An Update on the Appropriate Role for Hyperbaric Oxygen: Indications and Evidence

Quality of evidence supporting the role of hyperbaric oxygen therapy for diabetic foot ulcers

The goal of this overview of systematic reviews (SRs) and meta-analyses (MAs) was to methodically gather, evaluate and summarize the data supporting the use of hyperbaric oxygen therapy (HBOT) to treat diabetic foot ulcers (DFUs). The Cochrane Library, Embase, PubMed, Web of Science and Embase were all searched thoroughly to identify SRs/MAs that qualified. AMSTAR-2 tool, PRISMA checklists and GRADE system were applied by two reviewers independently to assess the methodological quality, reporting and evidence quality of the included SRs/MAs, respectively. Eleven SRs/MAs were enrolled in this overview. According to AMSTAR-2, a very low methodological quality assessment was given to the included SRs/MAs due to the limitations of items 2, 4 and 7. For the PRISMA, the overall quality of reporting is not satisfactory due to missing reporting on protocol, search, as well as additional analysis. The majority of outcomes had low- to moderate-quality evidence, and no high-quality evidence was found to support the role of HBOT for DFUs, according to GRADE. To conclude, the potential of HBOT in treating DFUs is supported by evidence of low to moderate quality. More rigorously designed, high-level studies are needed in the future to determine the evidence for HBOT for DFU, including the timing, frequency and duration of HBOT interventions.

Hyperbaric Oxygen Therapy for the Management of Mild and Moderate Traumatic Brain Injury: A Single-Center Experience

BACKGROUND

Hyperbaric oxygen therapy (HBOT) has been shown to be an effective modality in the management of a variety of conditions. However, its role in the treatment of traumatic brain injury (TBI) remains an area of controversy. This study aims to evaluate the safety and outcomes of HBOT in managing the long-term sequelae of TBI.

METHODS

The records of TBI patients who underwent increments of 40 sessions of HBOT at 1.5 atmosphere absolute at a single medical center were reviewed. The outcome measures included physical, cognitive (i.e., Trail Making Test, parts A and B; U.S. Department of Veterans Affairs' Evaluation of Cognitive Impairment and Subjective Symptoms tool), and single-photon emission computed tomography findings. The complications and withdrawals were recorded.

RESULTS

During the study period, 17 patients underwent HBOT to manage the long-term sequelae of their TBI. Of the 17 patients, 12 (70.6%) completed 120 HBOT sessions and were evaluated 3 months after treatment. All 12 patients had statistically significant improvements in their Trail Making Test, parts A and B, and U.S. Department of Veterans Affairs' Evaluation of Cognitive Impairment and Subjective Symptoms scores (P < 0.05). Additionally, single-photon emission computed tomography depicted increased cerebral blood flow and oxygen metabolism among studied subjects compared with the baseline values. A total of 5 patients withdrew from the study, which was related to new-onset headaches associated with HBOT for 1 patient.

CONCLUSIONS

HBOT using 1.5 atmosphere absolute in increments of 40 sessions was found to be a safe and effective modality in the management of the long-term sequelae of TBI. HBOT should be considered in the management of this patient population.

Pilot study: Utility of long-wave infrared thermography as a correlate to transcutaneous oximetry for candidates of hyperbaric oxygen therapy

Hyperbaric oxygen (HBO₂ ) has been used as an adjunctive treatment for the care of advanced non-healing diabetic foot ulcers (DFUs). A patient's in-chamber transcutaneous oximetry measurement (TCOM) is currently the most effective predictor for response to HBO₂ therapy but still excludes close to one in four patients who would benefit out of treatment groups when used for patient selection. Improving selection tools and criteria could potentially help better demonstrate HBO₂ therapy's efficacy for such patients. We sought to identify if long-wave infrared thermography (LWIT) measurements held any correlation with a patient's TCOM measurements and if LWIT could be used in a response prediction role for adjunctive HBO₂ therapy. To investigate, 24 patients already receiving TCOM measurements were enrolled to simultaneously be imaged with LWIT. LWIT measurements were taken throughout each patient's therapeutic course whether they underwent only standard wound care or adjunctive HBO₂ treatments. A significant correlation was found between in-chamber TCOM and post-HBO₂ LWIT. There was also a significant difference in the post-HBO₂ LWIT measurement from 1st treatment to 6 weeks or the last treatment recorded. These initial findings are important as they indicate a possible clinical use for LWIT in the selection process for patients for HBO₂ therapy. Larger studies should be carried out to further articulate the clinical use of LWIT in this capacity.

Combination of Hyperbaric Oxygen Therapy and Oral Steroids for the Treatment of Sudden Sensorineural Hearing Loss: Early or Late?

Background and Objectives: Several treatments are available for sudden sensorineural hearing loss (SSNHL), but no studies have compared the different treatments based on the delay from the onset of the disease. Our study aims to compare the effect of hyperbaric oxygen therapy (HBOT), oral steroids (OS) and combination of both therapies (HBOT + OS) for treating SSNHL. Materials and Methods: This randomized study analyzed 171 patients with SSNHL. Patients were evaluated by pure tone audiometry test (PTA) at baseline (T0) and 20 days after treatment (T1). Three groups were available HBOT-A-, OS-B- and HBOT + OS-C-. After baseline PTA, patients were randomly assigned to each group. Statistical analysis was performed by one-way ANOVA and Chi-square. Results: Patients in the HBOT + OS and HBOT groups improved their auditory function (p < 0.05). HBOT was the best choice for treatment when started by 7 days from SSNHL onset, while HBOT + OS in case of late treatment. Profound SNHL recovered equally by HBOT and HBOT + OS (p < 0.05). Upsloping SNHL obtained better auditory results by HBOT compared to HBOT + OS (p < 0.05). Downsloping and flat SSNHL had the most improvement with HBOT + OS compared to HBOT only (p < 0.05). Conclusions: Combination of HBOT and OS is a valid treatment for SSNHL both in case of early and late treatment. Combination of HBOT and OS was the choice with the best results in case of treatment started >14 days from symptom onset.

Global outcomes and lessons learned in the management of Fournier's gangrene from high-volume centres: findings from a literature review over the last two decades

INTRODUCTION

Fournier's Gangrene (FG) carries a high mortality and morbidity with underreported short and long-term outcomes. Our aim was to perform a review of the recent literature to evaluate the short and long-term outcomes in patients with FG in the acute setting from large-scale studies.

