Abstract
This thesis is concerned with the efficiency of patient support systems, principally beds, and with the causes and prevention of pressure sores and similar disorders. reviewing the limitations of traditional hospital beds and the particular problem of pressure sores, the numerous methods for preventing these sores are examined. Novel support systems are shown to have their own limitations and hazards. An improved general-purpose support system is advocated as a means of both reducing the incidence of pressure sores and avoiding various other identified hazards and disadvantages of contemporary general-purpose support systems. With this end in view the results of a series of experiments concerning force distributions at the patient/support interface are presented. The use of a novel system of mattress indenters has shown that much of the patient tissue distortion associated with pressure sores could be avoided by the use of stretchable mattress covers. The studies indicate that tangential forces at the patient/bed interface contribute to the development of ulceration, and a new method of measuring skin/support interface friction has been developed: the results of its use are presented here. These results indicate that the desirable coefficient of friction is approximately 0.4, and can be obtained (dry conditions), with at least five bedding materials. Two further factors considered here are the water vapour permeability of bedding materials which have to be waterproof, and a possible replacement for the hospital drawsheet. As a result of these studies a new patient support system, based on the King's Fund bedstead has been devised, and is described herein. The results of the various investigations are collated and discussed.