This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
[{'content': 'Rise in end tidal CO2 during thyroid surgery can be due to all except: \nSelect and explain. \nA. Anaphylaxis, B. Malignant hypehermia, C. Thyroid storm, D. Neuroleptic malignant syndrome', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Anaphylaxis Thyroid storm, malignant hypehermia, neuroleptic malignant syndrome and pheochromocytoma are hypermetabolic states with a massive increase in CO2 production, characterized by hyperpyrexia, tachycardia striking alteration in consciousness and rise in ET CO2 (end tidal CO2 on capnometery)Q. Anaphylaxis l/t hypotension and shock results in hypoperfusion of lungs and deceased ET CO2Q.', 'role': 'assistant'}]