Supplementing Diabetic Wound Care With Hyperbaric Medicine

Adam R. Johnson, DPM

As the diabetes mellitus epidemic continues to grow, so does the number of diabetic wounds in the lower extremity. Researchers have estimated that the number of individuals with diabetes mellitus who eventually develop a lower extremity ulceration may be as high as 25 percent.1


   Our goal as foot and ankle surgeons is to guide therapy to heal these ulcerations and prevent major lower extremity amputations. The backbone to healing these ulcerations starts with good wound care that includes: offloading of the wound site; regular debridement of devitalized and hyperkeratotic tissue; and ensuring an adequate vascular stasis to healing. One also needs to ensure regular follow up by the patient with his or her primary care physician for glycemic control and medical management.

   However, even with dedicated care, researchers have estimated that the risk of an individual with diabetes mellitus having an outcome that leads to a major lower extremity amputation is nearly 10 percent.2 When wound healing is not progressing, the use of hyperbaric oxygen therapy (HBOT) could provide the key to healing.

   Henshaw first devised the concept of treating diseases with an increased ambient pressure in 1662. He created a sealed chamber called the “domicilium” to treat various ailments. However, his chamber was not based on scientific data but rather that it “seemed like a good idea.”3 Modern use of hyperbaric medicine began in 1955 through the work of Churchill-Davidson, who utilized high oxygen environments to enhance the effects of radiation therapy in cancer patients.4 In 1956, Boerema demonstrated that hyperbaric oxygen could be useful in patients undergoing cardiac surgery.5 Subsequently, other researchers reported success with HBOT, noting an inhibitory effect on anaerobic infections and benefits with the treatment of carbon monoxide poisoning.6,7

Understanding The Physiological Effects Of Hyberbaric Oxygen

When oxygen is in an environment of increased pressure, it behaves like a drug, having specific indications and side effects. Placing a patient in a hyperbaric chamber at 2.8 ATA O2 raises the oxygen tension 10 to 13 times above the normal levels, saturating the plasma and causing hemoglobin to remain fully oxygenated on the venous side. Even though high levels of oxygen cause vasoconstriction, the increased blood oxygen levels more than compensate for this. Furthermore, hypoxic tissue does not respond with vasoconstriction due to local mechanisms that lead to a redistribution effect, which further oxygenates this tissue.8

   Collagen synthesis by fibroblasts is triggered by the lactate produced by macrophages in the wound environment. Fibroblasts are unable to synthesize collagen in a hypoxic state as it is required in the steps that produce cross-linking.9 When oxygen levels are low, the collagen framework is unable to be produced, vessel growth into the wound is diminished and subsequent healing stalls. This leads to the formation of a chronic, non-healing wound.

   However, within 15 minutes of HBOT, endothelial cells begin to proliferate. After 120 minutes, fibroblasts begin to produce a response, which can last up to 72 hours post-exposure.10 There are also effects in red blood cells as hyperbaric oxygen increases their deformability and improves the ability of these cells to pass through narrow capillaries. Leukocytes use oxygen to create high-energy radicals and their rate of formation is directly proportional to the amount of oxygen available. Leukocytes can then lend these radicals to neutrophils for increased phagocytosis of bacteria, helping to clean the wound and prevent infection.11

Is The Patient A Viable Candidate For HBOT?

When assessing whether a diabetic foot ulceration meets criteria for HBOT, Medicare requires that the wound be staged as a Wagner III (a full thickness ulceration having bone and/or soft tissue infection present) ulcer, which has failed standard care for at least 30 days.12 Hyperbaric oxygen therapy is also indicated for the treatment of gas gangrene and progressive necrotizing infections as an adjunct to surgical debridement and antibiotic therapy. Hyperbaric oxygen therapy can also be indicated for use with the preservation of skin grafts and flaps if concerns of failure are present. Furthermore, if the graft or flap does fail, one can use HBOT to prepare the wound bed for the next graft or flap.

   The use of transcutaneous oxygen pressure (TcPO2) measurements offers a simple and noninvasive diagnostic technique to provide a reliable objective assessment of the local skin perfusion in room air. One can also use TcPO2 measurements to gauge the effect HBOT might have on local tissue by measuring changes in perfusion while supplementing the patient with 100% O2 via a mask or a nasal cannula.The results of this test show if the patient has the ability to heal a wound by way of tissue perfusion in room air and if one can achieve a benefit via supplementation with HBOT.13 It should be noted that in the presence of infection, there is a local decrease in tissue oxygen perfusion that does resolve once the infection is eradicated.14

What About Contraindications For HBOT?

Hyperbaric oxygen therapy is not without risks and proper patient selection is important. If patients are taking the chemotherapeutic drug doxorubicin, HBOT is contraindicated as the drug can become cardiac toxic and lead to death.

   The use of Sulfamylon® (UDL Laboratories) cream on a wound is also contraindicated when a patient undergoes HBOT as this leads to local CO2 buildup and vasodilatation, which is further compounded by central vasoconstriction caused by HBOT. One should utilize a different topical wound agent or remove the ointment from the wound before starting a HBOT treatment.

   Untreated pneumothorax is also a contraindication. It is of benefit to screen patients with a chest radiograph to rule this out before starting HBOT. Other conditions that present a risk with HBOT include: seizure disorders, emphysema with CO2 retention, uncontrolled high fevers, a history of spontaneous pneumothorax, chronic sinusitis and upper respiratory tract infections, viral infections, a history of optic neuritis, previous otosclerosis surgery and congenital spherocytosis.8 However, authors have noted that one can take possible precautions if one of these conditions is present in order to allow HBOT to proceed.8








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