Efficacy of hyperbaric oxygen therapy as a supplementary therapy of sudden sensorineural hearing loss in the Slovak Republic

Abstract

We evaluated the efficacy of hyperbaric oxygen (HBO2) therapy used as a supplement to the first-line medical treatment of sudden sensorineural hearing loss (SSNHL). We tested 68 patients suffering from SSNHL within seven days of hearing loss: 21 patients received the standard treatment protocol of our department (control group) and 47 individuals were treated with an additional application of HBO2 therapy. Treatment success was assessed using pre- and post-treatment audiograms. Outcomes of our study showed a statistically significant improvement in auditory threshold in all frequency groups for the HBO2 group (P < 0.001), whereas in the control group the statistically significant mean auditory gain was observed only for the frequency zone 1,000 to 2,000 Hertz (P = 0.01). Furthermore, the rate of hearing gain in the HBO2 group was more than doubled (61.7%) compared to the control group (28.6%). Complete recovery of the hearing gain in the control group was observed only in the first two frequency groups (14.29%; 4.76%; 0.00%), whereas in the HBO2 group complete recovery was seen in all the frequency groups (19.15%; 21.13%; 6.38%) as well as in the whole frequency range (6.38%). The efficiency of both treatment protocols was statistically significant (P < 0.001) in both groups of patients, but supplementation of the therapy with HBO2 demonstrated a statistically significantly increase in the effect of pharmacotherapy (P < 0.001) by 11.5 decibels (dB) up to the final hearing gain of 20 dB. HBO2 is therefore a promising modality of SSNHL treatment, but specific mechanisms of HBO2 in patients with SSNHL arestill unknown. Further investigations are warranted to explore the mechanisms of action.

The Optimized Protocol of Hyperbaric Oxygen Therapy For Sudden Sensorineural Hearing Loss

“…In 2021, Tong et al showed in their RCT that 60.6% of patients in the HBOT + SS group achieved >15 dB hearing improvement compared with only 42.9% in the SS group 33 . Recently, combined therapy with SS, ITS, and HBOT has been introduced, and a systematic review of three prospective RCTs with 88 participants showed that the mean hearing gain (mean difference, 10.3 dB) and the odds ratio of hearing recovery (4.3) were higher with the triple combination therapy than with the control therapy 15–18 . Although triple combination therapy has been shown to be sufficiently effective, no standardized HBOT protocol has been established.…”

“…33 Recently, combined therapy with SS, ITS, and HBOT has been introduced, and a systematic review of three prospective RCTs with 88 participants showed that the mean hearing gain (mean difference, 10.3 dB) and the odds ratio of hearing recovery (4.3) were higher with the triple combination therapy than with the control therapy. [15][16][17][18] Although triple combination therapy has been shown to be sufficiently effective, no standardized HBOT protocol has been established. Considering that HBOT is a costly and time-consuming intervention compared with corticosteroid treatment, it is imperative to identify a protocol that can produce the maximum effect in the shortest time and under minimum pressure.…”

“…Although the protocol (pressure, time, and length of treatment) of HBOT varied across studies, most studies used a maximum oxygen pressure of 1.5–2.5 ATA and conducted 10–25 sessions in total 14 . A recent systematic review involving three RCTs proposed the following HBOT protocol for the management of SSNHL: a pressure of at least 2.0 ATA for 900 min, divided into 10 sessions of 90 min each or 15 sessions of 60 min each 15–18 . However, the pressure, frequency, and total time of HBOT remain variable among different studies.…”

“…14 A recent systematic review involving three RCTs proposed the following HBOT protocol for the management of SSNHL: a pressure of at least 2.0 ATA for 900 min, divided into 10 sessions of 90 min each or 15 sessions of 60 min each. [15][16][17][18] However, the pressure, frequency, and total time of HBOT remain variable among different studies. Therefore, the optimal HBOT protocol needs to be determined through comparisons in a well-designed investigation.…”

Avoiding Definitive Conclusions in Meta-analysis of Heterogeneous Studies With Small Sample Sizes

“…A major shortcoming was that most of its overall effects were predominantly driven by the over weighting of Khater et al, 4 an RCT with a total of only 22 participants, resulting in an unconvincing clinical conclusion. In a letter in reply, 5 the authors maintain the validity of their conclusion after excluding Khater et al 4 Their justification was given that the remaining 2 studies were also short of data consistency: the proportion of patients showing a hearing gain of 10 dB or greater was 81.7% (25 of 30 patients) in the control group of Cho et al 6 compared with 28.6% (6 of 21) in the control group of Krajčovičová et al 7 Naturally, this raises a second concern, that it could be challenging to examine the model assumptions if the number of studies is very small. Technically, the conventional I 2 statistic to test study heterogeneity for randomeffects modeling is biased in small meta-analyses.…”