A systematic review and meta-analysis of hyperbaric oxygen therapy for diabetic foot ulcers with arterial insufficiency

BackgroundDiabetic foot ulcers (DFUs) are frequently associated with peripheral arterial occlusive disease (PAOD) and may ultimately lead to amputations of the lower extremity. Adjuvant hyperbaric oxygen treatment (HBOT) might foster better wound healing and lower amputation rates in patients with DFU and PAOD. A systematic review was conducted to assess the effects of HBOT as an adjunctive therapy to standard treatment for patients with DFUs with PAOD.MethodsSystematic review using the MEDLINE, EMBASE, and Cochrane CENTRAL databases (from inception to October 2018). All original, comparative studies on the effect of HBOT on DFUs with PAOD were eligible. The primary outcome measures were amputation rate, amputation-free survival, complete ulcer healing, and mortality.ResultsEleven studies, totaling 729 patients, were included for analysis, including 7 randomized clinical trials, 2 controlled clinical trials, and 2 retrospective cohorts. Four were used for quantitative synthesis. Meta-analysis showed a significantly fewer major amputations in the HBOT group (10.7% vs 26.0%; risk difference, −15%; 95% confidence interval [CI], −25 to −6; P = .002; number needed to treat, 7; 95% CI, 4-20). No difference was found for minor amputations (risk difference, 8%; 95% CI, −13 to 30; P = .46). Three studies reporting on complete wound healing showed contrasting results. No significant difference was found for mortality or amputation-free survival.ConclusionsCurrent evidence shows that adjuvant HBOT improves major amputation rate, but not wound healing, in patients with DFUs and PAOD. Given the wide range of patients included in the trials, better patient selection may help define which patients with DFUs and PAOD benefit most from HBOT as standard adjunctive treatment.     

Topical oxygen therapy results in complete wound healing in diabetic foot ulcers

Diabetic foot ulcers (DFUs) are a significant problem in an aging population. Fifteen percent of diabetics develop a DFU over their lifetime, which can lead to potential amputation. The 5‐year survival rate after amputation is 31%, which is greater than the lifetime risk of mortality from cancer. Topical oxygen is a promising technique for the adjunctive therapy of chronic wounds including DFUs, but few controlled studies exist to support its clinical adoption. The aim of this study was to compare a portable topical oxygen delivery system in patients with nonhealing DFUs to standard best practice. Twenty patients were randomized into a topical oxygen group (n = 10), and a nonplacebo control group with regular dressings and standard care (n = 10), and attended the diabetic foot clinic once weekly for 8 weeks. Ulcer surface area over time was analyzed using standardized digital imaging software. DFUs were present without healing for a mean duration of 76 weeks prior to the study. They found a significant difference in healing rate between patients receiving topical oxygen and those receiving standard care. Topical oxygen, therefore, represents a potentially exciting new technology to shorten healing time in patients with nonhealing DFUs. More prospective randomized and powered studies are needed to determine the benefits of topical oxygen, but our current results are very promising.     

Hyperbaric oxygen stimulates epidermal reconstruction in human skin equivalents

The crucial role of oxygen during the complex process of wound healing has been extensively described. In chronic or nonhealing wounds, much evidence has been reported indicating that a lack of oxygen is a major contributing factor. Although still controversial, the therapeutic application of hyperbaric oxygen (HBO) therapy can aid the healing of chronic wounds. However, how HBO affects reepithelization, involving processes such as keratinocyte proliferation and differentiation, remains unclear. We therefore used a three-dimensional human skin-equivalent (HSE) model to investigate the effects of daily 90-minute HBO treatments on the reconstruction of an epidermis. Epidermal markers of proliferation, differentiation, and basement membrane components associated with a developing epidermis, including p63, collagen type IV, and cytokeratins 6, 10, and 14, were evaluated. Morphometric analysis of hematoxylin and eosin-stained cross sections revealed that HBO treatments significantly accelerated cornification of the stratum corneum compared with controls. Protein expression as determined by immunohistochemical analysis confirmed the accelerated epidermal maturation. In addition, early keratinocyte migration was enhanced by HBO. Thus, HBO treatments stimulate epidermal reconstruction in an HSE. These results further support the importance of oxygen during the process of wound healing and the potential role of HBO therapy in cutaneous wound healing.     

