The pathogenesis of skin wounds due to pressure

Wounds due to pressure arise in areas of anoxic necrosis. Blood is excluded from the skin by pressures in excess of the mean capillary pressure. In addition, trauma initiates haemostatic mechanisms which increase the extent of the vascular occlusion owing to the fact that endothelial cell retraction occurs and platelet thrombosis takes place. Endogenous factors potentiate this reaction in the base of the sore and the surrounding skin, Junctional complexes can be stabilised in animals by means of a single dose of ACTH in gelatine solvent administered four hours before operation and a marked diminution in the incidence of pressure sores occurs. Clinical trials are in progress in which the drug is administered to elderly patients prior to orthopaedic surgery. The extent of the vascular occlusion as well as the concomitant increase in tissue perfusion associated with wound healing can be determined thermographically and radiometrically. Three types of sore can be identified, each with a different prognosis. A non-intrusive technique is available which provides considerable assistance to those concerned with the management of patients with pressure sores.