Influence Of Hyperbaric Oxygen Therapy Research Articles

Abstract P2073: Hyperbaric Oxygen Therapy Protects The Myocardium From Reductive Stress-induced Proteotoxic Remodeling

Background: Oxygen is the prime source of reactive oxygen species (ROS) in cells. We hypothesize that hyperbaric oxygen therapy (HBOT) can be used as an effective intervention to maintain redox homeostasis in the myocardium. Here, we assessed whether HBOT could prevent RS through enhanced ROS signaling, thereby protecting the hearts from proteotoxic stress. Methods: Cardiac-specific human Nrf2 transgenic (hNrf2-TG) and their non-transgenic littermates (NTG) were used in this study. Mice at the age of 8 weeks were exposed to hyperbaric oxygen (2.5 Bars, 2 hr/day) for 8 weeks. The TG and NTG (n=6) mice without HBOT served as controls. Pre- and post- echocardiography (Vevo 2100) analysis were carried out to assess the structural and functional changes over time in response to HBOT exposure. The influence of HBOT on matrixins (MMP2/9), redox (GSH & NQO1), and cardiac hypertrophy markers (ANF, BNF) were examined using zymography, immunoblotting, and qPCR analysis. The aggregation of proteins in myocardial tissues was detected by Proteostat staining. Results: While the expression of hNrf2 induces RS in the mouse heart, we noticed that HBOT ameliorates the RS through enhanced ROS signaling. A decrease in systemic GSH levels along with the downregulation of ANF and BNF mRNA levels observed in the HBOT group indicates the restoration of the redox homeostasis as well as reduced remodeling of the myocardium. Interestingly, hNRF2-induced RS was suppressed by HBOT as supported by changes in the protein levels for NQO1, GCLC, and GCLM. The degree of protein aggregation in RS hearts was significantly reduced by HBOT. Vevo strain analysis reveals that 8 weeks of HBOT restored the diastolic stretch seen in the RS hearts to a normal diastole-systole velocity equal to NTG mice. A significant decrease in the ejection fraction (80% vs. 55% in TG vs. TG-HBOT), was evident in the TG mice that received HBOT. Repression of matrixins, observed in the hearts of HBOT-TG mice signifies the benefits of HBOT in RS hearts. Conclusion: HBOT directly improves myocardial structure at the tisuue level; maintain the redox status at systemic level, and improves the myocardial performance at functional level. Our study established that HBOT can rescue the myocardium from RS-induced proteotoxic insults.

Hyperbaric oxygen therapy efficacy on mandibular defect regeneration in rats with diabetes mellitus: an animal study

BackgroundThis study aimed to investigate the influence of hyperbaric oxygen therapy on mandibular critical-sized defect regeneration in rats with experimentally induced type I diabetes mellitus. Restoration of large osseous defects in an impaired osteogenic condition such as diabetes mellitus is a challenging task in clinical practice. Therefore, investigating adjunctive therapies to accelerate the regeneration of such defects is crucial.Materials and methodsSixteen albino rats were divided into two groups (n = 8/group). To induce diabetes mellitus, a single streptozotocin dosage was injected. Critical-sized defects were created in the right posterior mandibles and filled with beta-tricalcium phosphate graft. The study group was subjected to 90-min sessions of hyperbaric oxygen at 2.4 ATA, for 5 consecutive days per week. Euthanasia was carried out after 3 weeks of therapy. Bone regeneration was examined histologically and histomorphometrically. Angiogenesis was assessed by immunohistochemistry against vascular endothelial progenitor cell marker (CD34) and the microvessel density was calculated.ResultsExposure of diabetic animals to hyperbaric oxygen resulted in superior bone regeneration and increased endothelial cell proliferation, which were revealed histologically and immunohistochemically, respectively. These results were confirmed by histomorphometric analysis which disclosed a higher percentage of new bone surface area and microvessel density in the study group.ConclusionsHyperbaric oxygen has a beneficial effect on bone regenerative capacity, qualitatively and quantitively, as well as the ability to stimulate angiogenesis.

