Presentation recorded at the 6th International NPWT Expert Meeting, Berlin 20-21 March 2015.
Lawrence Lavery discussed animal, in vitro and clinical studies on adjunctive therapies, including silver dressings, irrigation/instillation and ultraviolet light. The aim of adjunct NPWT is to complement or negate the factors influencing or inhibiting wound healing – i.e. changing the healing profile. Animal studies have shown reduced bacterial load of both Pseudomonas and Staphylococcus when comparing silver impregnated gauze with standard sponges after six days (43% versus 21% Pseudomonas and 25% versus 11.5% in Staphylococcus aureus) and that combining topical negative pressure dressings and silver foam led to a synergistic inactivation in Pseudomonas species over three and five day treatment1. Using a silver dressing with NPWT has resulted in fewer surgical procedures, shorter treatment times, and thus, shorter hospital stay.2
Prof. Lavery went on to discuss instillation and intermittent irrigation (NPWTi). Phillips et al.,3 studied periodic instillation of antibacterial agents with NPWT in a swine model and concluded that NPWTi with active antimicrobial agents, enhances the reduction of CFUs by destruction and removal of biofilm bacteria. Conversely, Davis et al.,4 looked at continuous irrigation in a swine model and concluded that NPWT with simultaneous irrigation further reduced bioburden over control and NPWT-treated wounds; NPWT with simultaneous irrigation therapy (normal saline or PHMB), had a positive effect on bioburden in a porcine model. Prof. Lavery presented the unpublished data from his recent prospective, randomised, comparative effectiveness study comparing the instillation of saline with 1% polyhexanide (PHMB). There was a reduction in days to final surgery with NPWT (but only in normal saline group). A further study is underway using continuous instillation. Finally, he presented some data from an on-going study of pulsed UVA light (fibre-optic delivery system) under NPWT to reduce bioburden and accelerate granulation. Results to date show a 45% greater reduction in wound area, a 50% greater reduction in wound depth, and faster healing compared to control.