Hyperbaric oxygen therapy in adriamycin extravasation: an experimental animal study

Adriamycin extravasation is a serious problem that can lead to severe local necrosis and damage to underlying nerves, tendon, and muscle. There are some experimental studies in which conflicting results were reported about the beneficial effects of hyperbaric oxygen (HBO) in adriamycin-induced skin lesions. In this study the effect of HBO on the healing of adriamycin-induced wounds was investigated in the Wistar-Albino rat model. Ninety-five rats underwent injection of a 0.7-ml adriamycin solution (2 mg per milliliter) subcutaneously on the right upper hind legs. The HBO group (n = 43) received HBO treatment (at 2.5 ATA for 80 minutes) twice a day for 28 days. The control group (n = 42) did not receive any therapy. Lesion size was measured for 4 weeks. There was no significant difference in lesion size between the groups on days 7 (p = 0.1364) and 14 (p = 0.1123), but the lesion size was significantly smaller in the HBO group than in the control group on days 21 (p = 0.0251) and 28 (p = 0.0001). Of 36 animals with lesions in the HBO group, complete wound healing occurred in 16 animals by day 40. However, there was no complete wound healing in any of the 36 animals with lesions in the control group. The beneficial effect of HBO in adriamycin-induced skin lesions was observed in this experimental study.     

A retrospective study of diabetic foot ulcers treated with hyperbaric oxygen therapy

A retrospective review of patient medical records was conducted to assess what factors influence the outcomes of diabetic foot ulcers treated with hyperbaric oxygen (HBO) therapy. Patients referred to the Diving Diseases Research Centre for HBO therapy for the treatment of diabetic foot ulcers during a 2‐year period were included in this study. Data collected from 30 sets of patient records were entered into SPSS and statistical analysis was undertaken to investigate whether any underlying pathologies or confounding factors appeared to influence patient outcome. A 73·3% of patients achieved a successful outcome of partial healing, major amputation no longer required, amputation level lower than anticipated prior to HBO or healing at the end of HBO therapy and 70% remained successful 3 months later. A 13·3% of patients were lost to follow‐up at 3 months and one patient (3·3%) had a major amputation. Steroid therapy, peripheral vascular disease, previous minor amputation, type of diabetes, previous HBO therapy, larvae therapy, the use of interactive dressings and haemoglobin A1c levels were all observed to have had a significant relationship with patient outcome (P < 0·05). These results were compared with data from other published research conducted in this area on similar patient groups. A larger scale study focussing on the factors found to be significant in this study is recommended. An improvement of patient documentation would allow patient outcomes to be more consistently monitored in the future.     

Hyperbaric oxygen therapy (HBO): current standing

For more than thirty years hyperbaric oxygen therapy (HBO) has been an important and ultimate therapeutic tool in special indications. Hyperbaric oxygen improves tissue oxygenation, stimulates important mechanisms in wound healing and exerts beneficial effects on other biochemical and cellular processes. The properties of hyperbaric oxygen have built the rationale for its use as therapy of choice in patients with severe carbon monoxide poisoning, decompression sickness and arterial gas embolism, and as adjunctive therapy for the treatment of osteoradionecrosis, necrotizing fasciitis and compromised skin grafts and flaps. The efficacy of adjunctive hyperbaric oxygen in the treatment of lower extremity problem wounds in diabetic patients seems to be proven. There is little scientific support for other uses of hyperbaric oxygen and its therapeutical benefit should be further investigated. When used according to standard protocols hyperbaric oxygen treatment is a safe therapy with little adverse effects.     

