OBJECTIVE: To compare the incidence of MEB during hyperbaric oxygen therapy using two different chamber compression protocols.
DESIGN: Double-blinded, randomized controlled trial.
SETTING: Hyperbaric Medicine Unit, The Townsville Hospital, Queensland, Australia, September 2012 to December 2014.
PATIENTS: 100 participants undergoing their first hyperbaric oxygen therapy session.
INTERVENTION: Random assignment to a staged (n=50) or a linear (n=50) compression protocols. Photographs of tympanic membranes were taken pre- and post-treatment and then graded. Middle ear barotrauma was defined as an increase of at least one grade on a modified TEED scale.
RESULTS: The observed MEB incidence under the staged protocol was 48% compared to 62% using the linear protocol (P=0.12, exact one-sided binomial test), and thus the staged protocol did not show a significant improvement in MEB. However, the staged protocol resulted in significantly less severe deteriorations in MEB grades when compared to the linear protocol (P=0.028, exact one-sided Mann-Whitney type test).
CONCLUSION: The use of the assessed staged compression protocol for the first hyperbaric oxygen treatment showed no significant effect on the overall incidence of MEB when compared to the gold standard linear protocol but resulted in a significant improvement in the severity of the experienced MEBs. Further studies are needed to elucidate an optimal compression protocol to minimize middle ear barotrauma.
METHODS: A case-control study was carried out among patients with CSOM (cases) and controls were those with no ear pathology. The presence of CSOM was made through a medical history and otoscopic examination. Allergen testing was done by the skin prick test.
RESULTS: In all 124 subjects were recruited in this study with equal number of the cases and controls. The commonest positive reaction in the skin prick test in both groups was to house dust mites. Among CSOM cases, half (50%) of them had an allergy to Blomia tropicalis and 48.4% to Dermatophagoides while in the control group, 27.4% to Dermatophagoides and 25.8% to B. tropicalis. There were significant associations between CSOM and allergy to B. tropicalis (p=0.005), Dermatophagoides (p=0.016) and Felis domesticus (p=0.040). The prevalence of allergy at 95% confidence interval (95%CI) in CSOM and control groups were demonstrated as 59.7% (95%CI: 47.5, 71.9) and 30.6 % (95%CI: 19.1, 42.1) respectively. There was a significant association between allergy and CSOM (p=0.001).
CONCLUSION: Indoor allergens are the most prevalent in our environment and therefore good control may difficult to achieve. The hypersensitivity states of the subject are likely to have a role in the pathogenesis of CSOM especially in the tropical countries where allergy occurs perennially.