- Email: [email protected]
Wound Healing and Management
Wound Healing and Management
239
lipoproteins (HDLs) and decrease the levels of low-density lipoproteins (LDLs); (2) estrogen also helps in inhibiting the deposition of atherosclerotic plaque on the intima of arteries. Consequently, a sedentary lifestyle, poor diet, and poor physical fitness can lead to a higher risk of cardiovascular disease, especially coronary artery disease. Myocardial infarction is the leading cause of death among postmenopausal women.
Bibliography Benson JT: Clinical gynecology: urogynecology and reconstructive pelvic surgery, Philadelphia, 1999, McGraw-Hill. Goldfarb AF: Clinical gynecology: pediatric and adolescent gynecology, Philadelphia, 1998, Current Medicine. Heckman JD, Sassard R: Current concepts review: musculoskeletal considerations in pregnancy, J Bone Joint Surg 11:1720-1730, 1994. Ireland ML, Nattiv A: The female athlete, Philadelphia, 2002, WB Saunders. Merck & Co: Bone mineral density testing: a pocket guide to evaluation and reimbursement, West Point, Pa, 1999, Merck & Co. Pauls JA: Therapeutic approaches to women’s health: a program of exercise and education, Frederick, Md, 1996, Aspen Publishers. Pauls JA, Reed KL: Quick reference to physical therapy, Frederick, Md, 1996, Aspen Publishers. Pemberton J, Swash M, Henry M: The pelvic floor: its function and disorders, Philadelphia, 2002, WB Saunders. Sapsford R, Bullock-Saxton J, Markwell S: Women’s health: a textbook for physiotherapists, Philadelphia, 1998, WB Saunders. Schussler B, Laycock J: Pelvic floor re-education, New York, 1994, Springer-Verlag. Stephenson RG, O’Conner LJ: Obstetric and gynecologic care in physical therapy, ed 2, Thorofare, NJ, 2000, Slack. Travell JG, Simons DG: Myofascial pain and dysfunction: the trigger point manual, the lower extremities, Philadelphia, 1997, Lippincott Williams & Wilkins. Wilder E, editor: The gynecological manual, Alexandria, Va, 1997, Section of Women’s Health of the American Physical Therapy Association.
C h a p t e r
2 7
Wound Healing and Management Joseph M. McCulloch, PT, PhD, CWS
1. What is moist wound healing? Within the microenvironment of a wound, certain conditions provide optimal healing. Proper hydration and adequate perfusion facilitate the formation of granulation tissue and epithelial cell migration. As a result, the wound heals more quickly without the formation of a scab or eschar. Many modern synthetic dressings create just such a moist environment. When the standard “wet-
240
Special Topics
to-dry” gauze dressing is permitted to dry, however, tissue desiccation and a lengthened healing response can result. Select a dressing that creates a moist environment without permitting maceration or desiccation.
2. What is granulation tissue? Is too much a bad thing? Technically, granulation tissue consists of a gel-like matrix of collagen, hyaluronic acid, and fibronectin in a newly formed vascular network. Granulation tissue nourishes the macrophages and fibroblasts that have migrated into the wound and, as healing continues, provides a substrate for the migration of epidermal cells. Granulation tissue first appears as pale pink buds but later becomes bright red. Excessive granulation tissue, often referred to as “proud flesh,” sometimes occurs when no other signs of wound healing are evident. Pressure wraps are used frequently to control this problem. Some clinicians burn the tissue back with silver nitrate, but such a technique is of questionable merit. It serves as an acute injury stimulus, and additional granulation tissue may result.
3. What is meant by mechanical debridement and how effective is it? Mechanical debridement refers to the removal of devitalized tissue by mechanical means and very broadly includes such techniques as whirlpool, pulsatile lavage with suction, other forms of spray irrigation, and the traditional wet-to-dry dressing. Whirlpool and spray irrigation cleanse the wound but have minimal effect in removing adherent necrotic tissue. Furthermore, whirlpool debridement is fraught with other problems such as the potential for cross-contamination. Pulsatile lavage with suction removes debris more effectively and can deliver a controlled irrigation pressure in a sterile environment. Wet-to-dry dressings provide mechanical debridement by attaching to necrotic tissue and lifting off the tissue at dressing change. This debridement is nonselective, however, and viable tissue can be damaged.
4. Why are wet-to-dry dressings inappropriate for use in current wound care? In addition to the debridement complications mentioned in the previous question, other problems exist with wet-to-dry dressings. These dressings typically consist of a woven gauze dressing that is applied wet and allowed to dry before removal. The thought behind this type of dressing is that the moisture would initially facilitate the softening of necrotic tissue, which would then stick to the dressing and be removed at the time of dressing change. Anyone who has used such a dressing knows the pain and trauma associated with these dressings becoming adherent to viable tissue and damaging it on removal. In addition, the dryness of the dressing promotes an environment that is conducive only to cell death. As stated previously, moist healing is much preferred and is the standard of care. Additionally, the cotton fibers of the dressing are often left behind in the wound and create a foreign body response.
5. What is enzymatic debridement? Enzymatic debridement involves the application of a commercially prepared proteolytic enzyme to necrotic tissue to aid in removal. A variety of products are available and include such agents as collagenase, papain, urea, and fibrinolysin. Enzymes are generally used in conjunction with moist wound healing for the best results. Certain pharmaceutical antibacterial preparations, which contain silver or other heavy metals, can interfere with enzyme activity. Care should therefore be taken in combining the two types of therapy in a single treatment. Some commonly used enzymatic debriding agents are Accuzyme, Panafil, and Santyl.
