The effects of hyperbaric oxygen therapy on snake-bite-associated wounds in dogs.

OBJECTIVE: To assess the effect of hyperbaric oxygen therapy (HBOT) on Crotalinae envenomation-induced wound swelling and severity and pain in dogs, and to describe the safety and complications of HBOT. DESIGN: Prospective, randomized, controlled, blinded study (2017-2021). SETTING: University teaching hospital, private veterinary practice. ANIMALS: Thirty-six client-owned dogs presenting within 24 hours of a confirmed or suspected naturally occurring Crotalinae snake bite injury were enrolled between 2017 and 2021. INTERVENTIONS: In addition to the standard of care treatment, dogs received 2 interventions with either HBOT (n = 19) or control (n = 16) within 24 hours of hospital admission. Dogs receiving HBOT were pressurized over 15 minutes (1 psi/min), maintained at a target pressure of 2 atmosphere absolute (ATA) for 30 minutes, and decompressed over 15 minutes. Control dogs received 1 ATA for 1 hour. Local wound swelling, wound severity score, and pain score were assessed at admission, before and after each intervention, and at hospital discharge. MEASUREMENTS AND MAIN RESULTS: There was no significant difference in wound swelling (P = 0.414), severity score (P = 1.000), or pain score (P = 0.689) between HBOT and control groups. Pain decreased significantly over time regardless of the study intervention (P < 0.001). There were no major adverse effects associated with either study intervention. CONCLUSIONS: HBOT did not significantly alter the short-term recovery from Crotalinae envenomation in this study population. However, the study might be underpowered to detect a significant treatment effect.

Positive effects of hyperbaric oxygen therapy in a cat with cutaneous nocardiosis.

Hyperbaric oxygen therapy (HBOT) has been beneficial in treating people with nocardiosis. This report describes Nocardia spp. affecting a cat, with lesions confined to the skin. To the best of the authors' knowledge, this is the first report of HBOT, combined with amikacin, used to successfully treat feline cutaneous nocardiosis.

Le traitement à l'oxygène hyperbar (HBOT) a été bénéfique pour le traitement de la nocardiose chez l'homme. Cet article décrit un chat atteint par Nocardia spp. avec des lésions cantonnées à la peau. A la connaissance des auteurs, ceci est la première description de HBOT, combinée à l'amikacine, utilisée pour traiter avec succès une nocardiose féline.

La terapia con oxígeno hiperbárico (HBOT) ha sido beneficiosa para el tratamiento de personas con nocardiosis. Este informe describe un caso de infección cutánea con Nocardia spp. que afectaba a un gato, con lesiones limitadas a la piel. A entender de los autores, este es el primer informe de HBOT, combinado con amikacina, utilizado para tratar con éxito la nocardiosis cutánea felina.

A oxigenoterapia hiperbárica (OHB) tem sido benéfica no tratamento de pessoas com nocardiose. Este relatório descreve um caso Nocardia spp. afetando um gato, com lesões limitadas à pele. De acordo com o conhecimento dos autores, este é o primeiro relato do uso de OHB, combinado com amicacina, para tratar com sucesso a nocardiose cutânea felina.

Rationale for hyperbaric oxygen therapy in traumatic injury and wound care in small animal veterinary practice.

Hyperbaric oxygen therapy is in wide use in human medicine around the world. Although hyperbaric oxygen therapy is available for veterinary use, it is still significantly underutilised. The physical principles, gas laws and physiologic mechanisms by which hyperbaric oxygen therapy is therapeutic, especially in traumatic injuries and complicated wound care, are discussed. Then, considerations are offered for the implementation of hyperbaric oxygen therapy in veterinary practices. Finally, a review of clinical indications for veterinary practices, including a presentation of select literature, is provided. Applying hyperbaric oxygen therapy in an earlier and more consistent manner could improve short- and long-term outcomes in complicated wounds. The authors also hope this information may stimulate interest in the design of future, prospective studies for the various clinical situations described.

