EDAIC Neuroanesthesia and Neuromonitoring 2 — Questions and Answers
Question 1: Which intraoperative neuromonitoring modality is most sensitive for detecting ischemia in the motor cortex during carotid endarterectomy?
- Somatosensory evoked potentials (SSEPs)
- Motor evoked potentials (MEPs) (Correct answer)
- Electroencephalography (EEG)
- Brainstem auditory evoked potentials (BAEPs)
Correct answer: Motor evoked potentials (MEPs)
MEPs directly assess the corticospinal tract and are more sensitive than SSEPs for detecting motor cortex ischemia.
Question 2: During awake craniotomy for eloquent cortex tumor resection, which anesthetic technique is most appropriate for the 'asleep-awake-asleep' approach?
- Total intravenous anesthesia with propofol and remifentanil (Correct answer)
- Volatile anesthesia with sevoflurane
- Ketamine-based sedation throughout
- Neuraxial blockade with midazolam sedation
Correct answer: Total intravenous anesthesia with propofol and remifentanil
TIVA with propofol and remifentanil allows rapid titration and offset, facilitating reliable transitions between sedated and awake states.
Question 3: The Monro-Kellie doctrine states that a rise in volume of one intracranial compartment must be compensated by:
- Increased CSF production
- Reduction in another intracranial compartment volume (Correct answer)
- Elevated mean arterial pressure
- Dilation of cerebral arterioles
Correct answer: Reduction in another intracranial compartment volume
The skull is a rigid container, so an increase in any compartment (brain, blood, CSF) must be offset by a decrease in another to maintain constant ICP.
Question 4: Which volatile anesthetic agent is LEAST likely to increase cerebral blood volume and ICP at 1 MAC?
- Isoflurane
- Desflurane
- Sevoflurane (Correct answer)
- Halothane
Correct answer: Sevoflurane
Sevoflurane causes less cerebral vasodilation and ICP elevation than other volatile agents at equivalent doses, making it preferable in neurosurgery.
Question 5: In a patient with traumatic brain injury, which PaCO2 target is recommended during initial resuscitation to avoid secondary injury?
- 25-30 mmHg
- 30-35 mmHg
- 35-40 mmHg (Correct answer)
- 45-50 mmHg
Correct answer: 35-40 mmHg
Normocapnia (PaCO2 35-40 mmHg) is recommended; prophylactic hyperventilation reduces cerebral blood flow and can cause ischemia.
Question 6: Cerebral autoregulation maintains constant cerebral blood flow across which range of mean arterial pressure in a healthy adult?
- 40-60 mmHg
- 50-150 mmHg (Correct answer)
- 70-100 mmHg
- 100-180 mmHg
Correct answer: 50-150 mmHg
Cerebral autoregulation is intact between approximately 50-150 mmHg MAP in normotensive adults; outside this range, CBF becomes pressure-passive.
Question 7: Which drug is the preferred agent for inducing deliberate hypotension during intracranial aneurysm clipping to reduce transmural pressure?
- Sodium nitroprusside
- Nitroglycerin
- Adenosine (Correct answer)
- Labetalol
Correct answer: Adenosine
Adenosine-induced transient cardiac arrest or profound bradycardia provides brief profound hypotension for complex aneurysm clipping with rapid recovery.
