Salvage therapy for refractory sudden sensorineural hearing loss (RSSNHL): a systematic review and network meta-analysis.

OBJECTIVE: Approximately 30-50% of sudden sensorineural hearing loss (SSNHL) patients show poor response to systemic steroid therapy. Additionally, the most appropriate treatment for patients with refractory sudden sensorineural hearing loss (RSSNHL) is unknown. This study aimed to explore the best treatment for RSSNHL. DESIGN: Using a frequentist contrast-based model and PRISMA guidelines, this study compared five salvage regimes: intratympanic injection of steroids (ITS), hyperbaric oxygen (HBO) therapy, post auricle steroid injection (PSI), ITS combined with HBO therapy, and continued systemic steroids. STUDY SAMPLE: We searched the PubMed, EMBASE, Web of Science, and Cochrane Library databases for randomised controlled trials and cohort studies comparing treatment regimens for RSSNHL. RESULTS: Compared with the control group (no additional treatment), PSI and ITS demonstrated significant improvements. The mean hearing gain was greater after PSI (11.1 dB [95% CI, 4.4-17.9]) than after ITS (7.7 dB [95% CI, 4.8-10.7]). When a restricted definition of RSSNHL was used, the ITS + HBO therapy showed the largest difference in improvement for pure tone average compared with the control group (14.5 dB [95% CI, 4.2-25.0]). CONCLUSIONS: The administration of either PSI or ITS leads to the greatest therapeutic effect in patients with RSSNHL. However, a consensus on the definition of RSSNHL is needed.

Hypothesis: Drainage of the peripheral tissue edema by the hyperbaric oxygen therapy because of hyperoxygenation that constricts arterioles and alters the downstream capillary fluid traffic in affected tissues.

Hyperbaric oxygen (HBO) therapy still lacks proper interpretations of its many actions. This hypothesis is based on reports of temporarily elevated peripheral vascular resistance (PVR) during HBO sessions. Besides that, during HBO sessions, hyperoxygenated tissues can reduce their perfusion so much that CO2 can accumulate in them. Tissue perfusion depends on vascular innervation and on the balance between systemic constrictors and local dilators. During an HBO session, increased tissue oxygen levels suppress dilatory mechanisms. Tissue hyperoxygenation increases PVR, suggesting that the HBO action on an edematous tissue may be caused by an oxygen-induced disbalance among Starling capillary forces. The presented hypothesis is that oxygen-caused arteriolar constriction reduces the hydrostatic pressure in downstream capillaries. Thus, more tissue fluid is absorbed in vascular capillaries, under the condition that the plasma colloid osmotic pressure remains unaltered during the HBO session. Among several known mechanisms behind the HBO actions, the vasoconstriction has been listed as a therapeutic modality for the reduction of the tissue edema, for a crush injury, for burns (in an acute phase), and for the compartment syndrome. The Bell's palsy is among often listed indications for the HBO treatment, although evidence is poor and reports of randomized trials are scarce.

Ischemia as a common trigger for Alzheimer's disease.

Alzheimer's disease has various potential etiologies, all culminating in the accumulation of beta -amyloid derivatives and significant cognitive decline. Vascular-related pathology is one of the more frequent etiologies, especially in persons older than 65 years, as vascular risk factors are linked to both cerebrovascular disease and the development of AD. The vascular patho-mechanism includes atherosclerosis, large and small vessel arteriosclerosis, cortical and subcortical infarcts, white matter lesions, and microbleeds. These insults cause hypoperfusion, tissue ischemia, chronic inflammation, neuronal death, gliosis, cerebral atrophy, and accumulation of beta-amyloid and phosphorylated tau proteins. In preclinical studies, hyperbaric oxygen therapy has been shown to reverse brain ischemia, and thus alleviate inflammation, reverse the accumulation of beta-amyloid, induce regeneration of axonal white matter, stimulate axonal growth, promote blood-brain barrier integrity, reduce inflammatory reactions, and improve brain performance. In this perspective article we will summarize the patho-mechanisms induced by brain ischemia and their contribution to the development of AD. We will also review the potential role of interventions that aim to reverse brain ischemia, and discuss their relevance for clinical practice.

