Hyperbaric oxygen – its mechanisms and efficacy

Hyperbaric oxygen – its mechanisms and efficacy

Stephen R. Thom, M.D., Ph.D.

Institute for Environmental Medicine and Dept. of Emergency Medicine, University of

Pennsylvania Medical Center, Philadelphia, PA 19104

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This study reviews the therapeutic mechanisms and clinical efficacy of hyperbaric oxygen therapy (HBO2) for various medical conditions, particularly in the context of plastic and reconstructive surgery.

Mechanisms and Efficacy of Hyperbaric Oxygen Therapy ​

Hyperbaric oxygen therapy (HBO2) utilizes increased atmospheric pressure and 100% oxygen to enhance healing through various biological mechanisms. ​ This review discusses its therapeutic mechanisms, clinical efficacy, and the need for further research in specific applications. ​

Therapeutic Mechanisms of HBO2 ​

HBO2 therapy primarily works through the generation of reactive oxygen and nitrogen species, which play crucial roles in cell signaling and healing processes. ​

• Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during HBO2, influencing cell signaling pathways. ​
• HBO2 enhances neovascularization through angiogenesis and vasculogenesis, stimulating stem/progenitor cell (SPC) mobilization. ​
• Increased levels of hypoxia-inducible factors (HIF) are observed, promoting the expression of growth factors like vascular endothelial growth factor (VEGF). ​
• HBO2 improves collagen synthesis and extracellular matrix formation, essential for wound healing. ​

Clinical Applications of HBO2 ​

HBO2 has shown significant efficacy in treating refractory diabetic wounds and radiation injuries, with supportive evidence from clinical trials. ​

• HBO2 reduces the risk of major amputations in diabetic patients by an odds ratio of 0.236, indicating a significant decrease in amputation risk. ​
• The therapy improves healing rates in diabetic foot ulcers, with an odds ratio of 11.64 for enhanced healing outcomes. ​
• For radiation injuries, HBO2 is supported by randomized trials and independent reviews, demonstrating its effectiveness as an adjunct to standard care. ​

HBO2 in Wound Healing and Tissue Repair ​

The therapy is effective in promoting healing in chronic wounds and compromised flaps or grafts, with mechanisms linked to oxidative stress responses.

• Daily treatments of 1.5 to 2 hours for 20 to 40 days are typical for diabetic wound healing. ​
• HBO2 enhances neovascularization and collagen synthesis, crucial for effective wound healing. ​
• Clinical studies indicate a 29% improvement in graft survival when HBO2 is administered before and after skin grafting. ​

HBO2 in Ischemia-Reperfusion Injuries ​

HBO2 therapy is beneficial in managing ischemia-reperfusion injuries by inhibiting neutrophil adhesion and enhancing tissue tolerance. ​

• The therapy temporarily inhibits neutrophil β2 integrin function, reducing tissue damage during reperfusion. ​
• HBO2 has shown efficacy in various tissues, including brain, heart, and skeletal muscle, by inducing antioxidant enzymes and anti-inflammatory proteins. ​
• Prophylactic use of HBO2 can enhance ischemic tolerance, improving outcomes in critical conditions. ​

Risks and Considerations of HBO2 ​

While HBO2 has therapeutic benefits, there are potential risks associated with oxygen toxicity that need to be managed. ​​Air breaks during treatment can enhance pulmonary oxygen tolerance and mitigate some risks associated with hyperoxia. We advocate a 20min on, 5 min off Air Break system in-built in our system.