Hyperbaric oxygen therapy in wound healing in mice / [Oxigenoterapia hiperbárica na cicatrização de feridas em camundongos]

We investigated the local and systemic effects of hyperbaric oxygen therapy in BALB/C mice, exposed to two different exposure times, under 2.4 atmosphere (ATM). Fifteen animals were divided into three groups (GI, GII and Control) and underwent a surgical excision of a skin fragment of approximately one square centimeter of the dorsal region. The wounds were treated and monitored for 21 days. In the control group, the wound was cleaned once a day with sterile 0.9% NaCl solution. GI and GII mice were submitted to daily hyperbaric oxygen therapy of 30 or 60minutes sessions, respectively. The wounds were photographed every three days and their surfaces were analyzed by an image analyzer. At 21 days, all animals were euthanatized for histopathological analysis of the skin, lungs and liver in order to identify eventual alterations in wound healing or in the analyzed organs. Animals belonging to GI showed a faster skin wound healing in comparison to the other groups. Animals from GII, however, showed a delayed wound healing process and exhibited lung and microcirculatory alterations. These findings allow us to conclude that the exposure time to the oxygen in hyperbaric environment is crucial and can help or disturb skin wound healing or even be deleterious to other organs.(AU)

Investigaram-se os efeitos locais e sistêmicos da oxigenoterapia hiperbárica em camundongos BALB / C, submetidos a dois tempos de exposição diferentes, sob atmosfera 2,4 (ATM). Quinze animais foram divididos em três grupos (GI, GII e controle) e submetidos à excisão cirúrgica de fragmento de pele de aproximadamente um centímetro quadrado da região dorsal. As feridas foram tratadas e acompanhadas por 21 dias. No grupo controle, a ferida foi limpa uma vez ao dia, com solução estéril de NaCl 0,9%. Camundongos GI e GII foram submetidos à oxigenoterapia hiperbárica diária de 30 ou 60 minutos de sessões, respectivamente. As feridas foram fotografadas a cada três dias, e suas superfícies analisadas por um analisador de imagens. Aos 21 dias, todos os animais foram submetidos à eutanásia para análise histopatológica da pele, do pulmão e do fígado, em busca de eventuais alterações na cicatrização da ferida ou nos órgãos analisados. Animais pertencentes ao GI apresentaram cicatrização mais rápida de feridas cutâneas em comparação aos outros grupos. Já os animais do GII apresentaram retardo na cicatrização da ferida e alterações pulmonares e microcirculatórias. Esses achados permitem concluir que o tempo de exposição ao oxigênio em ambiente hiperbárico é fundamental e pode auxiliar ou atrapalhar a cicatrização de feridas cutâneas ou mesmo ser deletério para outros órgãos.(AU)

Effects of hyperbaric oxygen therapy on wound healing in veterinary medicine: A pilot study.

BACKGROUND: In veterinary medicine, wounds have a high incidence in clinical practice. A technique that can accelerate healing has been extensively studied, and the treatment with hyperbaric oxygen therapy (HBOT) is currently recognized as one of the best adjuvant treatments in this matter. AIM: The main objective of this pilot clinical study was to assess the therapeutic effect of HBOT in severe wounds classified according to the Modified Vancouver Scale (MVS) between 10 and 15 points or greater than 15 points (MVS > 10 and ≤ 15; MVS > 15). METHODS: A study population of 41 patients was divided into the dog group and the cat group and were treated at Lisbon Animal Rehabilitation and Regeneration Center, with 100% oxygen and 2.4 atmospheres absolute for 90 minutes. The patients' wounds were assessed using the MVS at the time of admission, in the first 24 hours, 48 hours, 72 hours after HBOT, and at the time of medical release. This study also sought to assess if HBOT is a safe therapy in small animal clinical practices by monitoring the major side effects (SEM) and minor side effects (SEm) observed throughout each session. RESULTS: The results obtained showed that HBOT allowed a decrease in the MVS classification. CONCLUSION: The results suggested that HBOT may be an interesting complementary therapy to be prescribed in wounds that present difficulty in healing. Furthermore, it was considered a safe therapy since in 289 sessions of HBOT, no SEM was observed, and as for SEm, the highest incidence was the act of swallowing. However, more studies should be carried out with HBOT in small animal clinical practices to confirm these results.