Hyperbaric oxygen treatment for University of Texas grade 3 diabetic foot ulcers: a retrospective cohort study.

Hard-to-heal diabetic foot ulcers (DFUs) may increase the risk of amputation. This study reports the positive influence of hyperbaric oxygen therapy (HBOT) on hard-to-heal DFUs involving underlying bone. A single-centre, retrospective cohort study reporting the results of HBOT and wound care on hard-to-heal University of Texas grade 3 DFUs (i.e., involving underlying bone) between 2013 and 2019. Outcome measures were primarily (near-) complete wound healing (i.e., ≥80% ulcer surface area reduction) and amputation rate (minor or major), and secondarily the number of hyperbaric sessions and improvement in quality of life (QoL) and pain score. The study included 206 patients, of whom 74 (36%) achieved complete wound healing, and 75 (36%) near-complete healing. Amputations were performed in 27 patients (13%): 12 (6%) minor and 15 (7%) major. The median number of HBOT sessions was 42. Participants who achieved complete healing received a median of 43 sessions, compared with 10 for those who required major amputation. Patients with at least 30 sessions were less likely to undergo amputation (odds ratio: 0.08; 95% confidence interval (CI): 0.03-0.21). Mean QoL increased by 7.6 points (95%CI: 3.9-11.3; p<0.01) and median pain score fell from 3 to 1 (0-3) (p<0.01). The addition of HBOT to standard wound care may lead to a decreased amputation risk, improved wound healing and increased QoL for people with a University of Texas grade 3 DFU. An adequate number of HBOT sessions is required to achieve optimal clinical results. Objective selection criteria and shared decision-making are suggested to improve dropout rates.

Influence of hyperbaric oxygen therapy on bone metabolism in patients with neoplasm.

Hyperbaric oxygen therapy (HBOT) is useful in the treatment of complications due to radiotherapy in patients with neoplasm. Its effects on bone metabolism are unclear. In our study, we analyzed the effects of HBOT on bone remodeling in oncological patients with radiotherapy. Prospective clinical study in 23 patients with neoplasms undergoing treatment with HBOT due to complications of radiotherapy (hemorrhagic cystitis, proctitis or radionecrosis) and 25 patients with chronic anal fissure. The average number of HBOT sessions was 20 ± 5 (100% oxygen, 2.3 atmospheres and 90 min per day). Serum levels of aminoterminal propeptide of type I collagen (P1NP), C terminal telopeptide of type I collagen (CTX), alkaline phosphatase (AP), 25hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), were measured at 3 time points: T0 (before beginning HBOT), T1 (at the end of HBOT) and T2 (6 months after HBOT). At baseline, the patients with neoplasm have higher bone turnover than those with anal fissure. These differences were 41% in CTX (0.238 ± 0.202 ng/mL in neoplasm and 0.141 ± 0.116 ng/mL in fissure; p = 0.04), 30% for PTH (46 ± 36 pg/mL in neoplasm and 32 ± 17 pg/mL in fissure; p = 0.04) and 15% for alkaline phosphatase (80 ± 24 U/L in neoplasm and 68 ± 16 U/L in fissure; p = 0.04). In the group with neoplasm, the values of P1NP decreased 6% after HBOT (T0: 49 ± 31 ng/mL, T2: 46 ± 12 ng/mL; p = 0.03). Also, there were non-significant decreases in PTH (-34%) and CTX (-30%). Patients with neoplasm and complications with radiotherapy have an increase in bone remodeling that may be diminished after HBOT.

Influence of hyperbaric oxygen therapy on sensorimotor functions in diabetic peripheral neuropathy: a controlled randomized trial

Influence of hyperbaric oxygen therapy on sensorimotor functions in diabetic peripheral neuropathy: a controlled randomized trial

Effects of Hyperbaric Oxygen Therapy in Children with Severe Atopic Dermatitis.

