title: An assessment of the validity of tympanometry compared to myringotomy performed under a nitrous oxide-free general anaesthetic.
abstract: To assess the validity of tympanometry as a test for the presence of middle ear effusion using a 'gold-standard' of myringotomy performed after a nitrous oxide-free general anaesthetic, we performed a prospective validity study comparing tympanometry traces obtained immediately pre-operatively from patients undergoing grommet insertion, with the otomicroscopic findings at myringotomy. Nitrous oxide was omitted from the anaesthetic gaseous mixture as it has been reported to displace middle ear effusions. One hundred and seventy-two patients (aged 1.5-15 years) with a clinically assessed 3 month history of middle ear effusion were included in the study. Sensitivity and specificity of a Jerger classification Type B tympanometric trace for the presence of middle ear effusion were 0.73 and 0.84, respectively. We conclude that tympanometry is a valid test in assessing the presence of middle ear effusion compared to a 'gold standard' of myringotomy performed after a nitrous oxide-free general anaesthetic.
authors.affiliation: ENT Department, Bromley Hospitals NHS Trust, Princess Royal University Hospital, Farnborough, UK. samfishpool@gmail.com
authors.forename: Samuel J C
authors.initials: SJ
authors.lastname: Fishpool
authors.forename: Damayanthi
authors.initials: D
authors.lastname: Kuhanendran
authors.forename: Dinesh
authors.initials: D
authors.lastname: Swaminathan
authors.forename: C V
authors.initials: CV
authors.lastname: Praveen
mesh_terms: D000158:Acoustic Impedance Tests / Q000379:methods*; D000293:Adolescent; D000768:Anesthesia, General; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008876:Middle Ear Ventilation / Q000379:methods*; D009609:Nitrous Oxide / Q000032:analysis*; D010034:Otitis Media with Effusion / Q000601:surgery*; D015203:Reproducibility of Results
chemical_list: D009609:Nitrous Oxide