Atmospheres Absolute Pressure Research Articles

Safety of hyperbaric oxygen therapy in non-emergent patients with a history of seizures: A retrospective cohort study.

Hyperbaric oxygen therapy (HBOT) is well established as a treatment for various medical conditions. However, it poses a risk of oxygen toxicity, which can cause seizures particularly in individuals with pre-existing seizure disorders. Consequently, seizure disorders are considered a relative contraindication to HBOT. Despite this, the relative risk of HBOT-induced seizures in this patient population remains unclear. This retrospective cohort study aims to evaluate the safety of HBOT among patients with pre-existing seizure disorders. After obtaining approval from the Research Ethics Board, we retrospectively reviewed the patient charts of individuals with a history of seizures who were referred to the Rouge Valley Hyperbaric Medical Center and Toronto General Hyperbaric Medicine Unit for HBOT between January 2020 and December 2023. Relevant demographic information, past medical history, and HBOT session treatment protocols, such as the treatment pressure set in absolute atmospheric pressure (ATA) and number of air breaks, were recorded. The collected data was analyzed using descriptive statistics. A total of 43 patients were referred to HBOT during the study period, and 21 patients did not proceed with the treatments. In total, 634 HBOT sessions were administered to 22 patients in monoplace chambers with five-minute air breaks, and one patient experienced a seizure event. Each patient completed an average of 29 (range 3-60) sessions lasting 90-120 minutes at 1.8 ATA (n = 3), 2.0 ATA (n = 18), or 2.4 ATA (n = 1). Fifteen patients were on oral antiseizure medications during the HBOT course. The overall incidence of seizures was one in 634 treatments. While patients with a history of seizures may develop seizure activity during HBOT, the majority can safely undergo treatment when predetermined protocols are followed. With careful management and adherence to established protocols, HBOT can be a viable treatment option for those with seizure histories.

Meclizine seasickness medication and its effect on central nervous system oxygen toxicity in a murine model.

Diving utilising closed circuit pure oxygen rebreather systems has become popular in professional settings. One of the hazards the oxygen diver faces is central nervous system oxygen toxicity (CNS-OT), causing potentially fatal convulsions. At the same time, divers frequently travel by boat, often suffering seasickness. The over-the-counter medication meclizine is an anticholinergic and antihistaminergic agent that has gained popularity in the treatment of seasickness. Reports have shown the inhibitory effect that acetylcholine has on glutamate, a main component in the mechanism leading to CNS-OT seizure. The goal of the present study was to test the effect of meclizine on the latency to CNS-OT seizures under hyperbaric oxygen conditions. Twenty male mice were exposed twice to 608 kPa (6 atmospheres) absolute pressure while breathing oxygen after administration of control solution (carboxymethyl cellulose solvent) or drug solution (meclizine) in a randomised crossover design. Latency to tonic-clonic seizures was visually measured. Mean latency to seizure did not significantly differ between the control group (414 s, standard deviation [SD] 113 s) and meclizine group (434 s, SD 174 s). Based on results from this animal model, meclizine may be an appropriate option for divers suffering from seasickness, who plan on diving using pure oxygen rebreather systems.

Hyperbaric oxygen therapy prevents epithelial atrophy in distal tubules and TGF-β1 overexpression in diabetic rat kidneys.

Diabetic nephropathy (DN) is one of the most relevant and prevalent microvascular complications associated with Diabetes Mellitus. In recent years, hyperbaric oxygen therapy (HBO) has been used to mitigate tissue damage caused by hypoxia, thereby attenuating inflammatory processes. This study aimed to explore morphological aspects associated with DN in rats subjected to HBO. Forty-eight Wistar rats were divided into the following groups: C (normoglycemic animals), n = 12; C + HBO (normoglycemic animals submitted to HBO), n = 12; D (diabetic animals) n = 12; D + HBO (diabetic animals submitted to HBO), n = 12. The C + HBO and D + HBO groups were daily treated with HBO at 2.5 atmospheres absolute pressure (ATA) for 60min, 5 days a week, for 5 weeks. Kidneys were collected for assessment of structural changes in the tissue parenchyma, assessment of renal fibrosis and renal protein expression of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1). Our results showed that group D had hyperglycemia and weight loss, and that there was also an increase in the renal corpuscle, Bowman's space, and distal tubular epithelium, as well as accumulation of collagen. HBO administration effectively prevented glomerular hypertrophy and attenuated the expression of TNF-α and TGF-β1. It also positively affected renal tubules, inhibiting the development of tubular atrophy. These findings suggest that HBO was effective in attenuating the initial alterations observed in DN.