Combined Acupuncture-Hyperbaric Oxygen-Steroids Therapy for Idiopathic Sudden Sensorineural Hearing Loss: A Retrospective Observational Study.

Objectives: Acupuncture, widely used in Chinese society, has been studied as an adjunct treatment of idiopathic sudden sensorineural hearing loss (ISSNHL). The purpose of this study is to investigate the effectiveness of combined acupuncture and hyperbaric oxygen therapy (HBOT) with conventional steroid therapy for ISSNHL. Methods: This retrospective chart review enrolled 154 patients who met the ISSNHL criteria and were categorized into three groups according to the different treatment regimens. Among these patients, 43 underwent steroid therapy only (S) group, 74 received steroid and HBOT (S-H) group, and the remaining 37 were treated with combined acupuncture-HBOT in addition to steroid therapy (S-H-A) group. The outcome was determined by comparing the differences in pure-tone thresholds and absolute hearing gains after treatment calculated at each audiometric octave frequency or grouped frequencies of audiograms. Hearing recoveries classified into three grades: complete, partial, and poor were also analyzed and compared among different treatment groups. Results: All subjects presented with initial severe hearing loss with averaged hearing thresholds >70 dB. The S-H-A group exhibited good hearing improvement outcomes at each audiometric octave frequency and grouped frequencies of audiograms, with greater hearing gain and had more favorable outcomes in hearing recovery grades compared with the S group and the S-H group. Conclusions: The results obtained in this study revealed a preliminary finding of ISSNHL patients benefiting from combined acupuncture, HBOT, and conventional steroid therapy. Acupuncture is a safe and nonpharmacologic treatment option and can be considered as an initial treatment strategy in such a clinical scenario.

Effect of HBO therapy on adipose-derived stem cells, fibroblasts and co-cultures: In vitro study of oxidative stress, angiogenic potential and production of pro-inflammatory growth factors in co-cultures1.

BACKGROUND: A key moderator of wound healing is oxygen. Wound healing is a dynamic and carefully orchestrated process involving blood cells, cytokines, parenchymal cells (i.e. fibroblasts and mesenchymal stem cells) and extracellular matrix reorganization. Human adipose derived stem cells as well as human fibroblasts produce soluble factors, exhibit diverse effects on inflammation and anti inflammation response and are involved in wound healing processes.Hyperbaric oxygen therapy is an effective adjunct treatment for ischemic disorders such as chronic infection or chronic wounds. In vitro effects of hyperbaric oxygen therapy on human cells were presented in many studies except for those on mono- and co-cultures of human adipose derived stem cells and fibroblasts. OBJECTIVE: The aim of this study was to investigate the effects of hyperbaric oxygen therapy on mono- and co-cultures of human adipose derived stem cells and fibroblasts. METHODS: Mono- and co-cultures from human adipose derived stem cells and fibroblasts were established. These cultures were exposed to hyperbaric oxygen therapy every 24 h for five consecutive days. Measuring experiments were performed on the first, third and fifth day. Therapy effects on the expression of VEGF, IL 6 and reactive oxygen species were investigated. RESULTS: After exposure to hyperbaric oxygen, cell culturess showed a significant increase in the expression of VEGF after 3 and 5 days. All cultures showed significantly reduced formation of reactive oxygen species throughout the experiments. The expression of IL-6 decreased during the experiment in mono-cultures of human adipose derived stem cells and co-cultures. In contrast, mono-cultures of human skin fibroblasts showed an overall significantly increased expression of IL-6. CONCLUSIONS: Hyperbaric oxygen therapy leads to immunmodulatory and proangiogenetic effects in a wound-like enviroment of adipose derived stem cells and fibroblasts.

The Effectiveness of Hyperbaric Oxygen Therapy as Salvage Treatment for Sudden Sensorineural Hearing Loss: A Retrospective Study.

