Middle ear barotrauma during hyperbaric oxygen therapy; a review of occurrences in 5,962 patients.

Hyperbaric-associated middle ear barotrauma (MEB) is one of the most common side effects of the exposure to hyperbaric oxygen (HBO2) therapy. This retrospective observational study of 5,962 patients undergoing longterm therapy for chronic conditions took place at the local Diving and Hyperbaric Medicine Unit (DHMU) in Villafranca-Verona (Italy), a DHMU that administers, in multiplace chambers, more than 20,000 HBO2 treatments per year. The study was designed to weight and analyze both the incidence and severity of MEBs at the facility. Thanks to a systematic recording method over eight years, 2003-2010, we observed 549 MEBs (9.2% of all HBO2 treatments). The majority of them were female patients older than 50. MEBs observed were usually of minor complexity, with minimal otoscopic changes (69.03% of our occurrences were registered as Wallace-Teed Grade 1). MEBs were registered in 20.3% of those patients already suffering from difficulties in equalizing ear pressure, and/or presenting ear pain during the initial compression phase (descent) of the hyperbaric treatment. Inflammatory diseases of the upper respiratory tract, with special attention to rhinitis, appear to be a condition capable of predisposing patients in developing MEB. MEB did lead to the suspension of therapy for 89 patients in our case series. This was 16.2% of all the MEBs registered, or 1.49% of all patients who underwent HBO2 at the facility in the considered time lapse.