In the course of atopic dermatitis (AD), the overactivity of the immune system, associated with predominant Th2 lymphocyte responses, is observed, which leads to an increased inflammatory reaction. Cases of a severe course of atopic dermatitis lead to the search for new therapeutic options. The aim of this study was to assess the effects of hyperbaric oxygen therapy (HBOT) treatment for severe cases of AD in children. A total of 15 children with severe AD underwent therapy. The influence of HBOT on the clinical course of AD and immunomodulatory effect of the therapy was analyzed by the SCORAD and objective SCORAD (oSCORAD) scales and by determining the serum concentration of immunological parameters (blood: nTreg lymphocytes, CD4+CD25highCD127-FOXP3+, NKT lymphocytes CD3+, CD16/56+, and serum: total IgE, cytokines IL-4, IL-6, and IL-10, before and after the 30-day treatment cycle). The study showed a significant effect of the therapy on the improvement of the skin condition. In all children, a reduction in the extent and intensity of skin lesions, reduction of redness, swelling, oozing/crusting, scratch marks and skin lichenification after HBOT was observed. Patients also reported a reduction in the intensity of pruritus and an improvement in sleep quality after therapy. In all children, a statistically significant decrease in the serum level of IgE was observed. However, no statistically significant changes in the blood levels of IL-4, IL-6 and IL-10, as well as the percentage of CD4+CD25highCD127−FOXP3+ Treg and NKT lymphocytes, were found. In conclusion, the use of hyperbaric therapy has a positive impact on treatment results in children with a severe course of atopic dermatitis.

Influence of hyperbaric oxygen therapy on thrombus formation ability in humans

Background: Hyperbaric oxygen (HBO2) therapy was introduced nearly 300 years ago. However, its effect on thrombus formation is unclear. This may be because platelet and coagulation functions are unstable, yielding variable results; hence, accurate measurement is difficult. Our study aimed to analyze changes in thrombus formation before and after HBO2 therapy by using a total thrombus formation analysis system (T-TAS). Methods: Six patients were prescribed HBO2 therapy for skin and soft tissue ulcers, and necrotic fasciitis. Blood samples were collected immediately before and after treatment. Then samples were put into a reservoir that connected to AR-chip to assess changes in the thrombus formation ability of both platelets and coagulation factors. We examined the differences in the thrombus formation ability using T-TAS. Time until the onset of white thrombus formation (T10) and complete occlusion of the capillary (T80) were analyzed by a two-way repeated measure analysis of variance (ANOVA). Results: The duration to pressure increase of samples after HBO2 therapy was longer than the duration before HBO2 therapy (p&lt;0.05). This suggests decreased clot adhesiveness to the inner surface of the simulated blood vessel and reduced clot formation ability. Conclusions: The results for T10 and T80 suggest that HBO2 therapy reduced thrombus formation ability in the enrolled patients. We believe that T-TAS is a promising method to predict the efficacy of HBO2 therapy.

The influence of hyperbaric oxygen therapy (HBOT) to intercausal relationship between blood vessels, osteoblast, and new bone formation during maxillary suture expansion

Introduction: Expansion appliance that can imply tooth movement and opening maxilla suture might affect the blood vessels, bone cells, and formation of the new bone. HBOT accelerated the rate of osteoblast differentiation leading to an increase in bone formation during osteonecrosis. Research about HBOT during maxillary suture expansion has never been investigated. The purpose of this research was to correlate the blood vessels number, osteoblast by administered 2.4 ATA HBOT from day 8-14 to imply new bone formation during maxillary suture expansion. Methods: Eighteen male guinea pigs with randomised post-test only control group design divided into 3 groups. Negative control group K(-), positive control with expansion appliance K(+), expansion appliance and HBOT (P). After 14 days guinea pigs were decapitated. Histological slide of the blood vessels number, osteoblast, and new bone formation were examined under a light microscope then were analysed by regression test. Results: Descriptive test showed increasing blood vessels number, osteoblast, and new bone formation on the administration of HBOT during maxillary suture expansion. Regression test showed that there was a strong correlation between the blood vessels number and osteoblast to the new bone formation with R=6.95 during maxillary suture expansion. Conclusion: 2.4 ATA HBOT influences the intercausal relationship between increasing blood vessels number, increasing osteoblast, and new bone formation during maxillary suture expansion.

