Use of nitrous oxide is contraindicated in all of the following surgeries except –

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. N2O is contraindicated in :- Pneumothorax, pneumoperitoneum, emphysema, volvulus, acute intestinal obstruction, microlaryngeal surgeries, Middle ear surgery, tympanoplasties, posterior fossa surgery, laproscopy surgery, pneumoencephalum, vitrolental surgery.