BCSE Principles of Anesthesia 3 — Questions and Answers
Question 1: Neostigmine is administered to reverse neuromuscular blockade. Which agent should always be co-administered?
- Epinephrine
- Atropine or glycopyrrolate (Correct answer)
- Ondansetron
- Flumazenil
Correct answer: Atropine or glycopyrrolate
An anticholinergic (atropine or glycopyrrolate) must accompany neostigmine to counteract muscarinic side effects including bradycardia and bronchospasm.
Question 2: A patient with a full stomach requires emergent general anesthesia. Which induction technique minimizes aspiration risk?
- Inhalational induction with sevoflurane
- Rapid sequence induction with cricoid pressure (Correct answer)
- Awake fiber-optic intubation under topical anesthesia
- Ketamine induction without muscle relaxant
Correct answer: Rapid sequence induction with cricoid pressure
Rapid sequence induction with cricoid pressure (Sellick's maneuver) is the standard technique to minimize pulmonary aspiration risk in patients with full stomachs.
Question 3: Which pulmonary function test finding best predicts post-operative pulmonary complications?
- FVC < 80% predicted
- FEV1/FVC ratio < 0.70
- FEV1 < 40% predicted (Correct answer)
- DLCO < 60% predicted
Correct answer: FEV1 < 40% predicted
An FEV1 < 40% predicted indicates severe obstructive disease and is associated with significantly increased risk of post-operative respiratory complications.
Question 4: Sugammadex reverses neuromuscular blockade by which mechanism?
- Inhibiting acetylcholinesterase at the neuromuscular junction
- Encapsulating rocuronium or vecuronium molecules (Correct answer)
- Competing with aminosteroid NMBAs at nicotinic receptors
- Enhancing acetylcholine release from motor nerve terminals
Correct answer: Encapsulating rocuronium or vecuronium molecules
Sugammadex is a modified gamma-cyclodextrin that encapsulates and inactivates steroidal neuromuscular blocking agents like rocuronium and vecuronium.
Question 5: Which type of breathing circuit minimizes rebreathing and eliminates the need for carbon dioxide absorbent?
- Circle system with soda lime
- Mapleson D (Bain) circuit at high fresh gas flows (Correct answer)
- Closed-circuit anesthesia system
- Low-flow circle system
Correct answer: Mapleson D (Bain) circuit at high fresh gas flows
The Mapleson D (Bain) circuit eliminates CO2 rebreathing at fresh gas flows ≥ 2× minute ventilation, making CO2 absorbent unnecessary.
Question 6: Epidural anesthesia is established at L3-L4. Which abdominal surgery would NOT be adequately covered by this block alone?
- Cesarean section
- Inguinal hernia repair
- Appendectomy
- Cholecystectomy (Correct answer)
Correct answer: Cholecystectomy
Cholecystectomy requires anesthesia to T4 level, and diaphragmatic irritation (phrenic nerve C3-C5) cannot be blocked by lumbar epidural, making general anesthesia necessary.
Question 7: What is the MOA behind ketamine's analgesic and dissociative properties?
- Mu-opioid receptor agonism
- NMDA receptor antagonism (Correct answer)
- GABA-A receptor potentiation
- Alpha-2 adrenergic receptor stimulation
Correct answer: NMDA receptor antagonism
Ketamine blocks NMDA glutamate receptors, producing dissociative anesthesia, analgesia, and bronchodilation while preserving airway reflexes.
BCSE Principles of Anesthesia 3
Neostigmine is administered to reverse neuromuscular blockade.
Which agent should always be co-administered?