Pressure, friction and shear
Recommendations
| Identify and Treat the Cause | ||
|---|---|---|
| 1 | Understand the role of mechanical forces, such as pressure, friction and shear in the development of pressure ulcers. | Level of Evidence Not Assessed |
| Address Patient-Centered Concerns | ||
|---|---|---|
| 2 | Inform and educate patients about the avoidance of mechanical forces to prevent the development of pressure ulcers | Level of Evidence Not Assessed |
| Provide Local Wound Care | ||
|---|---|---|
| 3 | Use appropriate moisture balance-dressings that minimize friction and shear | Level of Evidence Not Assessed |
| Provide Organizational Support | ||
|---|---|---|
| 4 | Educate and empower an interprofessional team to avoid pressure, friction and shear | Level of Evidence Not Assessed |
Background
Pressure ulcers are not due to pressure alone, but to the interaction of mechanical forces involved in the development of pressure ulcers are pressure, friction and shear.• Pressure: An external perpendicular force causing compression and distortion of soft tissue between two less compressible surfaces, such as a bony prominence and a firm mattress. External pressure exceeding the capillary pressure results in blood vessel occlusion and decreased tissue perfusion. A sustained disruption of blood flow leads to ischemia and tissue death.
Pressure ulcers are most likely to develop in tissue over bony prominences. Ulcers that develop in other parts of the body are usually due to an object, such as a catheter, or to poorly positioned extremities in an individual with severe contractures. Using bed and wheelchair support surfaces with low interface pressures, individualized turning schedules, and appropriate supports, such as pillows and foam wedges, can greatly reduce the incidence of pressure ulcers.
• Friction: A force generated by the movement of two surfaces across each other, such as skin moving over bed linens. Friction can result in abrasions and removal of superficial layers of skin.
Damage due to friction is most commonly caused by poor lifting techniques and voluntary or involuntary patient movements, especially on the elbows and heels. The potential for friction damage can be reduced by preventing this contact or by reducing friction between the skin and the surface of the bed.
• Shear: A mechanical force moving the skin and underlying tissues and structures in opposite directions. Shearing between two tissue layers can stretch or tear vessels in the subcutaneous tissues, leading to ischemia and tissue death. The combination of pressure and shear may produce significant tissue damage and result in deep pressure ulcers with undermining.
Shearing forces are most often generated when an individual slides down in bed or in a wheelchair, when they are pulled up to be repositioned, and during transfers. When the head of the bed is elevated and the patient slides down, the skin and superficial fascia can remain in the original position, while the deep fascia and skeleton slide downward. Most injuries caused by shear can be prevented by using proper positioning and transfer techniques.
For patients confined to a wheelchair, effective management of pressure, friction and shear across a patient’s activities of daily life can improve quality of life and avoid complications of bed rest.
References
| Essential Publications |
|---|
| 1 | Optimal Dressing for Shear Minimization |
Quality Indicator
|
Type: Case-control study (2 groups) |
| Nakagami G Sanada H Konya C Kitagawa A Tadaka E Tabata K. Comparison of two pressure ulcer preventive dressings for reducing shear force on the heel. J Wound Ostomy Continence Nurs. 33(3):267-72, 2006 May-Jun. | |||
| The study is useful because it suggests that dressings with low-friction external surfaces also reduce shear. This piece of information enables to practitioner to select an appropriate dressing for pressure ulcers that effectively minimizes shear. | |||