EFFECT OF HYPERBARIC OXYGEN THERAPY ON THE OSSEOINTEGRATION AROUND IMPLANTS AFTER MANDIBULAR RECONSTRUCTION BY DESTRACTION OSTEOGENESIS

Increases in mandibular width by distraction osteogenesis have recently been shown to be an acceptable and stable treatment option for deficiencies, and also, in the oral rehabilitation, where one of the major problems is the alveolar bone loss, and adjacent soft tissues.Aim: The aim of this study is to evaluate the influence of hyperbaric oxygen therapy (HBOT), on the osseointegration of implants retained partial mandibular overdenture after reconstruction of mandibular deficiency by distraction osteogenesis. Methods: This study was conducted on eight male patients with a lack of the anterior mandibular jaw bone due to anterior marginal mandibulectomy, and partially edentulous maxillary arch (different classes), selected from the maxillofacial outpatient clinic, Faculty of Dentistry, Misr University for Science and Technology, (mean age 43 years, minimum 35 years and maximum 51 years). For all patient, distraction the insufficient alveolar ridge by using an Extraosseous Track Alveolar Distractor (KLS Martin, Germany), after consolidation period, patients received maxillary and mandibular conventional acrylic partial dentures prior to implant insertion. Then, each patient received two endoosseous implants in the mandibular interforaminal region, (following two stage surgical protocols), to retain partial mandibular overdentures. Patients were randomly divided by closed envelops, into two equal groups. Group I; Patients were received hyperbaric oxygen therapy (HBOT), on a protocol of five sequential sessions (study group), while Group II; Patients were received no hyperbaric oxygen therapy (HBOT), as a control group. Ball attachments were screwed to the implants, after four months of surgery. All patients received new mandibular removable partial overdentures were retained by two implants, and designed as Kennedy class IV partial overdentures, to fitted partial mandibular overdentures. Marginal bone height changes and bone density were assessed using cone beam computed tomography(CBCT); at time of prosthetic loading, then after six, and twelve months.Results: Decrease in marginal bone height and increase in bone density through a follow-up period (one year) were observed in both groups , however; group I; that received HBOT revealed less marginal bone resorption and more increase in bone density than group II. Conclusion: After mandibular reconstruction by distraction osteogenesis, hyperbaric oxygen therapy effective treatment, and improve osseointegration around implants retained partial ovedentures, as it associated with increased bone density and reduced marginal bone loss after one year follow up.

Hyperbaric Oxygen Therapy to Reduce Blood Glucose Level on Patients Diabetes Mellitus

Oxygen hyperbaric therapy is a clinical treatment by inhalation of pure oxygen (FiO2 = 100%), resulting in increasing oxygen levels in the blood and tissues. Currently, hyperbaric oxygen therapy is used for additional management in diabetes mellitus. The purpose of this study was to know the effect of hyperbaric oxygen therapy in case of diabetes mellitus to changes in blood glucose level. Type of research was pre-experimental one group pre-test post design. The population in this study was diabetes mellitus patients, so that the sample obtained 47 respondents. Patients were given 100% oxygen inhalation with a pressure of 2.4 ATA in chamber hyperbaric oxygen. Blood glucose levels were measured before and after hyperbaric oxygen therapy. Glucose levels before the average therapy were 229 mg / dl and after treatment averaged 159 mg / dL. Statistical analysis with t test showed p value 0.000 &lt;α (0,05), so there was the influence of hyperbaric oxygen therapy with decreasing blood glucose level. There are improvements pancreatic beta cell function and increased tissue sensitivity to insulin due to increased oxidative phosphorylation process in pancreatic beta-cell mitochondria to increase ATP production in pancreatic beta cells. Checks need to be done periodically in one period with using the time series method, so that long-term effects can be known and need to be reviewed by the last use of anti-diabetes drugs and insulin