6. What are the advantages and disadvantages of autolytic debridement? Autolytic debridement implies that the body performs its own cleaning. Synthetic dressings, when appropriately used, can trap endogenous enzymes and other beneficial agents in the wound and
Wound Healing and Management
241
provide for adequate debridement. This is a highly selective form of debridement and is very nontraumatic. Though effective, autolytic debridement may take longer to debride a wound than the use of commercial enzyme preparations or more invasive forms of debridement.
7. What are some common topical agents that have been shown to delay healing? Any agent strong enough to kill bacteria on an inanimate object has the potential to disrupt healing. Some of the more common agents that have unfortunately persisted in the wound care arena include hydrogen peroxide, acetic acid, sodium hypochlorite solution (Dakin’s solution), and povidone-iodine. All of these substances, when used at standard clinical strength, have been demonstrated to cause the death of fibroblasts in vitro. If these agents are to be used at all, their use should be very focal in nature. Dakin’s solution, for instance, could be applied over necrotic tissue to soften the tissue and aid in debridement. Likewise, acetic acid could be used to help address localized colonization of Pseudomonas. In general, however, both agents should be discontinued as soon as the desired results are achieved and not simply used as a moistening agent for gauze.
8. What is the primary difference in the clinical presentation of venous and arterial ulcers? Although both types of ulcers may occur at varying points along the leg, venous ulcers typically are located over the medial malleolar area. They tend to be irregular in shape and possess a good granulation base. Venous ulcers often are associated with lower extremity swelling and generally are quite moist. Brownish staining of the skin caused by the pigment hemosiderin, which is released by lysed red blood cells, suggests a venous ulcer. Patients with venous insufficiency ulcers generally complain of pain after prolonged standing and report relief of pain with leg elevation. Arterial or ischemic ulcers, on the other hand, are noted most often on the distal aspects of the feet but may occur more proximally, depending on the occluded artery. Arterial ulcers have a punched-out appearance with a pale granulation base. Signs frequently associated with ischemic ulcers include a loss of hair on the extremity, poor capillary refill in the toes, and brittle nails. Patients with ischemic ulcers complain of pain whenever the leg is elevated and frequently hang the leg dependently to reduce symptoms.
9. What system is used to classify pressure ulcers? The most commonly used classification system for pressure ulcers is the Shea scale, which categorizes ulcers according to the degree of tissue involvement from partial- to full-thickness dermal erosion: • Stage 1—Nonblanchable erythema with intact skin • Stage 2—A partial-thickness lesion with a break in the skin and loss of epidermis • Stage 3—A full-thickness lesion with dermal involvement (no penetration of fascia) • Stage 4—A full-thickness lesion involving the dermis, fascia, and, to varying degrees, underlying muscles, bones, and joints
10. What is meant by reverse-staging of pressure ulcers? Why is it inappropriate? Reverse-staging implies that as an ulcer heals it moves to the next least involved stage of healing. For example, a stage 4 ulcer would be said to reverse to stage 3, then stage 2, and finally stage 1. This system of reverse-staging, although often required by third-party payors, is inappropriate because once full-thickness involvement has occurred, healing can take place only by wound contraction, scarring, and epithelialization—not by replacement of the original tissue. The dermis cannot regenerate. Reverse-staging is, therefore, an inaccurate description of healing. The more appropriate method is to state that the wound is a “healing stage 4, 3, or 2 pressure ulcer.”
242
Special Topics
11. How are plantar ulcers of the insensate foot staged? The most frequently used staging system for ulcers of the insensate foot is the Wagner grading system: • Grade 0—Intact skin • Grade 1—Superficial ulcer • Grade 2—Deep ulcer • Grade 3—Deep, infected ulcer • Grade 4—Partial foot gangrene • Grade 5—Full foot gangrene
12. How is total-contact casting of benefit to the healing of a plantar foot ulcer in diabetic patients? A total-contact cast is a minimally padded, closed-toe plaster cast with a walking heel. Totalcontact casting is indicated for Wagner grade 1 and 2 plantar ulcers and works by shifting weight from the plantar ulcer to the arch of the foot and the heel, through the walls of the cast, and to the tibia. Padding is placed over the spine of the tibia, medial and lateral malleoli, navicular prominence, wound, and toes. When properly applied, 30% of the weight-bearing load is transmitted to the cast wall. Total-contact casts are contraindicated in the presence of fluctuating edema, suspected osteomyelitis or other infection, heavily exudating wounds, and claustrophobia. Total-contact casts differ from traditional plaster fracture casts in that minimal padding is used and the toes are completely enclosed. Covering the toes prevents foreign bodies from entering the cast because insensitivity precludes their detection.
13. What are the most common locations for plantar ulcers in patients with diabetes? The most frequent locations of ulcerations in diabetic patients are the first metatarsal head, fifth metatarsal head, and great toe. These areas are predisposed to ulceration because pressure is shifted distally on the foot secondary to Achilles tendon shortening. Achilles shortening is a common finding in diabetic patients because of changes in the structure of collagen.