Hyperbaric oxygen therapy in the treatment of late-onset hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation

Introduction: Hemorrhagic cystitis (HC) is a common complication after allogeneic hematopoietic stem cell transplantation (HSCT), characterized by inflammation and bleeding of the bladder. Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of radiation-induced HC. However, the optimal treatment for HC after allogeneic HSCT has not yet been established. Furthermore, limited research has been conducted on the use of HBOT in this setting. This study aimed to evaluate the effectiveness and safety of HBOT in patients with late-onset HC after allogeneic HSCT. Methods: Twenty-five-year (1998–2022) retrospective analysis performed in all consecutive patients with confirmed late-onset HC after allogeneic HSCT treated with HBOT at two centers in Portugal. Medical records were reviewed for clinical and laboratory features, primary indications for allogeneic HSCT, conditioning regimen, and treatment strategies for HC. Patients received 100% oxygen at 2.1–2.5 atmosphere absolute pressure (ATA) for 70–90-minute periods, once daily, five times per week. Complete clinical response was defined as the absence of macroscopic hematuria sustained for at least 2 weeks, and partial response was described as a downgrading in the severity of HC. Statistical significance was considered for values of p < 0.05. Results: The sample included 61 patients with a mean age of 28.0 (SD 14.2) years, 33 males. Complete response was achieved in 72.1% (n = 44) of patients and partial response in 14.8% (n = 9). Concerning patients with a complete response, the median number of HBOT sessions was 15.5 sessions (IQR 10.0-26.8). Patients treated with 10 or more sessions of HBOT had a higher rate of complete or partial response (OR 12.5, 95%CI 1.9–83.2, p-value < 0.05). There was no response in 8 (13.1%) patients, and 6 interrupted the treatments early. Only 2 patients suspended the HBOT due to a lack of clinical benefit. Conclusion: Our study supports using of HBOT as an adjunctive treatment for late-onset HC after allogeneic HSCT. Furthermore, 10 or more HBOT sessions delivered seem to impact the rate of HC resolution. Prospective, randomized, and well-controlled trials are needed to establish HBOT’s definitive efficacy and safety.

The effect of hyperbaric oxygen therapy on psychological state and wound healing: a case report.

Hyperbaric oxygen therapy (HBOT), in which patients receive high concentrations of oxygen in a pressurized chamber, has been used in clinical practice to improve wound healing. More recent applications of HBOT have resulted in successful management of a wide range of conditions; however, the psychosomatic factors associated with these conditions remain understudied and require clarification. To investigate the effects of HBOT in a female patient without diabetes who presented with an atypical wound of 9 years' duration with no sign of healing as well as with psychosomatic factors. The patient underwent 20 once-daily sessions of HBOT for 120 minutes per session every Monday through Friday for 4 weeks at 2.4 ATA (atmosphere absolute pressure) and received daily dressing changes with a nonadherent dressing containing silver, alginate, and carboxymethylcellulose. The 36-Item Short Form Health Survey and the Hospital Anxiety and Depression Scale quality-of-life questionnaires were administered before treatment and after 1 year of treatment. HBOT resulted in complete lasting wound remission as well as subjective improvement in quality of life and in levels of anxiety and depression. HBOT has known therapeutic effects on wound healing, and it may also have a substantial effect on psychosomatic mechanisms.

Acute and chronic central nervous system oxidative stress/toxicity during hyperbaric oxygen treatment of subacute and chronic neurological conditions.

