• The following list provides a 'knowledge share base' working to collaborate and promote the benefits of Hyperbaric Oxygen Therapy.

  • Australia is not a leader in this field but lagging behind the rest of the world in relationship to the wider applications of modern Hyperbaric Oxygen Therapy using different 'pressure protocols for different conditions'. 

  • The information provided does not constitute a medical endorsement or recommendation. It is intended for informational purposes only, and no claims, either real or implied, are being made. 

Does the addition of hyperbaric oxygen therapy to conventional treatment modalities influence the outcome of soldiers with idiopathic sudden sensorineural hearing loss?

J R Army Med Corps 2018 Feb 3. Epub 2018 Feb 3.

Department of Otolaryngology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.​

Background: Idiopathic sudden sensorineural hearing loss (ISSNHL) is defined as a 30-decibel (dB) loss in hearing over three contiguous frequencies within 3 days. The cause remains unknown, and there is currently no consensus in the literature as to how it is best treated. Conventional treatment in our unit comprises steroids, pentoxyphiline and dextran, with the potential addition of hyperbaric oxygen therapy (HBOT).

Methods: A prospective randomised trial was performed on all soldiers diagnosed with ISSNHL in our institution from 1 January 2007 to 31 December 2016. Participants were randomly allocated to one of two groups. Group A was treated with conventional treatment plus HBOT. Group B was treated with conventional treatment only. Data collection included age, gender, clinical symptoms, pure-tone audiometry results and treatment outcome.

Results: 60 participants were enrolled (53 male, 7 female) with ages ranging from 18 to 65 years (mean age of 30.3). No significant differences were observed in the baseline characteristics between the two groups, including gender, age, site, associated symptoms, duration of symptoms and severity of hearing loss. Hearing recovery using Siegel's criteria on days 8 and 13 showed no significant differences between treatment groups. However, the hearing recovery on day 180 was significantly better in those who received the conventional treatment plus HBOT (P<0.05). Additionally, no significant side effects were observed in either group.

Conclusions: HBOT plus existing conventional treatment was associated with a better outcome than conventional treatment alone. We would recommend the addition of HBOT is recommended as a first-line treatment modality for all soldiers presenting with ISSNHL.

Ann Otol Rhinol Laryngol. 2018 Jul 1:3489418787832. doi: 10.1177/0003489418787832. [Epub ahead of print]

The Role of Hyperbaric Oxygen as Salvage Therapy for Sudden Sensorineural Hearing Loss.

Almosnino G1, Holm JR2, Schwartz SR1, Zeitler DM1.

We sought to evaluate hearing outcomes after salvage therapy with hyperbaric oxygen (HBO2) for the treatment of sudden sensorineural hearing loss (SSNHL).


Thirty-six patients (>18 years) diagnosed with SSNHL.


Patients received initial therapy with oral and/or intratympanic (IT) steroids with an incomplete response. Eighteen patients underwent salvage therapy with IT steroids and HBO2 (group 1). Eighteen matched controls underwent salvage therapy with IT steroids alone (group 2).


The main outcome measure was improvement in pure tone average (PTA) and word recognition score (WRS). Complications as a result of therapy were also monitored.


There were no significant differences in age, gender, or hearing between the 2 groups ( P > .05). There was no significant difference in mean post-treatment PTA between group 1 (60.3 dB) and group 2 (53.2 dB). There were no significant difference in mean post-treatment WRS between group 1 (42%) and group 2 (51%). Serviceable hearing was defined as a minimum WRS of 50%. Thirty-three percent in group 1 and 42% in group 2 went from nonserviceable hearing to serviceable hearing ( P > .05). PTA and WRS change scores were not significantly affected by age, gender, form of initial treatment, or pre-treatment PTA and WRS.


The present study demonstrated no significant difference in hearing outcomes between patients receiving salvage therapywith HBO2 and IT steroids compared to patients receiving IT steroids alone. Larger, prospective randomized trials are needed to better define the role of HBO2 as salvage therapy for SSNHL.

J Laryngol Otol. 2017 Jan;131(1):77-82. Epub 2016 Dec 5.

Prognostic factors for idiopathic sudden sensorineural hearing loss treated with hyperbaric oxygen therapy and intravenous steroids.

Hosokawa S1, Sugiyama K2, Takahashi G3, Takebayashi S4, Mineta H1.

Author information



This study evaluated the prognosis of idiopathic sudden sensorineural hearing loss when treated with hyperbaric oxygen therapy and intravenous steroids.


