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New Wound Dressing Techniques to Accelerate Healing Christopher H. Moon, MD* Thomas G. Crabtree, MD, FACS Address *Department of Surgery, Tripler Army Medical Center, Tripler, HI 96859, USA. E-mail: [email protected] Current Treatment Options in Infectious Diseases 2003, 5:251–260 Current Science Inc. ISSN 1523-3820 Copyright © 2003 by Current Science Inc. Opinion statement The purpose of dressing a wound is to promote an optimal healing environment by providing pain relief, protection from trauma and infection, a moist environment, and removal of debris. By simultaneously maximizing the patient’s nutritional status and providing meticulous wound care, most wounds will heal appropriately. A simple occlusive dressing consisting of an antibacterial ointment (nonadherent and absorbent layers) and securing tape is normally all that is needed for acute and sutured wounds to heal. For more complex chronic wounds and burns, treatment should be tailored uniquely to the patient’s situation. Introduction Wounds can be divided into two types: acute and chronic. They can heal primarily, secondarily, or by delayed primary closure. Healing by primary intention involves the surgical apposition of the wound edges, usually with sutures. The healing process is hastened and scarring is usually minimized by allowing direct contact. However, when the wound is contaminated, primary closure results in infection. Delayed primary closure closes the wound surgically after allowing time to pass. The wound has the capacity to clear the contamination and begin healing after direct surgical closure when time is allowed for the inflammatory process and angiogenesis to begin. Wounds healing by secondary intention are usually not amenable to surgical closure. As a result, the wound is left to granulate and epithelialize from the wound bed and edges. Numerous dressing products were developed during the past few years to accelerate this type of healing process. In 1962, Winter [1] noticed a shortened epithelialization time for occluded pig wounds versus wounds left open to air. Cho and Lo [2••] report that occlusive dressings increase re-epithelialization rates by 30% to 50% and collagen synthesis by 20% to 60% compared to wounds exposed to air. They do this by providing an optimal healing environment that exposes the wound continuously to the surrounding fluid of proteinases, chemotactic factors, complements, and growth factors. An electrical gradient that may stimulate fibroblast and epithelial cell migration is maintained. In addition, o c c l u s i ve d r e s s i n g s p r ov i d e a p hys i c a l b a r r i e r against further trauma to the wound. Pain is decreased by maintaining a moist environment. The use of nonadherent dressing prevents the stripping of the newly formed epithelial layer. This environment simultaneously stimulates the growth of bacteria and shifts the usual flora to more gram-negative organisms; however, studies show that the incidence of clinical infection, demonstrated by cellulitis and lymphangitis, remains the same. Infection should not be diagnosed on wound culture only, but on clinical signs of warmth, erythema, local tenderness, and edema. Thus, wound colonization should be differentiated from wound infection. The management of a wound begins by identifying the overall well-being of the patient. Dressings and the various topical medications are a small part of healing a wound. The key to successful wound healing is meticulous wound care and the optimization of the body’s wound-healing capacity. Impairments to wound healing such as malnutrition, edema, bacterial contami- 252 Skin and Skin Structure Infections nation, ischemia, and immunosuppression must be minimized. Wound healing is anabolic; protein, vitamin, and mineral intake must be adequate. When these factors are controlled, attention can be focused on the local aspects of the wound. The first step for acute and chronic wounds is to adequately clean and debride the wound of all foreign bodies, fibrinous exudates, and devitalized tissue that impede healing and serve as a nidus for infection. Irrigation with normal saline should be adequate for acute wounds. Kaye [3•] reports that antiseptics such as providineiodine are toxic to fibroblasts and epithelial cells and should not be used on open wounds. Sharp mechanical debridement may be necessary to expose viable tissue for large areas of fibrinous exudates or eschar. Chemical debridement