Hyperbaric oxygen therapy for deep second degree burns: an experimental study in the guinea pig

Simultaneous Administration of Hyperbaric Oxygen Therapy and Antioxidant Supplementation with Filipendula ulmaria Extract in the Treatment of Thermal Skin Injuries Alters Nociceptive Signalling and Wound Healing

Background and Objectives: Thermal skin injuries are a prevalent cause of skin damage, potentially leading to severe morbidity and significant mortality. In this study, we intended to estimate the effects of HBO (hyperbaric oxygen treatment) and antioxidant supplementation with Filipendula ulmaria extract, individually and simultaneously, in the treatment of thermal skin injuries. Materials and Methods: As a thermal skin injury experimental model, we used two-month-old male Wistar albino rats. Thermal injuries were made with a solid aluminium bar at a constant temperature of 75 °C for 15 s. Hyperbaric oxygen treatment was performed in a specially constructed hyperbaric chamber for rats (HYB-C 300) for seven consecutive days (100% O2 at 2.5 ATA for 60 min). Antioxidant supplementation was performed with oral administration of Filipendula ulmaria extract dissolved in tap water to reach a final concentration of 100 mg/kg b.w. for seven consecutive days. Results: Simultaneous administration of hyperbaric oxygen therapy and antioxidant supplementation with Filipendula ulmaria extract significantly ameliorated the macroscopic and histopathological characteristics of the wound area and healing. Also, this therapeutic approach decreased the local expression of genes for proinflammatory mediators and increased the expression of the μ-opioid receptor and the MT1 and MT2 receptors in the wound area and spinal cord, with a consequent increase in reaction times in behavioural testing. Conclusions: In conclusion, the presented results of our study allow evidence for the advantages of the simultaneous employment of HBO and antioxidant supplementation in the treatment of thermal skin injuries, with special reference to the attenuation of painful sensations accompanied by this type of trauma.

The History and Development of Hyperbaric Oxygenation (HBO) in Thermal Burn Injury

Background and Objectives: Hyperbaric oxygenation (HBO) denotes breathing of 100% oxygen under elevated ambient pressure. Since the initiation of HBO for burns in 1965, abundant experimental and clinical work has been done. Despite many undisputedly positive and only a few controversial results on the efficacy of adjunctive HBO for burn injury, the method has not yet been established in clinical routine. Materials and Methods: We did a retrospective analysis of the literature according to PRISMA-guidelines, from the very beginning of HBO for burns up to present, trying to elucidate the question why HBO is still sidelined in the treatment of burn injury. Results: Forty-seven publications (32 animal experiments, four trials in human volunteers and 11 clinical studies) fulfilled the inclusion criteria. Except four investigators who found little or no beneficial action, all were able to demonstrate positive effects of HBO, most of them describing less edema, improved healing, less infection or bacterial growth and most recently, reduction of post-burn pain. Secondary enlargement of burn was prevented, as microvascular perfusion could be preserved, and cells were kept viable. The application of HBO, however, concerning pressure, duration, frequency and number of treatment sessions, varied considerably. Authors of large clinical studies underscored the intricate measures required when administering HBO in severe burns. Conclusions: HBO unquestionably has a positive impact on the pathophysiological mechanisms, and hence on the healing and course of burns. The few negative results are most likely due to peculiarities in the administration of HBO and possibly also to interactions when delivering the treatment to severely ill patients. Well-designed studies are needed to definitively assess its clinical value as an adjunctive treatment focusing on relevant outcome criteria such as wound healing time, complications, length of hospital stay, mortality and scar quality, while also defining optimal HBO dosage and timing.