14. Define Charcot deformity. Charcot deformity initially was described in patients with tertiary syphilis but is now seen more commonly in patients with advanced stages of diabetic neuropathy. Although the exact pathogenesis is unknown, vasodilation secondary to autonomic dysfunction is thought to be a major factor. High-velocity blood flow in the insensate extremity leads to demineralization of the bone, and repeated unrecognized microtrauma may initiate the destructive process of fractures and subluxation of the midfoot. Initial signs often mimic cellulitis that is supposedly secondary to an underlying osteomyelitis. Often patients are inappropriately placed on antibiotics. If totalcontact casting (see question 12) is not initiated at the early signs of Charcot arthropathy, bony deformities can develop and may lead to pressure points on the feet, which, in turn, ulcerate and create chronic wounds. A common finding in diabetic patients with early Charcot changes is a strong pulse rate with associated diffuse erythema in a nonulcerated foot. Osteomyelitis, on the other hand, is generally associated with a chronic soft tissue ulceration that precedes the bony infection. The preferred diagnostic tests are magnetic resonance imaging and bone biopsy.
15. How are wound care dressings classified? Summarize the types, advantages, and disadvantages of the different types of dressings. One useful technique is to place the dressings along a continuum from totally occlusive and impermeable to oxygen to nonocclusive and permeable to oxygen. Less occlusive dressings generally tend to be absorptive but require frequent changes because wound fluid may penetrate to the outer dressing wrap. More occlusive dressings are generally designed to be left in place for longer periods (depending on absorbency) and, for that reason, are often helpful in promoting
Wound Healing and Management
243
autolytic debridement. The table below provides a classification according to permeability for the major dressing types.
Classification of Dressings Mechanism of Action
Advantages
Disadvantages
Use
Hydrocolloid
Absorbant colloid material and elastomers covered with polyurethane Absorbs Protects
Many are adherent Waterproof Vaporimpermeable Changed infrequently
Bunching and wrinkling Some are malodorous Can promote excessive granulation tissue
Maintains moisture Absorbs limited exudate Promotes autolytic debridement
Hydrogel
Cross-linked polymer gel with high water content Hydrates
Provides moist environment Thermal insulator
Can lead to maceration May be difficult to keep in place
Fiber
Carboxymethylcellulose Absorbs Gels
Can dehydrate dry wound
Alginate
Calcium or calcium-sodium alginate Absorbs
Can absorb large amounts of exudate Promotes moist environment Can absorb moderate amounts of exudate Promotes moist environment Some hemostatic properties
Softening eschar and necrotic tissue Providing moisture to desiccated wound, applied in thin layer Excellent for exudate absorption in variety of wounds
Type
Can dehydrate dry wound
Excellent for exudate absorption in variety of wounds but does not absorb as much as fiber dressing
Common Names DuoDerm (ConvaTex, Skillman, NJ); Comfeel (Coloplast, Marietta, Ga); Hydrocol (Bertek, Morgantown, WV) Spenco 2nd Skin (Spenco Medical, Waco, Tex)
AQUACEL (ConvaTec, Skillman, NJ)
Sorbsan (Bertek, Morgantown, WVa)
continued
244
Special Topics
Classification of Dressings continued Type
Mechanism of Action
Foam
Highly absorbant polyurethane Absorbs Provides padding
Film
Transparent polymer membrane covered with acrylic adhesive Protective covering
Advantages
Disadvantages
Use
Common Names
Depending on density can absorb large amounts of exudate over an extended period Promotes moist environment Conforms to odd surfaces Allows visualization of wound Provides protection against shear Bacterial barrier Good for stage 1 pressure ulcers Clear; can visualize wound
Can lead to wound maceration if too much fluid collects between changes Cannot absorb quickly
Excellent secondary dressing for alginates and fiber dressings
Flexzan (Bertek, Morgantown, WVa); Allevyn (Smith & Nephew, Largo, Fla)
Does not absorb
Used for superficial abrasions Useful as secondary dressing for alginates and fiber dressings
Bioclusive (Johnson & Johnson, Arlington, Tex); OpSite (Smith & Nephew, Largo, Fla)
16. Describe the function of hydrotherapy in wound care. Hydrotherapy, in the broadest sense, is the use of some form of water or other liquid for therapeutic purposes. For many years, whirlpool was used extensively in wound care to aid in cleansing wounds and burns. More recently, irrigation by other means, especially pulsatile lavage, has gained acceptance. This change is due to understanding of the negative effects of whirlpool, such as high pressure from whirlpool turbines, potential cross-contamination, and edema in dependent limbs. Pulsatile lavage, a form of irrigation that can be delivered at controlled pressures with the use of sterile water or saline as the irrigant, makes cleansing more wound-friendly, especially in clean wounds with beefy red granulation tissue. Whirlpool may be of some assistance in general cleansing in patients with wounds, but it should be avoided in patients with venous
Wound Healing and Management
245
insufficiency ulcers because the dependent position and warm water increase venous congestion in the extremity. While whirlpool in general has fallen into disfavor in wound care, there is some discussion of the possible benefits of warm water in stimulating healing. Chronic wound fluid is known to be inhibitory to dermal fibroblasts. When chronic wound fluid is heated to as little as 100° C, however, this inhibition is no longer present. While this does not mean that the moratorium on whirlpool in wound care is over, it certainly provides support for the warming of whatever type of irrigation solution is used in wound cleansing.
