ICP

 

ENLS Guidelines (ACLS like course)

 

Anatomy/Physiology

• 1200-1400g weight of brain

• 15-20% cardiac output

• CHO is main energy source (high O2 metabolic rate)

• 50% of energy goes to ion gradient restoration

• No energy storage capacity

• Cerebral blood flow (CBF)

  • 50mL/100g brain tissue per minute

• about 500mL/day (20cc/hr) of CSF is made

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Autoregulation

• CBF regulate over wide range of MAPS

• lost when brain is injured

• metabolic seems to be the main controller of autoregulation: local affect of acid or pH on vascular resistance

• CO2 dilates

• CBF increases when paO2 falls below 50

• CPP (MAP)/ CBF curve

• Baron, MARIK chest 2000;118:214

 

Intracranial HTN

• Cushings triad

• definition: >20mmHg for 5 minutes

• causes:

  • Venous sinuous thrombosis

  • Increased CSf production

• Monroe Kellie doctrine

  • "Something has got to give"

  • Brain parenchyma makes up 80%

  • Blood makes up 10%

  • CSF makes up 10%

• Kernohan’s flase localization sign

• Lateral Rectus Palsy, CN 6 (LR6 palsy)

  • elevated ICP should be suspected

• Venous pulsations with crisp disk is the normal look to the optic disk

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Cerebral Perfusion Pressure (CPP)

• >60 if have brain injury

• >75 in TBI not good

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Devices: 

Codman

• Liver patients

 

Bolt

 

EVD

• into ventricle

• Allows drainage of CSf

 

Leveled with the tragus

• when doing better, it's elevated higher and higher to allow the brain to start absorbing CSF

 

P1: arterial pulsation

P2: when higher = noncompliant brain

P3: aortic valve

 

Pathological “A” waves

 

CT SCAN Image

 

Loss of sulci/gyri

 

Acute hydrocephalus

• Dilated 4th ventricle

 

Poor Gray white differentiation

• Poor prognosis if seen with first 24hrs

• EVD done

 

Saggital MRI

 

Star appearance

• SAH

 

Quadrigeminal cistern

• Baby's bottom

 

Treatment:

 

 

• Manage airway

  • Not to be done by someone experienced

  • Reflex sympathetic response to laryngoscopy even if they are in a coma can occur which leads to herniation 

  • have neostigmine if can ready to go if becomes hypotensive

  • Peripheral pressors would be okay emergently if need be

  • RSI even if comatose

  • To blunt rise in ICP: short acting opiate fentanyl

  • Lidocaine not really used anymore (1 study found its effectiveness)

  • succinylcholine okay; has been debated because of the fascinations (Roc 1mg/kg is really the go to drug)

• CPP>60 (just availed hypotension)

• osmotic diuresed 1-1.5g/kg, HTS

  • Brain is 80% water

  • Effect occurs rapidly (less than 5 minutes)

  • can't be administered with blood products

  • Caution with renal failure and worsen ICP (rebound)

  • Target osmol 310-320 mOsm/L

  • If osmol gap > 55 then should stop using it

• hypothermia

  • 34-35

• CSF drainage

• Decompressive craniotom

• Hyperventilation

• sedation

  • Propofol

  • Thiopental

  • Pentobarbital (Tier 3)

• HOB >30

  • Don't tight ETT too tight

• Tier 2: 3% saline 10-20cc/hr

  • do q2hr Na check

  • You can adjust CVVHD To get Na up (155-160)

  • 23.4% HTS over 30 minutes

  • osmotic demyelination syndrome

 

Case example

25y/o female APAP ingwstion

Ammonia very helpful in acute liver failure

• herniating

  • Raise HOB

  • Hyperventilate (use end tidal)

  • Intubate

  • Manitol

  • Roc, etomidate, neo stick

  • Codman

  • 23.4% HTS

 

Cosmid grid

 

Hypothermia

• during weaning, see what ICP does; if goes up then recool them

• might consider getting a CT Brain before rewarming as a prognostication 

  • if looks "tight" than chances are rewarming is going to make things worse​