METHODS

A PubMed search was performed between January 2000 and December 2021 for studies reporting on patients with FG. Exclusion criteria included small samples (n < 100), review articles and animal studies. Primary outcomes of interest were mortality, number of operative episodes for surgical debridement and admission to intensive care unit (ICU). Other outcomes assessed included rate of faecal and urinary diversion, orchidectomy rate, penectomy rate and length of hospital stay.

RESULTS

From a total of 1182 studies, 18 were eligible for inclusion and included in this review. In total, data were analysed from 13,903 FG patients. Mean inpatient mortality rate was 7.3% (range 4.7-40.4%). Mean number of surgical debridement operations performed was 1.8 (range 1.5-4.2). On average, 6.8% (range 3.6-50.5%) and 7% (range 1.2-53.2%) underwent faecal and urinary diversions, respectively. Mean rate of orchidectomy was 5.6%, with rate of penectomy being lower at 0.2%. The mean length of hospital stay was 18.5 days (range 13.0-26.6). On average, 17.5% (range 10.1%-67.5%) required ICU admission for at least a single-system support.

CONCLUSION

Our review from the past twenty years of literature suggests that the mortality for FG, whilst still high, has fallen compared to previous years. Whilst inpatient metrics are well-covered in the literature there is a lack of large-scale studies detailing long-term patient outcomes.

The effect of hyperbaric oxygen therapy on cognition, performance, proteomics, and telomere length—The difference between zero and one: A case report

Introduction

Hyperbaric oxygen (HBO2) therapy has recently been suggested for the treatment of different brain injuries as well as for physical and cognitive enhancement. The author recently carried out a self-experiment to obtain objective information on the effects of HBO2 therapy on neurocognition, cardiopulmonary function, neuroimaging and its effect on novel biomarkers such as telomere length and proteomics. In the following case report, the author will present and discuss the results and the differences between zero and one.

Methods

This is a personal case report on a single subject, myself, who underwent a protocol of 60 daily HBO2 therapy sessions within 3 months. Pre- and post-therapy objective evaluation measured included computerized cognitive assessment, brain imaging, cardiopulmonary exercise test, physical assessments and blood tests including telomere length and proteomics.

Results

Neurocognitive results showed a 3.1–3.8% improvements in global cognitive function as well as all other cognitive function domains. In the perfusion MRI, there was a relative increase ranging from 43.3 to 52.3% in cerebral perfusion in various areas subserving memory, coordination, and visual motor cortex function. Similar improvements in cerebral perfusion were seen in the SPECT scans, which ranged from 8.79 to 16.12% increased perfusion in the temporal pole and entorhinal cortex subserving memory, as well as in the subcallosal area and lingual gyrus. MRI-DTI showed prominent increases in fractional anisotropy in several white matter areas including 9% in the body of the corpus callosum, 16.85% in for the fornix and 22.06% in the tapetum. In the physical domains, there were improvements in both anaerobic threshold, exercise endurance, muscle strength, gait speed and grip strength in the 7–15% range. The telomeres length was doubled and clusters of inflammatory proteins dropped around the 40th session and remained low at the 60th session.

Conclusion

The difference between zero and one in this single case study of HBO2 therapy confirmed improvement in objective biomarkers which measured cognition, memory, brain processing speed, athletic performance and neuroimaging modalities measuring cerebral perfusion, blood flow and tractography. Additional studies with larger sample size and randomized clinical trials using similar biomarkers are needed to confirm the results and to delineate the longevity of these improvements.

Hyperbaric Oxygen Improves the Survival and Angiogenesis of Fat Grafts after Autologous Fat Transplantation

Objective

Currently, autologous fat transplantation (AFT) still has a low graft survival rate. Elevation of the AFT graft survival rate is a challenge. This study investigated the effect of hyperbaric oxygen (HBO) on AFT.

Methods

Twelve adult male SD rats were randomly divided into two groups after AFT: the control group (n = 6) and the HBO group (n = 6). The rats were killed at 7, 14, and 28 days after transplantation to take the transplanted adipose tissues. The volume and weight of the tissues were detected. The pathological changes in the adipose tissues were observed after H&E staining. Microvessel density and levels of transforming growth factor- (TGF-) β, tumor necrosis factor- (TNF-) α, and malondialdehyde (MDA) in the transplanted adipose tissues were measured with CD31 immunohistochemical stain, ELISA, and biochemical reagents, respectively. Additionally, the protein expression levels of vascular endothelial growth factor- (VEGF-) A and platelet-derived growth factor- (PDGF) A in the adipose tissues were detected by Western blot.

Results

HBO significantly preserved the volume and weight of the transplanted adipose tissue (p < 0.01) and maintained the pathological structure of the transplanted adipose tissue. HBO therapy was effective in reducing inflammatory factor (TGF-β and TNF-α) levels and oxidative stress (MDA) in the transplanted adipose tissue (p < 0.01) and significantly increased the level of CD31 and angiogenesis-related factors including VEGF-A and PDGF-A (p < 0.01) to promote angiogenesis.

Conclusion

HBO therapy regulated the immune response of fat grafts, stimulated their angiogenesis, and ultimately promoted their survival after AFT.

Hyperbaric oxygen therapy induces transcriptome changes in elderly: a prospective trial

Introduction: Aging is characterized by the progressive loss of physiological capacity. Changes in gene expression can alter activity in defined age-related molecular pathways leading to cellular aging and increased aging disease susceptibility. The aim of the current study was to evaluate whether hyperbaric oxygen therapy (HBOT) affects gene expression in normal, non-pathological, aging adults.

Methods: Thirty-five healthy independently living adults, aged 64 and older, were enrolled to receive 60 daily HBOT exposures. Whole blood samples were collected at baseline, at the 30th and 60th HBOT session, and 1–2 weeks following the last session. Differential gene expression analysis was performed.

