Wound Care Basics

In the wound care community discussions often occur regarding the newest innovation or most current research studies, but in day-to-day practice a wound clinician will find themselves continually educating patients and other clinicians on the fundamentals of wound care. Almost weekly a patient will be thoroughly surprised as I explain to them that wounds should not be left open to dry. They often respond with a degree of anger, explaining that another healthcare professional advised them to do things like soak their diabetic feet or leave their wound open to air at night to “dry it out.” Explaining the reasoning behind avoidance of these types of interventions requires an understanding of the cellular biology and pathophysiology involved in the outcomes they influence. While each basic wound care practice has not only manuscripts, but book chapters and meta-analyses addressing it, the ability to explain these concepts in a concise manner at differing education levels allows the wound specialist to inform clinicians and patients alike, and spread the good word of evidence-based wound healing interventions.

The most frequent short educational explanations on the basics of wound care include not leaving wounds open to air, decreasing dressing change frequency, and avoidance of gauze dressings. A simple explanation is that wounds that are covered heal faster with less infection than wounds that are left open to air. White blood cells and healing cells need to be able to “swim around” in the wound to find bacteria and to heal. Most patients and providers understand that explanation.

Wound healing primarily occurs through granulation tissue formation and epidermal resurfacing: first the wounds fill in, then the edges creep across. Angiogenesis and extracellular matrix creation lead to granulation tissue formation in concert with epithelial cells including keratinocytes performing epidermal resurfacing by migrating centripetally until contact inhibition occurs.¹ These processes are facilitated in a moisture balanced wound. Leukocytes such as neutrophils and macrophages also require a moist wound environment to function optimally. When leukocyte migration is impaired bioburden in the wound increases as bacteria and necrotic debris are not cleared through phagocytosis.¹

Covering a wound with a protective dressing does more than maintain a moist wound environment. This is why dressings are generally indicated instead of simply using an occlusive ointment. While using ointments and barriers pastes as stand-alone wound treatments may be adequate for partial thickness wounds like Stage 1 and 2 pressure injuries and incontinence-associated dermatitis, it is generally avoided due to the added benefits dressings provide. These benefits include minimizing bacterial contamination, maintaining normothermia, and protecting wounds from trauma. Local hypothermia of the wound bed affects the chemical processes involved in healing, which include everything from the chemical reactions of enzymes to the production and use of growth factors. Local cooling at the wound bed also increases the risk for infection due to vasoconstriction and decreased migration and phagocytosis of leuokocytes.^1,2 When used over boney prominences dressings can also offload a small amount by dispersing the load throughout the dressing, and in some dressings absorbing shear as well.³

While some well-meaning patients and clinicians may feel that a gauze dressing can meet this purpose, gauze dressings are actually generally avoided for a number of reasons. Gauze does not protect the wound from bacterial contamination^2,4. We know that bacteria have been able to penetrate through over 60 layers of gauze⁵. Gauze also can contribute to inflammation in the wound environment by causing a foreign body reaction when fibers are retained. It is also unable to remove inflammatory wound fluids from the wound dressing interface. Newer dressings are able to hold drainage away from the wound bed, trapping bioburden including bacteria, proteases, and inflammatory cytokines away from the wound environment. Because gauze does not hold fluid away from the wound bed and periwound it must be changed at least daily. Frequent dressing changes expose the wound to potential bacterial contamination, contribute to trauma on healing tissues, cause hypothermia at the wound bed, and have negative cost and quality of life associations.^1-2,6

The seminal research on moist wound healing demonstrating expedited healing with dressings versus desiccation was published by Dr Winter in the journal Nature in 1962.⁷  Now, almost 60 years later, wound specialists are still often required to explain the need for advanced wound dressings to expedite wound healing, decrease infection rates, reduce pain, and facilitate better cosmetic outcomes. Wounds heal faster with less infection when they are covered appropriately.

References

1. Bryant R, Nix D. Acute & Chronic Wounds: Current Management Concepts, Fourth Edition. Elsevier. 2012.

2. Ovington LG. Hanging wet-to-dry dressings out to dry. Home Health Nurse. 2001;19(8):477-484. doi:10.1097/00004045-200108000-00007

3. de Wert LA, Schoonhoven L, Stegen JHCH, et al. Improving the effect of shear on skin viability with wound dressings. J Mech Behav Biomed Mater. 2016;60:505-514. doi:10.1016/j.jmbbm.2016.03.006

4. Cordrey R. Gauze, impregnated gauzes, and contact layers. Adv Skin Wound Care. 2012;1:120-125.

5. Lawrence JC. Dressings and wound infection. Am J Surg. 1994;167(1A):21S-24S. doi:10.1016/0002-9610(94)90006-x

6. Rippon M, Davies P, White R. Taking the trauma out of wound care: the importance of undisturbed healing. J Wound Care. 2012;21(8):359-368. doi:10.12968/jowc.2012.21.8.359

7. Winter GD. Formation of the scab and the rate of epithelization of superficial wounds in the skin of the young domestic pig. Nature. 1962;193:293-294. doi:10.1038/193293a0