is useful for those areas that are difficult to access by sharp debridement. When debridement is complete, dressings can be applied. The occlusive dressing is divided into a hydrating layer (antibiotic ointments or petrolatum jelly), a nonadherent contact layer, an absorbent and cushioning layer (gauze), and a securing layer (tape or wrap). A simple occlusive dressing composed of Polysporin ointment (bacitracin zinc, polymyxin B sulfate [Pfizer, New York, NY]), a nonadherent Telfa dressing (The Kendall Company, Mansfield, MA), and an absorbent layer of gauze secured with hypoallergic tape such as Hypafix (Smith and Nephew, London, UK) usually suffices for acute and sutured wounds. Alternatively, a polymer film such as Opsite (Smith and Nephew, London, UK) or Tegaderm (3M Pharmaceuticals, St. Paul, MN) provides occlusiveness and fixation. They are semipermeable to water vapors and oxygen but impermeable to liquids. Thus, a nonadherent Telfa, an absorbable gauze dressing, and Tegaderm on a sterile postoperative wound or a layer of Polysporin, absorbable gauze, and Tegaderm is appropriate. Although it is controversial whether topical antibiotics are effective prophylaxis of infection in superficial wounds, studies indicate that application of topical antibiotic ointment helps maintain a moist wound environment, decreases bacterial counts, and prevents dressing adherence to the wound site. Systemic antibiotics have no role in the management of wounds unless there is evidence of cellulitis or sepsis. For superficial burns treated on an outpatient basis, silver sulfadiazine can be used instead of Polysporin. Occlusive dressings should be applied within 2 hours of wounding and left on for at least 24 hours for optimal healing to occur for acute wounds. At Tripler Army Medical Center, the dressing is removed after 24 to 48 hours. Occlusive dressings should never be used on clinically infected wounds. Dressing changes can be performed once or twice daily if using the topical ointment and Telfa dressing. The wound should be cleaned gently with saline or tap water, but antiseptics should not be used. If other types of occlusives are used, the timing of the dressing changes will vary between 1 to 7 days, depending on the wound characteristics. An early attempt to switch from antibiotic ointment to petrolatum helps minimize hypersensitivity to the antibiotics. Smoking delays healing and should be strongly discouraged. Small and simple lacerations and wounds that require few epidermal sutures may be alternatively apposed with tissue adhesives consisting of octyl-2cyanoacrylate, such as Dermabond (Ethicon Inc., Cornelia, GA). When Dermabond is used, there is no need for topical agents and fluid contact can be immediate. Arpey and Whitaker [4] report that there is little need for additional wound care. Dermabond gradually falls off as the wound heals. Chronic wounds are defined as wounds that fail to heal after 3 months. Venous stasis ulcers, diabetic ulcers, pressure ulcers, and ischemic ulcers are the most common. Many of the new dressing products on the market are aimed at healing these wounds. The plethora of options for treating chronic ulcerations cannot be discussed adequately in this article. However, many of the dressing options that attempt to heal venous stasis ulcers are a variation on the classic paste compression bandage Unna’s boot. Ladin [5] reports that there is some evidence to suggest that products such as Regranex (Ortho-McNeil Pharmaceutical, Raritan, NJ) may be effective in healing clean-based lower extremity diabetic ulcers. However, most evidence suggests that the use of these adjuncts is no better than meticulous wound care. The definitive treatment for these wounds is optimization of the wound bed for closure. However, overall patient and local wound conditions often prevent using this option. These wounds can sometimes have large amounts of exudates that require frequent debridement. Alginates, foams, and other absorptives can be used in this situation. Because chronic wounds heal by slightly different mechanisms than those of acute wounds, experimentation with growth factors are being investigated. Regranex and Procuren (Curative Health Services, Inc., Hauppauge, NY) are the only medications approved by the US Food and Drug Administration (FDA). More studies are needed to determine the benefit of growth factors. The most significant wound-healing device of the past few years may be the wound VAC (vacuum-assisted closure). The