Update on hyperbaric oxygen therapy in burn treatment

Hyperbaric oxygen therapy (HBOT) has been shown to improve tissue hypoxia, neovascularization and ischemia reperfusion injury and reduce pathologic inflammation in various clinical settings and was proposed to be a game changer in treatment of burns. Improved and faster wound healing as well as a reduction of morbidity and mortality after thermal and concomitant carbon monoxide poisoning are expected. In defiance of the observed benefits for burn wounds and carbon monoxide poisoning in animal models and few randomized controlled trials there is an ongoing controversy regarding its use, indications and cost effectiveness. Furthermore, the use of HBOT, its indications and the evidence behind its efficiency are still widely unknown to most physicians involved in the treatment of burn patients. Therefore, a review of the up to date evidence-based literature was performed with a focus on available data of HBOT in burn care, to elaborate its use in acute thermal injury and carbon monoxide intoxication. Although beneficial effects of HBOT seem very likely insufficient evidence to support or disprove the routine use of HBOT in the treatment of burn care was found. Although difficult to carry out because of the high interindividual variability of burns and chronic wounds, the need for larger high-quality prospective randomized double-blinded controlled multicenter trials are necessary to be able to evaluate useful applications, expense and cost-efficiency of HBOT for burn care.

Hyperbaric Oxygen Therapy for Second-Degree Burn Healing: An Experimental Study in Rabbits

BACKGROUND:

The wound healing process includes inflammation, proliferation, and remodelling phases, the main features of which are inflammation, neoangiogenesis, and epithelialization. Hyperbaric oxygen therapy (HBOT) is one modality postulated to improve wound healing. The objective of this study was to determine whether HBOT could improve selected features of burn wound healing in an experimental rabbit model.

METHODS:

Researchers conducted an experimental study with 36 rabbits given second-degree burns. Subjects were separated into two groups: a control group (n = 18) and an intervention group that was given HBOT at 2.4 atmospheres absolute for 6 days (n = 18). The main outcome measure was wound healing.

RESULTS:

Compared with the control group, the HBOT group showed more robust inflammatory cells (P = .025) and epithelialization (P = .024), but no significant difference in angiogenesis (P = .442).

CONCLUSIONS:

The authors conclude that HBOT may improve second-degree burn healing by increasing inflammatory cell migration and re-epithelialization.

Mimicking oxygen delivery and waste removal functions of blood

In addition to immunological and wound healing cell and platelet delivery, ion stasis and nutrient supply, blood delivers oxygen to cells and tissues and removes metabolic wastes. For decades researchers have been trying to develop approaches that mimic these two immediately vital functions of blood. Oxygen is crucial for the long-term survival of tissues and cells in vertebrates. Hypoxia (oxygen deficiency) and even at times anoxia (absence of oxygen) can occur during organ preservation, organ and cell transplantation, wound healing, in tumors and engineering of tissues. Different approaches have been developed to deliver oxygen to tissues and cells, including hyperbaric oxygen therapy (HBOT), normobaric hyperoxia therapy (NBOT), using biochemical reactions and electrolysis, employing liquids with high oxygen solubility, administering hemoglobin, myoglobin and red blood cells (RBCs), introducing oxygen-generating agents, using oxygen-carrying microparticles, persufflation, and peritoneal oxygenation. Metabolic waste accumulation is another issue in biological systems when blood flow is insufficient. Metabolic wastes change the microenvironment of cells and tissues, influence the metabolic activities of cells, and ultimately cause cell death. This review examines advances in blood mimicking systems in the field of biomedical engineering in terms of oxygen delivery and metabolic waste removal.

The effect of hyperbaric oxygen treatment on the healing of burn wounds in nicotinized and nonnicotinized rats

The importance of oxygen in wound healing and the negative effects of cigarette smoking have been demonstrated in various studies. In this study, our aim was to investigate the effect of hyperbaric oxygen (HBO2) treatment on wound healing in nicotinized and nonnicotinized rats. The study was conducted on 32 Sprague Dawley rats. The rats were divided into four groups, with eight rats in each: group 1, nonnicotinized rats; group 2, nonnicotinized rats treated with HBO2; group 3, nicotinized rats; and group 4, nicotinized rats treated with HBO2. To prepare the nicotinized groups, the rats were given nicotine for 28 days. At the end of day 28, standard, deep, second-degree to third-degree burns were created on the rats. The HBO2-treated groups underwent HBO2 treatment once a day for 7 days after the creation of the burn damage. All rats were killed 21 days after injury, and the burns were subjected to macroscopic, histopathological, and microbiological evaluation. During this evaluation, the smallest necrotic areas and the lowest rate of fibrosis were observed in group 2. The largest necrotic areas and the highest inflammation and fibrosis rates were observed in the nicotine-treated group 3. When the nicotinized and nonnicotinized groups were compared separately, there was a significant difference in favor of the groups treated with HBO2. Bacterial growth was the highest in the nicotinized group 3, whereas no statistically significant difference was observed among the other groups. We conclude that HBO treatment accelerates the recovery of burn wounds and provides more effective healing by reducing the development of scars both in nicotinized and nonnicotinized rats.