The clinical data for 334 patients with idiopathic sudden sensorineural hearing loss treated by hyperbaric oxygen therapy and intravenous steroids at our hospital were retrospectively reviewed. These data included the initial averaged five-frequency hearing level, patient age, interval between onset of symptoms and treatment, vertigo as a complication, and co-existence of diabetes mellitus.


The overall improvement rate was 69.2 per cent, including better improvement (25.5 per cent), good improvement (21.0 per cent) and fair improvement (22.7 per cent).


Hyperbaric oxygen therapy appears to confer a significant additional therapeutic benefit when used in combination with steroid therapy for idiopathic sudden sensorineural hearing loss. If performed early, hyperbaric oxygen therapy may bring about hearing improvement in many patients who are unresponsive to initial therapy.

J Laryngol Otol. 2016 Oct;130(10):943-947. Epub 2016 Aug 30.

Is hyperbaric oxygen therapy a salvage treatment option for sudden sensorineural hearing loss?

Alimoglu Y1, Inci E2.

Author information



To investigate of the efficacy of hyperbaric oxygen therapy as a salvage treatment after unsuccessful oral corticosteroid therapy.


Case notes of patients who were followed up because of idiopathic sudden sensorineural hearing loss between 2005 and 2011 in a tertiary care centre were examined retrospectively. Audiograms from before and after hyperbaric oxygen therapy were examined in terms of mean gains in pure tone average and at 0.25, 0.5, 1, 2, 4 and 8 kHz. In addition, recovery according to Siegel's criteria was noted.


Mean gain in pure tone average was 10.55 ± 13.56 dB. Mean gains at 0.25, 0.5, 1, 2, 4 and 8 kHz were 16.66 ± 18.43 dB, 16.94 ± 19.93 dB, 12.63 ± 16.71 dB, 7.36 ± 15.28 dB, 5.27 ± 11.58 dB and 2.91 ± 12.44 dB, respectively. Three patients had complete recovery, 1 had partial recovery, 5 had slight recovery and 25 had no improvement.


Hyperbaric oxygen utilised as a salvage therapy after failed corticosteroid therapy may be beneficial in some patients. Studies with more patients are needed.

Braz J Otorhinolaryngol. 2016 Nov 22. pii: S1808-8694(16)30232-4. doi: 10.1016/j.bjorl.2016.10.013. [Epub ahead of print]

Intratympanic steroid injection and hyperbaric oxygen therapy for the treatment of refractory sudden hearing loss.

Gülüstan F1, Yazıcı ZM1, Alakhras WM1, Erdur O2, Acipayam H3, Kufeciler L1, Kayhan FT1.

Author information



Controversy surrounds the use of salvage therapies to treat sudden sensorineural hearing loss (SSNHL), with no consensus on recommendations. While several studies have demonstrated the effectiveness of intratympanic administration of steroids (ITS) and hyperbaric oxygen (HBO) treatment, few have compared the efficacy of ITS and HBO therapy in patients with refractory SSNHL.


We evaluated the efficiency of ITS and HBO therapy in patients with refractory SSNHL.


Patients who did not adequately benefit from systemic treatment were evaluated retrospectively. Refractory patients were defined as those who gained less than 20dB in hearing after initial treatment. All refractory patients were informed about salvage therapy options: ITS or HBO therapy, the advantages and disadvantages of which were explained briefly. ITS involved 4mg/mL dexamethasone administered through a 25 gauge needle. Patients underwent HBO therapy in a hyperbaric chamber where they breathed 100% oxygen for 120min at 2.5 atmospheric pressure. The hearing levels of both groups were evaluated before the salvage therapy and at 3 months after treatment. Improvements in hearing were evaluated according to the Furahashi criteria. We also compared the two therapies in terms of speech discrimination scores (SDSs) and the recovery of all frequencies.


The salvage therapies generated similar results. Changes in pure tone averages and SDSs were similar for ITS and HBO therapy (p=0.364 and p=0.113). Comparison of SDSs and hearing thresholds at all frequencies showed similar levels of improvement.


ITS and HBO therapy produced similar improvements in SSNHL patients, but the sample size was too small to draw definitive conclusions. Further randomized controlled studies are needed to identify the best therapy for patients with refractory sudden hearing loss.


Otolaryngol Head Neck Surg. 2015 Jun 17. pii: 0194599815589072. [Epub ahead of print]

Hyperbaric Oxygen Treatments Attenuate the Neutrophil-to-Lymphocyte Ratio in Patients with Idiopathic Sudden Sensorineural Hearing Loss

Li H1, Zhao D2, Diao M3, Yang C1, Zhang Y1, Lv Y1, Zhao J1, Pan S4.

