Quantifying the effects of external shear loads on arterial and venous blood flow: implications for pressure ulcer development.

Introduction: Forces applied to the skin cause a decrease in regional blood flow. This decrease in blood flow can cause tissue necrosis and lead to the formation of deep, penetrating wounds called pressure ulcers. These wounds are detrimental to individuals with compromised health, such as the elderly and spinal-cord injured.

Blood perfusion and transcutaneous oxygen level characterizations in human skin with changes in normal and shear loads--implications for pressure ulcer formation.

Background: Decubitus ulcers (pressure ulcers) are localized areas of tissue breakdown in the skin and the underlying regions. Decubitus ulcers affect approximately 3 million people in the USA every year, including seniors, individuals with diabetes, and those who spend long periods in wheelchairs. Experimental studies demonstrate that static or dynamic normal loads cause blood occlusion in the skin, while prolonged loading conditions can result in skin damage.