Background Sudden sensorineural hearing loss (SSNHL) is a medical emergency; its etiology is unknown in most cases, The treatment, in turn, is empiric and usually consists of various pharmacological agents, mainly steroids. Hyperbaric oxygen (HBO) therapy is used routinely as salvage therapy for refractory SSNHL. While several studies have demonstrated the effectiveness of HBO therapy as salvage treatment for refractory SSNHL, its results have varied among studies, and its efficacy is still unclear. Aim We aimed to stratify the effect of HBO therapy as salvage treatment after the failure of steroid therapy for SSNHL. Method This is a retrospective case series that involved eight SSNHL patients in the past three years at King Faisal Specialist Hospital & Research Centre (KFSHRC) in Riyadh, Saudi Arabia. Patients' records were reviewed and statistical analysis was performed. Results Eight patients were included in this case series; six of them were males, and the mean age of all patients was 46.88 ±20.9 years. One patient had herpes zoster as the cause of SSNHL and seven patients' disease was of unknown etiology. The mean period for the onset of disease was 4.12 ±2.17 days. One patient was managed with intravenous dexamethasone and the other patients were managed with oral steroids, and all patients were then treated by HBO therapy. Of the patients, two showed significant improvement but the others did not. The cause of SSNHL, age of patients, HBO start and cessation, comorbidities, and disease onset did not affect the improvement in disease in patients (p: ˃0.05). Conclusion Moderate-to-severe cases of SSNHL can be improved by HBO treatment along with oral steroids, while this therapy was ineffective in severe and profound cases. No factors could be found to predict improvement in patients.

Bladder and rectal incontinence without paraplegia or paraparesis after endovascular aneurysm repair.

Spinal cord ischemia is a well-known potential complication of endovascular aneurysm repair (EVAR), and it is usually manifested by paraplegia or paraparesis. We describe a case in which spinal cord ischemia after EVAR presented by isolated bladder and rectal incontinence without other neurological deficits. A 63-year-old woman presented with intermittent claudication secondary to an infrarenal abdominal aortic aneurysm (AAA), and a left common iliac artery obstruction, for which she underwent EVAR using an aorto-uniiliac (AUI) device and ilio-femoral artery bypass. On postoperative day 3, she developed urinary and fecal incontinence without signs of paraplegia or paraparesis. Magnetic resonance imaging (MRI) showed a hyper-intense signal in the spinal cord. She received hyperbaric oxygen (HBO) therapy and was discharged after 18 days when her urinary and fecal incontinence were almost resolved. This report suggests that spinal cord ischemia after EVAR for aortoiliac occlusive disease might present as bladder and rectal incontinence without other neurological manifestations.

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects.

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

Elevated serum ubiquitin C-terminal hydrolase-L1 levels in patients with carbon monoxide poisoning.

OBJECTIVE: Ubiquitin C-terminal hydrolase-L1 (UCH-L1) has been established as a reliable and potential biomarker of neuronal damage after acute neurologic insults, such as ischemic stroke, subarachnoid hemorrhage, and traumatic brain injury. However, the effect of serum UCH-L1 levels has not been investigated in carbon monoxide (CO)-poisoned patients. The aim of the present study was to evaluate whether serum UCH-L1 levels are a reliable marker of brain damage and the association of UCH-L1 with outcome. DESIGN AND METHODS: This case-control study enrolled 46 CO-poisoned subjects and 30 controls. Using an enzyme-linked immunosorbent assay (ELISA) kit, we studied the temporal profile of serum UCH-L1 levels at 6, 12, 24 and 48 h after acute CO poisoning. Poisoning severity was assessed using the Glasgow Coma Scale (GCS) score. Long-term outcome was assessed using the Glasgow Outcome Scale (GOS) at 6 months after poisoning. RESULTS: Compared with controls, CO-poisoned patients had significantly elevated serum levels of UCH-L1 at each time point after poisoning. There were significantly higher levels of UCH-L1 in CO-poisoned patients with a lower GCS score as well as in those with a poor 6-month outcome dichotomized GOS. CONCLUSIONS: Serum levels of UCH-L1 appear to have potential clinical utility in providing valuable information about poisoning severity and outcome after CO poisoning.