What is the recommended preoperative anesthesia plan for a neurosurgery case?

Recommended Preoperative Anesthesia Plan for Neurosurgery Cases

The recommended preoperative anesthesia plan for neurosurgery should focus on maintaining optimal cerebral physiology through euvolemia, normotension, isotonicity, normoglycemia, and mild hypocapnia, while ensuring thorough preoperative evaluation to identify risk factors that may affect neurological outcomes. 1

Preoperative Assessment Components

Comprehensive Medical Record Review

• Review previous medical records for history of airway difficulties with previous anesthetics, hypertension or other cardiovascular problems, and other congenital or acquired medical conditions 2
• Evaluate previous sleep studies if available, particularly in patients with suspected obstructive sleep apnea (OSA) 2
• Document baseline cognitive status using validated screening tools such as MiniCog to facilitate identification of postoperative neurocognitive disorders 2

Physical Examination with Focus on Neurological Status

• Conduct thorough airway assessment, including evaluation of nasopharyngeal characteristics, neck circumference, tonsil size, and tongue volume 2
• Perform baseline cognitive screening using validated tests in at-risk patients to identify those at higher risk for postoperative neurocognitive disorders 2
• Assess baseline neurological status to allow for comparison during postoperative evaluation 1

Hemodynamic Considerations

• Plan for direct arterial pressure monitoring, particularly when manipulating systemic pressure with vasoactive agents will be required 1
• Develop strategy for blood pressure management during surgery, including potential need for induced hypotension during specific phases of surgery 1
• Consider preoperative cardiac evaluation in patients with significant cardiovascular risk factors 2

Anesthetic Agent Selection

IV Anesthetics

• Consider propofol as primary induction and maintenance agent due to its favorable cerebral effects including decreased cerebral metabolic rate for oxygen (CMRO₂) and cerebral vasoconstriction 3
• Plan for total intravenous anesthesia (TIVA) technique when appropriate, as IV agents (except ketamine) decrease CMRO₂ and are cerebral vasoconstrictors, making them rational choices for neurosurgery 3
• Consider remifentanil for intraoperative analgesia due to its rapid onset and offset, allowing for quick neurological assessment 4, 5

Regional Anesthesia Considerations

• If regional anesthesia is planned, ensure thorough testing for block success to prevent the need for emergent conversion to general anesthesia 2
• Allow extra onset time for peripheral nerve blocks to reduce the risk of intraoperative conversion to general anesthesia 2
• Avoid excessive sedation with regional techniques to reduce the need for airway manipulation or interventions 2

Special Considerations

Obstructive Sleep Apnea

• For patients with suspected OSA, anesthesiologists should work with surgeons to develop a protocol for evaluation well before the day of surgery 2
• Consider whether to manage perioperatively based on clinical criteria alone or obtain sleep studies and initiate indicated OSA treatment in advance of surgery 2

COVID-19 Precautions (When Applicable)

• Follow institutional guidelines for preoperative COVID-19 testing when indicated 2
• Consider RT-PCR testing as the gold standard for diagnosing SARS-CoV-2 infection in the preoperative setting 2

Emergence Planning

• Develop a plan for careful emergence from anesthesia to avoid hypertension, which may lead to intracranial bleeding 1
• Consider depth of anesthesia monitoring to facilitate smoother emergence 6

Common Pitfalls to Avoid

• Failing to screen for and document baseline cognitive status, which is essential for identifying postoperative neurocognitive disorders 2
• Not allowing adequate time for thorough preoperative evaluation, particularly in patients with complex neurological conditions 7
• Overlooking the need for arterial pressure monitoring in cases requiring precise hemodynamic management 1
• Inadequate planning for emergence, which can lead to dangerous increases in intracranial pressure 1