Chronic wounds and ulcers are frequently encountered in patients with peripheral vascular disease (PVD) who often have insufficient distal arterial perfusion for wound healing. If the obstructed or stenosed inflow arteries can be bypassed or dilated, the wounds usually heal. However, the wound itself must be addressed surgically and medically along with revascularization. Until recently, wound care has not always been adequately emphasized in undergraduate medical programs.

This chapter addresses much of the current wound treatment available today. How one may incorporate these methods in one’s practice and when referral to a wound treatment center (WTC) may be appropriate for problem wounds will vary with each clinician and his practice environment.

Wound repair and regeneration following acute injury begins within minutes with spasm of blood vessels, coagulation of bleeding surfaces, and accumulation of platelets on the damaged cells. A fibrinous layer derived from activated fibrinogen, collagen, and other trapped cells fills the injured surface. Factors released from platelets activate monophages and leucocytes which remove debris and bacteria. This debris is ingested or destroyed using peroxidase, which is oxygen-dependent. The necessary proliferation of fibroblasts, leucocytes, and keratinocytes, as well as collagen production by fibroblasts also requires sufficient oxygen. If microvascular profusion of oxygen and nutrients is insufficient, the wound will not heal.

Most surgical incisions or other wounds heal rapidly in less than 30 days. Clinical treatment of wounds in healthy patients usually requires only cleaning with saline or antiseptic solutions and sterile wound coverage. If there is significant inflammation clinically associated with the wound one may add topical zinc oxide, or silver in addition to systemic antibiotics.¹

Wounds that fail to heal or to progress normally toward healing over a 30-day period may be defined as “chronic” or “problem” wounds. There are multiple factors that combine in most patients to cause problem wounds. These factors may be local or systemic. Photography or measurement of wounds allows for an objective method to analyze wound evolution.

Local factors involve the tissue immediately surrounding the wound. Examples of local factors include scars from past trauma, fractures, pressure points, diabetic neuropathy with sensory loss and foot deformity, arthritis, and bunions of feet. Fibrotic changes related to radiation, lupus, venous hypertension, and lymphedema may be present as well. Patients may have chronic ischemia from peripheral arterial disease (PAD) or acute ischemia of embolic nature to fingers, toes, and other areas of the body. Bacterial infection of the wound with inadequate or inappropriate treatment allows accumulation of necrotic infected biofilm or eschar. Lack of sharp or enzymatic debridement, poor choice of topical agents, inappropriate dressings, or inadequate tissue cultures are local factors related to inadequate medical care or patient neglect.

Systemic factors include malnutrition, poorly controlled diabetes, renal, or liver failure, age, chemotherapy, steroids, morbid obesity, congestive heart failure (CHF) with generalized edema, inadequate oxygen delivery including chronic obstructive pulmonary disease (COPD), and large-vessel arterial disease. Socioeconomic, spiritual, and psychosocial factors may include lack of transportation, insufficient supplies, poor family support, sedentary lifestyle, morbid obesity, and alcohol or drug addiction. Noncompliance with dressing changes, inattention to weight-bearing protocols, and missed office visits are frequently a problem. Autoimmune disorders, vitamin and mineral deficiencies, inadequate diet, and failure to “quit smoking” may contribute to nonhealing wounds.

Problem wounds affect patients and their physicians in a negative way. These wounds are costly, painful, unattractive, and malodorous creating a social embarrassment and a nuisance to the patient, the patient’s family, and even the treating physicians. Patients frequently spend 1.5 to 2 hours a day thinking about and caring for nonhealing wounds.² Limitation in activity is frustrating and depressing. Deterioration of health in patients with chronic wounds is very significant, especially in older patients.³

It is clear that good medical treatment of “problem wounds’ must include significant time, resources, and diagnostic skill from the physician. The frustration of a nonhealing wound to the treating physician is significant. The “guilt feeling” of unsuccessful treatment may result in unintentional projected anger or blame toward the patient. The problem wound presenting in the midst of a busy office day can be a significant inconvenience and frustration.⁴

Referral of patients with problem wounds to a specialized WTC may be a welcome and logical plan of action for both physician and patient.

Over the past decade, the understanding of the molecular, cellular, and biologic problems found in chronic wounds has led to rapid changes in the recommended treatment of problem wounds. Prolonged inflammation in the nonhealing wound results in elevated levels of cytokines, matrix metalloproteinases (MMP), neutrophil elastase, decreased levels of growth factors, and poorly responding or senescent wound cells.^5,6,7

With proper local wound treatment, and attention to critical local and general factors necessary to support healing, the molecular and biologic cellular profile of the chronic wound becomes similar to the acute wound and healing is observed.⁸

Debridement

We know that one reason chronic, infected wounds do not heal is because of bioburden. Bioburden includes bacteria, dead tissue, and senescent cells on wound margins with decreased mitogenic, and protease activity and a proinflammatory cytokine environment. Clean wounds with adequate arterial and venous flow usually heal. After appropriate cultures of the wound, the bioburden and senescent cells must be removed. Debridement to a healthy wound bed and skin margins turns a nonhealing chronic wound into an actively healing, clean, acute wound.

