[EEG recordings in prolonged hypercapnia during surgery of a cervico-mediastinal tumor in a 3-year-old child].

An EEG has been recorded during surgery for a cervico-mediastinal desmoid fibroma in a 3-year-old child. Soon after anesthetic induction a bronchospasm occurred, followed by major respiratory difficulties. During more than 3 h, hypercapnia reaching 15-24 kpa was noted without hypoxia. Meanwhile the EEG recording was inactive. The respiratory difficulties subsided only with the surgical liberation of the trachea. As the hypercapnia decreased, the EEG began to show "burst suppressive" activity. Progressively the tracing was more and more continuous with slow waves until complete recovery. The following day the EEG was quite normal. The mechanisms of these EEG features are discussed with regards to anesthetic drugs and to brain hypercapnic edema.