Oxygen toxicity has been defined as acute central nervous system (CNS), acute pulmonary, and chronic pulmonary oxygen toxicity. This study identifies acute and chronic CNS oxygen toxicity under 2.0 atmospheres absolute (ATA) pressure of oxygen. Methods: The authors' medical records from September 29, 1989 to January 20, 2023 and correspondence to the authors (9/1994 to 1/20.2023) from patients with signs and/or symptoms historically identified as acute CNS oxygen toxicity and those with neurological deterioration receiving hyperbaric oxygen for neurological conditions were reviewed. Acute cases were those occurring with ≤5 HBOTs and chronic cases >5 HBOTs. Chronic cases were separated into those at 1.5 ATA, > 1.5 ATA, or < 1.5 ATA oxygen. Cumulative dose of oxygen in atmosphere-hours (AHs) was calculated at symptom onset. Seven acute cases, average 4.0 ± 2.7 AHs, and 52 chronic cases were identified: 31 at 1.5 ATA (average 116 ± 106 AHs), 12 at >1.5 ATA (103 ± 74 AHs), and 9 at <1.5 ATA (114 ± 116 AHs). Second episodes occurred at 81 ± 55, 67 ± 49, and 22 ± 17 AHs, and three or more episodes at 25 ± 18, 83 ± 7.5, and 5.4 ± 6.0 AHs, respectively. Most cases were reversible. There was no difference between adults and children (p = 0.72). Acute intervention in cases (<3 months) was more sensitive than delayed intervention (21.1 ± 8.8 vs. 123 ± 102 AHs, p = 0.035). Outside sources reported one acute and two chronic exposure deaths and one patient institutionalized due to chronic oxygen toxicity. A withdrawal syndrome was also identified. Hyperbaric oxygen therapy-generated acute and chronic cases of CNS oxygen toxicity in chronic neurological conditions were identified at <2.0 ATA. Chronic CNS oxygen toxicity is idiosyncratic, unpredictable, and occurred at an average threshold of 103-116 AHs with wide variability. There was no difference between adults and children, but subacute cases were more sensitive than chronic intervention cases. When identified early it was reversible and an important aid in proper dosing of HBOT. If ignored permanent morbidity and mortality resulted with continued HBOT.

Prospective Pilot study of Quality of Life in patients with severe late-radiation-toxicity treated by Low hyperbaric-oxigen-therapy

Background/purposeThe aim of this study is to assess for the first time the immediate and long term impact on quality-of-life of HBO treatments(HBOT) at 1.45 ATA (Absolute Atmospheric Pressure) Medical Hyperbaric chamber. MethodsPatients over 18 years-old, suffering of grade 3 Common Terminology Criteria for Adverse Events (CTCAE) 4.0 radiation induced late toxicity and progressing to standard support therapy were included in this prospective study. HBOT was given daily, sixty minutes per session by a Medical Hyperbaric Chamber Biobarica System at 1.45 ATA at 100% O2. Forty sessions were prescribed for all patients given in 8 weeks. Patients reported outcomes (PROs) was assessed by the QLQ-C30 questionnaire, before starting, in the last week of the treatment, as well as during follow up. ResultsBetween February-2018/June-2021, 48 patients fulfilled the inclusion criteria. A total of 37 patients (77%) completed the treatment prescribed HBOT sessions. Patients with anal fibrosis (9/37) and brain necrosis (7/37) were the most frequently treated. The most common symptoms were pain (65%) and bleeding (54%). In addition, thirty out of the 37 patients who completed the pre- and post-treatment Patients Reported Outcomes (PROs) assessment also completed the follow up European Organization for Research and Treatment of Cancer, Quality of Life Questionnaire C30 (EORTC-QLQ-C30), and were evaluated in the present study. Mean follow up was 22,10 (6–39) months.The Median score of the EORTC-QLQ-C30, at the end of HBOT and during follow-up, was improved in all assessed domains, except in the cognitive aspect (p = 0.106). ConclusionsHBOT at 1.45 ATA is a feasible and well tolerated treatment, improving long term quality of life in terms of physical function, daily activities and general health subjective state of patients suffering severe late radiation-induced toxicity.