VAC accelerates the healing of chronic wounds. The machine uses a closed foam dressing system connected to an adjustable vacuum device that exposes a wound to negative pressure. Theoretically, experimentally, and practically, this allows increased tissue perfusion while decreasing wound debris and lowering bacterial count. Initial wound hypoxia is important for fibroblast proliferation and angiogenesis; however, continued hypoxia at the wound site delays wound healing. As a New Wound Dressing Techniques to Accelerate Healing Moon and Crabtree result, if an occlusive dressing is applied to an ischemic wound, healing is severely impaired. Hyperbaric therapy has become popular to help accelerate healing of chronic ischemic wounds such as those associated with chronic venous insufficiency and other wounds that are not amenable to revascularization surgery. Because of increasing technologic advances in creating skin substitutes, it is important to mention burns briefly. Most small partial-thickness burns can be managed on an outpatient basis using the occlusive dressing techniques described earlier. However, larger wounds that are not autografted, allografted, or xenografted can be managed with cellular wound dressings such as Integra (Johnson & Johnson, New Brunswick, NJ), TransCyte (Smith and Nephew, London, UK), and Apligraf (Organogenesis Inc., Canton, MA). These materials are not skin equivalents because they lack hair follicles, glands, nerves, and blood vessels. However, they try to mimic closely the protective and healing function of the epidermis and dermis. Some become permanently incorporated into 253 the wound and others are temporary. Kearney [6] reports that a few, such as Apligraf, have been used on chronic ulcers with limited success. In conclusion, few of the hundreds of dressing adjuncts on the market accelerate wound healing. In most cases, the use of these adjuncts is no better than the standard treatment of optimizing the patient’s nutritional status, meticulous wound care, and maintaining a moist wound environment. The use of negative pressure dressings (wound VAC) seems especially promising for chronic wounds. The future of fullthickness burns and problematic nonhealing chronic wounds is not in adjuncts that aid in the body’s reparative process but in adjuncts that aid in the body’s regenerative process. ACKNOWLEDGMENTS The views expressed in this abstract/manuscript are those of the author(s) and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US Government. Treatment Lifestyle factors and prevention • Meticulous wound care includes adequate cleansing, debridement, edema control, and prevention of ischemia, in addition to maintaining a moist wound environment and keeping the bacteria count as low as possible [7•]. • Impairments to wound healing include malnutrition, obesity, edema, bacterial contamination, and ischemia [8]. • Maximize nutritional status [9]: – Maintain serum protein (albumin > 3.0). – Vitamin A: Topical or systemic; fat soluble. 25,000 IU orally four times a day or 200,000 IU ointment three times daily. Necessary for fibroplasia, collagen cross-linking, and epithelialization. – Vitamin C: Necessary as cofactor for hydroxylation of proline and lysine in collagen synthesis and cross-linking. No set recommended daily allowance. May reverse glucocorticoid inhibition. – Essential fatty acids. – Zinc: Important cofactor; necessary for normal lymphocyte function and resistance to infection. – Copper: Cofactor of lysyl oxidase; necessary for collagen cross-linking. • There is no evidence to support the idea that megadoses of vitamins and minerals will accelerate healing. Excessive fat-soluble vitamin ingestion can lead to problems (ie, vitamin A). Procedures • Debridement (sharp, chemical, mechanical-washing, whirlpools, water irrigation) to clear fibrinous exudates and devitalized tissue that impedes healing and serves as a nidus for infection. 