Results: Following 60 sessions of HBOT, 1342 genes and 570 genes were differently up- and downregulated (1912 total), respectively (p < 0.01 FDR), compared to baseline. Out of which, five genes were downregulated with a >1.5-fold change: ABCA13 (FC = −2.28), DNAJ6 (FC = −2.16), HBG2 (FC = −1.56), PDXDC1 (FC = −1.53), RANBP17 (FC = −1.75). Two weeks post-HBOT, ABCA13 expression was significantly downregulated with a >1.5fold change (FC = −1.54, p = 0.008).

In conclusion, for the first time in humans, the study provides direct evidence of HBOT is associated with transcriptome changes in whole-blood samples. Our results demonstrate significant changes in gene expression of normal aging population.

The effect of hyperbaric oxygen therapy on the pathophysiology of skin aging: a prospective clinical trial

INTRODUCTION

Skin biopsies can be used to evaluate physiological effects of aging targeted intervention at the tissue/cellular levels. Recent clinical trials have shown that hyperbaric oxygen therapy (HBOT) can target aging hallmarks, including telomere shortening, senescent cells clearance and angiogenesis. The aim of this study was to evaluate the effects of HBOT on the skin of a normal, non-pathological, aging population.

METHODS

The study was performed as a prospective clinical trial. After signing informed consent and undergoing baseline evaluations, the subjects were assigned to a three-month control period followed by three months of HBOT daily sessions. Skin biopsies were taken at baseline, after three months of no intervention (control) and 1-2 weeks following the last HBOT session. Trichrome, Orecin, lipofuscin and CD31 staining were used to evaluate collagen fibers, elastic fibers, senescent cells and blood vessels, respectively.

RESULTS

Out of the cohort of 70 participants in the normal aging population study, thirteen male patients (age 68.07±2.5y) gave consent for repeated skin biopsies. Following HBOT, there was a significant increase in collagen density (p<0.001, effect size(es)=1.10), elastic fiber length (p<0.0001, es=2.71) and the number of blood vessels (p=0.02, es=1.00). There was a significant decrease in fiber fragmentation (p=0.012) and in tissue senescent cells (p=0.03, es=0.84) post-HBOT. No changes were noted in elastic fiber density or thickness.

CONCLUSIONS

The study indicates, for the first time in humans, that HBOT can significantly modulate the pathophysiology of the skin aging in a healthy aging population. The demonstrated mechanisms include angiogenesis and senescent cell clearance.

Integrative Role of Hyperbaric Oxygen Therapy on Healthspan, Age-Related Vascular Cognitive Impairment, and Dementia

Growing life expectancy will contribute to the on-going shift towards a world population increasingly comprised of elderly individuals. This demographic shift is associated with a rising prevalence of age-related diseases, among all age-related pathologies it has become crucial to understand the age-associated cognitive changes that remain a major risk factor for the development of vascular cognitive impairment and dementia (VCID). Furthermore, age-related Alzheimer's disease and other neurogenerative diseases with vascular etiology are the most prominent contributing factors for the loss of cognitive function observed in aging. Hyperbaric Oxygen Therapy (HBOT) achieves physiologic effects by increasing oxygen tension (PO2), raising oxygen tissue levels, decreasing intracranial pressure and relieving cerebral edema. Many of the beneficial effects of HBOT exert their protective effects at the level of the microcirculation. Furthermore, the microcirculation's exquisite pervasive presence across every tissue in the body, renders it uniquely able to influence the local environment of most tissues and organs, including the brain. As such, treatments aimed at restoring aging-induced functional and structural alterations of the cerebral microcirculation may potentially contribute to the amelioration of a range of age-related pathologies including vascular cognitive impairment, Alzheimer's disease, and vascular dementias. Despite the presented evidence, the efficacy and safety of HBOT for the treatment of age-related vascular cognitive impairment and dementia remains understudied. The present review aims to examine the existing evidence indicative of a potential therapeutic role for HBOT-induced hyperoxia against age-related cerebromicrovascular pathologies contributing to cognitive impairment, dementia and decreased healthspan in the elderly.

Quantifying the Effect of Topical Nitroglycerin on Random Pattern Flap Perfusion in a Rodent Model: An Application of the ViOptix Intra.Ox for Dynamic Flap Perfusion Assessment and Salvage

BACKGROUND

Near-infrared spectroscopy can detect changes in tissue oxygenation postoperatively that predict flap necrosis. The authors hypothesized that this technology can be applied along with topical nitroglycerin to measure an improvement in tissue oxygenation that correlates with tissue salvage.

METHODS

Dorsal, random pattern flaps measuring 10 × 3 cm were raised using Sprague-Dawley rats. Tissue oxygenation was measured after flap elevation in 10 locations using the ViOptix Intra.Ox. Animals were divided into three groups that received 30 mg of topical nitroglycerin daily, twice-daily, or not at all. Oxygenation measurements were repeated on postoperative day 1 and animals were euthanized on day 7 and evaluated for tissue necrosis.

RESULTS

Tissue necrosis was greatest in controls (51.3 mm) compared to daily (28.8 mm) and twice-daily nitroglycerin (18.8 mm; p = 0.035). Three flap perfusion zones were identified: healthy (proximal, 50 mm), necrotic (distal, 20 mm), and watershed. Immediate postoperative tissue oxygenation was highest in healthy tissue (57.2 percent) and decreased to 33.0 and 19.3 percent in the watershed and necrotic zones, respectively (p < 0.001). One day after treatment with nitroglycerin, oxygenation in the healthy zone did not increase significantly (mean difference, -1.5 percent). The watershed (17.8 percent; p < 0.001) and necrotic zones (16.3 percent; p <0.001) did exhibit significant improvements that were greater than those measured in control tissues (7.9 percent; both p < 0.001).

CONCLUSIONS

Serial perfusion assessment using the ViOptix Intra.Ox measured a significant improvement in flap oxygenation after treatment with topical nitroglycerin. Within the watershed area of the flap, this increase in tissue oxygenation was associated with the salvage of ischemic tissue.

