BCSE Principles of Anesthesia 4 — Questions and Answers
Question 1: Which inhalational agent is CONTRAINDICATED in patients with a history of renal insufficiency due to nephrotoxic fluoride metabolite production?
- Isoflurane
- Desflurane
- Methoxyflurane (Correct answer)
- Sevoflurane
Correct answer: Methoxyflurane
Methoxyflurane undergoes extensive hepatic metabolism releasing high levels of inorganic fluoride, causing polyuric renal failure.
Question 2: During general anesthesia, a patient's end-tidal CO2 suddenly rises while peak airway pressure increases. What is the most likely cause?
- Endotracheal tube cuff leak
- Esophageal intubation
- Endobronchial intubation
- Bronchospasm (Correct answer)
Correct answer: Bronchospasm
Bronchospasm causes increased airway resistance leading to rising peak pressures and CO2 retention due to impaired exhalation.
Question 3: Which local anesthetic is MOST associated with cardiovascular toxicity due to its high lipid solubility and slow sodium channel dissociation?
- Lidocaine
- Bupivacaine (Correct answer)
- Chloroprocaine
- Mepivacaine
Correct answer: Bupivacaine
Bupivacaine has high lipid solubility and slow dissociation from cardiac sodium channels, making ventricular arrhythmias difficult to resuscitate.
Question 4: A patient undergoing thyroidectomy is found to have a high-riding innominate artery. What is the anesthetic implication?
- Higher risk of air embolism during dissection
- Increased risk of arterial bleeding during tracheostomy (Correct answer)
- Difficult airway due to tracheal deviation
- Recurrent laryngeal nerve injury risk
Correct answer: Increased risk of arterial bleeding during tracheostomy
A high-riding innominate artery overlies the trachea at or above the sternal notch, creating significant hemorrhage risk during emergency tracheostomy.
Question 5: What is the effect of hyperventilation on cerebral blood flow during neuroanesthesia?
- Increases CBF by dilating cerebral vasculature
- Decreases CBF by causing cerebral vasoconstriction via hypocapnia (Correct answer)
- No effect on CBF
- Increases CBF by raising intracranial pressure
Correct answer: Decreases CBF by causing cerebral vasoconstriction via hypocapnia
Hypocapnia from hyperventilation causes cerebral vasoconstriction, reducing cerebral blood flow and intracranial pressure.
Question 6: Which muscle relaxant is SAFEST in a patient with severe hepatic failure?
- Rocuronium
- Vecuronium
- Cisatracurium (Correct answer)
- Pancuronium
Correct answer: Cisatracurium
Cisatracurium undergoes Hofmann elimination (spontaneous pH and temperature-dependent degradation), making it independent of hepatic or renal function.
Question 7: The Fick principle in cardiac output measurement states that CO equals oxygen consumption divided by which value?
- Arterial oxygen content minus mixed venous oxygen content (Correct answer)
- Pulmonary artery pressure minus pulmonary capillary wedge pressure
- Heart rate multiplied by stroke volume
- Systemic vascular resistance divided by mean arterial pressure
Correct answer: Arterial oxygen content minus mixed venous oxygen content
The Fick principle: CO = VO2 / (CaO2 - CvO2), where CaO2 is arterial O2 content and CvO2 is mixed venous O2 content.
BCSE Principles of Anesthesia 4
Which inhalational agent is CONTRAINDICATED in patients with a history of renal insufficiency due to nephrotoxic fluoride metabolite production?