Hyperbaric Oxygen Ameliorates The Expression of Tumor Growth Factor-β and Malondialdehyde in Pristane-induced Lupus Nephritis Mice Model

BACKGROUND: Lupus nephritis (LN) is associated with chronic renal failure and a high mortality rate. Tumor growth factor-β (TGF-β) plays a basic part in keeping up immune homeostasis, meanwhile extensive oxidation of the lipid membrane in LN causes the arrangement of malondialdehyde (MDA). Up to date, the mechanism of hyperbaric oxygen (HBO) therapy in LN has not been elucidated well. Hence this study was conducted to assess the impact of HBO therapy on TGF-β and MDA expression in the pristane-induced LN mice model.METHODS: Thirty-two mice aged 8-12 old weeks were isolated into 4 groups: normal saline-injected mice (group 1); pristane-injected mice (group 2); as well as pristane-injected followed by HBO-exposured with 2.4 (group 3) and 1.5 (group 4) atmosphere absolute (ATA) pressure. Pristane were injected intraperitoneal to initiate LN. Two months after pristane injection, the mice were placed within 24 hours in the special cage for metabolic examination to determined that pristane-induced LN mice model was successfully formed and marked by the occurring proteinuria. Oxidative stress was assessed by examining MDA, while systemic inflammation was assessed by examining by TGF-β. MDA and TGF-β serum were measured by enzyme-linked immunosorbent assay (ELISA).RESULTS: A significantly lower (p&lt;0.050) MDA expression was found in group 3 in comparison with group 2. The results also showed that TGF-β level was significantly increased (p&lt;0.050) in group 3 compared to group 2.CONCLUSION: HBO therapy ameliorates inflammation in LN by diminishing MDA and expanding TGF-β levels through activating antioxidants.KEYWORDS: lupus nephritis, hyperbaric oxygen, malondialdehyde, tumor growth factor-β

Sudden hearing loss and early hyperbaric oxygen therapy: A preliminary study

Sudden sensorineural hearing loss (SSNHL) is a time-sensitive urgent condition. The aim of this study was to evaluate the frequency of hearing improvement in patients with idiopathic SSNHL who only received hyperbaric oxygen (HBO2) therapy within 3 days of symptom onset, instead of conventional corticosteroid treatment. Methods: The medical charts of patients who experienced SSNHL between January 1, 2012, and December 31, 2021, were reviewed. The present study included all adult patients who were diagnosed with idiopathic SSNHL and started HBO2 therapy within 72 hours of symptom onset. These subjects did not take corticosteroids due to contraindications or because they were concerned about possible side effects. The HBO2 therapy protocol consisted of at least 10 sessions of 85 minutes each with pure oxygen inhalation at 2.5 atmospheres absolute pressure. Results: Overall, 49 subjects (26 males and 23 females) met the inclusion criteria, with a mean age of 47 (± 20.4) years. The mean initial hearing threshold was 69.8 dB (± 18.0). After HBO2 therapy, complete hearing recovery was observed in 35 patients (71.4%), and the mean hearing threshold improved significantly (P&lt;0.001) to 31.4 dB (± 24.5). In patients with complete hearing recovery, no significant differences were found between males and females (P=0.79), right and left ears (P=0.72) or initial grades of hearing loss (P=0.90). Conclusion: This study suggests that, in the absence of the confounding effect of concurrent steroid therapy, starting HBO2 therapy within 3 days of symptom onset could have a positive impact on patients with idiopathic SSNHL.

Sudden hearing loss and early hyperbaric oxygen therapy: a preliminary study

Purpose: Sudden sensorineural hearing loss (SSNHL) is a time-sensitive urgent condition. The aim of this study was to evaluate the frequency of hearing improvement in patients with idiopathic SSNHL who only received hyperbaric oxygen (HBO2) therapy within 3 days of symptom onset, instead of conventional corticosteroid treatment. Methods: The medical charts of patients who experienced SSNHL between January 1, 2012, and December 31, 2021, were reviewed. The present study included all adult patients who were diagnosed with idiopathic SSNHL and started HBO2 therapy within 72 hours of symptom onset. These subjects did not take corticosteroids due to contraindications or because they were concerned about possible side effects. The HBO2 therapy protocol consisted of at least 10 sessions of 85 minutes each with pure oxygen inhalation at 2.5 atmospheres absolute pressure. Results: Overall, 49 subjects (26 males and 23 females) met the inclusion criteria, with a mean age of 47 (± 20.4) years. The mean initial hearing threshold was 69.8 dB (± 18.0). After HBO2 therapy, complete hearing recovery was observed in 35 patients (71.4%), and the mean hearing threshold improved significantly (P&lt;0.001) to 31.4 dB (± 24.5). In patients with complete hearing recovery, no significant differences were found between males and females (P=0.79), right and left ears (P=0.72) or initial grades of hearing loss (P=0.90). Conclusion: This study suggests that, in the absence of the confounding effect of concurrent steroid therapy, starting HBO2 therapy within 3 days of symptom onset could have a positive impact on patients with idiopathic SSNHL.