Author information

  • 1Hyperbaric Oxygen Center of Chinese People's Liberation Army, Department of Hyperbaric Oxygen, Navy General Hospital, Beijing, China.

  • 2Department of Otolaryngology Head and Neck Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, ShaanXi, China.

  • 3Center of Otolaryngology of Chinese People's Liberation Army, Navy General Hospital, Beijing, China.

  • 4Hyperbaric Oxygen Center of Chinese People's Liberation Army, Department of Hyperbaric Oxygen, Navy General Hospital, Beijing, China



Hyperbaric oxygen therapy (HBOT) is a promising treatment in the management of idiopathic sudden sensorineural hearing loss (ISSNHL), but the specific mechanisms of HBOT in ISSNHL are still unclear. The curative effects of HBOT in many diseases are related to the attenuation of inflammatory response. The neutrophil-to-lymphocyte ratio (NLR) is a new inflammatory marker that can be assessed quickly. We investigated the relationship between HBOT and the inflammatory response in ISSNHL using the NLR.


Case series with chart review SETTING: Tertiary teaching and research hospital SUBJECTS AND METHODS: Between December 2007 and December 2013, 41 ISSNHL patients who underwent HBOT, 45 ISSNHL patients who did not undergo HBOT, and 14 healthy control subjects who underwent HBOT were included in the study. NLRs were assessed at 2 time points: at baseline (pretreatment) and on day 1 after 10 sessions of HBOT (posttreatment). Audiometric testing was performed at the above 2 time points.


The mean post-HBOT NLRs, neutrophil, and white blood cell count values of the ISSNHL patients were significantly lower than their pretreatment values (P < .001). Compared with the ISSNHL patients who did not undergo HBOT, the posttreatment NLR levels of the ISSNHL patients who underwent HBOT were much lower (P = .036). Higher relative hearing gains were significantly associated with a greater reduction in the NLR after HBOT (r = -0.885, P = .001).


The beneficial effect of HBOT on ISSNHL may be mediated at least in part by a decrease of inflammation.

J Formos Med Assoc. 2014 Sep;113(9):620-8. doi: 10.1016/j.jfma.2014.03.012. Epub 2014 Apr 29.

Repetitive hyperbaric oxygen therapy provides better effects on brain inflammation and oxidative damage in rats with focal cerebral ischemia

Chen LF1, Tian YF2, Lin CH3, Huang LY4, Niu KC4, Lin MT5.

Author information

  • 1Nursing Department, Cheng Kung University Hospital and Department of Nursing, Chang Jung University, Tainan, Taiwan.

  • 2Department of Surgery, Chi Mei Medical Center, Tainan, Taiwan; Department of Health and Nutrition, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan. Electronic address:

  • 3Department of Nursing, Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan; Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan.

  • 4Department of Hyperbaric Oxygen, Chi Mei Medical Center, Tainan, Taiwan.

  • 5Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan. Electronic address:



Repetitive hyperbaric oxygen (HBO2) therapy may cause excessive generation of reactive oxygen species. This study assessed whether repetitive or 2-4-day trials of HBO2 therapy (2 treatments daily for 2-4 consecutive days) provides better effects in reducing brain inflammation and oxidative stress caused by middle cerebral artery occlusion (MCAO) in rats than did a 1-day trial of HBO2 therapy (2 treatments for 1 day).


Rats were randomly divided into four groups: sham; MCAO without HBO2 treatment; MCAO treated with 1-day trial of HBO2; and MCAO treated with 2-4-day trials of HBO2. One treatment of HBO2 (100% O2 at 253 kPa) lasted for 1 hour in a hyperbaric chamber.


Therapy with the 2-4-day trials of HBO2 significantly and dose-dependently attenuated the MCAO-induced cerebral infarction and neurological deficits more than the 1-day trial of HBO2 therapy. The beneficial effects of repetitive HBO2 therapy were associated with: (1) reduced inflammatory status in ischemic brain tissues (evidenced by decreased levels of tumor necrosis factor-α, interleukin-1β, and myeloperoxidase activity); (2) decreased oxidative damage in ischemic brain tissues (evidenced by decreased levels of reactive oxygen and nitrogen species, lipid peroxidation, and enzymatic pro-oxidants, but increased levels of enzymatic antioxidant defenses); and (3) increased production of an anti-inflammatory cytokine, interleukin-10.


