Subarachnoid (SAH)

= 10% die prior to reaching the hospital
= 25% die within 24 hours of onset
= 45% die within 30 days
= 1/3 have a good outcome after treatment

Most important predictive factors for acute prognosis
= Level of consciousness and neurologic grade on admission
= Patient age (inverse correlation)
= Amount of blood on initial head CT scan (inverse correlation)

Common complications:
= rebleeding
= vasospasm and delayed cerebral ischemia
= hydrocephalus
= increased intracranial pressure
= seizures
= cardiac

= Intubation Indications:
- Glasgow Coma Scale (GCS) score ≤8
- Elevated intracranial pressure (ICP)
- Poor oxygenation or hypoventilation, hemodynamic instability
- requirement for heavy sedation or paralysis.
= Deep venous thrombosis (DVT) prophylaxis with pneumatic compression
- Subcutaneous heparin 5000 units tid after the aneurysm is treated.
= IV fluid administration to maintain euvolemia and normal electrolyte balance.
- Hyponatremia, is common and sodium levels should be checked at least daily.
= stool softeners and analgesia (eg, morphine sulfate) and kept at bedrest.
= Prophylactic therapy for gastrointestinal ulcers.
= Manage Hyperglycemia
= Manage Fever of infectious and noninfectious origin
- consider use of external cooling devices
= Treat anemia, some experts recommend a target above 8 to 10 g/dL
= Hypothalamic pituitary dysfunction is common. Routine administration of glucocorticoids is not recommended, but may be considered in patients who are unresponsive to vasopressor therapy for vasospasm
= Antithrombotic discontinuation
= Reversal of anticoagulant if indicated

Manage BP
2012 American Stroke Association guidelines
= decrease in systolic blood pressure to <160 mmHg is reasonable
Avoid Nitroprusside, nitroglycerin
Preferred Labetol, Nicardipine and enalapril

Lowering BP
- May decrease the risk of rebleeding
- Increase risk of infarction.
- Cerebral perfusion pressure (CPP) equals the MAP minus the ICP.
One study's results suggest that this CPP threshold may be 70 mmHg
= In the absence of ICP measurement, antihypertensive therapy is often withheld unless there is a severe elevation in blood pressure
- For alert patient, CPP is adequate and lowering the blood pressure may decrease the risk of rerupture; keep the systolic blood pressure below 140 mmHg.
- Patient with severe impaired LOC, antihypertensive therpay is withheld, until CPP can be measured

Antiseizure drug therapy
= Routine use is controversial
= a large case series suggests that antiseizure drug with phenytoin may be associated with worse neurologic and cognitive outcome
= Continuation of antiseizure drug therapy may not be necessary in most patients after undergoing aneurysmal clipping following a SAH, especially those without acute seizures who present with a good grade.

Antifibrinolytic therapy
2012 American Stroke Association guidelines state that when definitive treatment of the aneurysm is unavoidably delayed and there are no other contraindications, short-term therapy (<72 hours) with tranexamic acid or aminocaproic acid is reasonable
Meta-analysis of ten trials (1904 patients) concluded that antifibrinolytic treatment reduces the risk of rebleeding
It does not show any evidence of reducing poor outcome defined as death, vegetative state, or severe disability. There was substantial heterogeneity between trials. In earlier trials, this lack of overall benefit appeared to be due to an increased risk of cerebral ischemia in patients treated with antifibrinolytic agents, which offset the reduction in rebleeding.

Definitive treatment of the aneurysm
= Substantial risk of rebleeding (3 to 4 percent in the first 24 hours and 1 to 2 percent each day in the first month
= Rerupture is associated with a mortality that is estimated to be 70 percent.
= Aneurysm repair is the only effective treatment to prevent this occurrence and should be performed within 24 to 72 hours when possible
= Patients in whom aneurysm treatment is not possible or must be delayed may be candidates for antifibrinolytic therapy.
= Most common aneurysm repair: surgical clipping and endovascular coiling.

Prevention of vasospasm
= Clinically significant vasospasm in 20 to 30% thought to be related to spasmogenic substances generated during the lysis of subarachnoid blood clots
Begins at day 3 after hemorrhage, peak at days 7 to 8.
= Start Nomodipine 60 mg every 4 hours po or NG for 21 days
= Maintain euvolemia
= Statins: despite lack of conclusive evidence of benefit, it is reasonable to administer statin therapy to prevent vasospasm
initiate statin treatment pravastatin 40 mg daily or simvastatin 80 mg daily within 48 hours of aneurysmal SAH and continuing until discharge from intensive care.
Continue statin therapy for patients who were taking statins prior to SAH.
= Transcranial Doppler (TCD) sonography is useful for detecting and monitoring vasospasm in SAH
Velocity changes detected by TCD typically precede the clinical sequelae of vasospasm.