RESUMO
This study includes 24 paediatric patients with normal healthy ears. They were divided into 2 groups. In group I [18 patients], the maintenance of anaesthesia was achieved with halothane in N2O / Shibin El-Kom while in Group II [6 patients] halothane in oxygen was used. Middle ear pressure was measured prior to anaesthesia, during operation and post operative. Tympanometry was done ten days after operation. All patients of group I developed a negative pressure in one or both ears during the period of the study. Six patients developed bilateral secretory otitis media, while 4 patients developed secretory otitis media. In this study the relationship between persistent negative pressure developed in the middle ear following nitrous oxide anaesthesia and secretory otitis media in children is determined