The results provide the apparently contradictory finding that heightened oxygen tension reduced oxidative stress (and inflammation), which was reflected by increased antioxidant and decreased oxidant contents under focal cerebral ischemia.



Eur Arch Otorhinolaryngol. 2014 Oct 16. [Epub ahead of print]

Hyperbaric oxygen therapy as salvage treatment for sudden sensorineural hearing loss: a prospective controlled study

Pezzoli M1, Magnano M, Maffi L, Pezzoli L, Marcato P, Orione M, Cupi D, Bongioannini G.


The most commonly used treatment for sensorineural sudden hearing loss (SSHL) in clinical practice is the administration of steroids; however, a favorable result is not always obtained. We studied 58 patients who failed to recover after primary treatment with IV steroids, 44 of these met our inclusion criteria (mean age 50.7, 27 males, range 30-74). We treated 23 patients (mean age 47.3, 16 males, age range 22-74) with hyperbaric oxygen therapy (HBO) (2.5 ATA for 60 min for 15 treatments), while 21 (mean age 54.5, 11 males, age range 22-71) patients refused to be treated and served as a non-randomized control group. Patients treated with HBO had a mean improvement of 15.6 dB (SD ± 15.3), with 1 of them completely healed, 5 with a good recovery, 10 with a fair recovery and 7 unchanged. Patients who were not treated had a spontaneous mean improvement of 5.0 dB (SD ± 11.4) with 3 patients with a good recovery, 1 patient with a fair recovery and 17 patients unchanged.

Mean improvement was significantly better in patients treated with HBO compared to controls (p = 0.0133). Patients with worst hearing had the greater degree of improvement whether or not they were treated in the first 10 days after the onset of the hearing loss or between 11 and 30 days. In conclusion, hyperbaric oxygen therapy can lead to significant improvement of pure tone hearing thresholds in patients with SSHL who failed primary corticosteroid treatment and are within 4 weeks of the onset of deafness.



Nihon Jibiinkoka Gakkai Kaiho. 2014 Jun;117(6):802-8.

[Efficacy of intratympanic steroid treatment for idiopathic sudden sensorineural hearing loss after failure of intravenous steroid treatment]

[Article in Japanese]

Kawano T, Matsuura M, Ishitoya J, Oridate N.


This study investigated the efficacy of intratympanic steroid (ITS) therapy as a salvage treatment for idiopathic sudden sensorineural hearing loss after failure of intravenous steroid (IVS) therapy. Systemic steroid therapy is the only standard drug therapy. However, ethically, we could not simply compare ITS with IVS. Conventionally, we have treated idiopahic sudden sensorineural hearing loss patients after failure of systemic steroid therapy with the double combined therapy IVS and hyperbaric oxygen (HBO), as the salvage modality. We examined the effect of ITS by adding it to the double combined therapy with IVS and HBO.

Retrospectively, we clinically examined the effect of double combined therapy with IVS and HBO (A group) for 31 patients (12 men and 19 women) (median age: 54 years) with sudden hearing loss after failure of systemic steroid therapy between June, 2003 and July, 2010. Prospectively, we also examined clinically the effect of triple combined therapy with IVS and HBO, ITS (B group) for 29 patients (17 men and 12 women) (median age: 51 years) with sudden hearing loss after failure of systemic steroid therapy between August, 2010 and April, 2012. In the examination of patients treated within 30 days from the onset, one patient (3.2%) demonstrated remarkable recovery, 6 patients (19.4%) demonstrated mild recovery, while no change was noted in 24 patients (77.4%) in the A group. In the B group, 5 patients (17.2%) demonstrated complete recovery, 3 patients (10.3%) demonstrated remarkable recovery, mild recovery was seen in 14 patients (48.3%), and the remaining 7 patients (24.1%) showed no change. There was a significant difference (p < 0.05) between the A group and the B group. Furthermore, the hearing improvement in group B in five pure tone average was significantly better than in the group A (p < 0.05).

We concluded that the B group demonstrated better hearing improvement than the A group. Therefore, ITS could be effective for idiopathic sudden sensorineural hearing loss patients after failure of systemic steroid therapy.



Otol Neurotol. 2013 Oct;34(8):1411-6. doi: 10.1097/MAO.0b013e3182a1eb83.

Comparison of intratympanic steroid injection, hyperbaric oxygen and combination therapy in refractory sudden sensorineural hearing loss

Yang CH1, Wu RW, Hwang CF.