17. What is the role of electrical stimulation in wound healing? Numerous controlled studies have demonstrated the benefits of high-voltage galvanic stimulation (HVGS) in augmenting wound healing. The results have been particularly impressive in the management of pressure ulcers. A meta-analysis performed by Gardner et al. reported on the results of 591 chronic wounds treated with electrical stimulation compared to 212 controls. They noted that, based on the overall rates of healing, electrical stimulation increased the healing rate of chronic wounds by 144%. This has not been the case with electromagnetic therapy, however. A systematic Cochrane review was performed on the role of electromagnetic therapy in promoting wound healing in individuals with pressure ulcers and venous insufficiency ulcers. There was insufficient evidence to advocate the use of electromagnetic therapy in wound healing. Should electrical stimulation be considered as an adjunct to treatment of a chronic wound, the following technique is suggested. A high-voltage pulsed current stimulator should be used. Treatment should be 45 minutes to 1 hour in length, and the stimulus should be delivered at a frequency of 100 pulses per second at a submotor intensity (enough to produce a tingling paresthesia). Polarity of the active electrode plays an important role. The positive electrode (anode) should be placed over the wound when debridement or epithelialization is the objective. The negative pole (cathode) is used to stimulate production of granulation tissue or to promote antimicrobial or antiinflammatory effects. Typically the wound is filled loosely with salinemoistened gauze, and an aluminum foil electrode, connected to an alligator clip lead wire, is used for conductivity. Make sure that the foil electrode is smaller than the moistened gauze so that no portion of the foil comes in contact with intact skin.
18. What is negative pressure wound therapy and how can it benefit an orthopaedic wound? Negative pressure wound therapy (NPWT) involves the application of a localized negative pressure to the wound and its margins through a special foam dressing. The dressing is placed in a wound cavity, or over a flap or graft, and is covered with an occlusive film drape. The sealed wound is then connected to a computerized vacuum pump that is set to provide between 75 and 125 mm Hg of negative pressure, either continuously or intermittently, for 48 hours. The system helps to remove fluid from the wound and promote granulation tissue development and wound contraction. There are limited randomized controlled studies on the effectiveness of NPWT in wound healing. A 2000 Cochrane review indicated that only 2 small trials with a total of 34 patients existed, and the studies provided weak evidence that NPWT was any better than saline-moistened gauze in promoting wound healing. Since this review, several additional studies with small sample sizes have attested to the benefits of NPWT in speeding the healing process. There are, however, in excess of 100 case reports attesting to the benefits of NPWT in wound healing. NPWT is a great asset to treatment of large skin defects often encountered with traumatic injuries to the extremities or to dehisced surgical wounds. It can be used in conjunction with external fixator devices to minimize dressing changes and accelerate healing.
19. Are any of the topically applied growth factors of benefit in wound healing? Two growth factor preparations commonly encountered in clinical practice are Procuren and Regranex. Procuren is a platelet-derived growth factor developed from a sample of the patient’s
246
Special Topics
own blood. It is marketed for use in the management of chronic nonhealing wounds, but insufficient research supports its effectiveness. The clinical practice guideline from the Agency for Health Care Policy and Research, “Treatment of Pressure Ulcers,” concludes that the effectiveness of growth factors has not been sufficiently established to warrant recommendation for use. Regranex (becaplermin) gel, on the other hand, is a recombinant form of platelet-derived growth factor. It has been approved by the Food and Drug Administration for patients with neuropathic ulcers. Controlled clinical trials have demonstrated the effectiveness of Regranex gel in improving the healing rates of diabetic foot ulcers.
Bibliography Berendt AR, Lipsky B: Is this bone infected or not? Differentiating neuro-osteoarthropathy from osteomyelitis in the diabetic foot, Curr Diab Rep 4:424-429, 2004. Gardner SE et al: Effect of electrical stimulation on chronic wound healing: a meta-analysis, Wound Repair Regen 7:495-503, 1999. Guyton G, Saltzman C: The diabetic foot: basic mechanisms of disease, J Bone Joint Surg (Am) 83A: 1084-1096, 2001. Kloth LC: Electrical stimulation for wound healing: a review of evidence from in vitro studies, animal experiment, and clinical trials, Lower Extremity Wounds 4:23-44, 2005. Kloth L, McCulloch J: Wound healing: alternatives in management, ed 3, Philadelphia, 2001, FA Davis. Krasner D, Rodeheaver G, Sibbald G: Chronic wound care: a clinical source book for healthcare professionals, ed 3, Wayne, Pa, 2001, HMP Communications. McCallon S et al: Vacuum-assisted closure versus saline-moistened gauze in the healing of postoperative diabetic foot wounds, Ostomy/Wound Management 46:28-29, 31-22, 34, 2000. McCulloch J: The integumentary system—repair and management: an overview, PT—Magazine Phys Ther 12:52-56, 58, 60-64, 2004. Patout C Jr et al: A decision pathway for the staged management of foot problems in diabetes mellitus, Arch Phys Med Rehabil 82:1724-1728, 2001. Sheffield P, Smith A, Fife C: Wound care practice, Flagstaff, Ariz, 2004, Best Publishing. Sinacore D: Total contact casting for diabetic neuropathic ulcers, Phys Ther 76:296-301, 1996. Sussman K, Bates-Jensen B, editors: Wound care: a collaborative practice manual for physical therapists and nurses, Gaithersburg, Md, 2001, Aspen.