Hyperbaric oxygenation therapy for chronic occlusive arterial diseases of the extremities]

Therapeutic effects of hyperbaric oxygen therapy (HBO) in 50 patients with chronic occlusive arterial diseases were studied with determination of the transcutaneous oxygen pressure (TcPO2), plasma lipid peroxide level, and plasma superoxide dismutase (SOD) level. Necrosis or ulceration was present in 30 patients, rest pain without tissue loss in 6, infection and necrosis in 2, infection of the amputated stump in 2, delayed healing of the amputated stump wound in 8, and delayed union of bone fractures in 2. HBOs were carried out in 2-3 absolute atmospheres for 60 min for 3-40 times (mean, 12.7 times). In combination with HBO, sympathetic denervation was performed in 41 patients, and PGE1 infusions were administered in 46. Of patients with necrosis or ulceration, 16 were healed, 13 were improved, and one was unchanged. Of patients with rest pain, 5 had relief and one was unchanged. All patients with infection were cured. Of patients with delayed healing of amputation wounds, 7 were healed and one required reamputation. All patients with bone fractures obtained bone union. The TcPO2 markedly increased during HBO and remained at a high level for some time after HBO. The lipid peroxide and SOD levels were not changed significantly by HBO.     

Enhancement of wound healing by hyperbaric oxygen and transforming growth factor beta3 in a new chronic wound model in aged rabbits

HYPOTHESIS: Although hyperbaric oxygen (HBO) has been used clinically for 3 decades, there have been few controlled clinical trials. Animal models have not been adequate to test the efficacy of HBO in the treatment of chronic wounds, either by itself or in combination with growth factors. We hypothesize that HBO is as efficacious as a prototype growth factor in improving wound healing in a new animal model of ischemic chronic wounds. DESIGN: Twenty-five aged rabbits and 3 young rabbits had their ears rendered chronically ischemic and ulcers were created down to the level of cartilage. These ulcers were treated in 1 of 3 ways: with HBO, 90 minutes per day, Monday through Friday, for 4 weeks; with transforming growth factor beta(3) at 1 microg/cm(2); or with both modalities combined. Controls were treated with vehicle or hyperbaric room air or both. RESULTS: This model created an aged/ischemic wound that failed to heal spontaneously up to 26 days after wounding (88% reduction compared with aged/nonischemic controls). Hyperbaric oxygen alone and transforming growth factor beta(3) alone both improved healing rate (only 38% reduction in healing compared with aged/nonischemic controls). Combined therapy produced no additional improvement over either modality by itself. CONCLUSIONS: In aged animals, HBO and transforming growth factor beta(3) were equally effective in improving wound healing. Our data suggest that HBO alone may be more effective in the chronic wound than in the acute wound. There was no additive benefit to combining modalities as has been reported in the same wound model in young rabbits.     

Hyperbaric oxygen therapy as a treatment for stage-I avascular necrosis of the femoral head

Avascular necrosis (AVN) of the head of the femur is a potentially crippling disease which mainly affects young adults. Although treatment by exposure to hyperbaric oxygen (HBO) is reported as being beneficial, there has been no study of its use in treated compared with untreated patients. We selected 12 patients who suffered from Steinberg stage-I AVN of the head of the femur (four bilateral) whose lesions were 4 mm or more thick and/or 12.5 mm or more long on MRI. Daily HBO therapy was given for 100 days to each patient. All smaller stage-I lesions and more advanced stages of AVN were excluded. These size criteria were chosen in order to compare outcomes with an identical size of lesion in an untreated group described earlier. Overall, 81% of patients who received HBO therapy showed a return to normal on MRI as compared with 17% in the untreated group. We therefore conclude that hyperbaric oxygen is effective in the treatment of stage-I AVN of the head of the femur.     

