Intracranial hypertension

Presentation:

· Headache

· Vomiting

· Visual disturbance

· ↓GCS

· Cranial nerve palsies

· Cushing reflex: ↑BP, ↓HR

· Effacement of CSF spaces

· Herniation

· Loss of grey-white differentiation

Monroe-Kellie doctrine

· Fixed walls, single outlet

· Increase in one substance comes at expense of another

· Minimal compensatory capacity

· ↑ Contents -> ↑↑↑Pressure

Flow determinants

· Q = P1 – P2 / R

· CBF = [mAP – (CVP or ICP)] / CVR

Maximise P₁

· Volume

· Pressor

Minimise P₂

Physical:

· Head up 30°

· Loosen neck strictures

Physiological:

· ↑PaO₂

· ↓PaCO₂

· ↓Temp

Pharmacological:

· Hypnotic: propofol, thiopentone

· Anticonvulsant: levetiracetam (10mg/kg bd)

· Relaxant (prevent coughing)

· Osmotic: hypertonic saline (1.5-6mL/kg), mannitol (0.25-1g/kg)

Surgical:

· EVD

· Decompressive craniectomy

Big ticket items in OR

· mAP

· Position

· CO2

· Osmotics