Understanding Skin Barriers
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The skin barrier is the most important part of the pouching system. It protects the peristomal skin, holds the ostomy pouch in place, and provides a level pouching surface. Ideally, a skin barrier should mirror the shape of the peristomal plane. Thinner more flexible, erosion-resistant skin barriers available over the past decade are facilitating more variety in shape, depth, and degree of convexity and flexibility. Understanding how ostomy adhesives and accessory products are designed and work will help clinicians provide patients with the best pouching options.
Solid skin barriers are made up of several ingredients (ie, tackifiers, polymers, softeners, plasticizers, hydrocolloids, fillers, and pigment).1 Although the recipe may be unique across brands, the ingredients are similar.
Tackifiers provide a skin barrier with the initial “stick”. The amount and type of tackifier can determine the stickiness, but not necessarily the length of use. “Stick” also is dependent on the pressure applied to the appliance. In simple terms, think of a Post-it® note — if tossed against the wall, it will not stick, but when pressed in place, it adheres. Therefore, skin barriers are considered pressure-sensitive adhesives and must come in complete contact with the skin to adhere.
Polymers provide the strong bond to the skin. When warmed to body temperature, the polymers in the barrier soften and flow onto the skin, filling in the creases and crevices of the skin surface to create a larger surface area on the skin for the barrier to adhere. This mechanism is referred to as heat-activated adhesion. Understanding the polymer mechanism can guide practitioner use of skin prep (or skin sealant) — ie, a liquid polymer with solvents that provide a smooth breathable plastic-like coating on the skin. Sometimes the prep appears very shiny on the skin surface, creating a smooth surface.
When skin stripping is a problem under tape adhesives, a skin protectant can be used; however, it may inhibit adhesion in terms of skin barrier flow. Thus, protectants are not recommended for use with many of the current skin barriers on the market.
Hydrocolloids provide absorption; they may consist of carboxymethylcellulose (CMC), pectin, and gelatin. Absorptive products manage the effects of perspiration and secretions in order to maintain appliance placement. An adhesive needs to have the ability to absorb the metabolic products secreted from the skin while maintaining adhesion, as well as provide a healthy acid mantel to avoid fungal and bacterial invasion.
Long chain rigid polymers used in extended-wear barriers may require softeners to maintain pliability along with erosion resistance. Fillers and pigments are minor compounds that complete the list of ingredients.
Cohesion, Flexibility, and Shape
Cohesion (the ability of the skin barrier to maintain its integrity when exposed to moisture) and flexibility are important in maintaining a protective seal, optimizing a healthy skin environment, and providing comfort. A product’s cohesion is a factor in how much residue is left on the skin after its removal as well as in the skin barrier’s ability to protect the skin, maintain a seal around the stoma, and not wash out. Extended-wear adhesives are more cohesive than standard wear adhesives; degree of cohesiveness differs between brands. A skin barrier that leaves residue on the skin may require solvents to remove adhesives, which can be undesirable. Cohesive products that address comfort as well as promote improved skin integrity and provide the security of a comprehensive adhesive should be considered.
To assess a skin barrier for flexibility, the protective backing should be removed.