Removing the 'estimates and guesses' from practice--evidence based tissue viability.

The development of evidence based tissue viability is reviewed using the prevention and management of pressure sores as a specific example. Although data is limited, pressure sores may be more common at the end of the 1990's than they were fifteen years ago, despite changes in clinical practice. If evidence based tissue viability is to grow and mature, then two key obstacles must be overcome; changes in patient populations must be reflected within prevalence or incidence data (case-mix adjustment) so allowing interpretation of longitudinal changes in the occurrence of sores. Secondly, the efficacy and effectiveness of interventions such as pressure-redistributing beds and mattresses must be identified through rigorous and appropriate methodologies. Only through such steps can clinical skill be blended with research evidence to fully realise evidence based practice.