A General Overview on the Hyperbaric Oxygen Therapy: Applications, Mechanisms and Translational Opportunities

Hyperbaric oxygen therapy (HBOT) consists of using of pure oxygen at increased pressure (in general, 2-3 atmospheres) leading to augmented oxygen levels in the blood (Hyperoxemia) and tissue (Hyperoxia). The increased pressure and oxygen bioavailability might be related to a plethora of applications, particularly in hypoxic regions, also exerting antimicrobial, immunomodulatory and angiogenic properties, among others. In this review, we will discuss in detail the physiological relevance of oxygen and the therapeutical basis of HBOT, collecting current indications and underlying mechanisms. Furthermore, potential areas of research will also be examined, including inflammatory and systemic maladies, COVID-19 and cancer. Finally, the adverse effects and contraindications associated with this therapy and future directions of research will be considered. Overall, we encourage further research in this field to extend the possible uses of this procedure. The inclusion of HBOT in future clinical research could be an additional support in the clinical management of multiple pathologies.

Efficacy of hyperbaric oxygen therapy for diabetic foot ulcers: An updated systematic review and meta-analysis

The present systematic review and meta-analysis was performed to evaluate the efficacy of hyperbaric oxygen therapy (HBOT) in the treatment of diabetic foot ulcers (DFUs). Relevant articles were retrieved from PubMed, the Cochrane Library, EMBASE and other databases through November 2020. A total of 20 randomized clinical trials and 1263 trials were included in the meta-analysis. For each trial, the average difference, odds ratio and 95% confidence interval were calculated to evaluate the efficacy. Hyperbaric oxygen therapy increased the healing rate of diabetic foot ulcers (relative risk, 1.901; 95% CI = 1.484-2.435, p < 0.0001), shortened the healing time (MD = -19.360; 95% CI = -28.753~-9.966, p < 0.001), and reduced the incidence of major amputation (relative risk, 0.518, 95% CI = 0.323-0.830, P < 0.01). In summary, our meta-analysis confirmed that hyperbaric oxygen therapy offers great benefits in the treatment of DFU and the reduction of amputation. In addition, larger and well-designed randomized controlled trials need to be planned and conducted to verify this conclusion.

Results of hyperbaric oxygen treatment in an at-risk nasal flap following trauma

Hyperbaric oxygen treatment (HBOT) is widely used in otorhinolaryngology for various purposes. A 20-year-old male patient was admitted following a traumatic nasal wound which occurred several hours prior. He had a nasal glass cut from the radix to the supratip area which was primarily closed by non-absorbable suture. The following day, there was a haematoma and necrosis of the skin. The haematoma was drained under local anaesthesia. Blood supply to the nasal skin was severely compromised and only the columellar artery remaining intact, by definition designating this a difficult to heal wound with the risk of overall healing failure. Necrosis of the skin had developed within the first 24 hours. Accordingly, the patient underwent 30 HBOT sessions (two hours at 253.3 kPa) twice daily for four days and daily thereafter. Antibiotic cover and conservative wound management were also used. Complete healing was achieved without the need for additional surgical intervention. We conclude that timely use of HBOT may be a valuable adjunct to conservative wound management in a case of sharp nasal trauma.

Thermal Effects of Topical Hyperbaric Oxygen Therapy in Hard-to-Heal Wounds-A Pilot Study

Clinical studies have been performed to evaluate the thermal response of topical hyperbaric oxygen therapy (THBOT) in patients suffering from hard-to-heal wounds diagnosed as venous leg ulcers located on their lower extremities. It was found that this therapy leads to a temperature decrease in areas around the wound. Moreover, a minor temperature differentiation between all areas was seen in the third period of topical hyperbaric oxygen therapy (THBOT) that may suggest that microcirculation and thermoregulation improvement start the healing process. On the other hand, the results of the conducted studies seem to prove that thermal imaging may provide a safe and effective method of analyzing wound healing of hard-to-heal wounds being treated with THBOT. This is the first study that tries to show the possibilities of a very new method by evaluating treatment of hard-to-heal wounds using thermal imaging, similar to the hyperbaric oxygen therapy effects evaluated by thermal imaging and described previously. However, the first clinical results showed a decrease in temperature due to the THBOT session and some qualitative similarities in the decrease in temperature differentiation between the studied areas and the temperature effects obtained due to hyperbaric oxygen therapy.

Hyperbaric Oxygen Therapy in Management of Diabetic Foot Ulcers: Indocyanine Green Angiography May Be Used as a Biomarker to Analyze Perfusion and Predict Response to Treatment

SUMMARY

The authors present indocyanine green angiography to assess the effects of hyperbaric oxygen therapy and as a potential biomarker to predict healing of chronic wounds. They hypothesize that favorable initial response to hyperbaric oxygen therapy (improved perfusion) would be an early indicator of eventual response to the treatment (wound healing). Two groups were recruited: patients with chronic wounds and unwounded healthy controls. Inclusion criteria included adults with only one active wound of Wagner grade III diabetic foot ulcer or caused by soft-tissue radionecrosis. Patients with chronic wounds underwent 30 to 40 consecutive hyperbaric oxygen therapy sessions, once per day, 5 days per week; controls underwent two consecutive sessions. Indocyanine green angiography was performed before and after the sessions, and perfusion patterns were analyzed. Healing was determined clinically and defined as full skin epithelialization with no clinical evidence of wound drainage. Fourteen chronic-wound patients and 10 controls were enrolled. Unlike unwounded healthy volunteers, a significant increase in indocyanine green angiography perfusion was found in chronic-wound patients immediately after therapy (p < 0.03). Moreover, the authors found that 100 percent of the wounds that demonstrated improved perfusion from session 1 to session 2 went on to heal within 30 days of hyperbaric oxygen therapy completion, compared with none in the subgroup that did not demonstrate improved perfusion (p < 0.01). This study demonstrates a beneficial impact of hyperbaric oxygen therapy on perfusion in chronic wounds by ameliorating hypoxia and improving angiogenesis, and also proposes a potential role for indocyanine green angiography in early identification of those who would benefit the most from hyperbaric oxygen therapy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Hyperbaric oxygen therapy decreases mortality due to Fournier's gangrene: a retrospective comparative study

There is no consensus about the role of adjunctive hyperbaric oxygen therapy (HBOT) in the management of Fournier’s gangrene. The aim of this study was to compare the evolution of patients with Fournier’s gangrene treated with all classical measures with and without adjuvant HBOT. A retrospective comparative study regarding the evolution of patients treated for Fournier’s gangrene was conducted in two periods. In period I, from 1990 to 2002, patients received standard treatments for Fournier’s gangrene, which consisted of surgical debridement, antibiotic therapy and intensive care. In period II, from 2012 to 2019, adjunctive HBOT was added to the classical management strategy. All patients were assigned into four groups according to the anatomical severity classification and the area affected after the first debridement. This classification ensured that the groups could be comparable. The total number of patients in this study was 197, and these patients were divided into control group (118/59.9%) and HBOT group (79/40.1%). The mean age, comorbidities, and anatomical severity classification were similar between the two groups. In period I, 34 out of 118 (28.8%) patients died, while in the HBOT group, 3 out of 77 (3.7%) patients died (P < 0.001). The use of adjuvant HBOT in combination with classical treatment was associated with reduced mortality. This study was approved by the Institutional Review Board and the Ethics Committee of Ribeirão Preto Medical School, University of São Paulo, Brazil (No. 08/2018) on May 2, 2018.

