From the Guidelines
In medicine, shear refers to a mechanical force that occurs when two adjacent surfaces slide past one another in opposite directions, creating a parallel stress on tissues, as defined by the Pan Pacific Pressure Injury Alliance in 1. This force is particularly significant in patient care as it can damage skin and underlying tissues, especially in bedridden or immobile patients. Shear commonly occurs when a patient slides down in bed or is dragged across surfaces during transfers, causing the skin to remain fixed while deeper tissues move with the skeleton. This mechanical stress can disrupt blood vessels, impair circulation, and lead to tissue damage, contributing to pressure injuries and wound formation. Shear injuries are most concerning in patients with fragile skin, poor circulation, or reduced sensation. Prevention strategies include using proper lifting techniques rather than dragging patients, maintaining proper body alignment, using specialized support surfaces like air mattresses, and regularly repositioning immobile patients. Understanding shear forces is essential for healthcare providers to prevent tissue damage and promote healing in vulnerable patients, as highlighted in the context of pressure injury prevention and management guidelines in 1. Additionally, shear stress is also relevant in other medical contexts, such as aortic dissection and aneurysm formation, where it can contribute to the degradation of the vascular wall and increase the risk of rupture, as discussed in 1 and 1. However, the most recent and highest quality study on the topic of shear in medicine is 1, which provides a comprehensive overview of the concept of shear in the context of pressure injury prevention and management. Therefore, healthcare providers should prioritize the prevention of shear injuries in vulnerable patients by implementing evidence-based strategies, such as proper lifting techniques and regular repositioning, to reduce the risk of pressure injuries and promote healing, as recommended in 1. Key points to consider include:
- Shear forces can cause tissue damage and contribute to pressure injuries and wound formation
- Prevention strategies include proper lifting techniques, maintaining proper body alignment, and regularly repositioning immobile patients
- Shear injuries are most concerning in patients with fragile skin, poor circulation, or reduced sensation
- Understanding shear forces is essential for healthcare providers to prevent tissue damage and promote healing in vulnerable patients.
From the Research
Definition of Shear in Medicine
- Shear in medicine refers to a horizontal force that causes tissue deformation, often resulting from patient movement, nurse movement of the patient, or bed movement 2.
- Shear stress and shear strain play a significant role in the development of pressure injuries, as they can cause damage to soft tissue 3.
Effects of Shear on the Body
- Shear forces can lead to pressure ulcers, particularly at bony prominence sites such as the coccygeal bone and sacrum 2, 4.
- The effects of shear on the body can vary depending on body type, position, and movement, with slender body types tend to have higher shear forces at certain sites 4.
- Shear motion can also influence fracture healing, with oblique sliding motion promoting greater cartilage differentiation and expansion of the peripheral callus 5.
Clinical Implications of Shear
- Understanding the role of shear in pressure injury development and fracture healing can inform the selection of support surfaces and mitigation strategies to reduce risk 3, 2.
- Clinicians must carefully assess each patient's risk factors regarding shear forces and develop personalized care plans to prevent pressure injuries and promote optimal healing 3.
- The restoration of shear forces and endothelial function is also crucial in the treatment of sepsis, as it can help to preserve the endothelial-glycocalyx barrier and prevent microcirculatory breakdown 6.