Effect of hyperbaric oxygen therapy on the healing of postoperative wounds in bitches after hemimastectomy.

The use of hyperbaric oxygen therapy (HBOT) is an accepted method of supporting wound healing in human medicine. Yet, because of the risk of complications associated with HOBT, a safer modification of the therapy, known as L-HOBT (lower pressure and lower oxygen concentration), is increasingly used nowadays. Therefore, due to the lack of literature reports regarding the clinical use of L-HBOT in animals, the authors decided to present the results of L-HBOT supportive treatment of postoperative wounds after hemimastectomy compared to classic treatment. The study group included 12 bitches divided into two groups: group A (assisted L-HBOT) and group B (classic treatment). In addition to conventional treatment, the supportive therapy included 1.5 hours of hyperbaric chamber therapy for 5 consecutive days, starting 24 hours after surgery (1500hPa pressure and 26% oxygen concentration in the chamber). The patients were followed and evaluated throughout the course of the treatment by two independent doctors. The results of the treatment revealed no negative clinical impact of L-HOBT supportive therapy on the body of the animals. At the same time, postoperative wounds after L-HOBT healed faster and with fewer postoperative complications compared to the control group. This resulted in a shorter treatment period, terminating with an earlier skin suture removal.

Technological Advances in Wound Treatment of Exotic Pets.

Although most research about the use of technological advances for wound healing was performed in laboratory animals but oriented to human medicine, recent technological advances allowed its application not only to small animals but also to exotic pets. This article reviews the literature available about some of these techniques (negative wound pressure therapy, photobiomodulation [laser therapy], electrical stimulation therapy, therapeutic ultrasonography, hyperbaric oxygen therapy), and other advances in wound management (skin expanders, xenografts, and bioengineered autologous skin substitutes) in exotic pet species.

Pneumatosis Coli in a Dog.

The objective of this report is to document a case of pneumatosis coli in an immunosuppressed dog successfully treated with supportive care that included hyperbaric oxygen. A 9 yr old, neutered male Maltese was presented for hematochezia of ∼36 h duration. The dog had a history of immune-mediated thrombocytopenia that was well managed with prednisone and azathioprine. Initial evaluation was unremarkable except for increased rectal temperature and hematochezia on digital rectal examination. Abdominal radiographs revealed diffuse gas within the colonic wall consistent with pneumatosis coli. Scant-free air was also appreciated in the peritoneal and retroperitoneal cavities. The dog was managed for 4 days in hospital with broad spectrum antibiotic, anthelminthic, and gastroprotectant therapy. He received one session of hyperbaric oxygen therapy while in hospital. Repeat abdominal radiographs after 72 hr of medical management showed improvement of the pneumatosis coli. After 4 days of hospitalization, he was discharged with resolution of clinical signs. Pneumatosis coli is rarely diagnosed in dogs but should be considered in cases with clinical signs of colorectal disease.

Effects of hyperbaric oxygen therapy on uncomplicated incisional and open wound healing in dogs.

