Foundations and Mechanical Factors in Pressure Injuries

Vocabulary flashcards covering the foundation concepts and mechanical factors involved in pressure injury development.

Pressure Injury

Localized skin or tissue injury, usually over bone, caused by pressure with or without shear/friction.

Four External Factors Contributing to Pressure Injuries

Pressure, shear, friction, and moisture.

Effect of Sustained Pressure on Blood Vessels

Compresses them, causing ischemia and potentially necrosis.

Ischemia

Inadequate tissue oxygen supply due to reduced blood flow.

Shear

Opposing movement of deeper tissues and skin that stretches or tears vessels.

Bed Positioning Causing Shear

Elevating the head of bed while the patient slides downward.

Chair-Related Action Causing Shear

Sliding down in the chair.

Shear-Related Wound Shape

Deep, oval or oblong.

Structures Caused by Shear

Undermining and tunneling.

Friction

Rubbing that wears away the epidermis.

Appearance of Friction Damage

Often resembles an abrasion or superficial laceration.

Effect of Moisture on Skin

It causes maceration, weakening skin against pressure, shear and friction.

Body Fluids Contributing to Maceration

Urine, feces, sweat and wound drainage.

Mechanism of Tissue Death from Prolonged Pressure

Persistent vessel compression prevents oxygen delivery.

Difference Between Pressure and Friction

Pressure compresses tissues; friction rubs away surface skin.

Difference Between Shear and Friction

Shear distorts deeper tissue layers; friction damages the skin surface.