Hyperbaric oxygen therapy in the treatment of wounds, in plastic and reconstructive surgery]

After recalling the mechanism of action of hyperbaric oxygen (HBO) on healing processes, the authors review the principal indications for this technique in plastic and reconstructive surgery, such as crush injuries and acute post-traumatic ischemia of the limbs, skin flaps and skin grafts, when there is a risk of their not taking, and burns. They stress the importance of strict, stratified therapeutic protocols with control of the hyperoxygenation induced by HBO. In the authors' experience, transcutaneous measurements of the partial pressure of oxygen under the hyperbaric atmosphere is a very useful method with a predictive value to determine the indications for treatment with HBO and to monitor its effects.     

Factors influencing the outcome of lower-extremity diabetic ulcers treated with hyperbaric oxygen therapy

The objectives of this study were to report outcomes of a large number of patients receiving hyperbaric oxygen therapy (HBO(2)T) for diabetic lower-extremity ulcers, and to identify likely outcome predictors. Five hyperbaric facilities supplied data on 1,006 patients. A sixth clinic served as a validation sample for the regression-based prediction model, and later additional data from Memorial Hermann Hospital were added. The severity of lower-extremity lesions was assessed upon initiation of HBO(2)T using the Modified Wagner scale, and the outcome described as healed, partially healed, not improved, amputated, or died. Overall, 73.8% of patients improved (granulated or healed). Factors significantly related to outcome included renal failure, pack-year smoking history, transcutaneous oximetry, number of HBO(2)T treatments, and interruption of treatment regimen. Number of treatments per week and treatment pressure (2.0 vs. 2.4 atmospheres absolute) were not significant factors in outcome. Concomitant administration of autologous growth factor gel did not improve outcome. A multiple regression model was fitted to the data that can be used to predict the outcome of diabetic patients undergoing HBO(2)T. Given the high cost of amputation and rehabilitation, these data suggest that hyperbaric oxygen treatment should be an important adjunctive therapy to heal lower-extremity lesions, especially those with a Wagner grade of 3 or higher.     

Hyperbaric oxygen therapy in orthopedic conditions: an evaluation of safety

BACKGROUND: Because of the documented cellular and biochemical benefits of hyperbaric oxygen (HBO), HBO therapy is applied now with increasing frequency to various orthopedic conditions. Many traumatologists and orthopedic surgeons might refer their patients for adjuvant HBO therapy. However, the potential risks and risk-benefit ratio have often been underemphasized in therapeutic trials. METHODS: From October 2002 to September 2004, 240 patients with a total of 4,638 treatments received HBO therapy at the hyperbaric medicine center of our institution on an identical treatment protocol. HBO therapy patient treatment logs were reviewed to analyze the incidence of complications during HBO treatment. RESULTS: The overall incidence of complications was 1.83%. Over 94% of treatment complications were mild to moderate and designated as minor complications; fewer than 6% were severe or life threatening and designated as major complications. The incidence of major complications (central nervous system [CNS] oxygen toxicity in this series) was 0.109%. There was no mortality. Two patients with unusual presentation of CNS oxygen toxicity were observed during the study period. CONCLUSIONS: HBO therapy in orthopedic conditions is considered as a safe treatment because of a very low complication rate; however, analysis of patients with CNS oxygen toxicity revealed its unpredictability and inevitability. Although it is common sense that patients who develop a seizure in the hospital need help from the medical staff, it cannot be done in a monoplace hyperbaric chamber because of pressure unequalization. Therefore, a multiplace chamber equipped with an antechamber for medical contingency is possibly the better facility in consideration of safety.     