239
lipoproteins (HDLs) and decrease the levels of low-density lipoproteins (LDLs); (2) estrogen also helps in inhibiting the deposition of atherosclerotic plaque on the intima of arteries. Consequently, a sedentary lifestyle, poor diet, and poor physical fitness can lead to a higher risk of cardiovascular disease, especially coronary artery disease. Myocardial infarction is the leading cause of death among postmenopausal women.
Bibliography Benson JT: Clinical gynecology: urogynecology and reconstructive pelvic surgery, Philadelphia, 1999, McGraw-Hill. Goldfarb AF: Clinical gynecology: pediatric and adolescent gynecology, Philadelphia, 1998, Current Medicine. Heckman JD, Sassard R: Current concepts review: musculoskeletal considerations in pregnancy, J Bone Joint Surg 11:1720-1730, 1994. Ireland ML, Nattiv A: The female athlete, Philadelphia, 2002, WB Saunders. Merck & Co: Bone mineral density testing: a pocket guide to evaluation and reimbursement, West Point, Pa, 1999, Merck & Co. Pauls JA: Therapeutic approaches to women’s health: a program of exercise and education, Frederick, Md, 1996, Aspen Publishers. Pauls JA, Reed KL: Quick reference to physical therapy, Frederick, Md, 1996, Aspen Publishers. Pemberton J, Swash M, Henry M: The pelvic floor: its function and disorders, Philadelphia, 2002, WB Saunders. Sapsford R, Bullock-Saxton J, Markwell S: Women’s health: a textbook for physiotherapists, Philadelphia, 1998, WB Saunders. Schussler B, Laycock J: Pelvic floor re-education, New York, 1994, Springer-Verlag. Stephenson RG, O’Conner LJ: Obstetric and gynecologic care in physical therapy, ed 2, Thorofare, NJ, 2000, Slack. Travell JG, Simons DG: Myofascial pain and dysfunction: the trigger point manual, the lower extremities, Philadelphia, 1997, Lippincott Williams & Wilkins. Wilder E, editor: The gynecological manual, Alexandria, Va, 1997, Section of Women’s Health of the American Physical Therapy Association.
C h a p t e r
2 7
Wound Healing and Management Joseph M. McCulloch, PT, PhD, CWS
1. What is moist wound healing? Within the microenvironment of a wound, certain conditions provide optimal healing. Proper hydration and adequate perfusion facilitate the formation of granulation tissue and epithelial cell migration. As a result, the wound heals more quickly without the formation of a scab or eschar. Many modern synthetic dressings create just such a moist environment. When the standard “wet-
240
Special Topics
to-dry” gauze dressing is permitted to dry, however, tissue desiccation and a lengthened healing response can result. Select a dressing that creates a moist environment without permitting maceration or desiccation.
2. What is granulation tissue? Is too much a bad thing? Technically, granulation tissue consists of a gel-like matrix of collagen, hyaluronic acid, and fibronectin in a newly formed vascular network. Granulation tissue nourishes the macrophages and fibroblasts that have migrated into the wound and, as healing continues, provides a substrate for the migration of epidermal cells. Granulation tissue first appears as pale pink buds but later becomes bright red. Excessive granulation tissue, often referred to as “proud flesh,” sometimes occurs when no other signs of wound healing are evident. Pressure wraps are used frequently to control this problem. Some clinicians burn the tissue back with silver nitrate, but such a technique is of questionable merit. It serves as an acute injury stimulus, and additional granulation tissue may result.
3. What is meant by mechanical debridement and how effective is it? Mechanical debridement refers to the removal of devitalized tissue by mechanical means and very broadly includes such techniques as whirlpool, pulsatile lavage with suction, other forms of spray irrigation, and the traditional wet-to-dry dressing. Whirlpool and spray irrigation cleanse the wound but have minimal effect in removing adherent necrotic tissue. Furthermore, whirlpool debridement is fraught with other problems such as the potential for cross-contamination. Pulsatile lavage with suction removes debris more effectively and can deliver a controlled irrigation pressure in a sterile environment. Wet-to-dry dressings provide mechanical debridement by attaching to necrotic tissue and lifting off the tissue at dressing change. This debridement is nonselective, however, and viable tissue can be damaged.
4. Why are wet-to-dry dressings inappropriate for use in current wound care? In addition to the debridement complications mentioned in the previous question, other problems exist with wet-to-dry dressings. These dressings typically consist of a woven gauze dressing that is applied wet and allowed to dry before removal. The thought behind this type of dressing is that the moisture would initially facilitate the softening of necrotic tissue, which would then stick to the dressing and be removed at the time of dressing change. Anyone who has used such a dressing knows the pain and trauma associated with these dressings becoming adherent to viable tissue and damaging it on removal. In addition, the dryness of the dressing promotes an environment that is conducive only to cell death. As stated previously, moist healing is much preferred and is the standard of care. Additionally, the cotton fibers of the dressing are often left behind in the wound and create a foreign body response.
5. What is enzymatic debridement? Enzymatic debridement involves the application of a commercially prepared proteolytic enzyme to necrotic tissue to aid in removal. A variety of products are available and include such agents as collagenase, papain, urea, and fibrinolysin. Enzymes are generally used in conjunction with moist wound healing for the best results. Certain pharmaceutical antibacterial preparations, which contain silver or other heavy metals, can interfere with enzyme activity. Care should therefore be taken in combining the two types of therapy in a single treatment. Some commonly used enzymatic debriding agents are Accuzyme, Panafil, and Santyl.