Randomized controlled clinical trial evaluating the efficacy of hyperbaric oxygen therapy in facilitating the healing of chronic foot ulcers in diabetic patients: the study protocol

Background

Diabetic limb ulcers are highly prevalent and contribute to a significant increase in cost for the treatment of these patients in health services. However, healing of these wounds is a major health problem and may even lead to amputation. The primary aim of the current study is to evaluate the efficacy of hyperbaric oxygen therapy (HBOT) in facilitating the healing of diabetic foot ulcers, in addition to secondarily evaluating whether it reduces the number of amputations and improves the quality of life in these patients.

Methods

A non-blind randomized clinical study will be conducted in the city of Imperatriz, Maranhão state, Brazil, from 2019 to 2020, in diabetic patients with chronic foot ulcers (classified as Wagner grades 2, 3 and 4, persisting for more than 1 month). The outpatient follow-up for diabetic foot patients will be done at the Unified Health System, with a sample size of 120 patients (the randomization allocation will be 1:1, being 60 patients for each arm). Half of the patients will receive standard treatment, i.e. dressings, debridement, antibiotics and load relief, along with HBOT (HBOT group), and the other half will receive only standard treatment (control group). The patients of the HBOT group will be evaluated upon admission, after 10, 20, 30 and 35 HBOT sessions, and after 6 months and 1 year. The patients of the control group will also be evaluated at equivalent periods (upon admission, after 2, 4, 6 and 7 weeks, 6 months and 1 year). The SF-36 quality of life questionnaire will be filled upon admission and after 3 months of follow-up in both groups. The primary and secondary endpoints will be assessed with 1 year of follow-up.

Discussion

Diabetic foot ulcers are a highly prevalent complication of diabetes with serious consequences. A study to assess the efficacy of HBOT in healing the ulcers and reducing the rate of amputations in diabetic patients is justified, which will eventually aid in the development of guidelines for treating these ulcers.

Trial registration

Registration number RBR-7bd3xy. Registered on 17 July 2019—Retrospectively registered.

Hyperbaric Oxygen Therapy: Descriptive Review of the Technology and Current Application in Chronic Wounds

Hyperbaric oxygen therapy (HBOT) serves as "primary" or "adjunctive" therapy in a wide range of pathologies. It is considered the mainstay of management for potentially life-threatening conditions such as carbon monoxide poisoning, decompression illness, and gas embolisms. Moreover, HBOT has been utilized for decades as an adjunctive therapy in a variety of medical disciplines, including chronic wounds, which affect approximately 6.5 million Americans annually. In general, chronic wounds are characterized by hypoxia, impaired angiogenesis, and prolonged inflammation, all of which may theoretically be ameliorated by HBOT. Nonetheless, the cellular, biochemical, and physiological mechanisms by which HBOT achieves beneficial results in chronic wounds are not fully understood, and there remains significant skepticism regarding its efficacy. This review article provides a comprehensive overview of HBOT, and discusses its history, mechanisms of action, and its implications in management of chronic wounds. In particular, we discuss the current evidence regarding the use of HBOT in diabetic foot ulcers, while digging deeply into the roots of controversy surrounding its efficacy. We discuss how the paucity of high-quality research is a tremendous challenge, and offer future direction to address existing obstacles.

The Efficacy of the Transdermal Isosorbide Dinitrate Patch in Patients With Chronic Limb-Threatening Ischemia

Recently, the number of patients with peripheral artery disease (PAD), including those with chronic limb-threatening ischemia (CLTI), has increased because of the increasing number of diabetic or dialysis patients worldwide. Revascularization is an important therapy for patients with CLTI. However, we sometimes experience refractory cases with insufficient peripheral circulation or microcirculation after revascularization. In this situation, additional therapy can be administered, such as low-density lipoprotein apheresis, high-pressure oxygen therapy, and spinal cord stimulation. However, they are not effective in some cases. Some reports have also indicated that transdermal isosorbide dinitrate patch (ISDN-P) is a useful therapy for PAD. As the efficacy of ISDN-P for patients with CLTI is not well-known, we examined it in this study. We assessed the skin perfusion pressure (SPP) after affixing an ISDN-P on the foot, because SPP measurement has proved useful in the assessment of PAD and is a good indicator of wound healing potential. The SPP (dorsal and plantar aspects) after ISDN-P application on the foot of healthy volunteers increased (n = 8; mean ± SD, 12.6 ± 7.9 [P = .12], and 21.2 ± 7.7 mm Hg [P < .05], respectively), as did SPP of patients with CLTI (n = 10; mean ± SD, 19.8 ± 2.5 [P < .01], and 14.1 ± 5.9 mm Hg [P < .05], respectively). All the patients who received an ISDN-P on the foot had no major complication, and no significant change in blood pressure. In conclusion, the ISDN-P is one of the effective and safe therapies for patients with CLTI.

