0%) in group B (dual prophylaxis with Ampicillin/Sulbactam and Aztrenam) had CSF infection (P = 0·18).

• There was also no statistical significant difference between wound infection rate happened in eight patients (6·6%) in Group A and three patients (2·3%) in Group B (P = 0·17).

• Single board spectrum antibiotic prophylaxis with Cefepime was an effective alternative regimen for neurosurgical patients with an EVD in situ.

W. S. Poon FRCSEd Division of Neurosurgery, Prince of Wales Hospital, Chinese University of Hong Kong

Antibiotic Prophylaxis for External Ventricular Drains in Neurosurgical

Patients

• Intravenous cephalothin (1g 6-hourly for 24 hours) was the antibiotic of choice

• External ventricular drains were removed after five days and replaced if further monitoring or CSF drain-age was required

• Twelve patients with EVDs were identified in first 6 months and 15 patients with EVDs were identified in the 6 months following implementation of the protocol.

• Positive CSF Gram-stains were found in 3/12 (25%) patients in the pre-protocol group and in 0/15(0%) in the post-protocol group

• Statistically significant improvement in compliance with antibiotic prescription and reduction in the incidence of positive CSF cultures

M. A. LUCEY, J. A. MYBURGH Intensive Care Unit, The St. George Hospital, Sydney, NEW SOUTH WALES

Infection and Intracranial Pressure MonitorsRisk Factors and Antibiotic Prophylaxis

Rebuck et al. J Neurol Neurosurgery Psych 2000;69:381-384

• Review of 215 patients• Infection rate 7.5%• Not influenced by prophylaxis• Risk Factors (RR, 95% CI)

– Monitoring > 5 days 4.4 (1.3 - 11.9)– Ventriculostomy 3.4 (1.0 - 10.7)– CSF leak 6.3 (1.5 - 27.4)– Concurrent infection 3.4 (1.2 - 9.5)– Serial device placement 4.9 (1.7 - 13.8)

Bedside external ventricular drain placement for the treatment of acute

hydrocephalus B. Z. Roitberg; N. Khan, British Journal of Neurosurgery,15,(4 ),2001,324 - 327

• 103 consecutive cases over one year • Short tunnel ventriculostomy was performed at the

bedside in the neurosurgical intensive care unit • Long-term care included meticulous site care by a

dedicated NSICU nurse, daily cultures and prophylactic antibiotics

• The average duration of EVD was 10.7 days (range 1-28 days).

• There was one case of positive cerebrospinal fluid (CSF) culture. Additional complications included one small intraparenchymal hematoma and two cases of EVD disconnection.

• There was no correlation between the duration of EVD and infection

External ventricular drain infections are independent of drain duration:

An argument against elective revision

• A retrospective study of 199 patients with 269 EVDs

• 21 CSF infections. • Acinetobacter accounted for 10 (48%) of

these infections • The duration of drainage was not an

independent predictor of infection • Multiple insertions of EVDs was a

significant risk factor • Second and third EVDs in previously

uninfected patients were more likely to become infected than first EVDs

Cheng H. Lo, Departments of Neurosurgery and Intensive Care, The Alfred Hospital Melbourne, Australia

Failure of regular external ventricular drain exchange to reduce cerebrospinal fluid

infection: result of a randomised controlled trial

• 103 patients requiring external ventricular drains for more than five days and with no evidence of concurrent CSF infection were studied

• The patients were randomised to regular change of ventricular catheter (every five days) and no change unless clinically indicated.

• The CSF infection rates were 7.8% for the catheter change group and 3.8% for the no change group, respectively

• Regular changes of ventricular catheter at five day intervals did not reduce the risk of CSF infection

• A single external ventricular drain can be employed for as long as clinically indicated.

Dr W S Poon, Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong

Can a regular change of external ventricular drainage (EVD) prevent cerebrospinal fluid infection in patients

with intracranial hemorrhage?

• 50 patients per treatment group • Most of the patients needed EVD treatment because

subarachnoid hemorrhage (SAH) without (42 patients) and with (15 patients) intraventricular hemorrhage

• Randomly assigned to the treatment groups (changing or non-changing group)

• The infection rate in the changing group was 18% and clearly higher than in the non-changing group, infection rate of 8%, although this difference was not statistically significant (p=0,23).

• Regular changes of external ventricular drainage in patients with intracranial hemorrhage cannot lower infection rates. On the contrary, we observed higher infection rates when EVD was changed on a regular basis in these patients.

C. Mayer, Neurochirurgische Universitätsklinik , Klinikum der Universität Regensburg, German

http://www.egms.de/de/meetings/dgnc2006/index.shtml

Antibiotic-impregnated shunt catheters

• Retrospectively reviewed all pediatric patients undergoing CSF shunt insertion over a 3-year period

• 147 pediatric patients underwent 325 shunting procedures.

• 181 (56%) shunts were placed with non-impregnated catheters prior to October 2002.

• 144 (44%) shunts were placed with antibiotic-impregnated shunt catheters after October 2002

• Followed for 6 months after surgery • Sixteen (9%) patients with non-impregnated

catheters experienced shunt infection • Three (2%) patients with antibiotic-impregnated

catheters experienced shunt infection within the 6-month

Daniel M Sciubba MD, George I Jallo MDDepartment of Neurological Surgery, Johns Hopkins University, Baltimore, USA

p = 0.025.

Outline


Conclusion

• Maintain sterility when handling EVD• Accurate charting of amount and pattern of

drainage• To convert to internal CSF diversion system

as early as possible• Single broad spectrum antibiotics as

prophylaxis is useful to prevent CSF infection

• Regular change EVD does not change CSF infection rate

• Antibiotic-impregnated shunt catheters may lower CSF infection rate

external ventricular drain

Healthcare