Effects of Hyperbaric Oxygen Therapy on Inflammasome Signaling after Traumatic Brain Injury

Objective: Neuroinflammation plays an important role in secondary tissue damage after traumatic brain injury (TBI). Recently, the inflammasome-mediated inflammatory pathway has been observed in the inflammatory response of TBI. In this study, we investigated the influence of hyperbaric oxygen therapy (HBOT) on inflammasome activation after TBI. Methods: The experimental mice were randomly divided into 4 groups as follows: sham-operated normobaric air (21% O₂ at one absolute atmosphere), HBOT only, TBI + normobaric air and TBI + HBOT. Following the evaluation of motor deficits and brain edema, the expression of inflammasome components and effectors was measured by qRT-PCR and Western blotting. Moreover, alterations in IL-1β, IL-18 and high-mobility group box 1 (HMGB1) were calculated by enzyme-linked immunosorbent assay at each time point after injury. Results: HBOT improved motor score and reduced brain edema. Furthermore, it suppressed protein expression of inflammasome components and reduced the levels of IL-1β and IL-18, accompanied by the reduction of HMGB1 in brain tissues and serum. Conclusion: These results suggest that HBOT may alleviate the inflammatory response after TBI by inhibiting the activation of inflammasome signaling.

Hyperbaric oxygen therapy can improve the learning capacity and memory in vascular dementia

Objective To explore the influence of hyperbaric oxygen therapy (HBOT) on the learning and memory ability using a rat model of vascular dementia (VD). Methods Sixty Sprague-Dawley rats were selected and divided into a normal group, a sham operation group, a VD group and an HBOT group, each of 15 rats using a random number table. The improved four-vessel method was used to establish a VD model in all except the rats in the normal group, but for the sham operation group, the vertebral artery was not subjected to firing and the arteria carotis communis was not clipped. The HBOT group was then given HBOT for 7 days. The Morris water maze test was used to evaluate their learning and memory ability of all 4 groups. Results Compared to the normal group, the mean escape latency of the sham operation group, the VD group and the HBOT group was significantly longer in each case (P<0.05). Their platform quadrant crossing times were also significantly less, and their quadrant swimming distance as a proportion of their total swimming distance was significantly smaller (P<0.05). Compared with the sham operation group, the mean escape latency of the VD and HBOT groups was significantly longer (P<0.05), the times of crossing platform quadrant were less and their quadrant swimming distance was a smaller proportion of their total swimming distance. As compared with the VD group, the mean escape latency of the HBOT group was significantly shorter [(25.73±6.20) s], the average platform quadrant crossing times were significantly more [(9.51±2.25) times] and the platform quadrant swimming distance of the HBOT group was significantly longer [(494.72±208.26)], representing a significantly larger proportion of the total swimming distance [(28.71±5.32)%](P<0.05). Conclusion HBOT can effectively improve learning and memory in vascular dementia, at least in rats. Key words: Hyperbaric oxygen therapy; Vascular Dementia; Morris water maze; Learning; Memory

The influence of hyperbaric oxygen therapy on intestinal mucosal barrier function in rats with acute carbon monoxide poisoning

