Introduction. The aim of the study was to compare a new anti-decubitus mattress with other low-cost mattresses. Methods. Interface pressure measurements were made in supine and in sitting position. Results. The new mattress has significant lower interface pressures than other low-cost mattresses in both positions, and that there is no significant difference with an expensive anti-decubitus bed like the air-fluidized type. Measurements of shear between body and cover show that the shear is far below 10 kPa. This limit is known as a limit above which shear may play an important role in the causation of decubitus ulcers. Conclusion. The goals of the research have been achieved: the development of a low-cost anti-decubitus mattress with, in supine position, interface pressures comparable to the well-known and expensive beds; in sitting position interface pressures are also below the capillary pressure of 4.2 kPa.

An anti-decubitus mattress is introduced. Primary requirements were low costs, low pressure and shear in lying and sitting, favourable heat and humidity exchange and adaptation to body weight. The different media a mattress may consist of, are described. After analysis of physical properties air has been chosen because of equally distributed pressure along the body contour. Details of the construction of the mattress and the control system are described. A market research revealed that the price of the complete system has to be lower than Dfl 5000 (approximately US$ 3000). The present article describes how one of the main goals of the research has been achieved: a low-cost mattress. In part 2 pressure and shear are analysed in lying and sitting and a comparison is made with cheap as well as expensive anti-decubitus mattresses.