The Effect of a High Endurance Polymeric Skin Protectant on Friction and Shear Stress

Background: Patients in health care environments, and especially those with limited mobility, are exposed to friction and shear stress when their skin comes in immediate contact with surfaces such as bedding, clothing, or wound dressings. Exposure to both can result in damage to the epidermis. The coefficient of friction (CoF) is a value obtained by dividing a frictional force by a normal force and is a commonly understood indication for friction. A value of zero implies that a frictional relationship is absent and increasing values imply stronger frictional relationships among surfaces. In general, the effects of friction may lead to undesirable partial-thickness skin injuries. Of greater concern, however, is the potential outcome when friction is combined with shear stress. Shear stress occurs when two surfaces undergoing continual frictional forces are further subjected to the force of gravity. Friction pins the skin to the contacting surface and the force of gravity causes the juxtaposed anatomical structures to apply planar pressure against the skin and subcutaneous tissue. The resulting motion compresses, twists, or stretches the blood vessels impacting blood flow that leads to tissue necrosis.

Conclusion: Reduction in frictional forces between the skin and stationary surfaces reduces the effect of shearing and the detrimental consequences. Friction is typically discussed in context of pressure injury or moisture-associated skin damage with focus on the effects of support surfaces or bedding. Many individuals at risk for pressure injury may also be incontinent. Prevention and treatment of incontinence-related skin injury (Incontinence-associated Dermatitis (IAD)) has traditionally utilized moisture barrier creams, ointments and pastes. While widely used, the impact of these topical products on frictional force has not been previously assessed or reported.

Conclusion: A high endurance polymeric skin protectant had significantly lower CoF suggesting that the skin protectant provides more protection against friction and shear-related events than traditional moisture barriers.