This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intravenous Anesthetic Agents, Subject name: Anaesthesia
[{'content': 'Which side effect is seen with fentanyl? \nSelect and explain. \nA. Pain in abdomen, B. Hypeension, C. Tachycardia, D. Chest well rigidity', 'role': 'user'}, {'content': "Answer: D \nExplanation: Fentanyl induced chest wall rigidity is an uncommon complication, especially during sedation for routine bronchoscopy . It was first described by Hamilton and Cullen in 1953 . It primarily results in chest wall and abdominal wall rigidity, also known as the 'wooden chest syndrome . The reduced chest wall compliance makes rescue assisted ventilation difficult . This may also be contributed by vocal cords or jaw closure resulting in upper airway obstruction", 'role': 'assistant'}]