A Retrospective Study of Patients With Diabetes Mellitus After Partial Foot Amputation and Hyperbaric Oxygen Treatment

A retrospective chart review was conducted of 35 patients (40 feet) who received hyperbaric oxygen (HBO) therapy after partial foot amputation between 1990 and 2000. Preoperative transcutaneous partial pressure of oxygen (tcPO2) levels, the number of hyperbaric treatments, time to final outcome, use of revascularization procedures, and postsurgical outcome were extracted from the charts. Seventy percent (n = 28) had a successful outcome, defined as complete healing and absence of ulceration at the amputation site, and lack of further surgical procedures to heal the amputation site; whereas 30% (n = 12) had a failed outcome, defined as lack of healing or the presence of an ulcer at the site of amputation or the need for further surgery to heal the amputation site. The level of amputation, use of revascularization procedures, time to final outcome, and number of hyperbaric treatments were not significantly different (P > .05) between the 2 postsurgical outcome groups. The mean preoperative tcPO2 levels were greater (P < .01) in the successful (24 +/- mm Hg) than in the failed (11 +/- mm Hg) outcome groups. All patients with a tcPO2 level > 29 mm Hg had a successful outcome. Patients with a successful postsurgical outcome had a mean of 20 HBO treatments and took 44 days to final outcome, while those with a failed postsurgical outcome had 16 HBO treatments and took 216 days to final outcome.     

Hyperbaric oxygen in the treatment of postoperative infections in paediatric patients with neuromuscular spine deformity

The aim of this study is to evaluate possible benefits of hyperbaric oxygen (HBO) therapy in the treatment of deep postoperative infections in six high risk paediatric patients with neuromuscular spine deformity. The study involved review of medical records including radiology, office visits, and telephone contacts for six patients, referred for postoperative HBO therapy in 2003–2005. Infection control and healing without removal of implants or major revision surgery with a minimum of 2-year follow-up after index surgery were considered to represent success. All infections were resolved. Median time for wound healing, normalisation of blood tests and antibiotic weaning were 3 months. Radiological bony fusion, intact implants without any signs of radiolucent zones were seen in all cases at a mean follow-up of 54 months (37–72). Side effects of HBO treatment were minor. HBO is a safe and potentially useful adjuvance in the treatment of early deep postoperative infections in complex situations with spinal implants in high risk paediatric patients.     

Hyperbaric oxygen for treating wounds: a systematic review of the literature

OBJECTIVE: To determine whether hyperbaric oxygen (HBO) therapy is an effective adjunct treatment for hypoxic wounds. METHODS: We identified studies from technology assessment reports on HBO and a MEDLINE search from mid-1998 to August 2001. We accepted randomized controlled trials (RCTs), cohorts, and case series that reported original data, included at least 5 patients, evaluated the use of HBO for wound care, and reported clinical outcomes. Demographics, wound conditions, HBO regimen, adverse events, and major clinical outcomes were extracted from each study. RESULTS: Fifty-seven studies, 7 RCTs, 16 nonrandomized studies, and 34 case series involving more than 2000 patients are included in this review. None of the studies used wound tissue hypoxia as a patient inclusion criterion. The study results suggest that HBO may be beneficial as an adjunctive therapy for chronic nonhealing diabetic wounds, compromised skin grafts, osteoradionecrosis, soft tissue radionecrosis, and gas gangrene compared with standard wound care alone. Serious adverse events associated with HBO include seizures and pressure-related traumas, such as pneumothorax. A few deaths in the studies were associated with these adverse events. CONCLUSIONS: The overall study quality is poor, with inadequate or no controls in most studies. The studies suggest that HBO may be helpful for some wounds, but there is insufficient evidence to ascertain the appropriate time to initiate therapy and to establish criteria that determine whether patients will benefit. Serious adverse events may occur. High-quality RCTs that evaluate the short- and long-term risks and benefits of HBO are necessary to better inform clinical decisions.     

