EDAIC Neuroanesthesia and Neuromonitoring 3 — Questions and Answers
Question 1: Which intraoperative finding on EEG monitoring during carotid endarterectomy is the threshold most commonly used to place a carotid shunt?
- Loss of fast activity only
- 50% reduction in amplitude or frequency slowing (Correct answer)
- Burst suppression pattern
- Complete isoelectric EEG
Correct answer: 50% reduction in amplitude or frequency slowing
A 50% reduction in amplitude or significant frequency slowing in the ipsilateral hemisphere during carotid cross-clamping is the standard threshold for shunt placement.
Question 2: Jugular venous oxygen saturation (SjvO2) below what threshold indicates global cerebral ischemia?
- 75%
- 65%
- 55% (Correct answer)
- 45%
Correct answer: 55%
SjvO2 below 55% indicates increased oxygen extraction and global cerebral ischemia, requiring immediate intervention to increase oxygen delivery.
Question 3: During posterior fossa surgery in the sitting position, which complication is most immediately life-threatening?
- Macroglossia
- Venous air embolism (Correct answer)
- Peripheral nerve stretch injury
- Postoperative pneumocephalus
Correct answer: Venous air embolism
Venous air embolism can cause cardiovascular collapse and paradoxical arterial air embolism, making it the most immediately life-threatening sitting position complication.
Question 4: Which agent provides the best neuroprotection against cerebral ischemia by reducing cerebral metabolic rate of oxygen (CMRO2) to the lowest achievable level?
- Propofol
- Ketamine
- Barbiturates (thiopental) (Correct answer)
- Dexmedetomidine
Correct answer: Barbiturates (thiopental)
Barbiturates can produce burst suppression and maximum CMRO2 reduction (up to 50%), providing the greatest metabolic depression for neuroprotection.
Question 5: In transsphenoidal pituitary surgery, which intraoperative sign is the most reliable indicator of CSF leak into the operative field?
- Drop in end-tidal CO2
- Pulsatile clear fluid in the surgical field (Correct answer)
- Sudden decrease in arterial blood pressure
- Loss of somatosensory evoked potentials
Correct answer: Pulsatile clear fluid in the surgical field
Pulsatile clear fluid (CSF) appearing in the surgical field is the direct indicator of a dural breach and CSF leak during transsphenoidal surgery.
Question 6: The standard of care for managing malignant cerebral edema following large hemispheric ischemic stroke includes which intervention?
- IV dexamethasone 10 mg bolus
- Decompressive hemicraniectomy (Correct answer)
- Hyperbaric oxygen therapy
- Lumbar CSF drainage
Correct answer: Decompressive hemicraniectomy
Decompressive hemicraniectomy within 48 hours reduces mortality and improves functional outcomes in malignant MCA infarction with refractory edema.
Question 7: Which pharmacological agent is the first-line treatment for intraoperative cerebral vasospasm detected on transcranial Doppler during aneurysm surgery?
- Oral nimodipine
- Intra-arterial verapamil (Correct answer)
- IV nicardipine infusion
- Papaverine topical application
Correct answer: Intra-arterial verapamil
Intra-arterial verapamil delivered by interventional neuroradiology provides targeted, immediate vasodilation for symptomatic cerebral vasospasm.
EDAIC Neuroanesthesia and Neuromonitoring 3
Which intraoperative finding on EEG monitoring during carotid endarterectomy is the threshold most commonly used to place a carotid shunt?