6. What are the advantages and disadvantages of autolytic debridement? Autolytic debridement implies that the body performs its own cleaning. Synthetic dressings, when appropriately used, can trap endogenous enzymes and other beneficial agents in the wound and
Wound Healing and Management
241
provide for adequate debridement. This is a highly selective form of debridement and is very nontraumatic. Though effective, autolytic debridement may take longer to debride a wound than the use of commercial enzyme preparations or more invasive forms of debridement.
7. What are some common topical agents that have been shown to delay healing? Any agent strong enough to kill bacteria on an inanimate object has the potential to disrupt healing. Some of the more common agents that have unfortunately persisted in the wound care arena include hydrogen peroxide, acetic acid, sodium hypochlorite solution (Dakin’s solution), and povidone-iodine. All of these substances, when used at standard clinical strength, have been demonstrated to cause the death of fibroblasts in vitro. If these agents are to be used at all, their use should be very focal in nature. Dakin’s solution, for instance, could be applied over necrotic tissue to soften the tissue and aid in debridement. Likewise, acetic acid could be used to help address localized colonization of Pseudomonas. In general, however, both agents should be discontinued as soon as the desired results are achieved and not simply used as a moistening agent for gauze.
8. What is the primary difference in the clinical presentation of venous and arterial ulcers? Although both types of ulcers may occur at varying points along the leg, venous ulcers typically are located over the medial malleolar area. They tend to be irregular in shape and possess a good granulation base. Venous ulcers often are associated with lower extremity swelling and generally are quite moist. Brownish staining of the skin caused by the pigment hemosiderin, which is released by lysed red blood cells, suggests a venous ulcer. Patients with venous insufficiency ulcers generally complain of pain after prolonged standing and report relief of pain with leg elevation. Arterial or ischemic ulcers, on the other hand, are noted most often on the distal aspects of the feet but may occur more proximally, depending on the occluded artery. Arterial ulcers have a punched-out appearance with a pale granulation base. Signs frequently associated with ischemic ulcers include a loss of hair on the extremity, poor capillary refill in the toes, and brittle nails. Patients with ischemic ulcers complain of pain whenever the leg is elevated and frequently hang the leg dependently to reduce symptoms.
9. What system is used to classify pressure ulcers? The most commonly used classification system for pressure ulcers is the Shea scale, which categorizes ulcers according to the degree of tissue involvement from partial- to full-thickness dermal erosion: • Stage 1—Nonblanchable erythema with intact skin • Stage 2—A partial-thickness lesion with a break in the skin and loss of epidermis • Stage 3—A full-thickness lesion with dermal involvement (no penetration of fascia) • Stage 4—A full-thickness lesion involving the dermis, fascia, and, to varying degrees, underlying muscles, bones, and joints
10. What is meant by reverse-staging of pressure ulcers? Why is it inappropriate? Reverse-staging implies that as an ulcer heals it moves to the next least involved stage of healing. For example, a stage 4 ulcer would be said to reverse to stage 3, then stage 2, and finally stage 1. This system of reverse-staging, although often required by third-party payors, is inappropriate because once full-thickness involvement has occurred, healing can take place only by wound contraction, scarring, and epithelialization—not by replacement of the original tissue. The dermis cannot regenerate. Reverse-staging is, therefore, an inaccurate description of healing. The more appropriate method is to state that the wound is a “healing stage 4, 3, or 2 pressure ulcer.”
242
Special Topics
11. How are plantar ulcers of the insensate foot staged? The most frequently used staging system for ulcers of the insensate foot is the Wagner grading system: • Grade 0—Intact skin • Grade 1—Superficial ulcer • Grade 2—Deep ulcer • Grade 3—Deep, infected ulcer • Grade 4—Partial foot gangrene • Grade 5—Full foot gangrene
12. How is total-contact casting of benefit to the healing of a plantar foot ulcer in diabetic patients? A total-contact cast is a minimally padded, closed-toe plaster cast with a walking heel. Totalcontact casting is indicated for Wagner grade 1 and 2 plantar ulcers and works by shifting weight from the plantar ulcer to the arch of the foot and the heel, through the walls of the cast, and to the tibia. Padding is placed over the spine of the tibia, medial and lateral malleoli, navicular prominence, wound, and toes. When properly applied, 30% of the weight-bearing load is transmitted to the cast wall. Total-contact casts are contraindicated in the presence of fluctuating edema, suspected osteomyelitis or other infection, heavily exudating wounds, and claustrophobia. Total-contact casts differ from traditional plaster fracture casts in that minimal padding is used and the toes are completely enclosed. Covering the toes prevents foreign bodies from entering the cast because insensitivity precludes their detection.
13. What are the most common locations for plantar ulcers in patients with diabetes? The most frequent locations of ulcerations in diabetic patients are the first metatarsal head, fifth metatarsal head, and great toe. These areas are predisposed to ulceration because pressure is shifted distally on the foot secondary to Achilles tendon shortening. Achilles shortening is a common finding in diabetic patients because of changes in the structure of collagen.
