Subarachnoid Hemorrhage
Considerations
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Emergency, full stomach
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Unsecured aneurysm with potential for rebleeding:
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Avoid hypertension & changes in transmural pressure
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Potential massive hemorrhage
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↑ ICP & prevent secondary injury:
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Avoid cerebral ischemia: CPP 60-70/MAP 80-90 mmHg
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↓ ICP
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↓ CMRO2: barbiturate coma, burst suppression, mild hypothermia
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Maintain euglycemia, normocapnia
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Neurologic complications:
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Rebleed
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Cerebral vasospasm
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Obstructive hydrocephalus
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Seizures
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Medical complications:
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Neurogenic pulmonary edema
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Myocardial dysfunction, arrhythmias
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Electrolyte imbalances (hyponatremia due to cerebral salt wasting, SIADH)
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Goals
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Hemodynamic control & monitoring:
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Minimize transmural pressure to avoid rebleed
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Avoid acute hypertensive episodes (essential because rebleed is often fatal)
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Keep SBP < 160 mmHg (AHA guideline 2012) & keep MAP > 85 mmHg (to prevent ischemia)
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Facilitate surgical exposure/control ICP
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Protect from secondary brain injury:
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CPP 60-70/MAP 80-90 mmHg
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↓ ICP
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Normocapnia
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↓ CMRO2: mild hypothermia, barbiturates, DHCA (deep hypothermic circulatory arrest)
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Euglycemia: glucose < 11 mmol/L
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Prevent vasospasm (nimodipine, pravastatin)
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Conflicts
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Aspiration risk (RSI) vs tight hemodynamic control to prevent rebleed/cerebral ischemia (titrated induction)
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Minimize transmural pressure (deep induction to prevent rebleed) vs maintain CPP (hemodynamic support to prevent ischemia)
Pregnancy Management of Acute Intracranial Bleed
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Decision to proceed with surgery:
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If 3rd trimester (>32 weeks)
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Consider simultaneous procedure, or cesarean section first followed by intracranial procedure
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If pre-term viable (24-32weeks):
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Do intracranial surgery, then wait for fetal maturity
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Deliver if fetal distress
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If pre-term non-viable (<24weeks):
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Do intracranial surgery, then wait for fetal maturity
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Induction:
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Titrated to protect against rebleed vs secondary brain injury
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Accept aspiration risk
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Mannitol:
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Risk of fetal dehydration
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If tight head → give
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If non urgent indication → discuss with neurosurgery, avoid if possible
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PaCO2 management:
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Maintain around 30 mmHg
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Consider maintaining in high 20's if tight head
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