OBJECTIVE: To determine the safety of a hyperbaric oxygen therapy (HBOT) protocol and its influence on the healing of uncomplicated open and incisional wounds in dogs. STUDY DESIGN: Prospective, controlled experimental study. ANIMALS: Adult dogs (n = 10). METHODS: Two 2 × 2-cm open wounds and two 3-cm-long full-thickness dermal incisions were created on the dorsum of each dog. Dogs in the hyperbaric oxygen treatment group (HBO) received HBOT once daily (1.7 atmospheres absolute [ATA], 30 minutes on day 1; 2.0 ATA, 40 minutes on days 2-7) for 7 consecutive days, and dogs in the control group (CON) received standardized wound care. Dogs were monitored during HBOT for adverse side effects. Total wound area, percentage epithelialization, and percentage contraction were compared for the open wounds. Subjective wound scores were compared for the open and incisional wounds. Biopsies of both wound types were taken and used to determine histopathology scores. Bacterial cultures were completed on open wounds. RESULTS: No difference was detected between HBO and CON uncomplicated open and incisional wounds at any time for contraction, epithelialization, subjective wound scores, histopathology scores, or bacterial loads. All HBO dogs tolerated hyperbaric oxygen treatments with no adverse effects. CONCLUSION: The HBOT protocol tested here was safe but did not enhance the healing of uncomplicated acute wounds and incisions of dogs. CLINICAL SIGNIFICANCE: These results do not provide evidence to support the use of HBOT to manage uncomplicated wounds in dogs.

Safety and Tolerability of Hyperbaric Oxygen Therapy in Cats and Dogs.

This prospective clinical trial was designed to evaluate the safety of hyperbaric oxygen therapy (HBOT) in a population of cats and dogs with a variety of naturally occurring diseases. Seventy-eight dogs and twelve cats with various naturally occurring disease conditions, who had the potential to benefit from HBOT, were enrolled in the study. These patients were treated with HBOT in a monoplace hyperbaric oxygen chamber at 2 air pressure absolute for a treatment length of either 45 min or 60 min. There were 230 hyperbaric oxygen treatments performed during the study period. No major adverse effects were observed. There were 76 minor adverse effects recorded, which were not considered to be of clinical significance. Hyperbaric oxygen therapy was well tolerated and there were no major adverse effects recorded during treatment.

Expression of T helper cell-associated inflammatory mediator mRNAs in cells of bronchoalveolar lavage fluid samples and oxygen concentration in arterial blood samples from healthy horses exposed to hyperbaric oxygen.

OBJECTIVE To evaluate the mRNA expression of T helper (Th)1, Th2, and Th17 cell-associated inflammatory mediators in cells of bronchoalveolar lavage fluid samples collected from healthy horses exposed to hyperbaric oxygen (HBO) and to monitor blood oxygen concentration during and following HBO therapy. ANIMALS 8 healthy horses. PROCEDURES In a randomized controlled crossover design study, each horse was exposed (beginning day 1) to 100% oxygen at a maximum of 3 atmospheres absolute (304 kPa) daily for 10 days or ambient air at atmospheric pressure in the HBO chamber for an equivalent amount of time (control). Bronchoalveolar lavage fluid samples were collected on days 0 and 10. After validation of candidate reference genes, relative mRNA expressions of various innate inflammatory, Th1 cell-derived, Th2 cell-derived (including eotaxin-2), Th17 cell-derived, and regulatory cytokines were measured by quantitative PCR assays. For 3 horses, arterial blood samples were collected for blood gas analysis during a separate HBO session. RESULTS The optimal combination of reference genes was glyceraldehyde-3-phosphate dehydrogenase, hypoxanthine ribosyltransferase, and ribosomal protein L32. Compared with day 0 findings, expression of eotaxin-2 mRNA was significantly lower (0.12-fold reduction) and the percentage of neutrophils in bronchoalveolar lavage fluid samples was significantly lower on day 10 when horses received HBO therapy. Values of Pao2 rapidly increased (> 800 mm Hg) but immediately decreased to pretreatment values when HBO sessions ended. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that HBO therapy does not increase mRNA expression of inflammatory cytokines, but reduces eotaxin-2 mRNA transcription. The Pao2 increase was transient with no cumulative effects of HBO.

Hyperbaric Oxygen Therapy in Equine Rehabilitation: Putting the Pressure on Disease.

There are several beneficial physiologic and therapeutic effects of hyperbaric oxygen therapy (HBOT). The indications list for the use of HBOT in the horse has been developed through extrapolation from a review of human indications and from anecdotal clinical experiences. Hyperbaric therapy is a safe treatment option with very few side effects when administered properly.

Rectal temperature changes and oxygen toxicity in dogs treated in a monoplace chamber.

