Standard ASA monitors as well as an arterial catheter should be placed. Ideally, the arterial catheter should be placed pre-induction, but in a true emergent craniotomy, this may have to be placed post-induction. Central venous access may be indicated depending on the patient’s hemodynamic stability and should be considered on a case by case basis. Surgical decompression of a patient with elevated ICP can be associated with profound hypotension requiring vasopressor/inotrope use.
During the induction of anesthesia endotracheal intubation, TBI patients should be considered full stomach. Also, C-spine precautions should be utilized as up to 10% of TBI patients also have c-spine fractures. Rapid sequence induction with in-line C-spine stabilization should be used. Succinylcholine can cause a rise in ICP, but the rise is small and likely does not occur at all in TBI patients. Succinylcholine can be used for RSI if no other contraindications are found.
Maintenance of general anesthesia for craniotomies (evacuation of hematoma or craniectomy) is typically done with IV anesthetics, which primarily act as cerebral vasoconstrictors (with the exception of ketamine). For example, a combination of propofol and remifentanil can be used. Volatile anesthetics and nitrous oxide are often avoided due to vasodilatory effects and subsequent increases in ICP. If volatile agent is used, sevoflurane is probably the agent of choice, and should be used at less than 1 MAC. A goal cerebral perfusion pressure of 60-70 mmHg should be maintained. Excessive hyperventilation should be avoided (goal PaCO2 30-35 mmHg) in order to avoid further ischemic insult. Further reduction in ICP may be achieved using mannitol or hypertonic saline. Hypothermia has not been shown to improve outcomes. Hyperthermia should be avoided to minimize CMRO2. Albumin should be avoided (SAFE trial).