Codman ICP Monitor

OVERVIEW

  • intracranial pressure monitor
  • aka ‘bolt’

USES/INDICATIONS

Suspected raised intracranial pressure

  • severe head injury
    — unable to monitor neurologically
    — GCS < 8 and abnormal CT
    — GCS <8 and normal CT with 2/3 of: age >40y, motor posturing and SBP <90 mmHg
  • stroke
  • cerebral edema
  • hydrocephalus
  • hepatic encephalopathy

DESCRIPTION

  • strain gauge tipped catheter or fiberoptic device

METHOD OF INSERTION AND/OR USE

  • sterile technique
  • bolt through fronto-parietal suture-line, in line with pupil
  • zero at external auditory meatus
  • penetrates through dura into CSF or intraparencymally
  • held in place by bolt

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

ADVANTAGES

  • easy to insert (can be done at bedside)
  • less invasive than EVD
  • more accurate ICP measurements than extradural bolt
  • produces high fidelity wave forms
  • small

DISADVANTAGES/ COMPLICATIONS

  • infection
  • transducer tip may rest on brain and obstruct
  • aspiration of CSF not possible
  • tends to under-read pressures > 20mmHg
  • intracranial transducer cannot be calibrated once in situ
  • baseline drift (especially after 5 days)
  • remember they don’t give an indication of infratentorial pressure
  • no RCT evidence of benefit

CCC Neurocritical Care Series

Journal articles

  • Chesnut RM, Temkin N, Carney N, Dikmen S, Rondina C, Videtta W, Petroni G, Lujan S, Pridgeon J, Barber J, Machamer J, Chaddock K, Celix JM, Cherner M, Hendrix T. A trial of intracranial-pressure monitoring in traumatic brain injury. N Engl J Med. 2012 Dec 27;367(26):2471-81. PMC3565432.
  • Kirkman MA, Smith M. Intracranial pressure monitoring, cerebral perfusion pressure estimation, and ICP/CPP-guided therapy: a standard of care or optional extra after brain injury? Br J Anaesth. 2014 Jan;112(1):35-46. PMID: 24293327.

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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