Acute otitic barotrauma during hypobaric chamber training: prevalence and prevention.

Introduction: Barotitis media is known to be an adverse effect of altitude changes, but few studies have investigated this condition with respect to hypobaric chamber training and the resulting estimations of prevalence vary. Methods: In order to assess the prevalence of hypobaric chamber-related barotitis and evaluate a method of prevention, 335 healthy military pilots undergoing high altitude training were subject to clinical examination and tympanometry before entering the chamber. In order to minimize the risk of barotrauma, only subjects with normal preflight findings were cleared for altitude exposure. Barotitis media was diagnosed on the basis of ear pain and clinical findings according to Teed's classification. Results: Barotitis occurred in eight subjects; seven cases were monolateral and one bilateral, prevalence was 2.4%. Conclusion: The prevalence of barotitis after hypobaric chamber training is low in our study, suggesting that a pre-chamber medical check including clinical examination and tympanometry could be effective in identifying subjects at risk.