Diabetic foot ulcers are a worldwide problem and a major cause of morbidity. The annual global incidence of ulcerations and amputations is as high as 10.7% and 1.8%, respectively. The etiology of diabetic foot ulcers is multifactorial, often resulting from neuropathy, ischemia, and/or infection. Peripheral neuropathy in the lower extremity typically manifests as a stocking-distribution loss of sensation and subsequent foot deformity. Ultimately the plantar pressures of the foot become redistributed and increased pressure points lead to ulcerations.
Wound healing is comprised of 3 major phases: inflammatory, proliferative, and maturation, all of which are oxygen dependent.
The inflammatory phase, which occurs 1-7 days after the initial insult, consists of an influx of platelets and leukoctyes, the release of cytokines, and coagulation.The proliferative phase, which takes place 5-20 days after injury, involves the production of collagen fibers, angiogenesis, and wound contraction. The last phase of wound healing, maturation, takes place 3 weeks to several years following trauma and includes deposition of collagen and a return to a pre-injury state.
Oxygen delivery is a crucial element involved in wound healing and it is widely recognized that limited oxygenation can lead to a chronic nonhealing ulcer.
Collagen deposition, which is also oxygen dependent, is another primary step in wound healing. Collagen provides the matrix for angiogenesis and tissue remodeling.
Hyperbaric oxygen therapy is defined by the Undersea and Hyperbaric Medical Society as a treatment where the patient breathes 100% oxygen, with the chamber being pressurized > 1 atmosphere absolute (ATA). Patients who are eligible for HBOT often have 1 of the following ailments: acute carbon monoxide poisoning, decompression illness, gas gangrene, acute traumatic peripheral ischemia, crush injuries, necrotizing fasciitis, acute peripheral insufficiency, compromised skin grafts, osteomyelitis, cyanide poisoning. The benefits of HBOT are numerous, however there are some contraindications that must be considered when using this treatment. These include opthalmopathies (eg, cataract formation); central nervous system toxicity and seizures; ear trauma (eg, otitis media or tympanic rupture), pulmonary barotraumas and pneumothorax; fetal complications from pregnancy (eg, spina bifida); claustrophobia.
Topical oxygen therapy is a low-pressure treatment that applies oxygen directly to the wound site at 1.03 atmospheres of pressure. Treatments of topical oxygen for all patients consist of one 90-minute session per day for 4 consecutive days, with a rest period of 3 days; cycle is repeated until the wound is healed.
In any case necrotic debris should be removed from the wound surface prior to treatment and the patient should be kept well hydrated.
A retrospective review comparing healing rates of diabetic foot ulcers utilizing HBOT or TOT was performed. Twenty-two healed wounds were examined; 11 treated with TOT and 11 treated with HBOT. The study endpoints were overall wound closure for ≥ 1 month. The wounds treated with HBOT closed faster than those treated with TOT.
Hyperbaric oxygen therapy creates higher levels of oxygen absorption by the blood, thereby causing hyperoxygenation in the tissues and perhaps leading to this faster rate of closure.
Authors: Brittany Winfeld
Newspaper: WOUNDS. 2014;26(5):E39-E47.