Functional regulation of osteoblastic MC3T3E-1 cells by hyperbaric oxygen treatment

ObjectivesThe purpose of the present study was to examine the influence of hyperbaric oxygen (HBO) on the function of osteoblastic MC3T3-E1 cells. DesignMurine MC3T3-E1 cells were exposed to HBO treatment (at 2.5 absolute atmospheric pressure with 100% oxygen, 90 min per day) for 28 days. Alkaline phosphatase (ALP) staining, activity, and calcium (Ca) content were measured. Gene expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hypoxia-inducible factor-1α (HIF-1α), type 1 collagen (COL1), and osteocalcin (OCN) was assessed using real-time quantitative polymerase chain reaction after a single HBO exposure for 1.5, 6, and 12 h. Furthermore, adenosine triphosphate (ATP) levels were measured using a luminescent cell viability assay. ResultsALP activity and Ca content were higher in the HBO group compared to those in the control group. Gene expression of bFGF, COL1, and OCN was upregulated in the HBO group; however, that of VEGF and HIF-1α significantly decreased in the HBO group in comparison with that in the control group. ATP levels were significantly higher in the HBO group compared to those in the control group. ConclusionsThese findings suggest that HBO accelerates bone formation by increasing the ATP levels of osteoblasts, and bFGF can act as a substitute for VEGF in vascularization by HBO application.

Hyperbaric oxygen treatment for long coronavirus disease-19: a\xa0case report

BackgroundThe coronavirus disease 2019 pandemic has resulted in a growing population of individuals who experience a wide range of persistent symptoms referred to as “long COVID.” Symptoms include neurocognitive impairment and fatigue. Two potential mechanisms could be responsible for these long-term unremitting symptoms: hypercoagulability, which increases the risk of blood vessel occlusion, and an uncontrolled continuous inflammatory response. Currently, no known treatment is available for long COVID. One of the options to reverse hypoxia, reduce neuroinflammation, and induce neuroplasticity is hyperbaric oxygen therapy. In this article, we present the first case report of a previously healthy athletic individual who suffered from long COVID syndrome treated successfully with hyperbaric oxygen therapy.Case presentationA previously healthy 55-year-old Caucasian man presented 3 months after severe coronavirus disease 2019 infection with long COVID syndrome. His symptoms included a decline in memory, multitasking abilities, energy, breathing, and physical fitness. After evaluation that included brain perfusion magnetic resonance imaging, diffusion tensor imaging, computerized cognitive tests, and cardiopulmonary test, he was treated with hyperbaric oxygen therapy. Each session included exposure to 90 minutes of 100% oxygen at 2 atmosphere absolute pressure with 5-minute air breaks every 20 minutes for 60 sessions, 5 days per week. Evaluation after completing the treatment showed significant improvements in brain perfusion and microstructure by magnetic resonance imaging and significant improvement in memory with the most dominant effect being on nonverbal memory, executive functions, attention, information procession speed, cognitive flexibility, and multitasking. The improved cognitive functions correlated with the increased cerebral blood flow in brain regions as measured by perfusion magnetic resonance imaging. With regard to physical capacity, there was a 34% increase in the maximum rate of oxygen consumed during exercise and a 44% improvement in forced vital capacity. The improved physical measurements correlated with the regain of his pre-COVID physical capacity.ConclusionsWe report the first case of successfully treated long COVID symptoms with hyperbaric oxygen therapy with improvements in cognition and cardiopulmonary function. The beneficial effects of hyperbaric oxygen shed additional light on the pathophysiology of long COVID. As this is a single case report, further prospective randomized control studies are needed.

