• Causes of intracranial hemorrhage include cerebrovascular aneurysm or arteriovenous malformation (AVM) rupture, malignant hypertension, trauma, anticoagulation therapy, and tumors.
• Intracranial hemorrhage carries a high-risk for morbidity and mortality; therefore, prompt diagnosis and medical and/or surgical management are cornerstones of therapy.
• Medical management is usually performed for small hemorrhages with minimal deficits, as clot can be absorbed by the body. It is also performed before and after surgical aneurysm clipping to gain the best outcome and includes seizure prophylaxis and therapy, management of intracranial pressure, and prevention of vasospasm. However, despite ongoing research, major advancements and improvements have not been made in recent years.
• Surgical management may be performed for aneurysm clipping as the risk of re-bleed can reach up to 35% within 14 days of the initial bleed (focus of this chapter), AVMs, or large hemorrhages near the surface of the brain that are accompanied by neurologic deterioration, brainstem compression, or hydrocephalus.

• Determined by the site of aneurysm (80% occur in the anterior circulation), AVM, or hematoma, surgeon preference, and patient factors such as intracranial pressure (ICP). Possibilities include supine, semilateral, lateral, prone, and sitting; variations of these positions can also be employed.
• Some degree of head elevation is usually employed to aid in venous drainage and brain relaxation. Air embolism remains a risk, even when head elevation is minimal.
• The sitting position must be chosen very carefully, and is typically only for patients where either brain relaxation cannot be achieved because of very high ICP, or due to the surgical access site. The risk of clinically significant venous air embolism is high and steps should be taken to reduce the risk and ensure early detection (volume loading, precordial Doppler, and central venous catheter placement at the superior vena cava-right atrium junction to aspirate air).
• These procedures tend to be long, and therefore, it is imperative to pay very close attention to proper positioning, heavy padding, and securing of the patient.

Depends on the location of the lesion and surgeon preference.

Very variable, from 90 minutes to 16 hours

• Typically on the order of a few hundred milliliters for aneurysms that do not rupture.
• If the aneurysm ruptures, blood loss will be brisk, and if the aneurysm is not rapidly clipped, patients can exsanguinate.
• It is advisable to have at least two units of packed red blood cells immediately, and further blood products and volume expanders easily available.

Operating microscope, possibly 3D navigational equipment, and electrophysiological monitoring equipment.

Incidence

• Subarachnoid hemorrhage (SAH): 9 out of 100,000 people annually. By cause:
  • Ruptured aneurysms: 85%
  • AVMs: 10%
  • Cerebral hemorrhage: 10%
  • Others (tumors)
• Risk increases with age

Prevalence

About 1–2% of the population has at least one cerebral aneurysm.

• If the early course after aneurysm rupture is survived, 25% of patients will have significant restrictions in their lifestyle, and only 20% will have no residual symptoms.
• Other problems include long-term cognitive impairment, depression, fatigue, headache, posttraumatic stress disorder (PTSD), and hypopituitarism.

Overall, survival is poor with the death rate after SAH approaching 50%.

History

Most intracranial aneurysms are asymptomatic and remain undetected until the time of rupture.

Signs/Physical Exam

A thorough neurologic exam needs to be performed to assess the baseline status of the patient so that it can be compared to the postprocedure exam. In this fashion, subtle changes can be picked up, and further diagnostics and therapeutics can be pursued in a timely fashion.

Labs/Studies

• CBC to assess hemodilution during triple H therapy.
• Chem 7 to assess for cerebral salt wasting (hyponatremia and hypokalemia) due to release of brain and atrial natriuretic hormone or syndrome of inappropriate antidiuretic hormone secretion (SIADH).
• EKG: SAH often leads to changes that are consistent with acute ischemia (QT prolongation, Q waves, cardiac dysrhythmias).
• Echocardiogram only needs to be obtained if cardiac ischemia or failure is suspected.
• Chest radiograph is usually not indicated unless there is a suspicion of neurogenic pulmonary edema.
• Imaging modalities include CT angiogram, angiogram, MRI/MRA

• Patients with altered sensorium or with increased ICP should be cautiously, if at all, premedicated; small changes in CO₂ tension can lead to large changes in ICP and obtundation.

Potential for prolonged intubation and pharmacologic induced coma.

Cefazolin for skin organisms q4h prophylactically.

General endotracheal anesthesia

• Standard ASA monitors
• Foley catheter
• Arterial line allows for tight BP monitoring and aids in resuscitation should the aneurysm or AVM re-rupture.
• Central line should be strongly considered given the risk for a venous air embolism, massive blood loss, and the possible need for vasoactive and barbiturate administration.
• EEG monitoring and evoked potentials are not the standard of care, but should be strongly considered in cases of giant and wide neck aneurysms, aneurysm in close proximity to other vessels, high ICP, large SAH, or in those who are otherwise at risk for cerebral ischemia. No trial has shown an outcome benefit. Findings may be used to further direct therapy and intervention.

• There is no single recommended induction choice. Goals are as follows:
  • Keep the aneurysm's transmural pressure gradient stable.
  • Maintain adequate cerebral perfusion and oxygenation.
  • Avoid rapid changes in ICP.
• The risk of aneurysm rupture with induction is about 1% (data on re-rupture is not available). Good choices for induction are propofol, IV lidocaine, esmolol, and short-acting opioids such as remifentanil, but other agents may be used with equal efficaciousness.
• Usually, intermediate-acting nondepolarizing muscle relaxants are used. Succinylcholine will raise the ICP transiently, but to a lesser degree than an unsmooth induction.

• Positioning and head pinning are stimulating events, and may need further doses of induction agents. Scalp infiltration with local anesthetics is useful in attenuating the stress response. Long-acting agents are avoided due to the risk of hypotension.
• Brain relaxation. Reducing the content of the cranial vault for surgical exposure is paramount.
  • Mannitol 0.5–1 mg/kg over a period of about 20–30 minutes. Administration may cause severe hypotension, especially in hypovolemic patients.
  • Furosemide
  • Cerebrospinal fluid drainage
  • Head elevation
  • Avoidance of venous outflow obstruction by limiting head rotation (aids in brain relaxation)
  • If brain relaxation is inadequate, switching from volatile agents (usually kept below one MAC) to a propofol infusion will improve relaxation significantly.
• BP is kept close to normal during the case. However, if the surgeon applies temporary clips or the aneurysm is secured, BP is elevated to improve collateral flow.
• Cerebral protection. At this time, no cerebral protection study has shown a decrease in the risk of ischemia.
  • Mild hypothermia will reduce cerebral metabolic rate of oxygen (CMRO₂), but will not affect morbidity or mortality. It will, however, aid in brain relaxation, and if the temperature does not fall below 34.5°C, it has no negative effect on infection rate, bleeding, and wound healing.
  • Barbiturate administration titrated to burst suppression is used in some centers to protect the brain from ischemia and provide brain relaxation. Again, no outcome evidence exists to support this practice.

• Nausea should be preempted with multimodal therapy.
• Extubation should be smooth. Postoperative intubation may be considered in patients with high-grade hemorrhage or if there is any doubt about their ability to protect their airway.
• Hypertension in the early postoperative period is common. Mild hypertension (20%) should be left untreated as it will aid in collateral flow and is part of the "triple H" therapy to avoid vasospasm. Hypertension beyond this range will need to be treated with calcium channel or beta blockers.
• Pain medications should be given cautiously to avoid clouding of the sensorium, and respiratory depression.
• Early neurological exam is paramount as to guide whether CT scanning, angiography, or initiation of "triple H" therapy is warranted.