254 Skin and Skin Structure Infections • Chemical debridement: – Collagenase: Used directly on chronic wound bed. Removed with saline irrigation. If left on for prolonged periods, it may damage new epithelium. Conforms to irregular contours on wound and is useful for debriding areas not amenable to sharp mechanical debridement. – Streptokinase/streptodornase: Debridement equivalent to zinc oxide/ gauze at 8 weeks. – Trypsin: No more effective than mechanical gauze debridement. – Papain/urea: Measurable debridement in 4 days. – Maggots: Renewed interest. Useful for removing necrotic tissue while leaving healthy tissue intact. Especially useful when antibacterialresistant pathogens are present [10]. Topical agents Antiseptics Chlorhexidine, providine-iodine, alcohol, hydrogen peroxide, triclosan Indications Because of tissue toxicity, no use in the management of open wounds. Antibacterials Bacitracin, mupirocin, silver sulfadiazine, neomycin, polymyxin, honey inhibine [3•] Indications Used as prophylaxis of infection at epidermis and superficial dermis. Ointment matrix serves to maintain moist wound environment. Burns (silver nitrate compresses, chlorhexidine gluconate, mafenide acetate cream 0.5%, providoneiodine, nitrafurazone, silver sulfadiazine). Application Concurrent with each dressing change. Contraindications Allergic reactions. Complications Usually without risk of systemic toxicity. Local adverse effects include contact dermatitis (ie, neomycin is as high as 34%). Application of silver sulfadiazine has been associated with neutropenia in a small number of patients. Special points Use is controversial. Bacitracin zinc is extremely popular because of low cost, low toxicity, and low allergic contact dermatitis. Relatively safe; topical antibiotics have low systemic absorption. Cost effectiveness Inexpensive. A 15-g tube of bacitracin costs $0.59. Growth factors • Regulates cell proliferation, migration, and secretion. CT-102 (Procuren; Curative Health Services, Inc., Hauppauge, NY) Indications Chronic wounds. Composition Autologous platelets are extracted and activated. Resulting supernatant-containing platelet-derived growth factors reapplied to the wound. Application Directly on healthy granulating wound bed, secured with occlusive dressing. Change dressing twice daily but apply growth factor for 12 hours only. Contraindications If patient cannot tolerate autotransfusion. Malignancy. Complications Transfusion-related. Special points Available only through wound centers operated by Curative Health Services of Hauppauge, NY. Cost effectiveness Expensive. Specific amount contracted to each health center. New Wound Dressing Techniques to Accelerate Healing Moon and Crabtree 255 Becaplermin (Regranex; Ortho-McNeil Pharmaceutical, Raritan, NJ) [5] Indications Clean based diabetic wounds up to 5 cm2. Approved by the FDA for clean diabetic forefoot ulcers only. Composition Recombinant platelet-derived growth factor. Application Directly on healthy granulating wound bed. Secured with occlusive dressing. Change dressing twice daily but apply growth factor for 12 hours only. Continue for 20 weeks or until wound has healed. Contraindications Hypersensitivity to materials. Malignancy. Complications Nonhealing. Special points All studies conducted with meticulous wound care. Wounds healed 4 to 6 weeks faster. Rate of recurrence is significant; approximately 30% at 3 months. Cost effectiveness A 30-g tube costs approximately $300 to $400. Dressings • No dressing is effective if basic wound care is not adhered to. • Occlusive. Polymer films Bioclusive (Johnson & Johnson, New Brunswick, NJ), Polyskin II (The Kendall Company, Mansfield, MA), Opsite (Smith and Nephew, London, UK), Tegaderm (3M Pharmaceuticals, St. Paul, MN) Indications Acute partial- or full-thickness wounds with minimal exudates. Nondraining primarily closed wounds. Good for catheter sites, first- and second-degree burns, grade 1 decubitus ulcers, graft donor sites. Composition Semiocclusive/semipermeable polyurethane or copolyester, approximately 0.2 mm thick. Application Directly over the wound with a layer of gauze or antibiotic ointment underneath. Contraindications Hypersensitivity to the adhesive backing. Complications Sometimes difficult to apply because of adhesive backing and must adhere to 1 to 2 cm on healthy skin. Not good for wounds with large exudates or serous fluid. May strip new epithelium in adhesive backing allowed to come in contact with wound base. Special points Elastic and transparent; allows continuous inspection of the wound. Permeable to gases and water vapor but impermeable to bacteria and liquids. Cost effectiveness Relatively inexpensive. The cost is a few dollars per package of sheets. Polymer foams Allevyn (Smith and Nephew, London, UK ), Flexzan (Bertek Pharmaceuticals, Morgantown, WV), Lyofoam (Acme United Corp, Fairfield, CT), Sof-Foam (Johnson & Johnson, New Brunswick, NJ) Indications Acute or chronic partial-thickness wounds with large exudates that require mechanical debridement. Good for chronic venous stasis ulcers and deep cavity wounds. Composition Hydrophilic or hydrophobic, semiocclusive. Bilaminate. High absorbency. Polyurethane or gel film coated. Application Place on wound bed with or without antibacterial ointment or hydrogel. Then secure in place with tape. Once exudates are minimal, create occlusive dressing. Contraindications Hypersensitivity to materials. Complications Opaque. Cannot be applied to dry wounds. Must be changed at least every 3 days or it could be incorporated into the wound. Special points Permeable to fluids and gases. Nonadherent, thus requires a securing layer. Can be form fitted. Cost effectiveness A 4 × 4 inch sheet of Allevyn costs $3. 