In one of my previous articles, I wrote about the many possible goals of seating. This month, I would like to take a closer look at one goal in particular – skin protection.
I know that the people reading my articles have a wide range of experience and knowledge. Let’s start with the basics – this may be new information for some and a review for others.
What is a pressure ulcer? The International NPUAP-EPUAP definition is as follows: “A pressure ulcer is localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear. A number of contributing or confounding factors are also associated with pressure ulcers; the significance of these factors is yet to be elucidated” (European Pressure Ulcer Advisory Panel and National Pressure Ulcer Advisory Panel, 2009).
Pressure ulcers can be staged or categorized. In a Stage I pressure ulcer, the skin remains intact, but may feel either warmer or cooler to the touch. The tissue may feel either firm or soft and may be either painful or itchy. The skin will have a different colour in the area – persistent redness in lightly pigmented skin or persistent red, blue or purple hues in darker skin tones.
A Stage II pressure ulcer is a partial thickness skin loss, involving the epidermis, the dermis or both. The ulcer may look like a blister, an abrasion or a shallow crater.
A Stage III pressure ulcer is a full thickness skin loss. Subcutaneous fat may be visible, but muscle, tendon and bone are not visible. The ulcer may look like a deep crater.
A Stage IV pressure ulcer is a full thickness tissue loss, with exposed bone, tendon or muscle. There are also pressure ulcers that are unstageable because the depth of the ulcer is unknown due to the presentation of the wound bed.
So, we know what a pressure ulcer is and how they are staged. Let’s consider the contributing factors that are associated with pressure sores. We can divide them into extrinsic, or external, factors, and intrinsic factors.
Extrinsic factors include pressure, friction, shear, moisture and heat. So what is the difference between friction and shear? Friction is the surface resistance of the outer tissue layers due to skin sliding against a surface. Shear is the distortion of the tissue caused by the body being pulled in one direction against the static support surface, which stretches, thins, and kinks the blood vessels to occlude or reduce blood flow (Pratt, 2006). The way to differentiate pressure and shear is that pressure is the effect of gravity on the body in contact with a support surface in a perpendicular plane, while shear is the force on the body in contact with a support surface in a tangential direction.
The intrinsic factors associated with pressure sores include poor nutrition, incontinence, muscle atrophy, aging skin, orthopedic deformities, excessive body heat, impaired circulation and decreased cognitive status (e.g. client does not remember to shift weight on a consistent basis).
A therapist must be aware of a client’s level of risk of developing pressure sores as this knowledge will influence the generic seating product parameters that are appropriate for a particular client. The Braden Scale is one example of a tool to quantify someone’s level of risk of developing a pressure ulcer.
Some strategies to prevent the occurrence of a pressure ulcer include: daily skin inspection; regular weight shifting; ensuring the skin remains clean and free from moisture and heat build-up; and ensuring equipment is maintained. Skin must be inspected daily, particularly the areas most vulnerable to pressure ulcers, which include the ischial tuberosities, sacrum/coccyx, trochanters, heels, ankles, knees, scapulae and elbows. Weight shifting techniques allow the skin to be replenished with oxygen. Such techniques include the full push-up, side leaning and forward leaning. If a client is unable to perform effective weight shifts on a consistent basis, the use of either manual or power tilt systems for the wheelchair should be considered. A weight shift should be performed every 15 to 30 minutes (Consortium for Spinal Cord Medicine Clinical Practice Guidelines, 2000).
So, this month, I have talked about pressure sores, staging of pressure sores, factors associated with pressure sores and some prevention strategies. Next month, I plan to talk more about pressure reduction through seating and mobility. Until then, please feel free to provide your comments, questions and suggestions regarding Clinical Corner on my blog at www.clinical-corner.com.
Sheilagh Sherman, OT Reg. (Ont.)
Clinical Rehab Product Consultant
Consortium for Spinal Cord Medicine Clinical Practice Guidelines. (2000). Pressure Ulcer Prevention and Treatment Following Spinal Cord Injury: A Clinical Practice Guideline for Health-Care Professionals. Paralyzed Veterans of America.
European Pressure Ulcer Advisory Panel and National Pressure Ulcer Advisory Panel. (2009). Prevention and treatment of pressure ulcers: quick reference guide. Washington DC: National Pressure Ulcer Advisory Panel.
Pratt, S. (2006). Seating for Function & Mobility. A Clinical Perspective, Linking Clinical Thinking with Technology. Sunrise Medical Inc.