Evidence-based recommendations for negative pressure wound therapy: treatment variables (pressure levels, wound filler and contact layer)--steps towards an international consensus.

Negative pressure wound therapy (NPWT) is becoming a commonplace treatment in many clinical settings. New devices and dressings are being introduced. Despite widespread adoption, there remains uncertainty regarding several aspects of NPWT use. To respond to these gaps, a global expert panel was convened to develop evidence-based recommendations describing the use of NPWT. In a previous communication, we have reviewed the evidence base for the use of NPWT within trauma and reconstructive surgery. In this communication, we present results of the assessment of evidence relating to the different NPWT treatment variables: different wound fillers (principally foam and gauze); when to use a wound contact layer; different pressure settings; and the impact of NPWT on bacterial bioburden. Evidence-based recommendations were obtained by a systematic review of the literature, grading of evidence and drafting of the recommendations by a global expert panel. Evidence and recommendations were graded according to the Scottish Intercollegiate Guidelines Network (SIGN) classification system. In general, there is relatively weak evidence on which to base recommendations for any one NPWT treatment variable over another. Overall, 14 recommendations were developed: five for the choice of wound filler and wound contact layer, four for choice of pressure setting and five for use of NPWT in infected wounds. With respect to bioburden, evidence suggests that reduction of bacteria in wounds is not a major mode of action of NPWT.