SAH

Question 1

Causes

Answer 1

• Most commonly, burst aneurysm in subarachnoid space, usually circle of willis
• Trauma
• AVM - arteriovenous malformations
• ICH with extension of bleed into SA space

Question 2

What happens

Answer 2

Blood leaks into SA space, increasing ICP, therefore decreasing CPP, tissue ischemia, hemorrhagic stroke

Question 3

Grading SAH from aneurismal burst

Answer 3

Grade 1 - 70% survival • Minimal or no bleed • Slight headache • No neuro deficits - watch and wait interventions
**Grade 2 – 60% survival • Mild bleed • Moderate-severe H/A • Awake and alert • Some nuchal rigidity
**Grade 3 – 50% survival • Drowsiness, confusion • Mild focal deficit(s)
** candidate for surgical intervention
~Grade 4 – 20% survival • Stupor • Mild-to-severe hemiparesis • Poss. early decerebrate rigidity
~Grade 5 – 10% survival • Deep coma • Decerebrate rigidity • Moribund appearance
~ basically gonna die, so usually no surgical

Question 4

Surgical options for SA aneurysm

Answer 4

• clipping

- coiling

Question 5

Named theory about intracranial pressures and components

Answer 5

Monroe-Kellie Hypothesis
Intracranial spaces filled with non-compressible components of brain, blood and CSF, increase one and the others have to decrease in volume to accommodate. Ie increase blood, brain herniated out the foremen magnum

• Brain can increase from Tumors Hematomas Abscesses Cerebral edema
• CSF increases in spina bifida, tumours, infection, inhibited CSF reabsortion (in SAH)
• Blood increases in hemorrhage, inc CO2, acidosis, hypoxia (vasodilation), changes in map in absense of autoregulation, venous outflow obstruction (inc PEEP, tight collars/ties)

Question 6

Cerebral compliance

Answer 6

With good cerebral compliance, A change in volume will not change ICP.

In brain injury, a small change in volume, will change ICP dramatically. Poor cerebral compliance. Same as lungs.

Question 7

Preop nursing responsibilities

Answer 7

• Control BP, slow/prevent further bleeding
• Adequate CVP for perfusion
• Anticipate fevers - blood in subarachnoid space is irritant
• Manage pain/stimulus to keep demand low

Question 8

Post Op Nursing responsibilities

Answer 8

• Maintain MAP > 80, SBP 150-180, maintain CPP
• Statins in prevent vasospasms, promotes endothelial NO synthase
• Maintain CO2 within range to avoid vasodil/constrict
• Control ICP with EVD? CSF drain
• Monitor vitals
• HOB keep pressure okay

Question 9

Symptoms and treatment of vasospasm

Answer 9

• Presents with stroke-like symptoms 3-12 days post op
• Triple H tx
  
  • Hypervolemia - CVP 8-10 - increase blood flow
  • Hemodilution - HCT 0.32-0.35 - dec viscosity
  • Hypertension - increase MAP by 30% with levo to support CPP
• Nimodopine - Ca channel blocker to prevent and tx vasospasm

Question 10

How do we manage ICP directly

Answer 10

IVC - intraventricular catheter- inserted directly to ventricle, allowing continuous ICP monitoring

W/ EVD - external ventricular drain - drain away CSF/blood to decrease ICP. Normally 5-15cc/hour out. If >30cc/hr or increase of 10cc/hr more than usual, notify neurologist
-levelled at foramen of Monroe, usually temple