Nitrous oxide use in ear-nose-throat-surgery

The use of nitrous oxide (N2O) in ear-nose-throat (ENT)-surgery is open to discussion. The aim of this overview is to highlight the main topics that are of particular concern to this subject. These topics are the question of waste anaesthetic gas concentrations in the operation room, the significance of the diffusion of nitrous oxide into the tympanic cavity and the particular problem of post-operative nausea and vomiting (PONV) in a growing outpatient surgery. The probably unavoidable occupational exposure of the ENT-surgeon to higher concentrations of this potentially toxic gas means that in the future the use of less toxic agents would be preferable in ENT. The diffusion of nitrous oxide into mucosa-coated cavities such as the middle ear suggests that it should, at least, be avoided in those patients having an impaired auditory tube function. One major problem concerning the specific literature about PONV after N2O in ENT is the lack of more randomized studies.