A Method of Reducing the Distorting Curvature of Insulated Glass Units Due to Partial Rarefaction in Interglass Space

Currently, insulated glass units (hereinafter abbreviated as IGU) are the main type of translucent filling used in curtain walls. Under the influence of climatic loads in IGU, the thickness of the inter-glass space changes, leading to the deformation of the glasses. Deformations of glass lead to optical distortions on curtain walls. The paper considers the technical solutions used in the existing engineering practice to reduce the distorting curvature of IGU: the use of more rigid external glasses as part of IGU, the use of double-skin facades with external independent single glass, the use of vacuum IGUs. A new method is proposed to reduce the distorting curvature of IGUs by fixing the thickness of the interglass space. It is achieved by installing other point or linear supports between the panes. The introduction of other supports solves the problem of reducing deformations only when IGU is compressed. When the interglass space is expanded, the supports are turned off from operation and the glass is freely deformed. Therefore, to avoid such deflections, it is necessary to pre-compress the IGU under a load equivalent to the climatic load on the IGUs operating in the construction area of the object. Calculations show that for the climatic conditions of the city of Moscow, the required degree of rarefaction the interglass spaces is only 5 % of the absolute atmospheric pressure.

Hyperbaric oxygen for refractory osteomyelitis

Refractory osteomyelitis is defined as a chronic osteomyelitis that persists or recurs after appropriate interventions have been performed or where acute osteomyelitis has not responded to accepted management techniques [1]. To date, no randomized clinical trials examining the effects of hyperbaric oxygen (HBO2) therapy on refractory osteomyelitis exist, and the number of new osteomyelitis clinical trials conducted over the past decade has been limited. However, based on a comprehensive review of the scientific literature, the addition of HBO2 therapy to routine surgical and antibiotic treatment of previously refractory osteomyelitis appears to be both safe and ultimately improves infection resolution rates. In most cases, the best clinical results are obtained when HBO2 treatment is administered in conjunction with culture-directed antibiotics and initiated soon after clinically indicated surgical debridement. Where extensive surgical debridement or removal of fixation hardware is relatively contraindicated (e.g., cranial, spinal, sternal, or pediatric osteomyelitis), a trial of culture-directed antibiotics and HBO2 therapy prior to undertaking more than limited surgical interventions provides a reasonable prospect for osteomyelitis cure. HBO2 therapy is ordinarily delivered on a once daily basis, five-seven days per week, for 90–120 minutes using 2.0–3.0 atmospheres absolute (ATA) pressure. Where prompt clinical improvement is seen, the existing regimen of antibiotics and HBO2 therapy should be continued for approximately four to six weeks. Typically, 20–40 HBO2 sessions are required to achieve sustained therapeutic benefit. In contrast, if prompt clinical response is not noted or osteomyelitis recurs after this initial treatment period, then continuation of the current antibiotic and HBO2 treatment regimen is unlikely to be effective. Instead, clinical management strategies should be reassessed and additional surgical debridement and/or modification of antibiotic therapy considered. Subsequent reinstitution of HBO2 therapy will again help maximize the overall chances for treatment success in these persistently refractory patients.

The effect of hyperbaric oxygen therapy combinedwithhair transplantationsurgery for the treatment of alopecia.

Transplanted hair follicles suffer from various injuries, which are difficult to prevent. Hyperbaric oxygen therapy (HBOT) was reported to be an excellent procedure to promote capillary regeneration and reduce ischemia-reperfusion injury. To evaluate the clinical efficacy of HBOT as an adjuvant therapy for hair transplantation surgery. Thirty-four patients with II-IV alopecia were divided into the control group and HBOT group randomly. The control group was treated with routine FUE procedure, while HBOT group combined with HBOT. Patients were treated with 100% oxygen under 2.0 atmospheres absolute pressure for 60minutes through a facemask during HBOT and take the therapy daily for 7days continuously after operation. Satisfaction and clinical improvement were evaluated at the fourth week and the sixth month postoperatively. Itching and folliculitis were significantly decreased in HBOT group (11.8% vs 35.3%). In addition, HBOT resulted in a lower postoperative shedding rate (27.6±2.6% vs 69.1±2.4%); nevertheless, the survival rate at 9months showed no significant difference between HBOT (96.9±0.5%) and control (93.8±0.6%). The early postoperative satisfaction in control group was much lower than HBOT group (52.9% vs 88.2%), whereas all patients showed satisfaction with the final result. Hyperbaric oxygen therapy is able to minimize the postsurgical follicle shedding and lead to less folliculitis and itching, which provides evidence for HBOT to act as an adjuvant therapy for hair transplantation surgery.