Hyperbaric oxygen treatments are increasingly administered to pet dogs, using veterinary-specific monoplace chambers. The basic physiologic responses, chamber performance and oxygen toxicity rates have not yet been evaluated in dogs in a clinical setting. As a result, a series of consecutive 45-minute, 2-atmospheres absolute (atm abs) hyperbaric treatments with 100% oxygen were evaluated in a veterinary rehabilitation center (n = 285). 65 dogs with a mean body weight of 21 ± 15 kg (1.4-71 kg) were treated with an average of four sessions each. The mean rectal temperature of canine patients decreased 0.07 degrees C (0.1 degrees F) during treatments (p = 0.04). Intra-chamber temperature and humidity both increased: +1.0 degrees C (1.7 degrees F, p < 0.0001) and +5.7% (p < 0.0001), respectively. The mean maximal oxygen concentration measured before depressurization of the veterinary-specific commercial chamber was 98.0 ± 0.9%. No strong correlations (r > 0.75) were identified between body weights, body condition scores, maximal oxygen concentrations, starting or ending rectal temperature, chamber humidity and chamber temperature. Oxygen toxicity was not observed during the observational period. Patients were most commonly treated for intervertebral disc disease (n = 16 dogs) and extensive traumatic wounds (n = 10 dogs), which represented a large number of the total study sessions (19% and 16%, respectively).

The influences of hyperbaric oxygen therapy with a lower pressure and oxygen concentration than previous methods on physiological mechanisms in dogs.

Recently, hyperbaric oxygen therapy with a lower pressure and oxygen concentration (L-HBOT) than previous methods has been used for dogs in Japan; however, the influences of L-HBOT on dogs have not been clarified. To verify the influences of L-HBOT on physiological mechanism in dogs, we investigated blood gas parameters, glutathione peroxidase (GPx) activity, heart rate variability, stress-related hormones and skin conductance (SC) in 4 clinically normal beagle dogs with catheters in their carotid arteries and jugular veins when they were quiet, after running, after receiving L-HBOT (30% oxygen concentration, 1.3 atmospheres absolute, 30 min) or after not receiving L-HBOT. The results showed there were no changes in blood gas parameters, heart rate variability and catecholamine levels after L-HBOT. GPx activity was significantly higher, and the SC and cortisol level were lower in dogs that received L-HBOT than those when they were quiet. These results suggested that L-HBOT may have a small influence on oxygenation dynamics, activate antioxidant enzymes such as GPx, restrain autonomic nervous activity and control the balance between oxidation and antioxidation inside the body.

Hyperbaric oxygen therapy.

Hyperbaric oxygen therapy (HBOT) is emerging in veterinary medicine as an effective treatment or adjunct therapy for a variety of disorders in which improving oxygen delivery to tissues is a priority. The primary mechanisms of action of HBOT are (1) immediate hyperoxygenation of plasma and tissues and (2) decreased gas bubble (air embolus) size. With each hyperbaric 'dive,' secondary physiologic effects are set into motion. This article provides an introduction to HBOT, as well as its benefits, potential indications, contraindications, complications, and future directions in small animal veterinary medicine.

Effects of hyperbaric oxygen treatment on horses with experimentally induced endotoxemia.

OBJECTIVE: To determine the effectiveness of preinduction hyperbaric oxygen treatment (HBOT) in ameliorating signs of experimentally induced endotoxemia in horses. ANIMALS: 18 healthy adult horses. PROCEDURES: Horses were randomly assigned to 1 of 3 equal-sized treatment groups to receive normobaric ambient air and lipopolysaccharide (LPS), HBOT and LPS, or HBOT and physiologic saline (0.9% NaCl) solution. Horses were physically examined, and blood was obtained for a CBC and to determine concentration or activity of plasma tissue necrosis factor-α, blood lactate, and blood glucose before the horses were treated with HBOT and then intermittently for 6 hours after administration of LPS or physiologic saline solution. RESULTS: All LPS-treated horses developed signs and biochemical and hematologic changes consistent with endotoxemia. Treatment with HBOT significantly ameliorated the effect of LPS on clinical endotoxemia score but did not significantly improve other abnormalities associated with endotoxemia. CONCLUSIONS AND CLINICAL RELEVANCE: The protective effect of HBOT was minimal, and results did not support its use as a treatment for horses prior to development of endotoxemia.