Hyperbaric oxygen in animal model of rheumatoid arthritis: Analysis Of HIF-1α, ACPA and IL-17a

Antigen and collagen-induced arthritis (ACIA) is animal model of rheumatoid arthritis. The aim of this study was to identify the effect of different doses of hyperbaric oxygen (HBO) exposure in reducing inflammation on ACIA through analysis hypoxia inducible factor-1α (HIF-1α), anticyclic citrullinated peptide antibody (ACPA) and interleukine 17a (IL-17a). 24 male Balb/C mice were divided into 3 groups, 8 mice did not receive HBO exposure as a control group (G1) and 16 mice received HBO exposure as treatment group (G2 and G3). G2 was ACIA which was exposed to HBO 2.4 ATA O2 100% 90 minutes divided by 3 each 30 minutes intervals 2 times 5 minutes breathing with normal air for 10 consecutive days. G3 was ACIA which was exposed to HBO 2.4 ATA O2 100% 90 minutes divided by 3 each 30 minutes intervals 2 times 5 minutes breathing with normal air for 5 consecutive days, break 5 days, 5 consecutive days.ACPA and IL-17a were measured by enzyme-linked immunosorbent assay (ELISA) technique. The expression of HIF-1α was measured by immunohistochemistry technique. There was significant decrease of ACPA levels, IL-17a levels and HIF-1α expression (P< 0.05) in G2 and G3 compared to G1. There was not significant decrease of ACPA levels (P> 0.05), there was significant decrease of IL-17a levels and HIF-1α expression (P<0.05) in G2 compared to G3. G2 was a group with a higher oxygen partial pressure than G3. HBO 2.4 ATAO2 100% 90 minutes divided by 3 each 30 minutes intervals 2 times 5 minutes breathing with normal air for 10 consecutive days more effective in reducing inflammation than exposure 5 consecutive days, break 5 days, 5 consecutive days in ACIA. HBO has therapeutic potential for the treatment of RA.

Study of the Effect of Hyperbaric Oxygen Therapy on the Viability of Dorsal Cutaneous Flaps in Tobacco-Exposed Rats

BACKGROUND

Smoking causes a threefold increase in the risk of surgical complications in flaps. Hyperbaric oxygen therapy (HBOT) increases the viability of chronic wounds. However, there are few studies concerning the effects of HBOT on surgical flaps in patients who smoke. This study aimed to analyze the effect of HBOT on the viability of cutaneous flaps in tobacco-exposed rats.

METHODS

Twenty Wistar rats were exposed to tobacco smoke for two months. Following this period, all animals underwent a dorsal cutaneous flap (3 × 10 cm) surgery and were divided into two groups: control (n = 10) and HBOT (n = 10). HBOT was performed in seven daily sessions (2 ATA, 90 min). After seven days, the animals were euthanized. The outcomes were total area, viable area, viable area/total area rate, analysis of dermal appendages and angiogenesis (hematoxylin-eosin), and gene expression analysis of iNOS and VEGF-a biomarkers.

RESULTS

The HBOT group showed an increase in viable area compared with the control group (84% versus 47%, p = 0.009, respectively). The HBOT group also showed an increase in appendage units (1.69 ± 0.54 versus 1.87 ± 0.58, p = 0.04) and angiogenesis density (1.29 ± 0.45 versus 1.82 ± 0.64, p < 0.001) compared to the control group. There was a difference between the control and HBOT groups in iNOS levels (0.926 ± 1.4 versus 0.04 ± 0.1 p = 0.002, respectively). However, this study did not show a difference between the groups concerning the gene expression of VEGF-a.

CONCLUSION

The use of hyperbaric oxygen therapy increased the viability of cutaneous flaps in tobacco-exposed rats and decreased iNOS mRNA levels; however, it did not change VEGF-a levels. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Hyperbaric Oxygen Therapy for Large Composite Grafts: An Alternative in Pediatric Facial Reconstruction

BACKGROUND

Management of pediatric facial defects can be challenging, as reattachment of large composite grafts is usually unsuccessful. Hyperbaric oxygen therapy (HBO) has been researched to augment composite graft survival, but clinical use for this application remains anecdotal. The authors present their successful experience managing select cases with large composite grafts and HBO as an adjunct.

METHODS

A retrospective chart review identified children presenting with facial defects and managed operatively with large composite grafts (≥1.5 × 1.5 cm) and HBO therapy. Records were reviewed for defect characteristics, management details, and outcomes at last follow-up.

RESULTS

Nine children (avg. 8.4 years, range 1.6-15.1) presented with ear or nose defects secondary to dog bites (n=7), falls (n=1), or congenital causes (n=1). Three experienced ear amputations, and six suffered nasal avulsions of varying degrees. All avulsed ears were reattached. Three cases of nose avulsions were reattached; the other three underwent secondary reconstruction with composite ear grafts. HBO was initiated immediately and continued for 8-10 days. All grafts survived at least 80% with no postoperative complications. At last follow-up (avg. 30.1 months; 0.8-63.9), all patients demonstrated good cosmetic results with minimal residual deformity.

CONCLUSION

When reconstruction of pediatric facial defects warrants a large chondrocutaneous graft, immediate postoperative HBO therapy can increase survival. Particularly when reattaching amputated segments, if successful, this approach offers an anatomically ideal result without donor site morbidity. If unsuccessful, it does not "burn bridges" and decreases the extent of secondary reconstruction. The authors present their HBO protocol along with a review of available literature.

HBO Promotes the Differentiation of Neural Stem Cells via Interactions Between the Wnt3/β-Catenin and BMP2 Signaling Pathways

Hyperbaric oxygen (HBO) therapy may promote neurological recovery from hypoxic-ischemic encephalopathy (HIE). However, the therapeutic effects of HBO and its associated mechanisms remain unknown. The canonical Wnt/β-catenin signaling pathways and bone morphogenetic protein (BMP) play important roles in mammalian nervous system development. The present study examined whether HBO stimulates the differentiation of neural stem cells (NSCs) and its effect on Wnt3/β-catenin and BMP2 signaling pathways. We showed HBO treatment (2 ATA, 60 min) promoted differentiation of NSCs into neurons and oligodendrocytes in vitro. In addition, rat hypoxic-ischemic brain damage (HIBD) tissue extracts also promoted the differentiation of NSCs into neurons and oligodendrocytes, with the advantage of reducing the number of astrocytes. These effects were most pronounced when these two were combined together. In addition, the expression of Wnt3a, BMP2, and β-catenin nuclear proteins were increased after HBO treatment. However, blockade of Wnt/β-catenin or BMP signaling inhibited NSC differentiation and reduced the expression of Wnt3a, BMP2, and β-catenin nuclear proteins. In conclusion, HBO promotes differentiation of NSCs into neurons and oligodendrocytes and reduced the number of astrocytes in vitro possibly through regulation of Wnt3/β-catenin and BMP2 signaling pathways. HBO may serve as a potential therapeutic strategy for treating HIE.

