Prognostic factors for hearing outcomes in patients that undergo adjuvant hyperbaric oxygen therapy for sudden sensorineural hearing loss

Introduction The aim of this study is to explore the potential factors in hearing outcomes and verify the role of oxidant‐antioxidant equilibrium on the prognosis of sudden sensorineural hearing loss (SSNHL) treated with hyperbaric oxygen therapy (HBOT). Methods Ninety‐two patients who were diagnosed with SSNHL between January 2018 and December 2019 in our hearing clinic center were included in this study. All patients were treated with intravenous dexamethasone, and 72 cases were treated with additional HBOT for 10 consecutive days. Peripheral blood was collected prior to any treatment to determine the blood cell count and hemoglobin (HGB), hematocrit (HCT), and superoxide dismutase (SOD) levels. Pure tone audiometry was measured before and after treatment. Complete and overall recovery rate was evaluated. Multivariate logistic analysis was used to identify prognostic factors. Results The rate of overall recovery was significantly higher in the patient with combined therapy compared to patients treated with steroids only (51.4% vs 25.0%, p = .036). The levels of HGB, HCT, and SOD were much higher in the patients with better hearing outcomes (p = .027, .033, and .011, respectively). Multivariate logistic analysis demonstrated that patients with higher initial hearing thresholds, or hearing loss at overall frequency, were more prone to have poor hearing gains after HBOT. Conclusion HBOT is effective as an early adjuvant therapy for SSNHL. Hearing loss at low frequency, low initial hearing thresholds, as well as high HBG, HCT, and SOD levels are positive prognostic factors for SSNHL patients treated with HBOT.