Hyperbaric oxygen treatment of postoperative neurosurgical infections

OBJECTIVE: To evaluate the clinical usefulness of hyperbaric oxygen (HBO) therapy for neurosurgical infections after craniotomy or laminectomy. METHODS: The study involved review of medical records, office visits, and telephone contacts for 39 consecutive patients who were referred in 1996 to 2000. Infection control and healing without removal of bone flaps or foreign material, with a minimum of 6 months of follow-up monitoring, were considered to represent success. RESULTS: Successful results were achieved for 27 of 36 patients, with a mean follow-up period of 27 months (range, 6-58 mo). One patient discontinued HBO therapy because of claustrophobia, and two could not be evaluated because of death resulting from tumor recurrence. In Group 1 (uncomplicated cranial wound infections), 12 of 15 patients achieved healing with retention of bone flaps. In Group 2 (complicated cranial wound infections, with risk factors such as malignancy, radiation injury, repeated surgery, or implants), all except one infection resolved; three of four bone flaps and three of six acrylic cranioplasties could be retained. In Group 3 (spinal wound infections), all infections resolved, five of seven without removal of fixation systems. There were no major side effects of HBO treatment. CONCLUSION: HBO treatment is an alternative to standard surgical removal of infected bone flaps and is particularly useful in complex situations. It can improve outcomes, reduce the need for reoperations, and allow infection control without mandatory removal of foreign material. HBO therapy is a safe, powerful treatment for postoperative cranial and spinal wound infections, it seems cost-effective, and it should be included in the neurosurgical armamentarium.     

Hyperbaric oxygen in the treatment of calciphylaxis: a case series.

BACKGROUND: Calciphylaxis, also referred to as calcific uraemic arteriolopathy, is a syndrome associated with end-stage renal disease (ESRD), and causes necrotic skin ulcers, often leading to a fatal outcome. Hyperbaric oxygen (HBO(2)) therapy has been used to enhance wound healing, but its role in the treatment of calciphylaxis is unclear. METHODS: We undertook a retrospective study of patients on renal replacement therapy with biopsy-proven calciphylaxis who were treated with HBO(2) between March 1997 and February 2000. RESULTS: Five patients were treated with HBO(2): three patients were on continuous ambulatory peritoneal dialysis (CAPD) and two were on chronic haemodialysis therapy. None of the patients had uncontrolled hyperparathyroidism and none underwent parathyroidectomy. The patients each received 25-35 treatments of HBO(2) at 2.5 atmospheres for 90 min per treatment. Two of these patients had complete resolution of extensive necrotic skin ulcers, with no adverse effects of HBO(2) therapy. Both had improvement in wound area transcutaneous oxygen pressure (P(tc)O(2)) with administration of 100% oxygen when measurements were taken at normobaric and hyperbaric pressures. In the other three patients receiving HBO(2), the skin lesions did not resolve. P(tc)O(2) was measured in two of these patients, neither of whom showed improvement with 100% oxygen administered at normobaric pressure. CONCLUSIONS: The data support a role for HBO(2) in the treatment of some patients with calciphylaxis, particularly as in the absence of uncontrolled secondary hyperparathyroidism there are few therapeutic options.     

The Effects of Hyperbaric Oxygen Therapy on Colonic Anastomosis in Rats With Peritonitis

The aim of this study is to investigate the healing effect of hyperbaric oxygen (HBO) on colonic anastomoses in the presence of experimentally induced peritonitis. Thirty-two rats were allocated randomly into short-term anastomosis (STA), short-term anastomosis + HBO treatment (STA+HBO), long-term anastomosis (LTA), and long-term anastomosis + HBO (LTA+HBO) treatment groups. The STA and LTA groups were administered fluid resuscitation and antibiotics for 3 and 7 days, respectively, whereas the HBO treatment groups received additional HBO therapy for 3 and 7 days, respectively. The rats were reoperated on the third and the seventh days of anostomoses for evaluation. The bursting pressures in STA+HBO and LTA+HBO therapy groups were significantly higher than those in groups with anastomoses alone (p <. 001 and p <. 01). HBO therapy did not affect the fibrotic index neither in STA nor in LTA groups (p >. 05 for both); however, it was significantly higher in LTA+HBO group than that in STA+HBO group (p <. 05). The hydroxyproline level was significantly higher in LTA group than in STA group (p <. 05), yet HBO therapy did not affect the hydroxyproline levels in STA or LTA groups (p >. 05 for both). It is concluded that hyperbaric oxygen treatment has positive effects on colonic anastomotic healing in case of peritonitis.     

