RESUMEN
This study evaluates 53 overlays (six types of alternating pressure overlays) which were purchased, placed into the hospital pool and examined for mechanical malfunction and mismanagement every working day (excluding 22 days' annual leave) for one year. Reasons for malfunction were recorded and categorised. Results show that 69 mechanical failures and seven cases of physical damage were recorded. There were significant differences between the different types of overlay in performance and the length of time to effect repairs. There were 56 errors in management (mainly units not plugged in or not switched on) and five cases of design features contributing to mismanagement. Although some alternating pressure overlays perform better than others, mechanical unreliability remains a problem for most.