Assessing and Managing a Moist Wound Environment

AUTHOR:
Keith G. Harding, MB, MRCGP, FRCS
University of Wales

CITATION: 
Harding KG. Assessing and managing a moist wound environment. Consultant. 2012;52(3):214.

Chronic wounds are notorious for copious exudate production. Too much exudate can inhibit wound repair and cause periwound maceration because chronic wound fluid can break down extracellular matrix proteins and growth factors, prolong inflammation, inhibit cell proliferation, and potentially degrade the wound tissue matrix.^1,2

However, maintaining a moist wound environment can improve collagen synthesis and granulation tissue; hasten cell migration and epithelialization; temper the formation of crust, scabs, and eschar; and, compared to dry wounds, lessen infection rates and pain during dressing wear and removal.^3,4

CLINICIAN OPTIONS

Control exudate levels. The first approach to maintaining an appropriately moist wound environment is to manage the exudate level according to wound etiology. This can be accomplished through cleansing to remove cellular debris and bacteria; implementing compression therapy, when indicated, to improve venous return and reduce edema; and by debriding, even though removing necrotic tissue can increase exudate levels.

Select the dressing. Occlusive dressings prevent wound desiccation by containing the wound’s natural moisture and inhibiting or lowering the wound’s moisture vapor transmission rate.⁵ These dressings have been found to increase cell proliferation and activity by retaining vital proteins and cytokines contained within the wound exudate produced in response to injury.⁶

Once feared to increase infection risk because they sealed nonhealing as well as healing agents into the wound, occlusive dressings were shown in numerous studies⁷ to maximize the natural bacteriostatic and bacteriocidal components of wound fluid; plus, neutrophils attracted to the moist wound surface help provide a barrier to external organisms.

Under moist conditions revascularization occurs earlier in the wound healing process.⁸ Occlusion is thought to enhance the concentration of matrix metalloproteinases, which play an important role in all phases of wound healing.⁹

Occlusive dressings are available in a number of forms and can be infused with medications such as
silver and steroids to enhance wound healing potential in appropriate patients.

Alginates. Alginates are polysaccharide dressings that utilize wound exudate to form a gel in order to maintain a moist environment. Depending on the secondary dressing used, these dressings can dry out like gauze, causing re-injury and pain upon removal.⁵

Films. Because they are not absorbent, transparent polyurethane films are used in low-exudating wounds.⁵

Foams. Foams can be used to manage deep, highly exudative wounds and require a secondary bandage for securement.⁵

Hydrogels. Hydrogels can comprise up to 96% water; these three-dimensional networks of cross-linked hydrophilic polymers interact with the wound by swelling. Most are nonadherent and require a secondary dressing, which will impact their moisture vapor transmission rate. They do not provide a good bacterial barrier. In addition to their use in the management of chronic wounds, hydrogels are used for partial-thickness burns and donor sites.⁵

Hydrocolloids. Hydrocolloids were derived from materials used in ostomy products—a combination of elastomeric, adhesive, and gelling agents. The moist healing environment under hydrocolloids is impermeable to moisture vapor and gases. These dressings do not require a secondary cover, but the residue they leave must be removed, sometimes at risk to the nascent epithelium.⁵ 

Professor Keith Harding is a Professor of Rehabilitation Medicine (Wound Healing) and the Director of the Wound Healing Research Unit at the University of Wales, College of Medicine.

REFERENCES:

1. Falanga V, Grinnell F, Gilchrist B, et al. Workshop on the pathogenesis of chronic wounds. J Invest Dermatol. 1994;102:125-127.

2. Trengrove NJ, Stacey MC, MacAuley S, et al. Analysis of the acute and chronic wound environments. Wound Rep Regen. 1999;7:442-452.

3. Winter GD. Formation of a scab and the rate of epithelialization of superficial wounds in the skin of the young domestic pig. Nature.1962;193:293-294.

4. Jones V, Harding K. Moist wound healing. In: Frasner DL, Rodeheaver GT, Sibblad RG (eds). Chronic Wound Care: A Clinical Sourcebook for Healthcare Professionals. 3rd ed. Wayne, PA: HMP Communications; 2011:245-252.

5. Helfman T, Ovington L, Falanga V. Occlusive dressings and wound healing. Clin Dermatol.1994;12:121-127.

6. Jones V, Harding K. Moist wound healing: optimizing the wound environment. In: Krasner DL, Rodeheaver GT, Sibbald RG (eds). Chronic Wound Care: A Clinical Sourcebook for Healthcare Professionals. 4th ed. Malvern, PA: HMP Communications; 2007:199-204.

7. Buchan IA, Andrews JK, Lang SM, et al. Clinical and laboratory investigation of the composition and properties of human skin wound exudate under semipermeable dressings. Burns. 1980:7:326-334.

8. Dyson M, Young S, Pendle CL, Webster DE. Lang SM. Comparison of the effects of wet and dry conditions on dermal repair. J Invest Dermatol. 1988;91(5):434-439.

9. Chen WY, Rogers AA, Lydon MJ. Characterization of biologic properties of wound fluid collected during early stages of wound healing. J Invest Dermatol. 1992;99(5):667-672.