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

EEG detects hemispheric ischemia in real time during carotid cross-clamping, enabling the surgeon to place an intraluminal shunt when perfusion is inadequate.

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

ECG/pulse artifact appears on EEG as repetitive deflections synchronized with the heartbeat, easily identified by comparing EEG timing to simultaneously recorded ECG.

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

Single-channel noise almost always reflects a high-impedance or poorly adhered electrode; checking impedance and reseating the electrode is the fastest and most effective first step.

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

A falling alpha-delta ratio reflects a shift toward slower delta activity relative to alpha, which can signal cerebral ischemia or increasing anesthetic suppression.

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

Barbiturates produce dose-dependent global EEG suppression through GABA-A potentiation; bilateral suppression following a documented barbiturate dose is an anticipated, reversible pharmacological response.

CNIM - Certification for Neurophysiological Intraoperative Monitoring Practice Test

CNIM - Certification for Neurophysiological Intraoperative Monitoring Practice Test

CNIM Electroencephalography (EEG) in the Operating Room 3