Cath Lab Digest

The superficial layer of the skin, the stratum corneum, provides a protective barrier. This layer consists of keratin-filled corneocytes organized in a matrix of highly ordered multilamellar lipid sheets, described as a brick wall-like structure (the corneocytes forming the bricks and the intercellular lipids representing the mortar).¹ If the stratum corneum breaks down, the barrier function of the skin is impaired, a risk factor associated with the formation of pressure ulcers.^2,3

Factors that can impair barrier function include irritants, moisture, abrasion, and biological influences that result in dry, compromised skin. Patients with incontinence are at particular risk for barrier impairment. If untreated or poorly managed, incontinence will impair the barrier, predominately due to skin maceration but also as a result of irritants and abrasion from bed linens. A review article on current practices and principles for skin care of frail, elderly, dependent, patients with incontinence⁴ reported that fecal incontinence is a greater risk factor for skin breakdown than urinary incontinence. Another review, published by the Canadian Association of Wound Care,⁵ indicated that maceration of the skin via fecal or urinary incontinence causes skin breakdown and pressure ulcers and included 12 recommendations for best practices in the prevention and treatment of pressure ulcers that focus on an interdisciplinary, patient-centered approach.

Managing patients with incontinence commonly involves skin protectant use. An understanding of diaper dermatitis and its treatment in infants⁶ has yielded valuable information regarding incontinence dermatitis.^6,7 Irritant diaper dermatitis (IDD), a form of contact dermatitis, occurs in the diaper area as a consequence of disrupting the skin’s barrier function through prolonged contact with feces and urine. The available evidence⁸ suggests that maceration of the stratum corneum by water increases susceptibility to frictional damage and epidermal permeation of irritants. The most important irritants underlying IDD are the proteolytic digestive enzymes persisting in feces, particularly when activated by the high pH of urine. The stratum corneum barrier itself is broken down further by ceramidase enzymes secreted by Candida spp. and Staphylococcus aureus. The ensuing penetration of endotoxin activates the inflammatory response.

Barrier preparations are used to protect the skin by coating the surface of the skin and/or by supplying lipids that can penetrate the intercellular spaces of the stratum corneum. Effective products may contain barrier lipids, enzyme inhibitors, antimicrobial agents, inflammatory agents, and a physical barrier such as clay or zinc oxide to prevent undesirable microbes from binding to the skin; thereby, preventing dermatitis. However, the barrier should not be overhydrated through the addition of strong humectants because the skin’s barrier in both diaper dermatitis and elderly incontinence dermatitis is already overhydrated, which leads to rapid maceration.

Studies have shown that a good protocol of care can reduce the risk of pressure ulcers.^9,10 This underscores the fact that barrier products are an important component of care for the prevention of pressure ulcers and skin breakdown.