256 Skin and Skin Structure Infections Hydrogels Carrasyn (Carrington Laboratories, Inc., Irving, TX), Intrasite (Smith and Nephew, London, UK), Lamin (ProCyte Corporation, Redmond, WA), Nu-gel (Johnson & Johnson, New Brunswick, NJ), Vigilon (Bard Home Health, Murray Hill, NJ) Indications Acute or chronic partial-thickness wound with minimal exudates. Good for dermabrasion, superficial burns, and chronic ulcers with decreased exudates. Composition 80% to 99% water. Cross-linked polymers (polyethleneoxide, polyvinyl pyrrolidone, acrylamide). Application Applied onto wound bed usually in conjunction with a topical antibiotic. Then securing layer applied. Contraindications Hypersensitivity to materials. Complications Poor barrier protection against bacteria. Selects gram-negative bacteria colonization. Special points Semitransparent. Can absorb significant fluid volume without significant increase in size. Semipermeable to fluids and vapors. Nonadherent to wound base. Requires a securing layer. Substantial pain relief because of cooling effect of materials. Frequent dressing changes required every 1 to 3 days, depending on amount of exudates. Cost effectiveness Inexpensive. Nu-gel costs $2 to $4 per 30-g tube. Hydrocolloids Comfeel (Coloplast, Humlebaek, Denmark), Cutinova (Beiersdorf-Jobst, Hamburg, Germany), DuoDERM (ConvaTec, Princeton, NJ), Intrasite (Smith and Nephew, London, UK), Replicare (Smith and Nephew, London, UK), Hyprapad (Beiersdorf-Jobst, Hamburg, Germany) Indications Acute or chronic partial- or full-thickness wounds. Good for stage 1 to 3 decubitus ulcers and chronic venous stasis ulcers. Also used for plaque psoriasis, bullous disorders, burns, and dermabrasions. Composition Hydrophilic colloidal particles in an adhesive mass. Outer polyurethane foam, middle gelling agent such as sodium carboxymethyl cellulose, and an inner adhesive layer. Application Can be applied directly to wound. Perform dressing changes every 3 to 7 days. Saline irrigation cleans colloidal layer. Contraindications Hypersensitivity to materials. Cannot be used over eschars or over exposed tendons. Complications New epithelium may still be removed by the adhesive backing if gelling agent is not completely transformed to viscous layer. May overhydrate the wound to cause macerations. Gel is odiferous and can be confused with purulent discharge. Special points Impermeable to liquids and vapors. Can be cut and shaped without the need for a securing layer. Absorbs moderate wound exudates forming a viscous, colloidal layer that prevents wound adherence to the adhesive. Impregnated enzymes chemically debride wound. Cost effectiveness DuoDERM costs $10 per 4 × 4 inch sheet and $20 per 10 × 10 inch sheet. Alginates Algosteril (Johnson & Johnson, New Brunswick, NJ), AlgiSite (Smith and Nephew, London, UK), Kaltostat (ConvaTec, Princeton, NJ), Sorbsan (Bertek Pharmaceuticals, Morgantown, WV) Indications Acute postoperative wounds that require hemostasis. Good for wounds with moderate exudate, chronic ulcers, partial- and full-thickness burns, split-thickness skin grafts. Composition Polysaccharide dressing derived from seaweed. Packaged as twisted fibers or nonwoven mats. Application Directly on wound bed and secured with a fixation layer. Can be left for 7 days or when wound is soaked. Saline irrigation used to remove gel during dressing changes. Contraindications Hypersensitivity to materials. Thyroid abnormalities. New Wound Dressing Techniques to Accelerate Healing Moon and Crabtree 257 Complications Secondary dressing layer must be used to prevent dessication. May be odiferous and can be confused with purulent discharge. New epithelial layer can be stripped if the gel is allowed to dessicate and is removed. Special points Forms an alginate gel when combined with wound exudate, creating an