Increased ICP & Acute Traumatic Brain Injury

Summarized from Weingart…….emcrit podcast 78

http://emcrit.org/podcasts/high-icp-herniation/

…..listen to this…read below and to cram it into your brain…….

 

Assessment

•       Cushing’s Triad

  • Hypertension
  • Bradycardia
  • Irregular respirations

•       Ocular nerve sheath USS

  • Tegaderm over the closed eyelid
  • Linear array USS
  • Pt should be looking directly in front (most coma patients will be)’
  • Stripe’ at back of globe = ocular nerve sheath
  • Width is directly proportional to ICP (9-10 articles & 1 article showing reduction in size correlates with reducing ICP - therefore can be used to monitor treatment)
  • Location of measurement = 3mm down from back of globe & across at that level
  • <5mm = normal / 5-6 = grey zone / >6mm = raised ICP
  • Can therefore start Rx before patient goes to CT

 

Management (head injury / neuro-critical care patient)

 

•       Overall AIMS = CPP > 60 & ICP <20

 

General Mx:

•       Head of bed up (30-45 degrees) - allows venous drainage

•       Head straight / midline - allows venous drainage

•       Control temperature (normothermia)

  • High temp = increased metabolic requirement
  • ‘Brain fever’ also common
  • Usually require ‘active’ cooling

•       Fluids

  • Want to start stetting up ‘osmotic gradient’
  • No ‘hypotonic solutions’
  • So…..NO - glucose / dextrose / hartmanns
  • Normal saline is good
  • Aim to try and push sodium to 150ish

•       Steroids

  • Good for abscess / tumor or other inflammatory process to reduce vasogenic oedema
  • NOT for TBI

•       Pain relief

  • Need good pain relief
  • Fentanyl is a good choice

•       PaCO2

  • Aim low normo-caponea - 35-38 mmHg
  • ETCO2 is OK but if end tidal is low then PACO2 is not accurate - only if it is high / normal
  • In practice - take ETCO2 down to 35 then send blood gas to confirm
  • Only drive CO2 <35 in dire emergency if ‘rushing to theatre’ & coning as will only buy you a few minutes of reduced ICP (see below)

 

Osmotic agents

•       Mannitol

  • Use in hypertensive patient with increased ICP
  • Improves cerebral flow and +/- osmotic
  • Dose = 1-1.2g / kg over 10mins
  • NEED fluids as is osmotic diuretic:
  1. SO….mannitol / folley (catheter) / fluids
  2. Empirically 500ml crystalloid bolus with mannitol is good practice

•       Hypertonic saline (3% / 23.4%)

  • Use in normotensive / hypotensive patients
  • Dose (3%) = Paeds = 3-5ml/kg or Adult = 250ml over 10-15 mins
  • Dose (23.4%) = 30ml over 10-15mins (via CENTRAL line only) - probably better if have it
  • May be more effective than mannitol

•       Sodium Bicarbonate

  • Shown to be at least as effective as hypertonic saline
  • Dose = 1-2 ampules or 100ml (8.4%) over 10mins

 

Surgical options

•         Intra-parenchymal monitor (aim for ICP <20)

  • Only measures pressure

•            EVD (external ventricular drain)

  • Advantage = drains and monitors
  • Disadvantage = infection

 

Other management

·      Sedate well to help reduce cerebral metabolic rate

  • Propofol is a good agent - may need high doses
  • Phenobarbitone also possible

·      Other management

  • Consider Seizure Prophylaxis (phenytoin) 
  • Craniotomy
  • Pentobarbitone infusion - to aim for burst suppression
  • Hyper-ventilation ONLY good for very short term Mx (CO2 down to 20)
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