Ischemia/Reperfusion Injury Revisited: An Overview of the Latest Pharmacological Strategies

Ischemia/reperfusion injury (IRI) permeates a variety of diseases and is a ubiquitous concern in every transplantation proceeding, from whole organs to modest grafts. Given its significance, efforts to evade the damaging effects of both ischemia and reperfusion are abundant in the literature and they consist of several strategies, such as applying pre-ischemic conditioning protocols, improving protection from preservation solutions, thus providing extended cold ischemia time and so on. In this review, we describe many of the latest pharmacological approaches that have been proven effective against IRI, while also revisiting well-established concepts and presenting recent pathophysiological findings in this ever-expanding field. A plethora of promising protocols has emerged in the last few years. They have been showing exciting results regarding protection against IRI by employing drugs that engage several strategies, such as modulating cell-surviving pathways, evading oxidative damage, physically protecting cell membrane integrity, and enhancing cell energetics.

Revisiting the expanded use of hyperbaric oxygen therapy for treatment of resistant migraines

There are currently 13 indications approved by the U.S. Food and Drug Administration for use of hyperbaric oxygen therapy. The European Consensus Conference on Hyperbaric Medicine has 28 indications approved for its use. However, neither includes the use of hyperbaric oxygen therapy for neurological conditions such as migraines with aura. Recent research has made the attempt to fully understand the use of hyperbaric therapy in treatment of neurological conditions, but results have so far been inconclusive. We report a 23-year-old female with an 11-year history of migraines with aura who has received inadequate pharmacological treatment for her migraines since she began having them. Migraines have led her to significant loss of function. The patient underwent treatment at 1.5 absolute atmospheres in a hyperbaric chamber Monday through Friday for 1 hour each day for a total of 40 sessions but reported missing a few sessions over the 8-week period. No more than 1 session during a given week was missed and the patient received no other treatments for her migraines throughout this time period. By her 24th treatment, the patient had only experienced a single migraine with aura but without debilitating pain. The patient stated she had never had a migraine with such little intensity prior to initiation of hyperbaric treatment and did not have to take any days off from work or school. Follow-up at the end of her 40-day treatment period revealed a highly-satisfied patient who had only experienced the single episode of a mild migraine during the entire course of treatment. Thus, we believe that further research needs to be done to realize the full potential of hyperbaric oxygen therapy in the treatment of neurological conditions as this case highlights the potential for using hyperbaric oxygen therapy as prophylaxis against attacks in patients with treatment resistant migraines with aura.

Changes in Skin Perfusion Pressure After Hyperbaric Oxygen Therapy Following Revascularization in Patients With Critical Limb Ischemia: A Preliminary Study

Hyperbaric oxygen (HBO) therapy promotes wound healing in patients with ischemic disease; however, HBO-induced changes in skin peripheral circulation have not been evaluated in clinical practice. Here, we investigated these changes in patients with critical limb ischemia (CLI), with a focus on the angiosome of crural blood vessels with blood flow improved by endovascular therapy (EVT). Six patients with CLI and ulcers who were treated with HBO after EVT (7 limbs; 1 patient had ulcers in the bilateral limbs) and 3 healthy subjects (6 limbs) were enrolled. HBO therapy was performed at 2 atm under 100% oxygen for 90 min per session. Skin perfusion pressure (SPP) was measured in the dorsum and sole of the foot 1 hour before (pre-SPP) and after (post-SPP) HBO therapy. ΔSPP was calculated as post-SPP minus pre-SPP. SPP measurement regions were divided into those that did (direct region) and did not (indirect region) correspond to the vascular angiosome in which angiography findings of the crus were improved after EVT; i.e., when the anterior tibial artery was effectively treated with EVT, the dorsum was the direct region and the sole was the indirect region, and vice versa when the posterior tibial artery was treated. In the direct, indirect, and healthy subject groups, the ΔSPPs were 20.5±8.7 (p=0.002), -6.4±10.9, and -15.1±18.1 (p=0.014), respectively; that of the direct group was significantly greater than that of the other groups. These results suggest that short-term improvement of the peripheral circulation by HBO therapy was significant in patients with successful revascularization.

Immediate Reconstruction of Amputated Ear With Fascia Flap

BACKGROUND

Various surgical methods have been used for reconstruction of an amputated ear, including microsurgical replantation and delayed reconstruction using synthetic material or autologous rib cartilage. The authors share our experience of immediate reconstruction using amputated cartilage and discuss the advantages compared to other techniques of reconstruction.

MATERIALS AND METHODS

The authors retrospectively reviewed the medical records of 3 patients who underwent immediate reconstruction of amputated ear by a single operator. In the cases, the amputees were washed; the skin and cartilage were separated. The ear cartilage was fixed to its original position with non-absorbable suture. Regional fascia flap was elevated and covered the ear cartilage. The amputee skin was redraped to cover the fascia flap. Several months after the operation, photographic assessment was done.

RESULTS

All 3 cases showed well-defined convolution, tolerable skin color, and patient satisfaction without any major complications. A patient showed mild temporal incision site alopecia.

CONCLUSION

The above immediate reconstruction method can achieve reliable and favorable result with minimal complications.

Hypoxia and hyperbaric oxygen therapy: a review

Hypoxia causes a cascade of activity from the level of the individual down to the regulation and function of the cell nucleus. Prolonged periods of low oxygen tension are a core feature of several disease states. Advances in the study of molecular biology have begun to bridge the gap between the cellular response to hypoxia and physiology. Hyperbaric oxygen therapy is a treatment for hypoxic- and inflammatory-driven conditions, in which patients are treated with 100% oxygen at pressures greater than atmospheric pressure. This review discusses hypoxia, the physiologic changes associated with hypoxia, the responses that occur in the cells during hypoxic conditions, and the role that hyperbaric oxygen therapy can play as part of the treatment for many patients suffering from diseases with underlying hypoxia.

