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': 'Use of nitrous oxide is contraindicated in all of the following surgeries except – \nSelect and explain. \nA. Cochlear implant, B. Microlaryngeal surgery, C. Vitrioretinal surgery, D. Exentration operation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Exentration is enucleation along with wide dissection of periorbital tissue. There is no air containing cavity or dead space formation, therefore N2O is not contraindicated.\nN2O is contraindicated in :- Pneumothorax, pneumoperitoneum, emphysema, volvulus, acute intestinal obstruction, microlaryngeal surgeries, Middle ear surgery, tympanoplasties, posterior fossa surgery, laproscopy surgery, pneumoencephalum, vitrolental surgery.', 'role': 'assistant'}]