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 Historical reference searches on several articles in addition to basic physiologic concepts were also reviewed.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.