BCA BCA Neuroanesthesia & Neurosurgical Procedures 1 — Questions and Answers
Question 1: Which anesthetic agent is MOST commonly used for neurosurgical procedures due to its ability to decrease cerebral metabolic rate?
- Ketamine
- Propofol (Correct answer)
- Etomidate
- Nitrous oxide
Correct answer: Propofol
Propofol reduces cerebral metabolic rate of oxygen (CMRO2) and decreases intracranial pressure, making it a preferred agent for neurosurgical procedures.
Question 2: During craniotomy, a sudden bradycardia with hypertension (Cushing's triad) most likely indicates:
- Anesthetic overdose
- Malignant hyperthermia
- Raised intracranial pressure (Correct answer)
- Vasovagal response
Correct answer: Raised intracranial pressure
Cushing's triad (hypertension, bradycardia, irregular respirations) is a classic sign of critically elevated intracranial pressure threatening brainstem herniation.
Question 3: Which position is MOST associated with venous air embolism risk during neurosurgery?
- Supine
- Lateral decubitus
- Sitting (beach chair) (Correct answer)
- Prone
Correct answer: Sitting (beach chair)
The sitting position places surgical sites above the heart level, creating negative venous pressure that dramatically increases the risk of venous air embolism.
Question 4: The BEST method to detect venous air embolism intraoperatively is:
- End-tidal CO2 monitoring
- Transesophageal echocardiography
- Precordial Doppler ultrasound (Correct answer)
- Pulmonary artery catheter
Correct answer: Precordial Doppler ultrasound
Precordial Doppler ultrasound is the most sensitive noninvasive monitor for detecting venous air embolism, able to detect as little as 0.05 mL of air.
Question 5: Hyperventilation is used in neurosurgery primarily to:
- Increase cerebral blood flow
- Decrease PaCO2 to cause cerebral vasoconstriction (Correct answer)
- Increase oxygen delivery to the brain
- Prevent pulmonary atelectasis
Correct answer: Decrease PaCO2 to cause cerebral vasoconstriction
Hyperventilation lowers PaCO2, inducing cerebral vasoconstriction that reduces cerebral blood volume and intracranial pressure, creating better surgical conditions.
Question 6: During spinal cord surgery, which electrophysiological monitoring modality assesses dorsal column (sensory) pathway integrity?
- Motor evoked potentials (MEPs)
- Somatosensory evoked potentials (SSEPs) (Correct answer)
- Electroencephalography (EEG)
- Electromyography (EMG)
Correct answer: Somatosensory evoked potentials (SSEPs)
SSEPs monitor the dorsal column–medial lemniscal pathway (sensory), while MEPs assess the anterior corticospinal (motor) tracts.
BCA BCA Neuroanesthesia & Neurosurgical Procedures 1
Which anesthetic agent is MOST commonly used for neurosurgical procedures due to its ability to decrease cerebral metabolic rate?