It's all about timing, early treatment with hyperbaric oxygen therapy and corticosteroids is essential in acute acoustic trauma.

BACKGROUND: Acute acoustic trauma (AAT) is an acute hearing impairment caused by intense noise-impact. The current management strategy for AAT with substantial hearing loss in the Dutch military is the combination therapy with corticosteroids and hyperbaric oxygen therapy (HBOT). In a previous study, early initiation of the combination therapy was associated with better outcomes. Therefore, we performed a new analysis to assess the difference in hearing outcome between patients in whom combination therapy was started within two days, versus after more than two days. METHODS: A retrospective analysis was performed on military patients diagnosed with AAT with substantial hearing loss who presented between February 2018 and March 2020. Absolute and relative hearing improvement between first and last audiograms were calculated for all affected frequencies (defined as loss of ≥20 dB on initial audiogram). We also determined the amount of patients who recovered to the level of Dutch military requirement, and performed speech discrimination tests. RESULTS: In this analysis, 30 male patients (49 ears) with AAT were included. The median age was 24.5 years (IQR 23-29). The median time to initiation of therapy with corticosteroids and HBOT were one and two days, respectively. HBOT was started within two days in 31 ears, and after more than two days in 18 ears. The mean absolute and relative hearing gains were 18.8 dB (SD 14.6) and 46.8% (SD 31.3) on all affected frequencies. The 100% discrimination/speech perception level improved from 64.0 dB to 51.7 dB (gain 12.3 dB ± 14.1). There was significantly more improvement in absolute and relative hearing improvement when HBOT was started in ≤2 days, compared to >2 days. CONCLUSION: Our analysis shows results in favor of early initiation (≤2 days) of the combination treatment of HBOT and corticosteroids in patients with AAT.

Effect of hyperbaric oxygen therapy and corticosteroid therapy in military personnel with acute acoustic trauma.

INTRODUCTION: Acute acoustic trauma (AAT) is a sensorineural hearing impairment due to exposure to an intense impulse noise which causes cochlear hypoxia. Hyperbaric oxygen therapy (HBO) could provide an adequate oxygen supply. The aim was to investigate the effectiveness of early treatment with combined HBO and corticosteroid therapy in patients with AAT compared with corticosteroid monotherapy. METHODS: A retrospective study was performed on military personnel diagnosed with AAT between November 2012 and December 2017. Inclusion criteria for HBO therapy were hearing loss of 30 dB or greater on at least one, 25 dB or more on at least two, or 20 dB or more on three or more frequencies as compared with the contralateral ear. RESULTS: Absolute hearing improvements showed significant differences (independent t-test) between patients receiving HBO and the control group at 500 Hz (p=0.014), 3000 Hz (p=0.023), 4000 Hz (p=0.001) and 6000 Hz (p=0.01) and at the mean of all frequencies (p=0.002). Relative hearing improvements were significantly different (independent t-test) at 4000 Hz (p=0.046) and 6000 Hz (p=0.013) and at all frequencies combined (p=0.005). Furthermore, the percentage of patients with recovery to the functional level required by the Dutch Armed Forces (clinical outcome score) was higher in the HBO group. CONCLUSIONS: Early-stage combination therapy for patients with AAT was associated with better audiometric results at higher frequencies and better clinical outcome score.

The use of hyperbaric oxygen therapy in acute hearing loss: a narrative review.

INTRODUCTION: Acute hearing loss can have a major impact on a patient's life. This holds true for both acute acoustic trauma (AAT) and idiopathic sudden sensorineural hearing loss (ISSHL), two devastating conditions for which no highly effective treatment options exist. This narrative review provides the rationale and evidence for HBOT in AAT and ISSHL. METHODS: Narrative review of all the literature available on HBOT in acute hearing loss, studies were retrieved from systematic searches on PubMed and by cross referencing. DISCUSSION: First, the etiological mechanisms of acute hearing loss and the mechanism of action of HBOT were discussed. Furthermore, we have provided an overview of 68 studies that clinically investigated the effect of HBOT in the last couple of decades. For future studies, it is recommend to start as early as possible with therapy, preferably within 48 h and to use combination therapy consisting of HBOT and corticosteroids. IMPLICATIONS FOR PRACTICE: HBOT has been used quite extensively for acute hearing loss in the last couple of decades. Based on the amount of studies showing a positive effect, HBOT should be discussed with patients (shared decision making) as optional therapy in case of AAT and ISSHL.