occlusive, nonadherent, moist environment. A securing layer must be applied. Hemostatic. Cost effectiveness AlgiSite costs $20 to $30 per 4 × 4 inch sheet. Impregnates Aquaphor-Gauze (Beiersdorf Jobst, Hamburg, Germany), Adaptic (Johnson & Johnson, New Brunswick, NJ), Biobrane (Bertek Pharmaceuticals, Morgantown, WV), Scarlet Red (The Kendall Company, Mansfield, MA), Xeroform (The Kendall Company) Indications Acute or chronic partial-thickness wounds with minimal to moderate exudate. Good for burns and split-thickness donor sites. Composition Fine mesh gauze impregnated with moisturizing, antibacterial, or bactericidal compounds. Nonadherent. Application Direct contact with wound bed. Contraindications Hypersensitivity to materials. Complications Sometimes adheres through fibrous bonds, which damages re-epithelialization and delays healing. Increased infection rate compared to other occlusive dressings. Will not adhere to full-thickness wounds. Special points Does not contain adhesive, but sometimes adheres to wound site by creating fibrous bonds. Cost effectiveness Biobrane is expensive. All others inexpensive. Adaptic costs less than $1 per 3 × 3 inch sheet. Scarlet Red costs $10 to $15 dollars for 12 sheets (5 x 9 inch). Absorptive powders and pastes Cutinova (Smith and Nephew, London, UK), Polywic (Ferris Manufacturing Corp., Burr Ridge, IL), Bard Absorption Dressing (Bard Home Health, Murray Hill, NJ), DuoDERM Granules (ConvaTec, Princeton, NJ) Indications Chronic full-thickness wounds with large exudates. Composition Starch, copolymers, or colloidal hydrophilic particles. Can absorb up to 100 times their weight in fluid. Application Placed directly on the wound bed. Securing layer must be applied. Contraindications Hypersensitivity to materials. Complications Has potential to macerate tissue if left on too long. Special points High absorbancy. Fibrinolytic. Cost effectiveness Cutinova costs $15 to $20 for a 6 × 8 inch box of three. Skin substitutes, synthetic/biosynthetic Integra (Johnson & Johnson, New Brunswick, NJ) Indications Bovine collagen, shark cartilage; matrix used for partial- and full-thickness burns. Special points Two-layer membrane. Top layer is a peelable silicone layer-simulating epidermis. Bottom layer is absorbed by the body and becomes permanently incorporated into the wound. Cell free. Dermagraft (Smith and Nephew, London, UK) Indications Nonimmunogenic neonatal fibroblast on polyglactin mesh. Used for burns. Special points Has been used experimentally with diabetic foot ulcers. 258 Skin and Skin Structure Infections OrCel (Ortec International, New York, NY) Indications Fibroblasts layered onto bovine collagen matrix. Used for burns and epidermolysis bullosa. TransCyte (Smith and Nephew, London, UK) Indications Shipped frozen for use on partial- and full-thickness burns. Composition Dual layer, synthetic epidermal layer with dead fibroblasts layered onto a nylon mesh. Standard procedure Temporary covering; trim away as wound heals. Skin substitutes, biological Apligraf (Organogenesis Inc., Canton, MA) Composition Dermis-like matrix from cultured heterogenous human foreskins and bovine collagen type 1. Has epidermal and dermal components. Indications Used for diabetic venous ulcers and burns. Special points Permanently applied. Body absorbs matrix. Short shelf-life. Cost effectiveness High cost. $1000 per 7-cm circle. Mediskin I (Brennan Medical Inc., St. Paul, MN) Composition Porcine xenograft. Contraindications Contraindicated in patients with pork allergies. Special points Adjunct to granulating tissue. Occlusive biological dressing that may be left on wound for 7 to 10 days without wound care. Can become malodorous. Must be secured in place with sutures. Applied until granulating bed develops, then other occlusive methods should be used. Oasis (Cook Biotech, West Lafayette, IN) Composition Porcine, small-intestine submucosal dressing. Special points Longer shelf-life because it is dehydrated. Rehydrate when needed. A secondary dressing is needed to prevent desiccation. Alloderm (LifeCell Corp., Branchburg, NJ) Composition Allogenic human dermal matrix. Preserved by freeze-drying. Cell free. Biological and synthetic matrix, may have cells. Indications Partial- and full-thickness burns. Some diabetic and venous stasis ulcers. Most used as a temporary measure until definitive treatment with autograft [11]. Application Directly on wound. Contraindications Hypersensitivity reactions. Complications Materials are made