The clinician should understand that sharp or enzymatic debridement of ischemic wounds or dry gangrene will only damage marginally perfused tissue leading to more rapid and progressive necrosis. One must first improve local tissue health by addressing contributing general health factors and arterial and venous circulation. Chronic wounds close secondarily from the edges by epithelialization and contraction. This process requires excision of necrotic tissue, callous, and overhanging wound edges. Pressure points and movement of wound edges during patient activity disrupts new skin growth and must be addressed. Surgeons tend to use sharp debridement while other physicians may favor enzymatic or mechanical measures. Often unsuspected foreign objects are found in the depths of a wound during sharp debridement. Until all foreign material is removed, a wound will not heal. Plain films may be helpful in assessing for the presence of a foreign body.

Types of Debridement

For years, wet-to-dry has been the most common dressing used by physicians and involves moistened gauze that is placed on the wound and then removed after drying. It is commonly assumed that removing the dry gauze and replacing it with wet gauze is an effective way to debride the wound. However, if left dry too long, healthy cells may become desiccated and necrotic. Unfortunately, during removal of the dry gauze, healthy new cells may be torn off the wound along with eschar. Wet-to-dry gauze is labor-intensive requiring multiple changes daily.

Autolytic debridement by covering the wound with an occlusive sheet of hydrocolloid changed every 3 days is slow, but very selective in removing dead tissue and avoiding injury to healthy cells. Enzymatic therapy is faster, but may be painful and may injure surrounding skin if applied too liberally. Blunt debridement with moist gauze may be used to carefully clean the wound. More recently “pulse lavage” with 8 to 10 psi or less has been utilized in some wound centers.

Necrotic tissue may be pulled bluntly from the wound if directed from the wound edge toward the center to avoid injury to the wound edges. Sharp debridement with knife or curette is fast and effective in the hands of a skilled vascular specialist. However, it is the most harmful if used indiscriminately. One must generally avoid sharp debridement over grafts, tendons, bones, joints, or very vascular tissue. Gauze moistened with 4% lidocaine applied 15 minutes before debridement will help control pain. Bleeding may be controlled with pressure, elevation, silver nitrate sticks, Monsel’s solution (ferric sulfate), or electrocautery.

Dressings

Over the last 50 years, wound care has evolved along with other advances in medicine. This has been especially true in the last two decades. In the 1950s and 1960s, wounds were left open or betadine and dry dressings applied. Wet-to-dry dressing for debridement or application of gauze impregnated with antibiotic under dry gauze was also common. As the benefits of a moist wound environment became known, adhesive, semipermeable dressings, and hydrocolloids were used. Hydrocolloids are now used to hydrate wounds and reduce pain. Foams and alginates can absorb secretions in venous stasis ulcers and may be used under compression dressings. Alginates may be impregnated with silver to control bacterial load. Collagen dressings normalize cellular activity and stimulate wound matrix activity. Collagen may promote epithelial growth.

Large, irregular, or deep wounds and wounds with overhanging skin edges are difficult management problems. The vacuum assisted closure device (VAC; Kinetic Concepts, Inc San Antonio, TX) has gained wide acceptance as an effective dressing for these complex wounds.

A VAC foam dressing is cut to fit the contour of the wound approximating the edge, but not overlying healthy skin. Several pieces of foam may be used for irregular wounds. The evacuation tube is pushed through a small cut in the foam so that the vent openings are inside the foam. An adhesive film supplied with the VAC is placed over the foam dressing and the tube. The film should extend at least 3.5 cm peripherally over surrounding healthy skin and be airtight. The open end of the tubing is connected to the vacuum pump and the proper suction (50–125 mm Hg) selected. The foam is usually reapplied every 2 to 4 days depending on the type of wound.

The benefits of VAC dressings include faster contraction and healing of the wounds with more effective bacterial and exudate clearance, accelerated growth of granulation tissue, contraction of the wound, and increased oxygen tension. The VAC may be used to prepare wounds for skin grafts and also used immediately after applying the grafts.

Large, acute, and surgical wounds, pressure ulcers, venous ulcers, drained abscess cavities, and diabetic foot ulcers have responded favorably when treated with the VAC.^9,10,11,12

There are several thousand wound care products and dressings available. The choice of dressings is influenced by the need to remove eschar and debride (if not done surgically), to keep the wound moist, and to avoid excessive exudate accumulation that will macerate the tissue. Dressings must also protect the wound from further injury. The relative cost of various wound care products is also very important to the physician and facility.

Many dedicated WTCs may effectively utilize hyperbaric oxygen (HBO) in some chronic wounds such as diabetic ulcers, deep ischemic wounds with osteomyelitis, failing skin grafts or flaps, and nonhealing wounds in previously irradiated tissue (Figure 43-1). These problem wounds may have continuing ischemia despite appropriate vascular evaluation and treatment.