Hyperbaric Oxygen Therapy in the Management of Zygomatic Bone Osteomyelitis.

Zygomatic bone osteomyelitis is a rare condition having an incidence of 1.42%. Zygomatic osteomyelitis can be due to haematogenous infection with tubercle bacillus, facial bone fractures or very rarely due to an unknown aetiology like in our case. If surgically managed alone, it would lead to complete loss of zygomatic bone, causing high morbidity to the patient in terms of function and aesthetics like loss of globe support causing dystopia, loss of facial projection causing facial asymmetry. Restoration of facial symmetry and globe support would require extensive procedures such as non-vascular bone grafting or patient-specific implant placement or microvascular bone flap transfer. Hyperbaric oxygen therapy (HBOT) was used to try and preserve the zygoma by promoting revascularisation. The patient received 100% oxygen at 2.5 absolute atmospheric pressure for 90 min, one session per day for 5 days in a week using a mask system in a multiplace chamber. The patient was reviewed clinically and radiologically after each 5 dives of HBOT sessions. After a total of 30 dives of HBOT, CT examination was repeated. There was partial reconstitution of cortical bone without any additional residual bone lesion. Minimal residual sequestra were noted. At this stage, the patient underwent conservative sequestrectomy in contrast to extensive surgery if HBOT was not contemplated. HBOT has the potential to be a very useful adjunct in the treatment of osteomyelitis in head and neck surgery; however, there is a need for carefully designed trials, avoiding methodological bias due to the great variability of patients, infectious agents, antibiotic resistance, host factors, to broaden the evidence of this therapeutic modality.

Hyperbaric Oxygen Treatment Improves Intestinal Barrier Function After Spinal Cord Injury in Rats

Intestinal barrier dysfunction is often observed clinically after spinal cord injury (SCI) and seriously affects long-term quality of life. Hyperbaric oxygen (HBO) treatment has been proved to promote barrier function recovery after injury, but the influence of HBO on intestinal barrier function following SCI is unclear. We aimed to investigate the effect and mechanisms of HBO treatment on intestinal barrier function by measuring the level of tight junction (TJ) proteins and the Ras homolog (Rho)/Rho-associated coiled-coil forming protein kinase (ROCK) signaling pathway. SCI model was established in rats, and the animals were randomly assigned into three groups: sham-operation group (SH), SCI group and SCI+HBO group. In the SCI+HBO group, the rats inhaled 100% O2 for 1 h at 2.0 atmospheres absolute pressure (ATA) once per day after surgery. Neurological function and intestinal permeability were assessed after surgery, and the jejunum tissue was excised for histological and intestinal barrier function evaluations. The protein levels of TJ and the Rho/ROCK signaling pathway were also measured. The results showed that in the SCI group, intestinal mucosal injury score, intestinal permeability, and levels of Rho and ROCK1 were higher, and TJ proteins occludin and ZO-1 were lower than those in the SH group (P < 0.01). HBO treatment significantly inhibited the expression of Rho and ROCK1, increased occludin and ZO-1 expression, decreased intestinal permeability, and alleviated intestinal mucosal injury as compared with the SCI group (P < 0.05, P < 0.01). The SCI+HBO group showed higher Basso–Beattie–Bresnahan (BBB) scores relative to the SCI group on postoperative days 7 and 14 (P < 0.01). There was a significant negative correlation between BBB score and intestinal mucosal injury score in rats after HBO treatment (P < 0.05). We concluded from this study that HBO treatment promoted the expression of TJ proteins possibly through inhibiting Rho/ROCK signaling pathway, which protected the intestinal barrier function and improved the intestinal permeability after SCI in rats.

