Lindsay Attaway MD ANESTHETIC GOALS FOR CEREBRAL ANEURYSM

INTRACRANIAL ANEURYSMS Arise in Circle of Willis Mostly in anterior circulation Rupture and SAH greatest concern Account for 75-80% of SAH 1/3 die from initial bleed 1/3 severe disability/delayed death 1/3 with acceptable outcome

SURGICAL CONSIDERATIONS Clipping confers benefit when aneurysm exceeds 10 mm Initial 72 hr window Beyond delayed days- risk of vasospasm

ANESTHETIC CONSIDERATIONS Primary concern- prevent rupture Mortality of rupture on induction exceeds 75% Likelihood of rupture depends on size, prior rupture, wall strength and transmural pressure Transmural pressure CPP= MAP – ICP Critical periods: induction, dura/arachnoid exposure, hematoma evac, dissection

INDUCTION Avoid acute increases in blood pressure while preserving CPP Consider awake A-line, lidocaine, beta blockers, narcotics Avoid aggressive hyperventilation and hypocapnia

A 45 YO FEMALE IS EXPERIENCING PROGRESSIVE MENTAL DETERIORATION OVER A 6 HR PERIOD, 5 DAYS OUT FROM EMERGENT SAH EVACUATION AND ANEURYSM CLIPPING. MOST LIKELY CAUSE IS: A: Cerebral edema B: Hyponatremia C: Recurrent cerebral hemorrhage D: Vasospasm E: Improper placement of the aneurysm clip

VASOSPASM Subarachnoid bleeders at risk for vasospasm and further ischemia Rare in day 1-3 Peaks at day 7 Resolves around day Symptoms may include: Change in mentation New neurologic deficit Respiratory changes Diagnosis by angiography and transcranial Doppler

THERAPY THAT IS USEFUL IN THE TREATMENT OF CEREBRAL VASOSPASM INCLUDES ALL OF THE FOLLOWING EXCEPT: A: Blood pressure elevation B: Hemodilution C: Diuretics D: Calcium channel blockers E: Avoiding hyperglycemia

HHH HEMODILUTION, HYPERTENSION, HYPERVOLEMIA Strategy to augment CBF past strictures by  CPP and IV volume Keep MAP normal prior to clipping, High/Normal after clipping Not indicated for elective aneurysm clipping

OTHER CONSIDERATIONS Blood pressure control during pinning and positioning Surgeon desires cerebral relaxation Gentle hyperventilation Osmotic diuretics Surgeon prefers isoelectric EEG Bolus and infusion of propofol or etomidate Increase MAP after deployment Wake up Avoid straining, coughing, bucking, and HD liability