ABSTRACT
Objective The incidence rate of pressure ulcer is high in critical patients and off-loading mattresses and reposi-tioning are known as effective interventions for the prevention of pressure ulcers .However, evidence is lacking for selection of the right type of mattresses and suitable interval of repositioning .This study was to compare the effects of two types of off-loading mattresses with two different repositioning intervals in preventing pressure ulcers in critical patients . Methods According to the design of this ran-domized controlled trial , we made a training plan concerning the participants , methods of intervention and comparison , criteria and methods of observation , and methods of recording , and trained 26 nurses from 7 hospitals .Using non-inferiority design and the method of stratified blocked randomization , we divided 1194 patients with the risk of pressure ulcer into a trial group ( n=596) and a control group ( n=598) , a viscoelastic sponge mattress with every-four-hours repositioning used for the former and an automatic aeration mat-tress with every-two-hours repositioning for the latter , both for 7 successive days .We examined the patients every day , recorded the in-cidence and stages of pressure ulcer , and compared the data obtained between the two groups of patients . Results The total inci-dence rate of pressure ulcer was 1.09%(13/1194), significantly lower in the trial than in the control group (0.34%[2/596] vs 1.84%[11/598], P=0.012). Conclusion A viscoelastic sponge mattress with every-four-hours repositioning is superior to an automatic aeration mattress with every-two-hours repositioning and therefore is preferred to the latter in preventing the incidence of pressure ulcer in critical patients in the ICU .