By: Alan Donald
Ulcers are caused due to a breach in the skin which fails to heal. Initiated by injuries, skin infections, poor blood circulation, or sensory loss, foot ulcers may become a serious complication in up to 15 percent of all diabetic patients. Chronic diabetic foot ulcers (DFUs) need prolonged treatment and may even lead to amputation.
Diabetes, being a metabolic disorder, causes a protracted period of inflammation and delayed healing. The layering of connective tissue which closes the wound is impeded in diabetics, and complications may involve the nervous, circulatory, and skeletal systems. Wound management therefore becomes vital for patients with diabetes.
The “Standard Wound Care” (SWC) protocol for treatment of non-healing DFUs involves three basic components: debridement, offloading, and infection control. Debridement is the removal of dead skin and tissue from the wound. It reduces the risk of infection and promotes wound contraction and healing.
The subsequent dressing should prevent desiccation, absorb excess fluid, and protect the wound from infection. A wide range of dressings is available in the marketplace. These include hydrogels, foam, and absorbent polymers. The advanced ones are soaked with growth factors and skin replacements. Unfortunately, moist bandages may cause fluid retention and are not suitable for exudative (substance-releasing) wounds.
DFUs have been shown to heal faster if the affected limb does not bear the body weight for a period of time. This is referred to as offloading.
The last segment in wound care involves addressing possible microbial infections in a DFU. Methicillin-resistant staphylococcus aureus are difficult to treat. Other pathogens that can infect DFUs include streptococcus, pseudomonas, and some species of anaerobic gut bacteria.
Research by several groups has led to the development of new techniques for treating DFUs, with varying degrees of success. Negative-pressure wound therapy uses a vacuum to remove fluid and necrotic tissue to aid the debridement process. Stem cell therapy shows promise but is still in its nascent stages. Vascular surgery and microsurgery are viable options in specific DFU cases that doctors worry could lead to amputation.
Oxygen therapy relies on the premise that increased oxygen concentration in tissues enhances cell division and fibrous tissue deposition, thereby reducing the risk of bacterial infection and promoting healing. Hyperbaric oxygen therapy (HBOT), as the name suggests, exposes the patient to 100 percent oxygen at a pressure two to three times greater than the ambient pressure. It is delivered in special hyperbaric chambers. HBOT has been shown to be effective in treating DFUs, but it has its detractors and accompanying risks.
The three most vital and effective elements of wound therapy: moisture, antibiotics, and oxygen have been combined and can be efficiently delivered by a new system called the VHT® Wound Treatment System, developed and marketed by Cure Care, Inc. It is a portable unit that incorporates these multiple therapeutic agents into “vaporous hyperoxia therapy” (VHT). It delivers a mixture of hyperoxia (higher than normal oxygen), water vapor, and the clinician’s choice of antibiotics infused under tension in a closed chamber.
Cure Care’s 510K application to the FDA announcing its intent to market VHT has been cleared by that agency. A small clinical trial proved that this multi-modal therapy gives remarkable results when used as an adjunct to standard wound care.
Twenty-six diabetic patients (average age 61 years) with 32 refractory diabetic foot ulcers were enrolled in the study. Their wounds averaged 1130 mm³ in size and the patients’ non-responsiveness to standard wound care ranged from three months to eight years.
Pre-treatment protocol involved cleaning and debriding the wounds, after which each patient was seated comfortably with the affected foot placed in a clear plastic bag in a tank in front of the unit. The plastic panels were gently and carefully secured around the patient’s upper calf, avoiding any vascular compression. This allowed sealing of the chamber, resulting in oxygen and vapor containment.
Patients were free to read, converse, watch television, or simply relax during the procedure. They reported experiencing a uniformly pleasant feeling. The therapist then placed the chosen antibiotic (if selected) into the dispensing chamber. The temperature-controlled mixture of water vapor and antibiotic was administered to the patient’s foot for 10 minutes, followed by five minutes of oxygen.
The one-hour treatment module, consisting of four cycles of application of mist, antibiotics, and oxygen, was repeated twice a week for the duration of the VHT therapy, usually until wound closure. The foot was dried, dressed, and evaluated after each session. The average number of treatments required for the wound to heal was 12.
The study used the device in its normal mode and diluted ionic silver was incorporated as the antimicrobial agent. Although non-cytotoxic (has no toxic effect on cells) in nature, it is a broad-range fungicidal and bactericidal agent.
Significant improvement in neuropathic wound healing was observed with the VHT system. Total wound closure occurred in all but two of the patients, who required skin grafts, which were successful. The proportion of healed wounds with VHT was nearly three times higher when compared to SWC at 12 and 20 weeks: 76.7 percent versus 24.2 percent, and 90.7 percent compared to 30.9 percent, respectively. No adverse events occurred during the study and no patient developed any local or systemic complication, or an aggravation of diabetes. None reported any pain or discomfort during or after the procedure.
It is evident from the clinical trial data that treatment with the VHT system represents a major improvement in diabetic wound care. Challenging wounds were successfully treated in short periods, avoiding hospitalization, infection, surgery, and amputation. Most importantly, it offered patients an improved quality of life after healing of the foot ulcers, which may otherwise have had disastrous consequences.
The combined strategy of using both VHT and SWC healed 91 percent of the patients. The results also indicate that the novel approach of a combined application of hyperoxia, moisture, and antimicrobial agents is highly successful in treating DFUs. The damaged and dry vascular system is rejuvenated with the diffusion of oxygen and moisture through the skin. Restoration of blood flow through the tissues is more healthful and desirable than artificially created vacuum or pressure.
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Alan Donald, MS, MBA, RAC, FRAPS, is president of San Diego-based Matrix Medical Consulting, Inc.