External Ventricular Drain

OVERVIEW

  • ICP monitor than allows CSF drainage

USES

  • measurement and treatment of raised ICP
  • hydrocephalus of at risk of hydrocephalus following TBI

DESCRIPTION

  • gold standard of ICP measurement
  • catheter inserted in lateral ventricle at operation via a burr hole
    — passes through brain tissue
    — transducer is usually remote but catheter tip transducer also available
    — zero level is the external auditory meatus
EVD-1

Components

  • Sampling port
  • Connector for transducer cable
  • Safety pin to attach to pillow
  • Filter
  • Transducer
  • Collection tubing
  • Collecting chamber
  • Level marker connected to chamber
  • Measuring column (in centimetres)
  • Collecting bag

METHOD OF USE

  • Attach flushed transducer to fluid-filled catheter – do not inject
  • Set transducer to reference level (EAM or aortic root)
  • Attach drainage manometer and set at 10-20 cm H2O at level of EAM
  • Monitor ICP continuously with intermittent drainage (hourly) unless clinically indicated, for which drainage may be increased in frequency or continuously
  • Septic surveillance of CSF daily ( or as per protocol)

OTHER INFORMATION

Interpretation of Waveforms

  • High amplitude of 50-100mmHg sustained for 15 min (‘A waves’) – raised ICP
  • Saw tooth with small changes in pressure every 0.5-2 minutes (‘B waves’) – poor intracranial compliance
  • Low amplitude oscillations up to 20mmHg for 1 min (‘C waves’) – normal
  • Flat ICP trace – compression or kinking of transducer
  • Rounded appearance of the waveform – raised ICP
ICP Monitor

ADVANTAGES

  • gold standard
  • ventricular pressure considered more reflective of global ICP than subdural, extradural or subarachnoid pressure
  • less prone to occlusion
  • allows therapeutic withdrawal of CSF
  • compliance can be measured
  • zero calibration
  • cheap
  • new devices are antibiotic impregnated to reduce the risk of infection (e.g. Clindamycin/Rifampicin)

DISADVANTAGES/ COMPLICATIONS

  • more difficult to insert than a Codman
  • infection (ventriculitis)
  • haemorrhage
  • damage to brain
  • accidental venting of CSF
  • cannot be inserted in coagulopathy
  • no RCT evidence of benefit

Introduction to ICU Series

CCC Neurocritical Care Series

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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