Hyperbaric oxygen increases the partial pressure of O2 in arterial blood and tissues and thereby relieves cellular hypoxia. We investigated whether this treatment changes biochemical parameters and intestinal mucosal barrier function in rats exposed to toxic levels of CO. Groups of ten Sprague–Dawley rats were treated with CO, with hyperbaric oxygen, or with CO followed by hyperbaric oxygen. A fourth group maintained under normal atmospheric conditions served as a control. CO poisoning increased red blood cell distribution width and the amount of alanine aminotransferase, urea nitrogen, and tight junction creatine kinase but decreased the mean corpuscular hemoglobin (Hb). These changes were reversed after hyperbaric oxygen therapy, which increased the number of red blood cells, hematocrit level, total protein, and Hb level. Hyperbaric oxygen therapy also increased tight junction protein 1 expression and reduced toll-like receptor 4 expression in the rat colon. In conclusion, hyperbaric oxygen resulted in an improved oxic condition in CO-poisoned rats and restored energy metabolism by repairing, to some extent, the organs injured by CO. The therapy may also improve the function of the intestinal mucosal barrier.

Influence of hyperbaric oxygen therapy on peri‐implant bone healing in rats with alloxan‐induced diabetes

The influence of hyperbaric oxygen therapy (HBOT) on peri-implant bone healing in rats with alloxan-induced type-1 diabetes was studied. Forty-eight male rats were randomly divided into six groups: (1) healthy rats (HR) that received no HBOT; (2) HR that underwent 10 sessions of HBOT before implant installation; (3) HR that underwent 10 sessions of HBOT after implant installation; (4) rats with induced diabetes (DR) without HBOT; (5) DR that underwent 10 sessions of HBOT before implant installation; (6) DR that underwent 10 sessions of HBOT after implant installation. A screw-shaped titanium implant was inserted into the femur. The animals were killed 28days after implantation. The percentage of bone-to-implant contact (BIC) within the implant threads was evaluated. Lower BIC was observed in DR (35.35±18.04) compared with the HR (69.07±09.01) (p=0.001). However, with HBOT, either before or after implantation, BIC was increased in DR. HBOT before implantation was p=0.03; HBOT after implantation was p=0.08. This increase reversed the negative effect of diabetes; therefore, the differences between DR and HR were not significant with HBOT (p≥0.21). HBOT, either before or after implantation, increased the BIC in DR to the level of HR.

Thermal imaging and TC oximetry measurements of hyperbaric oxygen therapy (HBO) effects on trophic ulceration of the crura

We performed studies on the influence of hyperbaric oxygen therapy on the trophic ulceration of the crus using thermal imaging and TC oximetry. Thermograms for two groups of volunteers, one suffering from trophic ulceration of the crus (11 patients aged 63.6 ± 15.2) and one healthy (6 people aged 42 ± 8), were completed before and after hyperbaric oxygenation. In addition, the oxygen tension in each patient’s crus was measured. Hyperbaric oxygenation has an influence on biological as well as physiological processes that occur in the tissue. It is apparent that these processes may have an impact on the differentiation of tissue temperature. The studies showed some differences in skin temperature between research groups. A bigger differentiation of skin temperature was observed for patients who suffered from ulceration. It follows that there are statistically significant differences between the mean temperature for all chosen regions of interest obtained before (p = 0.0003) and after (p = 0.03) hyperbaric oxygen therapy. Moreover, the differences (ΔT = TmeanAR01 − TmeanAR04) between mean temperature characterization in chosen areas seem to be a little smaller. We observed that this difference changed from ΔT = 3.3 °C, estimated before hyperbaric oxygenation, to 2.5 °C, obtained after hyperbaric oxygenation, which may suggest improvement in the thermoregulation process. A similar situation was observed for the healthy group, but the temperature changes were smaller. The changes of the mean temperature may be correlated to some changes in wound cellular metabolism and the increase of microcirculation due to neoangiogenesis as well as the improvement of thermoregulation in the ulceration due to a rebuilding of the right cellular matrix. In addition, we observed that the mean values of oxygen pressure in the tissues (TCPO2) increased from 22 to 39 mmHg after hyperbaric oxygenation for patients with ulceration in their lower extremities. We also detected that oxygen pressure measurements and infrared imaging seem to be useful in the qualitative analysis of hyperbaric oxygenation treatment, and may offer some useful information about the hyperbaric oxygen therapy effects in trophic ulceration.

