What is the recommended anesthesia regimen for neurosurgical procedures?

Anesthetic Management for Neurosurgical Procedures

Total intravenous anesthesia (TIVA) with propofol and remifentanil is the recommended anesthesia regimen for neurosurgical procedures due to its favorable effects on intracranial pressure, cerebral perfusion, and rapid recovery times. 1, 2

General Principles

• Maintain euvolemia, normotension, isotonicity, normoglycemia, and mild hypocapnia to ensure optimal cerebral physiology during intracranial procedures 3
• Avoid profound hypocapnia unless specifically indicated for control of brain swelling 3
• Direct arterial pressure monitoring is essential, particularly when manipulating systemic pressure with vasoactive agents 3

Recommended Anesthetic Regimen

Induction

• Propofol (1-2 mg/kg) for induction provides hemodynamic stability and reduces cerebral metabolism 2
• High-dose fentanyl (3-5 μg/kg), alfentanil (10-20 μg/kg), or remifentanil TCI (target-controlled infusion) with Cpt ≥ 3 ng/ml 4
• Neuromuscular blockade with rocuronium (1 mg/kg) or suxamethonium (1.5 mg/kg) 4
• Have vasoconstrictors (ephedrine or metaraminol) available to treat immediate hypotension 4

Maintenance

• TIVA with propofol (100-200 μg/kg/min) and remifentanil (0.05-2 μg/kg/min) is preferred over inhalational anesthetics 1, 2
• Remifentanil should be administered as a continuous infusion at 0.25 μg/kg/min (range 0.05-2 μg/kg/min) with supplemental IV bolus doses of 1 μg/kg as needed 5
• Avoid nitrous oxide due to its potential to increase cerebral blood flow and intracranial pressure 4

Required Monitoring

• Standard monitoring includes ECG, SpO2, NIBP, and capnography, which should be checked before induction and continued throughout anesthesia 4
• Processed electroencephalogram (pEEG) monitoring is essential when TIVA is administered with neuromuscular blocking drugs 4, 6
• Quantitative neuromuscular monitoring should be used whenever neuromuscular blocking drugs are administered 4
• Direct arterial blood pressure monitoring with the transducer placed at the level of the tragus 4

Hemodynamic Management

• Maintain blood pressure targets specific to the neurosurgical condition (e.g., lower targets for aneurysm surgery, higher for traumatic brain injury) 4
• Induced hypotension may be useful during certain phases of surgery but should be used cautiously in patients with impaired cerebral autoregulation 3
• TIVA provides better hemodynamic stability during induction compared to balanced anesthesia, with less increase in blood pressure after intubation 7

Advantages of TIVA for Neurosurgery

• Reduces intracranial pressure and increases cerebral perfusion pressure compared to volatile anesthetics 2
• Provides better surgical field access due to decreased brain swelling 2
• Allows for faster and more predictable recovery with shorter time to orientation and concentration 7
• Reduces operative time compared to inhalational anesthesia with sevoflurane 1
• Preserves cerebral autoregulation better than volatile anesthetics 2

Recovery Considerations

• Careful emergence from anesthesia is crucial to avoid hypertension, which may lead to intracranial bleeding 3
• TIVA with propofol and remifentanil allows for rapid emergence and early cognitive recovery 1, 2
• For patients undergoing procedures where postoperative pain is anticipated, alternative analgesics should be administered prior to discontinuation of remifentanil 5

Special Considerations

• For elderly patients (>60 years), target a lighter level of anesthesia with a BIS of approximately 50 to reduce postoperative delirium 6
• In patients with elevated ICP, TIVA is particularly beneficial as it avoids the ICP-increasing effects of volatile anesthetics 2
• For transfer of brain-injured patients, maintain PaCO2 at 4.5-5.0 kPa and PaO2 ≥ 13 kPa 4

TIVA with propofol and remifentanil has emerged as the preferred anesthetic technique for neurosurgical procedures due to its favorable effects on cerebral physiology, surgical conditions, and recovery profile. The combination provides optimal conditions for neurosurgery while minimizing the risk of increased intracranial pressure and allowing for rapid emergence from anesthesia.