Curbing inflammation in burn patients

Patients who suffer from severe burns develop metabolic imbalances and systemic inflammatory response syndrome (SIRS) which can result in multiple organ failure and death. Research aimed at reducing the inflammatory process has yielded new insight into burn injury therapies. In this review, we discuss strategies used to curb inflammation in burn injuries and note that further studies with high quality evidence are necessary.

Transforming growth factor-beta3-loaded microtextured membranes for skin regeneration in dermal wounds

Adverse effects of wound healing, such as excessive scar tissue formation, wound contraction, or nonhealing wounds represent a major clinical issue in today's healthcare. Transforming growth factor (TGF)-beta3 has specifically been implicated in wound healing. Our hypothesis was that local administration of TGF-beta3 to excisional dermal wounds would diminish wound contraction and scar formation. Microtextured wound covers, containing different concentrations of TGF-beta3, were placed onto full-thickness excisional skin wounds in guinea pigs. Tattooed reference marks were used to quantify wound contraction. Sixty-four male guinea pigs in four study groups (5 ng TGF-beta3, 50 ng TGF-beta3, no growth factor, sham wound) were followed for up to 6 weeks. We analyzed 19 different parameters of wound healing. Results showed that, in some instances, the 50-ng TGF-beta3 group gave less contraction, whereas the 5-ng TGF-beta3 group gave more contraction. These differences confirm that TGF-beta3 has an optimum working concentration, and suggest this concentration to be closer to 50 ng than to 5 ng TGF-beta3. However, only very few significant differences occurred, and thus we conclude that the clinical relevance of our findings is negligible. Earlier studies, reporting clinically improved wound healing by TGF-beta3, could therefore not be confirmed by this study.

The Evaluation of Subatmospheric Pressure and Hyperbaric Oxygen in Ischemic Full-Thickness Wound Healing

We evaluated the efficacy of subatmospheric pressure and hyperbaric oxygen (HBO) as adjuncts in the treatment of hypoxic full-thickness wounds in a rabbit model. We hypothesized that subatmospheric pressure and HBO independently are effective in improving wound healing in the ischemic wound model and that when they are used in combination there is an increased positive effect on wound healing. Using a standard ischemic wound model four full-thickness wounds were created on each ear of 41 male New Zealand white rabbits (N = 82 ears). On each rabbit one ear was dressed with the vacuum-assisted closure (VAC) device and connected to suction; the other was dressed identically without the suction and suction tubing. Twenty rabbits were treated with HBO daily for 10 days at 2.0 atmospheres absolute for 90 minutes plus descent and ascent times. Necropsy on all rabbits was performed on postoperative day 10. Four ischemic wound treatment groups were evaluated: Group 1 (N = 21) VAC dressing alone; Group 2 (N = 20) VAC dressing plus HBO; Group 3 (N = 21) VAC dressing to suction alone; and Group 4 (N = 20) VAC dressing to suction and HBO. Using light microscopy a veterinary pathologist blinded to treatment groups quantified peak granulation tissue, granulation tissue gap, and epithelialization tissue gap. Data were analyzed by analysis of variance with significance indicated by P < 0.05. Statistical significance was found in a comparison of VAC dressing to suction and VAC dressing alone for peak granulation tissue and granulation tissue gap both with and without use of HBO. VAC device use appears to increase the rate of healing in a rabbit ischemic wound model. HBO therapy did not significantly affect the rate of healing in this model.