Increased Intracranial Pressure in TBI
OVERVIEW
- normal ICP 7-15mmHg
- sustained increases > 20mmHg is associated with ischaemic brain injury
MONRO-KELLIE DOCTRINE
- cranium can be thought of a fixed box such that any changes in volume of its contents leads to an increase in pressure
- contents: blood, CSF, brain tissue
CAUSES
- artefact
- coughing/valsalva
- intracranial blood: haematoma (epidural, subdural, SAH, intraparenchymal)
- CSF: hydrocephalus
- parenchyma: oedema, tumour, abscess
- other: tension pneumocephalus
MANAGEMENT
- exclude artefact/measurement errors
- ensure adequate oxygen delivery
— PaO2
— treat clinically significant anaemia - maintain cerebral perfusion pressure to > 60mmHg (CPP = MAP – ICP)
– fluids (avoid albumin–SAFE TBI)
— inotropes, vasopressors - optimise venous return from brain:
— head up positioning, no venous obstruction (remove hard collar), low PEEP - avoid cerebral vasoconstriction
— PaCO2 35-40mmHg - decrease cerebral metabolic rate:
— sedation, analgesia
— paralysis
— avoid hyperthermia
— treat seizures
— barbiturate coma - osmotherapies:
—mannitol 0.25 to 1 g/kg, target Osm 300-320 mOsm/kg
— hypertonic saline, target Na+ 145-155 - Repeat CT scan to exclude a new mass lesion
- Consider hypothermia (decrease cerebral metabolism, possible neuroprotection)
— Adverse outcome in paediatric TBI RCT from CCCTG
— McIntyre MA suggesting titrated to ICP and prolonged duration maybe beneficial
— Ongoing trials including POLAR in ANZ - Consider surgical techniques (to reduce volume in the ‘box’, or to ‘open the box’):
— EVD (if already present, ensure patent and draining)
— haematoma evacuation
— decompressive craniectomy (controversial)
Decompressive craniotomy is contentious
- DECRA showed decreased ICP and reduced ICU length of stay but no mortality benefit and a greater number of patients with an unfavourable neurological outcome in those who received decompressive craniectomy
- Patients with mass lesions(unless too small to require surgery) were excluded
- Only a single surgical intervention was used
References and Links
LITFL
- CCC — Traumatic Brain injury Overview
- ECG Library — Raised Intracranial Pressure
- Eponymictionary – Monro-Kellie doctrine
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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