Objective To explore the effect of wound bed preparation principles applied to Ⅲ and Ⅳ stage pressure sores.Methods62 patients with Ⅲ,Ⅳ stage pressure sores admitted in our hospital from June 2013 to June 2014 were selected as the subjects and divided into the control group and the observation group in accordance with the random grouping method.The control group were treated by the conventional treatment method,and the observation group were treated by the wound bed preparation principles.And the patient ou...