title: Pre-operative prediction of 'dry taps'.
abstract: OBJECTIVE
  The treatment of children with 'glue ear' often presents surgeons with the question of whether or not to insert a grommet when myringotomy reveals no fluid in the middle ear. We present a study designed to assess which factors contribute to the presence of a 'dry tap'.
  
  
  METHODS
  We prospectively gathered data from a cohort of 280 children (504 myringotomies). The cohort included two subgroups, one received halothane and nitrous oxide anaesthesia, and the other received enflurane anaesthesia.
  
  
  METHODS
  The ENT department of a district general hospital.
  
  
  METHODS
  Children (aged less than 17 years) requiring myringotomy.
  
  
  METHODS
  The presence of a 'glue' or dry tap at myringotomy was documented. We also recorded data on the following: pre- and post-induction tympanometry; age; season; anaesthetic type; and the delay from listing to actual operation.
  
  
  RESULTS
  A non type B pre-induction tympanogram and delay to operation were strong indications of finding a dry tap at surgery.
  
  
  CONCLUSIONS
  In our study population, the proportion of dry taps at myringotomy was 18 per cent. The presence of a dry tap was rarely due to the induction of anaesthesia. Multivariate analysis revealed that the combination of factors most likely to predict a dry tap were non type B tympanogram and delay to operation.
authors.affiliation: Department of Otolaryngology Head & Neck Surgery, Cumberland Infirmary, Carlisle, UK. scott.henney@doctors.org.uk
authors.forename: S
authors.initials: S
authors.lastname: Henney
authors.forename: P
authors.initials: P
authors.lastname: Counter
authors.forename: S
authors.initials: S
authors.lastname: Mirza
authors.forename: P
authors.initials: P
authors.lastname: Gedling
authors.forename: C
authors.initials: C
authors.lastname: Watson
mesh_terms: D000293:Adolescent; D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D004432:Ear, Middle / Q000601:surgery*; D004737:Enflurane / Q000009:adverse effects; D006221:Halothane / Q000009:adverse effects; D006801:Humans; D008876:Middle Ear Ventilation / Q000379:methods*; D015999:Multivariate Analysis; D009225:Myringoplasty / Q000379:methods*; D009609:Nitrous Oxide / Q000009:adverse effects; D010034:Otitis Media with Effusion / Q000175:diagnosis* / Q000601:surgery; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012075:Remission, Spontaneous; D014432:Tympanic Membrane / Q000601:surgery*
chemical_list: D018685:Anesthetics, Inhalation; D004737:Enflurane; D009609:Nitrous Oxide; D006221:Halothane