from animal and human products that may transmit diseases and cause hypersensitivity reactions. Polymyositis/dermatomyositis are rarely seen. Special points Not very efficacious on chronic wounds. Cost effectiveness Cost variable but all are relatively expensive and range from $50 to $500. New Wound Dressing Techniques to Accelerate Healing Moon and Crabtree 259 Other treatments Tissue glue Dermabond (Ethicon Inc., Cornelia, GA) Indications Small, simple lacerations and wounds that require 5-0 or smaller epidermal sutures. Composition Octyl-2-cynaoacrylate. Application If deep dermal sutures are required, place topically with epidermis apposed evenly after dermal sutures are placed. Contraindications Large wounds and lacerations. Infected wounds. Hypersensitivity to material. Mucosal surfaces or mucocutaneous junction (oral cavity, lips). Complications If wound becomes infected, glue is difficult to remove and does not allow for wound exploration without removal of glue. Special points Requires no further wound care. Application is not painful in contrast to sutures. Cost effectiveness More expensive than sutures. Hyperbaric therapy • Raises PO2 tension in chronic ischemic wounds. Increased usage with diabetic foot ulcers and irradiated wounds. Wound vacuum-assisted closure Indications Constantly evolving. Used for chronic ulcers, pressure sores, sternal wound breakdown, skin graft dressing, and flap salvage [12]. Composition Special wound vacuum pump. Silastic hose. Foam. Transparent film. Application Fit and apply wound form into wound cavity, cover with air-tight transparent film, connect to low-suction vacuum machine through a silastic hose. Empty effluent container as needed. Change foam every 2 to 7 days as needed. Contraindications Malignancy in wounds. Exposed vessels. Fistulas. Complications Some wounds fail to close. Skin irritation at site where foam overlies normal tissue. Hypersensitivity to components such as polyurethane sponge or adhesive to transparent film. Special points Monitor patients carefully if anticoagulated or if patient has wound that drains copiously. Cost effectiveness The vacuum pump costs $67.50 per day to rent. The dressings cost $25 to $40 per change. Emerging therapies • Growth factors: Topical epidermal growth factor, fibroblast growth factors used in conjunction with split-thickness skin grafts. Granulocyte colonystimulating factor used in chronic wounds. Interleukin 1 used in infected wounds. Transforming growth factor used for neovascularization, reepithelialization, reduced scar formation, and increased collagen deposition. Vascular endothelial growth factor promotes angiogenesis. • Skin equivalents: From embryonic stem cells. • Proteinase inhibitors: Used to improve healing in chronic ulcers. • Gene therapy: Provide important relevant healing genes directly to wound site. 260 Skin and Skin Structure Infections References and Recommended Reading Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance 1. Winter GD: Formation of the scab and rate of epithlialisation of superficial wounds in the skin of the young domestic pig. Nature 1962, 193:293–294. 2.•• Cho CY, Lo JS: Excision and repair: dressing the part. Dermatol Clin 1998, 16:25–47. This study provides a general overview on wound healing and dressings. 3.• Kaye ET: Topical antibacterial agents. Infect Dis Clin North Am 2000, 14:321–339. This is a fairly comprehensive report on the use of topical antibiotics, antiseptics, and wound healing. 4. Arpey CJ, Whitaker DC: Postsurgical wound management. Dermatol Clin 2001, 19:787–797. 5. Ladin D: Becaplermin gel (PDGF-BB) as topical wound therapy. Plast Reconstr Surg 2000, 105:1230–1231. 6. Kearney JN: Clinical evaluation of skin substitutes. Burns 2001, 27:545–551. 7.• Thomas DR, Kamel HK: Wound management in postacute care. Clin Geriatr Med 2000, 16:783–804. This article discusses chronic wound management. 8. Harding KG, Morris HL, Patel GK: Healing chronic wounds. BMJ 2002, 324:160–163. 9. Reynolds TM: The future of nutrition and wound healing. J Tissue Viability 2001, 11:5–13. 10. Natarajan S, Williamson D, Stiltz A, et al.: Advances in wound care and healing technology. Am J Clin Dermatol 2000, 1:269–275. 11. Balasuramani M, Kumar TR, Babu M: Skin substitutes: a review. Burns 2001, 27:534–544. 12. Hopf HW, Humphrey LM, Puzziferri N, et al.: Adjuncts to preparing wounds for closure: hyperbaric oxygen, growth factors, skin substitutes, negative pressure wound therapy. Foot Ankle Clin 2001, 6:661–682.