Decubitus Risk: Is Shear More Important than Pressure?

Abstract

A mechanical load through which the capillaries are closed causes tissue ischaemia of the skin. Most authors agree that it is this tissue ischaemia that is the main factor in the cause of pressure sores. Different combinations of mechanical load on the skin may have the same effect within the skin. The aim of this study is to evaluate the effect that different combinations of pressure and shear have on blood flow within the skin. The skin blood flow was measured by means of skin oxygen tension. Different load combinations on the skin surface, for which the maximum shear stress within the skin remained equal, showed no significant difference in skin blood flow. Research should therefore focus on load situations within the skin instead of pressure measurements on the skin surface only.