Comparison of therapeutic results in sudden sensorineural hearing loss with/without additional hyperbaric oxygen therapy: a retrospective review of 465 audiologically controlled cases

Objective: To investigate the necessity of routine application of hyperbaric oxygen therapy for sudden sensorineural hearing loss. Design/setting and participants: A retrospective chart review looked at 465 patients, with 353 of them receiving pharmacologic treatments alone. Among these patients, 76 underwent systemic steroid treatment only (steroid group) and 277 received systemic steroids and dextran (steroid-dextran group). The remaining 112 patients were treated with hyperbaric oxygen in addition to pharmacologic agents (steroid-dextran-hyperbaric oxygen group). Main outcome measures: The outcome was determined by comparing the difference of pure-tone thresholds and absolute hearing gains after treatment calculated at each audiometric octave frequency or grouped frequencies of audiograms. On the basis of the severity of initial hearing loss, patients were classified at three scales of hearing impairments measured in decibels hearing level (dBHL): <= 70 dBHL, less severe; 71-90 dBHL, severe; and 91 dBHL, profound. The outcomes of their hearing recovery were classified into three recovery grades: good, fair and poor. Results: In those patients with initial hearing loss > 90 dBHL, the addition of hyperbaric oxygen to steroid-dextran gave a significant hearing gain difference (P = 0.030) by showing a greater hearing gain of 24.5 +/- 2.7 dB compared with steroid only (12.9 +/- 3.7 dB) or steroid-dextran (15.6 +/- 2.7 dB). This outcome was confirmed when we compared the outcome using the recovery grading; steroid-dextran-hyperbaric oxygen group showed that more patients with initial profound (91 dBHL) hearing loss responded to hyperbaric oxygen treatment by exhibiting good and fair recoveries (2% and 70%) as compared with steroid only (0% and 42%) or steroid-dextran (8% and 46%) groups (P = 0.043), while the patients with initial severe (71-90 dBHL) and less severe (<= 70 dBHL) hearing loss responded to the addition of hyperbaric oxygen treatment with less favourable recoveries. Furthermore, the addition of dextran in steroid-dextran group showed no significant benefit compared with the steroid group (P = 0.435). Conclusions: When applied as an adjuvant to pharmacologic agents, hyperbaric oxygen benefits patients with initial profound sudden sensorineural hearing loss. Therefore, we recommend the routine application of hyperbaric oxygen in conjunction with pharmacologic agents for those patients. The addition of dextran to steroid has no benefit and cannot be recommended.