Transcutaneous oxygen measurements predict a beneficial response to hyperbaric oxygen therapy in patients with nonhealing wounds and critical limb ischemia.

Hyperbaric oxygen (HBO) therapy may be a useful adjunct in the treatment of patients with wounds associated with critical limb ischemia. These patients either cannot undergo a successful bypass or may not heal after vascular reconstruction alone. Identification of patients likely to benefit from HBO is essential before treatment, as this therapy is time-consuming, costly, and not without risk. Transcutaneous oxygen measurements (TCOM) can be used to evaluate the degree of hypoxia in ischemic tissue. In this study we evaluated whether TCOM could be used to identify those patients who would or would not benefit from HBO therapy. Our hypothesis is that a difference in transcutaneous oxygen tension readings measured near the ischemic lesion with the patient breathing room air and while breathing 100 per cent oxygen at ambient pressure may be predictive of wound healing with adjunctive hyperbaric oxygen therapy. Thirty-six patients with critical limb ischemia and nonhealing ulcers were referred for HBO therapy. They were deemed either nonreconstructible from a vascular surgical viewpoint, had failed prior revascularization attempts, or could not achieve complete wound healing even after a successful revascularization. Pretreatment assessment included a room air and post-100 per cent-O2 challenge TCOM reading obtained in the vicinity of the open wound. Hyperbaric oxygen treatments at 2.0 to 2.5 atm were then administered until healing occurred or failure was confirmed. All patients undergoing HBO had a baseline TCOM of <40 torr. Twenty-seven patients had an increase in TCOM of >10 torr with oxygen inhalation at initial evaluation. Of these patients, 19 (70%) healed their wounds with HBO therapy. Conversely the increase in TCOM was <10 torr in nine patients, and only one of these patients (11%) ultimately healed (P < 0.01). Patients with nonhealing ischemic extremity wounds may heal with adjunctive HBO therapy. We can predictably identify patients who are likely to benefit from this modality using TCOM at the time of initial evaluation. An increase of tissue O2 tension of > or =10 torr when breathing pure O2 suggests that the patient may benefit from HBO therapy. Those patients with an increase of <10 torr are unlikely to receive benefit from this treatment modality.     

Wound healing and hyperbaric oxygen. Experimental study of the angiogenesis phase in the rat]

Hyperbaric oxygen therapy (HBO) is widely reported as highly favourable to wound healing. The experimental models generally used to investigate its effects are difficult to set up and reliable quantification of the results obtained is rarely achieved. The underlying pathophysiological mechanisms occurring during HBO remain poorly understood and its mode of application for clinical practice is difficult to standardise. Our study was carried out to assess the contributions of oxygen and hyperbaric pressure on the initial steps of wound healing. It was based on qualitative and quantitative analysis of the development of the angiogenic process in a granulation tissue bud, using animals implanted with fibrin chambers, an in vivo model initially described by Dvorak in guinea pigs. In our study, rats were further submitted to HBO (OHB group) or hyperbaric air (Air-HB group) treatments. The control group (Control group) consisted of rats maintained in the treatment tank under normal atmospheric conditions. Nine specific parameters were determined and analysed during the course of the angiogenic process by classical histological techniques. The vascular density and the height of the bud were particularly examined at day 7, 14 and 21 following chamber implantation. At D7 the neovessel density and bud height were significantly higher in OHB group than in Air-HB or Control groups, thus confirming the beneficial effects of this treatment on the initial steps of wound healing. Nevertheless, the results reported herein also suggest a possible inhibitory effect of hyperbaric therapy alone on this very early process, although the pathophysiological significance of this effect on wound healing remains to be determined.