Which of the following symptoms did the patient most likely experience upon recovery from sedation?

Correct Answer: C

Rationale: The correct answer is C: Anterograde amnesia. Upon recovery from sedation, the patient most likely experienced anterograde amnesia, which is the inability to form new memories after sedation. This occurs due to the effects of sedative medications on the brain's ability to encode and store new information temporarily. This symptom is commonly associated with sedative medications and is a typical outcome of sedation procedures. A: Nausea and vomiting are common side effects of sedation but are more likely to occur during or shortly after sedation, rather than upon recovery. B: Increased respiratory rate may occur during sedation due to the effects of sedative medications on the respiratory system, but it is not a typical symptom upon recovery. D: Limb muscle spasms are not typically associated with recovery from sedation and are more likely to be a sign of a different medical condition or side effect of a different medication.

Correct Answer: D

Rationale: The correct answer is D: The addition of nitrous oxide. Nitrous oxide is known to decrease minimum alveolar concentration (MAC) of anesthetic agents, leading to a lower concentration needed to maintain anesthesia. This is due to its anesthetic properties and synergistic effects with other anesthetics. Choice A (cancer) and C (age) are unlikely to directly affect MAC levels. Choice B (use of two anesthetics) might actually increase MAC rather than decrease it, making it an incorrect choice.

Correct Answer: D

Rationale: The correct answer is D: Convulsions. Lidocaine is a local anesthetic that can cause central nervous system toxicity, leading to symptoms like seizures or convulsions. When administered near the brachial plexus for a peripheral nerve block, lidocaine can inadvertently reach systemic circulation, increasing the risk of CNS side effects. Ventricular tachycardia (A) is a cardiac adverse effect, not commonly associated with lidocaine toxicity. Abdominal colic (B) is unrelated to lidocaine administration near the brachial plexus. Drowsiness (C) is a common systemic side effect of lidocaine but is less likely to occur after administration near the brachial plexus compared to CNS effects like convulsions.

Correct Answer: B

Rationale: The correct answer is B: Vecuronium. Vecuronium is a non-depolarizing neuromuscular blocking agent that inhibits acetylcholine from binding to nicotinic receptors, leading to muscle paralysis including respiratory muscles, thus decreasing spontaneous breathing. Diazepam (A) is a benzodiazepine that acts on the central nervous system but does not directly affect respiratory muscles. Botulinum toxin (C) blocks acetylcholine release at the neuromuscular junction but is not suitable for systemic use to decrease spontaneous breathing. Dantrolene (D) is a muscle relaxant that acts on skeletal muscles but does not directly inhibit respiratory muscles.

Correct Answer: B

Rationale: The correct answer is B: Somatic nerve terminals. Botulinum toxin acts by inhibiting the release of acetylcholine at the neuromuscular junction, leading to muscle paralysis. In the context of ocular muscles in strabismus, the toxin would target the somatic nerve terminals that innervate the extraocular muscles. This action results in the relaxation of the affected muscle, helping to correct the misalignment of the eyes. Choices A, C, and D are incorrect as they do not directly relate to the mechanism of action of botulinum toxin at the neuromuscular junction.