[Pneumomediastinum: complications due to the use of a jet of compressed air].

We present a case-report of pneumomediastinum and surgical emphysema of the head, neck and upper thorax following the use of a high-pressure air-jet during dental surgery under general anaesthesia with N2O. This rare complication may be forgotten by the anaesthetist. The pneumomediastinum was diagnosed at the end of surgery and the cause subsequently determined during the immediate postoperative period. The possible deleterious effects of using such a dental air-jet are discussed as well as the potential dangers of the administration of nitrous oxide in such situation.