Hyperbaric air therapy in dogs for clinical veterinary medicine: a basic study.

Hyperbaric air therapy (HBA) is a treatment in which an animal is exposed to air pressurized to about 1.3 atmosphere absolute (ATA). Although HBA has already been administered to humans in medical applications, it has not been reported in clinical veterinary medicine. Therefore, we aimed to determine a safe protocol for dogs. To elucidate oxygen dynamics during HBA, we measured partial pressure of arterial oxygen, oxygen saturation of tissue, and partial pressure of transcutaneous oxygen in dogs. HBA could be performed safely with a protocol of pressurizing speed up to 0.1 ATA/min, maximum chamber pressure of up to 1.3 ATA, and pressure duration of around 45 min per treatment. Under these conditions, tissue was adequately oxygenated during and after treatment.

Hyperbaric oxygen therapy. Part 1: history and principles.

OBJECTIVE: Review the historical development and physiologic principles of hyperbaric oxygen therapy (HBOT) based on human and veterinary experimental literature and current equipment in use. DATA SOURCES: Review of basic physiologic concepts. Data from human and veterinary journals were reviewed through Pubmed and Veterinary Information Network database searches as well as reference searches on several articles covering hyperbaric therapy in clinically applicable situations. HUMAN DATA SYNTHESIS: HBOT has been gaining acceptance as an adjunctive treatment in human medicine. The understanding of the physiology and application of hyperbaric therapy is increasing through ongoing research and greater access to hyperbaric equipment. VETERINARY DATA SYNTHESIS: Several animal models have been utilized to examine the effects of HBOT. Most models utilize dogs and rats but pigs, cats, and other species have been studied. CONCLUSIONS: Hyperbaric therapy utilizes several physiologic principles of how gases respond under pressure and more specifically of how oxygen responds under pressure. The increase in concentration of oxygen in solution, based on its solubility under pressure, increases the diffusion gradient for its delivery deeper into tissues, which is the premise of HBOT. Ultimately the increases in dissolved oxygen generated by hyperbaric therapy have several physiologic effects that can alter tissue responses to disease and injury. As this technology becomes more available to clinical practice, HBOT should be considered as a therapeutic option.

Hyperbaric oxygen therapy. Part 2: application in disease.

OBJECTIVE: Review the mechanisms of action and clinical application of hyperbaric oxygen therapy (HBOT) based on human and veterinary clinical and experimental literature. DATA SOURCES: Pubmed and Veterinary Information Network databases were searched for human and veterinary journal articles on hyperbaric therapy in clinically applicable situations. Historical reference searches on several articles in addition to basic physiologic concepts were also reviewed. HUMAN DATA SYNTHESIS: HBOT has gained acceptance as an adjunctive treatment in clinical conditions other than diving-related injuries, such as select problem wounds and central nervous system diseases, in human medicine. Access to hyperbaric therapy has increased and ongoing research has furthered understanding of the mechanisms and potential therapeutic uses of HBOT. VETERINARY DATA SYNTHESIS: Several animal models have been utilized to examine the effects of HBOT; primarily rodents (mice, rats) and rabbits but also dogs, cats, and pigs. Data related to animal model research as it pertains to clinical application of HBOT is reviewed. CONCLUSIONS: There is a substantial body of literature that has examined the adverse and beneficial effects of HBOT in animal models. As technology becomes more readily available to clinical practice and more clinical trials are performed to define its effectiveness, HBOT may be considered as an additional therapeutic option in many conditions including select problem wounds, spinal cord injury, and cerebral ischemic injury. Understanding the mechanisms by which HBOT exerts its effects will help guide research and use of the modality in clinical patients.