Diab Foot

Why So Long To Heal?

•Reduced collagen synthesis and deposition

•Increased levels of proteases

•Decreased levels of cytokines such as growth factors

•Compromised micro- and macrovascular perfusion

•Impaired WBC chemotaxis and phagocytosis

(from Acute & Chronic Wounds Current Management Concepts 3rd Ed. RA Bryant & DP Nix 2007)

There are a number of factors that explain why patients with diabetes experience impaired wound healing. A few are listed on this slide. Critical building blocks necessary for wound closure, like the protein collagen and growth factors are only present in deficient quantities. Increased levels of proteases contribute to the wound remaining in a chronic state of inflammation. Sluggish white blood cell movement and their sluggish ability to engulf invading microorganisms contributes to increased infection risk. In addition, if a patient has a soft tissue or bone infection (oftentimes signs and symptoms of infection are blunted and therefore not identified), the wound will not heal until the infection is adequately treated. Compromised small and large vessel perfusion slows wound healing. Because of these factors, it is critical to preserve skin integrity. The longer a diabetic foot ulcer remains open the greater the risk for devastating complications. Ron Santo, the Chicago Cubs Hall of Famer, was a prime example of this.

Topical Wound Care

•Assess and treat soft tissue and bone infections

•Provide pressure relieve and off-loading

•Evaluate vascular status

•Debride ulcer and callus

• Select dressing according to

type of tissue present,

amount of exudate, size/

location of wound,

bioburden, $$, ease of use

Local treatment of the wound needs to be aggressive in order to facilitate a more rapid closure of the wound. Blood sugar levels must be adequately controlled and the infection treated. A referral to an infectious disease specialist is recommended. The patient must stay off the ulcer 24/7—there are no exceptions to this rule. Non-invasive, or if indicated, invasive evaluation of perfusion is required to determine if this wound can heal. Serial sharp debridement of the wound and the callus in order to maintain a clean granular wound bed to stimulate healing, is a standard of diabetic ulcer management. Advanced moisture retentive dressings such as hydrogels, alginates, foams, and silver dressings are appropriate topical modalities. Frequent wet-to-dry dressings have no place in contemporary wound management. Negative pressure therapy or vacuum assisted closure technologies may also be used to facilitate more rapid wound closure.

Adjunctive Technologies

•Hyperbaric Oxygen (HBO)

•Nitric Oxide

• Monochromatic Infrared Photo

Energy (Anodyne Therapy)

•

• Topical non-contact

• Normothermic wound therapy

(Warm Up)

•

• Tissue Engineered products

(Dermagraft, Apligraf)

The use of these adjunctive technologies may be tried in an attempt to facilitate closure of a difficult foot wound, particularly in those wounds that have been unresponsive to previously-attempted evidence-based interventions.

Hyperbaric Oxygen, or HBO’s effects on wound healing include improved local tissue oxygenation and epithelial cell migration, increased white blood cell (or WBC) killing ability, promotion of both collagen deposition and new blood vessel formation, all of which could benefit diabetic foot wound patients. The Wound, Ostomy and Continence Nursing Society (or WOCN) recommends considering its use in limb-threatening wounds of the lower-extremities of Wagner grades III and IV, and for lower-extremity ischemic ulcers with a tcPO2 level less than 40mmHg. Wounds have shown improvement in periwound tcPO2 levels to about 100% pure oxygen at normobaric pressures (Bryant and Nix, 2007 p.429, 431).

Nitric Oxide, or NO is most important during the inflammatory phase of wound healing; people with diabetes may have reduced levels of production. Some studies have shown that administering NO to persons with diabetes enhances collagen synthesis.

Anodyne Therapy has been shown to enhance, temporarily, sensory perception in people with diabetes and may assist in wound healing by increasing nitric oxide levels at a cellular level.

Warm Up: Most wounds are hypothermic and result in vasoconstriction that impairs the normal function of the immune system, thus making the host more vulnerable to infection and delayed wound healing. This therapy/device warms the skin and subcutaneous tissues toward core body temperature thereby increasing blood flow to the wound delivering more oxygen and growth factors to the area.

Tissue Engineered-Skin Substitutes: these products have been used for the treatment of both venous and neuropathic diabetic foot ulcers. A matrix of collagen and living fibroblasts, and/or keratinocytes is implanted into the wound thereby acting as a skin substitute.