The influence of hyperbaric oxygen therapy started at different time on patients with acute cerebral infarction

目的 探讨不同时机高压氧(HBO)治疗对急性脑梗死患者疗效的影响.方法 60例急性脑梗死患者按开始进行HBO治疗的时间分为两组,即伤后48 h至7 d组(早期组)和伤后8～15 d组(晚期组)各30例,对两组患者在HBO治疗前、治疗30 d后分别进行神经功能缺损程度、简式Fugl-Meyer和改良Barthel指数评定,并进行两组之间的比较.结果 HBO治疗30 d后,早期组患者的神经功能缺损程度和运动功能改善较晚期组显著,两组间简式Fugl-Meyer和改良Barthel指数评分比较,差异有统计学意义(P＜0.05).结论高压氧治疗急性脑梗死疗效可靠,在伤后7 d以内开始HBO治疗效果更好。

Acute respiratory distress syndrome in patients after blunt thoracic trauma: the influence of hyperbaric oxygen therapy.

The rate of mortality from acute respiratory distress syndrome (ARDS) has reportedly reached as high as 50–75%.1−3 The risk of ARDS development increases after severe blunt thoracic trauma (BTT) because of a higher likelihood for lung contusion4 and acute depression of cardiac function.5, 6 Monitoring of oxygen transport in patients with ARDS has shown that oxygen delivery and consumption were significantly higher in the survivors compared to nonsurvivors.7 This suggests that maintenance of oxygen delivery at optimal levels can potentially enable the reversal of ARDS.8 In cases of severe BTT, these oxygen transport variables may be induced by early cardiorespiratory dysfunction6, 9 which requires inotropic support.6, 8, 10 On the strength of these data, it is reasonable to conclude that the prevention and correction of oxygen deficiency are basic to intensive care during ARDS.

The influence of intensive hyperbaric oxygen therapy on skin flap survival in a swine model.

Conflicting reports exist regarding the influence of hyperbaric oxygen therapy on random skin flap survival. The present investigation sought to demonstrate enhanced survival of experimental random skin flaps in swine using an intensive and tapering hyperbaric oxygen therapy regimen that would have direct application in human clinical trials. Random cutaneous flaps were surgically constructed on 12 domestic pigs. Flaps were designed to obtain a predictable length of necrosis. Six pigs did not undergo hyperbaric oxygen therapy and served as surgical controls. Six pigs were subjected to an intensive tapering hyperbaric regimen within 1.5 hours of completing the surgical procedure. Treatments were administered in a research hyperbaric vessel at a depth of 2.0 atm absolute (10 m of seawater) for 90 minutes of oxygen treatment in a tapering schedule over 6 days. This was structured to provide intensive therapy initially during the period of maximum tissue trauma and ischemia. Extent of flap necrosis was assessed by tracing clear plastic templates at necropsy, then converting to square centimeters using a computer digitizer tablet. The difference in flap necrosis between groups was significant, with random flaps subjected to hyperbaric oxygen therapy demonstrating a mean 35% less necrosis than surgical controls. Skin flaps treated with hyperbaric oxygen therapy demonstrated a mean survival of 77%, with a range of 56% to 100%. This reflected a 12% improvement in mean surviving area for hyperbaric oxygen therapy flaps over untreated surgical controls. We are unaware of similar studies reporting a comparable degree of enhancement in random skin flap survival using hyperbaric oxygen therapy alone. Adjunctive hyperbaric oxygen therapy in an intensive tapering schedule significantly improved flap survival in this model. Further investigations need to determine the optimum frequency of treatments and depth necessary to attain maximum tissue viability.