14. Define Charcot deformity. Charcot deformity initially was described in patients with tertiary syphilis but is now seen more commonly in patients with advanced stages of diabetic neuropathy. Although the exact pathogenesis is unknown, vasodilation secondary to autonomic dysfunction is thought to be a major factor. High-velocity blood flow in the insensate extremity leads to demineralization of the bone, and repeated unrecognized microtrauma may initiate the destructive process of fractures and subluxation of the midfoot. Initial signs often mimic cellulitis that is supposedly secondary to an underlying osteomyelitis. Often patients are inappropriately placed on antibiotics. If totalcontact casting (see question 12) is not initiated at the early signs of Charcot arthropathy, bony deformities can develop and may lead to pressure points on the feet, which, in turn, ulcerate and create chronic wounds. A common finding in diabetic patients with early Charcot changes is a strong pulse rate with associated diffuse erythema in a nonulcerated foot. Osteomyelitis, on the other hand, is generally associated with a chronic soft tissue ulceration that precedes the bony infection. The preferred diagnostic tests are magnetic resonance imaging and bone biopsy.
15. How are wound care dressings classified? Summarize the types, advantages, and disadvantages of the different types of dressings. One useful technique is to place the dressings along a continuum from totally occlusive and impermeable to oxygen to nonocclusive and permeable to oxygen. Less occlusive dressings generally tend to be absorptive but require frequent changes because wound fluid may penetrate to the outer dressing wrap. More occlusive dressings are generally designed to be left in place for longer periods (depending on absorbency) and, for that reason, are often helpful in promoting
Wound Healing and Management
243
autolytic debridement. The table below provides a classification according to permeability for the major dressing types.
Classification of Dressings Mechanism of Action
Advantages
Disadvantages
Use
Hydrocolloid
Absorbant colloid material and elastomers covered with polyurethane Absorbs Protects
Many are adherent Waterproof Vaporimpermeable Changed infrequently
Bunching and wrinkling Some are malodorous Can promote excessive granulation tissue
Maintains moisture Absorbs limited exudate Promotes autolytic debridement
Hydrogel
Cross-linked polymer gel with high water content Hydrates
Provides moist environment Thermal insulator
Can lead to maceration May be difficult to keep in place
Fiber
Carboxymethylcellulose Absorbs Gels
Can dehydrate dry wound
Alginate
Calcium or calcium-sodium alginate Absorbs
Can absorb large amounts of exudate Promotes moist environment Can absorb moderate amounts of exudate Promotes moist environment Some hemostatic properties
Softening eschar and necrotic tissue Providing moisture to desiccated wound, applied in thin layer Excellent for exudate absorption in variety of wounds
Type
Can dehydrate dry wound
Excellent for exudate absorption in variety of wounds but does not absorb as much as fiber dressing
Common Names DuoDerm (ConvaTex, Skillman, NJ); Comfeel (Coloplast, Marietta, Ga); Hydrocol (Bertek, Morgantown, WV) Spenco 2nd Skin (Spenco Medical, Waco, Tex)
AQUACEL (ConvaTec, Skillman, NJ)
Sorbsan (Bertek, Morgantown, WVa)
continued
244
Special Topics
Classification of Dressings continued Type
Mechanism of Action
Foam
Highly absorbant polyurethane Absorbs Provides padding
Film
Transparent polymer membrane covered with acrylic adhesive Protective covering
Advantages
Disadvantages
Use
Common Names
Depending on density can absorb large amounts of exudate over an extended period Promotes moist environment Conforms to odd surfaces Allows visualization of wound Provides protection against shear Bacterial barrier Good for stage 1 pressure ulcers Clear; can visualize wound
Can lead to wound maceration if too much fluid collects between changes Cannot absorb quickly
Excellent secondary dressing for alginates and fiber dressings
Flexzan (Bertek, Morgantown, WVa); Allevyn (Smith & Nephew, Largo, Fla)
Does not absorb
Used for superficial abrasions Useful as secondary dressing for alginates and fiber dressings
Bioclusive (Johnson & Johnson, Arlington, Tex); OpSite (Smith & Nephew, Largo, Fla)
16. Describe the function of hydrotherapy in wound care. Hydrotherapy, in the broadest sense, is the use of some form of water or other liquid for therapeutic purposes. For many years, whirlpool was used extensively in wound care to aid in cleansing wounds and burns. More recently, irrigation by other means, especially pulsatile lavage, has gained acceptance. This change is due to understanding of the negative effects of whirlpool, such as high pressure from whirlpool turbines, potential cross-contamination, and edema in dependent limbs. Pulsatile lavage, a form of irrigation that can be delivered at controlled pressures with the use of sterile water or saline as the irrigant, makes cleansing more wound-friendly, especially in clean wounds with beefy red granulation tissue. Whirlpool may be of some assistance in general cleansing in patients with wounds, but it should be avoided in patients with venous
Wound Healing and Management
245
insufficiency ulcers because the dependent position and warm water increase venous congestion in the extremity. While whirlpool in general has fallen into disfavor in wound care, there is some discussion of the possible benefits of warm water in stimulating healing. Chronic wound fluid is known to be inhibitory to dermal fibroblasts. When chronic wound fluid is heated to as little as 100° C, however, this inhibition is no longer present. While this does not mean that the moratorium on whirlpool in wound care is over, it certainly provides support for the warming of whatever type of irrigation solution is used in wound cleansing.
