Background  Noise induced hearing loss (NIHL) is a slow progressive sensorineural deafness which can cause headache, dizziness, insomnia, hypertension, etc by the development of disease. Due to no effective treatment, it will seriously affect flight safety.

  Objective  To evaluate the effects of hyperbaric oxygenations (HBO) in treating NIHL, and provide more effective guidance for clinical treatment.

  Methods  Randomized controlled trials of HBO-treated NIHL (the experimental group was given HBO for intervention while the control group was not, both groups could be treated with other drugs or intervention) were retrieved from databases of CKNI, Wanfang, VIP and PubMed. The methodological quality assessment on included literature was processed by Jadad quality scoring method, and RevMan 5.3.0 was adopted to conduct Meta-analysis.

  Results  A total of 4 clinical randomized controlled trials met the inclusion criteria, including 284 patients (142 cases in experimental group and 142 cases in control group). Results of meta-analysis indicated that after HBO treatment, there was a statistically significant improvement of NIHL patients’ pure ton auditory threshold 0.5 kHz MD=-5.95, 95%CI(-7.14 - -4.74), P＜0.01, 1 kHz MD=-4.45, 95% CI (-5.34 - -3.56), P＜0.01, 2 kHz MD=-4.58, 95% CI (-5.69 - -3.47), P＜0.01, 4 kHz MD=-11.75, 95% CI (-13.73 - -9.77). No adverse reaction was reported.

  Conclusion  HBO treatment in NIHL patients can reduce the PTA threshold at 0.5 k, 1 k, 2 k, 4kHz without side effects. However, the PTA threshold reduction is need to be verified by high-quality clinical studies.