title: A prospective analysis of independent patient risk factors for middle ear barotrauma in a multiplace hyperbaric chamber.
abstract: BACKGROUND
  Middle ear barotrauma (MEBT) is the most common complication of hyperbaric oxygen therapy (HBOT). We wished to determine whether independent risk factors could predict which patients will require tympanostomy tubes in order to continue HBOT.
  
  
  METHODS
  Data regarding demographics, medical history and physical examination were collected prospectively over one year. Multivariate logistic regression was used to analyse the data.
  
  
  RESULTS
  One hundred and six patients were included. The cumulative risk of MEBT over the first five treatments was 35.8% and that for needing tympanostomy tubes was 10.3%, while that for needing tubes at any time was 13.2%. Risk factors for MEBT on bivariate analysis were older age, history of ENT radiation and anticoagulant use. Risk factors for requiring tympanostomy tubes included a history of cardiovascular disease and patients being treated for an infective condition. The adjusted multivariate logistic model identified history of difficulty equalising as the only characteristic significantly associated with MEBT during the first five treatments, adjusted odds ratio (AOR) (95%CI): 11.0 (1.1 - 111.7). Being female, AOR (95%CI): 24.7 (1.8 - 339.7), and having a history of cardiovascular disease, AOR (95%CI): 20.7 (2.0 - 215.3), were significantly associated with the need for tympanostomy tubes during the first five HBOT, but there was no significant association between any other characteristics and the need for tubes at any point.
  
  
  CONCLUSIONS
  Despite some significant risk factors for MEBT being identified, we were unable to predict accurately enough which patients needed tympanostomy tubes during their HBOT to recommend these being placed prophylactically in selected patients.
authors.affiliation: Registrar, Hyperbaric Medicine Unit, c/o The Townsville Hospital, PO Box 670, Townsville, QLD 4810, Australia Phone: +61-(07)-4433-1111, E-mail: katherine_commons@health.qld.gov.au.
authors.forename: Katherine H
authors.initials: KH
authors.lastname: Commons
authors.forename: Denise F
authors.initials: DF
authors.lastname: Blake
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001273:Atmosphere Exposure Chambers; D001469:Barotrauma / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy; D002318:Cardiovascular Diseases / Q000150:complications; D004432:Ear, Middle / Q000293:injuries*; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008876:Middle Ear Ventilation; D009934:Organization and Administration; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult
keywords: Ear barotrauma; hyperbaric oxygen therapy; hyperbaric research; morbidity; risk factors