CNIM Electroencephalography (EEG) in the Operating Room 3

Question 1

During carotid endarterectomy (CEA), the primary clinical purpose of continuous EEG monitoring is to:

Accepted Answer

Detect cerebral ischemia during carotid cross-clamping to guide shunt placement

Answer

Assess adequacy of neuromuscular blockade

Answer

Monitor auditory pathway integrity throughout the case

Answer

Measure cardiac output changes related to blood pressure management

Question 2

Which EEG artifact appears as rhythmic, large-amplitude deflections occurring at the same rate as the patient's heart rate?

Accepted Answer

ECG/pulse artifact

Answer

Electrocautery artifact

Answer

Movement artifact from patient shivering

Answer

60 Hz power line artifact

Question 3

When a single EEG channel displays excessive high-amplitude noise while all other channels appear normal, the FIRST troubleshooting step is:

Accepted Answer

Check and reseat the electrode at that specific site to reduce impedance

Answer

Replace the entire electrode cap

Answer

Increase the sensitivity setting on that channel

Answer

Switch from a bipolar to a referential montage

Question 4

The alpha-delta ratio (ADR) in intraoperative EEG is clinically useful because a decreasing ADR:

Accepted Answer

Suggests progressive slowing of brain activity, which may reflect ischemia or deepening anesthesia

Answer

Indicates adequate neuromuscular blockade

Answer

Confirms proper electrode impedance below 5 kΩ

Answer

Measures the numerical depth of anesthesia on a standardized scale

Question 5

Bilateral EEG suppression observed immediately after a known bolus dose of sodium thiopental should be interpreted as:

Accepted Answer

An expected, dose-dependent pharmacological effect on global brain activity

Answer

A sign of bilateral cerebral ischemia requiring emergency intervention

Answer

Electrode disconnection that must be repaired before monitoring continues

Answer

Evidence of anaphylaxis requiring immediate reversal

Question 6

In awake craniotomy EEG monitoring, which pattern would MOST urgently prompt the neurophysiologist to alert the surgical team of impending seizure activity?

Accepted Answer

Sudden-onset rhythmic discharges that evolve in frequency and amplitude

Answer

Gradual diffuse increase in delta power over several minutes

Answer

Bilateral synchronous alpha waves in posterior channels

Answer

Diffuse low-amplitude beta activity across all channels

Question 7

EEG monitoring during spinal cord surgery is BEST used in conjunction with which other modalities to comprehensively assess neural integrity?

Accepted Answer

Somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP)

Answer

Nerve conduction studies and repetitive nerve stimulation alone

Answer

Brainstem auditory evoked potentials (BAEP) alone

Answer

Needle EMG of paraspinal muscles only