Hyperbaric oxygen therapy restored traumatic stress-induced dysregulation of fear memory and related neurochemical abnormalities

Individuals with posttraumatic stress disorder (PTSD) are characterized by fear memory problems and hypocortisolemia of which traumatic stress-induced monoaminergic disruption over infralimbic (IL) cortex is considered the key mechanism. Hyperbaric oxygen therapy (HBOT) has recently proven its utility in treating several mental disorders but remains unexplored for PTSD. The present study aimed to examine the effects of 5-day HBO paradigm on traumatic stress (single prolonged stress, SPS, an animal model of PTSD)-induced dysregulation of fear memory/anxiety profiles and related abnormalities in IL monoamines and plasma corticosterone. Rats were randomly assigned to four groups (CON-sham, CON-HBOT, SPS-sham, and SPS-HBOT) and received Pavlovian fear conditioning test or elevated-T maze (ETM). The extracellular and tissue levels of monoamines over the IL cortex and the activity of the hypothalamus-pituitary-adrenal axis (i.e., the plasma corticosterone level and expression of the glucocorticoid receptor (GR) in the IL, hippocampus, amygdala, and hypothalamus) were measured. The results demonstrated that HBOT restored behaviorally the SPS-impaired fear extinction retrieval ability and SPS-induced conditioned anxiety, and neurochemically the SPS-reduced IL monoamines efflux level, and the corticosterone profiles. The present study shows some positive effects of HBOT in both behavioral and neurochemical profiles of PTSD outcomes.

A Perioperative Approach to Increase Limb Salvage When Treating Foot Ulcers in Patients With Diabetes

Foot ulceration in patients with diabetes increases the risk of lower extremity amputation. Major amputations produce substantial adverse consequences, increase length of hospital stay, diminish quality of life, and increase mortality. In this article, we describe approaches that decrease amputations and improve the quality of life for patients with diabetes and foot ulcers. We highlight the role of the perioperative nurse, who is essential to providing optimal patient care in the perioperative period. Perioperative care of patients with diabetes involves providing optimal surveillance for a break in the skin of the foot, screening for neuropathy, following guidelines for foot ulcer infections, preparing for pathophysiology-based debridement, using adjuvant therapies, and offloading the patient's affected foot. Nurses should understand the disease process and pathophysiology and how to use these approaches in the perioperative setting to assist in curtailing the morbidity and mortality associated with foot ulcers in patients with diabetes.

Salvage of Unilateral Complete Ear Amputation with Continuous Local Hyperbaric Oxygen, Platelet-Rich Plasma and Polydeoxyribonucleotide without Micro-Revascularization

In many cases of complete ear amputation, microvascular surgery is required for tissue perfusion and organ survival. However, microvascular reconstruction is not always feasible in the absence of suitable vessels. Here, we present the case of a 76-year-old man who underwent complete amputation of the left ear after a collapse at home because of cardiogenic syncope. He was treated with primary replantation and underwent a postoperative salvage course including continuous local hyperbaric oxygen therapy (HBOT), platelet-rich plasma (PRP) injections, and polydeoxyribonucleotide (PDRN) injections. The ear was almost completely salvaged, with a tiny eschar at the mid-scapha on both the anterior and posterior aspects. This case demonstrates the efficacy of local HBOT with PRP and PDRN injections.

A new approach to clinical research: Integrating clinical care, quality reporting, and research using a wound care network-based learning healthcare system

The disparity between ideal evidence from randomized controlled trials and real-world evidence in medical research has prompted the United States Food and Drug Administration to consider the use of real-world data to better understand safety and effectiveness of new devices for a broader patient population and to prioritize real-world data in regulatory decision making. As the healthcare system transitions from volume- to value-based care, there is a growing need to harness the power of real-world data to change the paradigm for wound care clinical research and enable more generalizable clinical trials. This paper describes the implementation of a network-based learning healthcare system by a for-profit consortium of wound care clinics that integrates wound care management, quality improvement, and comparative effectiveness research, by harnessing structured real-world data within a purpose-built electronic health record at the point of care. Centers participating in the consortium submit their clinical data and quality measures to a qualified clinical data registry for wound care, enabling benchmarking of their data across this national network. The common definitional framework of the purpose-built electronic health record and the 21 wound-specific quality measures help to standardize the potential sources of bias in real-world data, making the consortium data useful for comparative effectiveness research. This consortium can transform wound care clinical research and raise the standards of care, while helping physicians achieve success with the Merit-Based Incentive Payment System.

Harnessing electronic healthcare data for wound care research: Standards for reporting observational registry data obtained directly from electronic health records

The United States Food and Drug Administration will consider the expansion of coverage indications for some drugs and devices based on real-world data. Real-world data accrual in patient registries has historically been via manual data entry from the medical chart at a time distant from patient care, which is fraught with systematic error. The efficient automated transmission of data directly from electronic health records is replacing this labor-intensive paradigm. However, real-world data collection is unfamiliar. The potential sources of bias arising from the source of data and data accrual, documentation, and aggregation have not been well defined. Furthermore, the technological aspects of data acquisition and transmission are less transparent. We explore opportunities for harnessing direct-from-electronic health record registry reporting and propose the ABCs of Registries (Analysis of Bias Criteria of Registries), which are an evaluation framework for publications to minimize potential bias of real-world data obtained directly from an electronic health record method. These standards are based on a point-of-care data documentation process using a common definitional framework and data dictionaries. By way of example, we describe a wound registry obtained directly from electronic health records. This qualified clinical data registry minimizes bias by ensuring complete and accurate point-of-care data capture, standardizes usual care linked to quality reporting, and prevents post-hoc vetting of outcomes. The resulting data are of high quality and integrity and can be used for comparative effectiveness research in wound care. In this way, the effort needed to succeed with the Quality Payment Program is leveraged to obtain the real-world data needed for comparative effectiveness research.

Application of hyperbaric oxygen in liver transplantation

In recent years, hyperbaric oxygen (HBO) has been used in the treatment of a lot of diseases such as decompression sickness, arterial gas embolism, carbon dioxide poisoning, soft tissue infection, refractory osteomyelitis, and problematic wound, but little is known about its application in liver transplantation. Although several studies have been conducted to investigate the protective effects of HBO on liver transplantation and liver preservation, there are still some controversies on this issue, especially its immunomodulatory effect. In this short review, we briefly summarize the findings supporting the application of HBO during liver transplantation (including donors and recipients).