  • 1*Department of Otolaryngology, and †Hyperbaric Oxygen Therapy Center, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan, Republic of China.



The objective of this study was to compare the efficacy of intratympanic steroid injection (ITS), hyperbaric oxygen (HBO), and combination therapy as salvage treatment in patients with sudden sensorineural hearing loss (SSNHL) after failure of systemic therapy.


A historical cohort study.


Academic medical center.


One hundred three refractory SSNHL patients are enrolled. Among them, 35 received ITS alone (ITS group), 22 received HBO alone (HBO group), 19 received combined ITS and HBO (combined group), and 27 received no salvage therapies (control group). Hearing outcomes were determined by hearing gains in pure-tone average (PTA), recovery rate, and word recognition score (WRS) measured by audiometry before and after salvage therapies.


Significant larger hearing gains in PTA were found in the ITS, HBO, and combined groups than the control group. The combination of ITS and HBO resulted in a significantly larger WRS improvement than the control group (p = 0.035) and larger hearing gains than the ITS and HBO groups in 250 Hz (p < 0.05).


ITS, HBO, and combined therapy offered some benefits in hearing improvement. Combined ITS/HBO may result in a larger WRS improvement and recovery of hearing, especially in lower frequencies. Further randomized prospective studies are needed for confirmation.



Otol Neurotol. 2013 Aug;34(6):1021-6. doi: 10.1097/MAO.0b013e318297638a.

Randomized prospective trial of hyperbaric oxygen therapy and intratympanic steroid injection as salvage treatment of sudden sensorineural hearing loss

Cvorovic L1, Jovanovic MB, Milutinovic Z, Arsovic N, Djeric D.



To compare the effects of hyperbaric oxygen (HBO) and intratympanic (IT) steroid injection on hearing after the failure of primary treatment in patients with idiopathic sudden sensorineural hearing loss (ISSHL).


A prospective randomized trial.


Tertiary referral center.


Fifty patients with failure of primary therapy for ISSHL.


After primary treatment with systemic steroids and failure of therapy, defined as less than 10-dB hearing gain, 50 patients were enrolled in the study and received either hyperbaric oxygen or intratympanic steroid treatment. The patients were not matched and not similar.


Hearing gain at 0.25, 0.5, 1, 2, and 4 kHz after treatment.


There were significant differences between hearing thresholds at all frequencies before and after the HBO treatment. Similarly, there were significant differences between hearing thresholds at most frequencies (except 2 kHz) before and after the treatment in the IT group. The subgroups of patients with pure tone average less than 81 dB and were younger than 60 years had better response to HBO treatment than those with profound deafness and in the elderly.


HBO and IT steroid therapy could be successfully used as salvage therapies in patients with sudden deafness. Further study is needed to demonstrate superiority of one of the treatments.

J Laryngol Otol. 2010 Feb;124(2):e2. doi: 10.1017/S0022215109992052. Epub 2009 Nov 30.

Hyperbaric oxygen therapy as salvage treatment for sudden sensorineural hearing loss: review of rationale and preliminary report

Muzzi E1, Zennaro B, Visentin R, Soldano F, Sacilotto C.

  • 1ENT Clinic, Santa Maria della Misericordia University Hospital, Udine, Italy.



The management of sudden sensorineural hearing loss has not yet been standardised. Hyperbaric oxygen therapy influences recovery from sudden sensorineural hearing loss, but the underlying mechanism is unknown and the appropriate indications and protocols undetermined.


Nineteen patients affected by sudden sensorineural hearing loss were treated after unsuccessful medical therapy, either in an acute or chronic setting. Pure oxygen inhalation at 2.5 atmospheres absolute pressure was administered for 90 minutes, for 30 sessions. Frequency-specific and average pure tone hearing thresholds were determined before and after hyperbaric oxygen therapy. The number of hyperbaric oxygen therapy sessions, the patient's age and any therapeutic delay were considered as quantitative variables possibly influencing outcome. Stepwise multivariate analysis was performed.


Salvage hyperbaric oxygen therapy appeared to improve patients' pure tone hearing thresholds, particularly at low frequencies. Positive results were more likely with increased patient age and reduced delay in receiving hyperbaric oxygen therapy.


Hyperbaric oxygen therapy has a strong scientific rationale, and improves pure tone hearing thresholds in cases of sudden sensorineural hearing loss unresponsive to medical therapy. Further research may be able to identify those patients with sudden sensorineural hearing loss for whom hyperbaric oxygen therapy would be most cost-effective