17. What is the role of electrical stimulation in wound healing? Numerous controlled studies have demonstrated the benefits of high-voltage galvanic stimulation (HVGS) in augmenting wound healing. The results have been particularly impressive in the management of pressure ulcers. A meta-analysis performed by Gardner et al. reported on the results of 591 chronic wounds treated with electrical stimulation compared to 212 controls. They noted that, based on the overall rates of healing, electrical stimulation increased the healing rate of chronic wounds by 144%. This has not been the case with electromagnetic therapy, however. A systematic Cochrane review was performed on the role of electromagnetic therapy in promoting wound healing in individuals with pressure ulcers and venous insufficiency ulcers. There was insufficient evidence to advocate the use of electromagnetic therapy in wound healing. Should electrical stimulation be considered as an adjunct to treatment of a chronic wound, the following technique is suggested. A high-voltage pulsed current stimulator should be used. Treatment should be 45 minutes to 1 hour in length, and the stimulus should be delivered at a frequency of 100 pulses per second at a submotor intensity (enough to produce a tingling paresthesia). Polarity of the active electrode plays an important role. The positive electrode (anode) should be placed over the wound when debridement or epithelialization is the objective. The negative pole (cathode) is used to stimulate production of granulation tissue or to promote antimicrobial or antiinflammatory effects. Typically the wound is filled loosely with salinemoistened gauze, and an aluminum foil electrode, connected to an alligator clip lead wire, is used for conductivity. Make sure that the foil electrode is smaller than the moistened gauze so that no portion of the foil comes in contact with intact skin.
18. What is negative pressure wound therapy and how can it benefit an orthopaedic wound? Negative pressure wound therapy (NPWT) involves the application of a localized negative pressure to the wound and its margins through a special foam dressing. The dressing is placed in a wound cavity, or over a flap or graft, and is covered with an occlusive film drape. The sealed wound is then connected to a computerized vacuum pump that is set to provide between 75 and 125 mm Hg of negative pressure, either continuously or intermittently, for 48 hours. The system helps to remove fluid from the wound and promote granulation tissue development and wound contraction. There are limited randomized controlled studies on the effectiveness of NPWT in wound healing. A 2000 Cochrane review indicated that only 2 small trials with a total of 34 patients existed, and the studies provided weak evidence that NPWT was any better than saline-moistened gauze in promoting wound healing. Since this review, several additional studies with small sample sizes have attested to the benefits of NPWT in speeding the healing process. There are, however, in excess of 100 case reports attesting to the benefits of NPWT in wound healing. NPWT is a great asset to treatment of large skin defects often encountered with traumatic injuries to the extremities or to dehisced surgical wounds. It can be used in conjunction with external fixator devices to minimize dressing changes and accelerate healing.
19. Are any of the topically applied growth factors of benefit in wound healing? Two growth factor preparations commonly encountered in clinical practice are Procuren and Regranex. Procuren is a platelet-derived growth factor developed from a sample of the patient’s
246
Special Topics
own blood. It is marketed for use in the management of chronic nonhealing wounds, but insufficient research supports its effectiveness. The clinical practice guideline from the Agency for Health Care Policy and Research, “Treatment of Pressure Ulcers,” concludes that the effectiveness of growth factors has not been sufficiently established to warrant recommendation for use. Regranex (becaplermin) gel, on the other hand, is a recombinant form of platelet-derived growth factor. It has been approved by the Food and Drug Administration for patients with neuropathic ulcers. Controlled clinical trials have demonstrated the effectiveness of Regranex gel in improving the healing rates of diabetic foot ulcers.
Bibliography Berendt AR, Lipsky B: Is this bone infected or not? Differentiating neuro-osteoarthropathy from osteomyelitis in the diabetic foot, Curr Diab Rep 4:424-429, 2004. Gardner SE et al: Effect of electrical stimulation on chronic wound healing: a meta-analysis, Wound Repair Regen 7:495-503, 1999. Guyton G, Saltzman C: The diabetic foot: basic mechanisms of disease, J Bone Joint Surg (Am) 83A: 1084-1096, 2001. Kloth LC: Electrical stimulation for wound healing: a review of evidence from in vitro studies, animal experiment, and clinical trials, Lower Extremity Wounds 4:23-44, 2005. Kloth L, McCulloch J: Wound healing: alternatives in management, ed 3, Philadelphia, 2001, FA Davis. Krasner D, Rodeheaver G, Sibbald G: Chronic wound care: a clinical source book for healthcare professionals, ed 3, Wayne, Pa, 2001, HMP Communications. McCallon S et al: Vacuum-assisted closure versus saline-moistened gauze in the healing of postoperative diabetic foot wounds, Ostomy/Wound Management 46:28-29, 31-22, 34, 2000. McCulloch J: The integumentary system—repair and management: an overview, PT—Magazine Phys Ther 12:52-56, 58, 60-64, 2004. Patout C Jr et al: A decision pathway for the staged management of foot problems in diabetes mellitus, Arch Phys Med Rehabil 82:1724-1728, 2001. Sheffield P, Smith A, Fife C: Wound care practice, Flagstaff, Ariz, 2004, Best Publishing. Sinacore D: Total contact casting for diabetic neuropathic ulcers, Phys Ther 76:296-301, 1996. Sussman K, Bates-Jensen B, editors: Wound care: a collaborative practice manual for physical therapists and nurses, Gaithersburg, Md, 2001, Aspen.