Anaesthesia is one of the major determinants of a successful outcome after neurosurgical procedures. Pre-operative assessment, induction of anaesthesia, maintenance of anaesthesia, the process of extubation, and immediate post-operative care are interlinked and enable surgery to proceed smoothly. Good neuroanaesthesia produces a relaxed brain and optimal operating conditions. Additional manipulation of the patient’s physiology may be necessary according to the procedure. The care of the patient and the maintenance of a favourable intracranial/intraspinal environment remain with the anaesthetist into the recovery room and, at times, the intensive care unit.

Pre-operative assessment

The anaesthetist faces a number of challenges when assessing the neurosurgical patient.

1. Many patients will be transferred as an emergency directly to theatre from other hospitals. Communication regarding the patient’s intracranial pathology, the proposed position for surgery and the expected time of arrival can speed the time to incision, and allow the anaesthetist to prepare for the case. Excellent communication between the transferring and receiving team is essential. It must include the patient’s medical history as far as is known, mechanism of injury, neurology at scene, treatments received so far, and other injuries identified. Limited information will be available from blood investigations.

2. Patients with intracranial pathology may have receptive or expressive dysphasia, a low GCS, neuropsychiatric disorders or capacity issues.

3. Patients with low GCS, or neurological weakness of whatever cause do not exert themselves physically and assessing cardio-respiratory reserve is a challenge.

4. Patients with sudden acute elevation of intracranial pressure can have a ‘sympathetic surge’ and subsequent myocardial events – myocardial infarction, Takatsubo (stress-induced) cardiomyopathy, arrhythmias.

5. Patients frequently require surgery without delay to avoid devastating complications – paralysis, blindness and death. Conditions that can be readily optimised should be; conditions that require lengthy investigation or treatment will often be postponed until after surgery, if it is safe to do so.