Effects of hyperbaric oxygen treatment on calvarial bone regeneration in young and adult mice

ObjectiveThe present study aimed to investigate the effects of hyperbaric oxygen (HBO) treatment on calvarial bone regeneration in young and adult mice. MethodsCalvarial defects of 6.0 mm diameter were created in sixteen 3-week (young) and sixteen 32-week old (adult) mice. The mice were divided into two groups of eight animals each (HBO-treated and control). The 90-min HBO treatment at 2.5 absolute atmospheric pressure and 100 % oxygen was performed for five days a week for 12 weeks. After 2-weeks from the operation, micro-computerized tomography and video microscopy were used to evaluate the regenerated bone volume and microcirculation every two weeks. The protein concentrations of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in exudates of the calvarial tissue field were measured at 1, 2, 3, and 4 weeks after surgery. After 12 weeks, histochemical examination of regenerated calvarial bone was conducted. ResultsRegenerated bone was formed earlier in young mice than in adult mice treated with HBO. HBO stimulates angiogenesis in the periosteum around regenerated bone area in both young and adult mice at 2 weeks. VEGF concentrations in the calvarial tissue field were lower in the HBO group than in the control 1 week after operation, although bFGF were higher till the 2nd week in the HBO group than in the control. ConclusionsHBO accelerates bone regeneration earlier in young mice than in adult mice. In the HBO-treated group, bFGF expression was promoted at an early stage, although the expression of VEGF was inhibited.

Protective effect of hyperbaric oxygen treatment on rat intestinal mucosa after mesenteric ischaemia and reperfusion.

Mesenteric ischaemia results from a lack of adequate blood flow to and oxygenation of the mesentery and intestines. The aim of the present study was to evaluate the effect of hyperbaric oxygen treatment (HBOT) on the healing process in intestinal mucosa of rats undergoing mesenteric ischaemia and reperfusion. Thirty-two Wistar-Albino rats were divided into four groups of eight: 1) ischaemia/reperfusion (I/R); 2) sham operation; 3) I/R+HBOT started 6 hours after reperfusion; 4) I/R+HBOT started 12 hours after reperfusion. In the I/R groups, a vascular clamp was placed across the superior mesenteric artery to occlude arterial circulation for 60 minutes, followed by reperfusion. A dose of HBOT consisted of 100% oxygen breathing for 90 minutes at 2.5 atmospheres absolute pressure. Thirteen doses of HBOT were administered after ischaemia. The rats were sacrificed on the eighth day, and their intestinal tissues were harvested for histopathologic analysis. The tissue levels of catalase, malondialdehyde, and glutathione were determined. The histopathological scores (HSCORE) were consistent with macroscopic examinations. The scores were significantly higher (worse) in Group 1 compared to Group 2, Group 3, and Group 4 (for all comparisons, P < 0.05). Group 4's HSCORE was significantly higher than those of Group 2 and Group 3 (for both comparisons P < 0.05). Group 3's HSCOREs were only marginally higher than Group 2. Group 3 exhibited higher glutathione levels than Group 1 (P < 0.05). There were no significant differences across the groups with respect to malondialdehyde and catalase levels. A beneficial effect of HBOT was observed on oxidative stress and inflammation in acute mesenteric ischaemia-reperfusion.

Hyperbaric oxygen therapy for dermal ischemia after dermal filler injection with calcium hydroxylapatite: a case report

Dermal injection of fillers is a popular and relatively safe aesthetic procedure. Severe complications are rare, but they do occur. One of the most threatening complications after dermal filler injection is skin necrosis due to vascular occlusion. Different treatment options are available, including the use of hyperbaric oxygen (HBO2) therapy. A 46-year-old female received facial dermal filler injections with calcium hydroxylapatite at an aesthetic clinic. A few days after injection she developed a burning pain, numbness of the skin and white discoloration in the injected area. Two days after injection treatment was started with hyaluronidase and warm compresses. In addition, the patient received prednisolone, sildenafil and nifedipine. After the start of these treatments, the pain, numbness and discoloration of the skin persisted. Because of dermal ischemia and to improve healing she was referred for HBO2. Treatment consisted of 10 sessions of 100% oxygen for 90 minutes in a multiplace chamber at 2.5 atmospheres absolute pressure. During HBO2 the discoloration resolved, pain and numbness disappeared, and the tissue healed completely. After a six-month follow-up she had an excellent cosmetic outcome. Given the pathophysiologic mechanisms of vascular complications after dermal filler injection, HBO2 should be considered when treating these complications.