Negative pressure wound therapy: past, present and future

Abstract

Negative pressure wound therapy (NPWT), which was introduced as a commercial product (V.A.C.® Therapy, KCI USA, Inc., San Antonio, TX) less than 20 years ago, has revolutionised the treatment of complex wounds. Indicated for wide variety of wound types, NPWT is an adjunctive therapy that can be used safely in a range of care settings. Current research indicates that there are four primary NPWT mechanisms of action: macrodeformation, microdeformation, fluid removal and environmental control of the wound. The interaction of the primary mechanisms results in secondary effects through cell signalling (e.g. granulation tissue formation, cell proliferation and modulation of inflammation). Better understanding of the mechanisms of action also provides insight into future directions for NPWT research that could create better solutions for patients with complex wounds.

Wound Penetration of Cefazolin, Ciprofloxacin, Piperacillin, Tazobactam, and Vancomycin During Negative Pressure Wound Therapy

“…NPWT has shown clinical benefit for a variety of acute and chronic wounds, 1-3 especially complex wounds. 4 In addition to isolating the wound environment and stabilizing osmotic gradients through the evacuation of fluid with accompanying electrolytes and proteins, An additional benefit of NPWT may be an overall decrease in the bacterial burden in the wound bed, but the effect of NPWT on bioburden remains controversial.…”

“…NPWT has shown clinical benefit for a variety of acute and chronic wounds, [1][2][3] especially complex wounds. 4 In addition to isolating the wound environment and stabilizing osmotic gradients through the evacuation of fluid with accompanying electrolytes and proteins, NPWT has been shown to reduce healing time through macrodeformation (pulling the wound edges closer together) and microdeformation (pulling the interior, cellular surfaces together within the open-pore foam), resulting in the modulation of inflammation and a variety of cellular responses that stimulate angiogenesis and the formation of new granulation tissue. 6 With the increasing prevalence of complex wounds 4 and the efficacy of NPWT in promoting wound healing, 6 the use of NPWT is becoming increasingly common.…”

“…Evidence has shown a reduction in counts of Gram-negative bacilli with NPWT compared with conventional wet-to-dry dressings, 8 but reductions in Gram-positive bacilli, such as Staphylococcus aureus, are not consistently observed 8,9 and highlight the need for studies on the relationship between NPWT and wound infections. NPWT produces changes in localized blood flow, tissue oxygenation and inflammation, and directly removes pathogens through vacuum pressure, [10][11][12] all of which have been suggested to play a role in the overall reduction in bacterial load during NPWT 4 but may also impact the pharmacokinetics or pharmacodynamics of drugs at or near wounds, especially antibiotics.…”

“…NPWT has shown clinical benefit for a variety of acute and chronic wounds, 1-3 especially complex wounds. 4 In addition to isolating the wound environment and stabilizing osmotic gradients through the evacuation of fluid with accompanying electrolytes and proteins, An additional benefit of NPWT may be an overall decrease in the bacterial burden in the wound bed, but the effect of NPWT on bioburden remains controversial.7 Furthermore, the hypothesized mechanisms responsible for any potential reduction remain unclear. Evidence has shown a reduction in counts of Gram-negative bacilli with NPWT compared with conventional wet-to-dry dressings, 8 but reductions in Gram-positive bacilli, such as Staphylococcus aureus, are not consistently observed 8,9 and highlight the need for studies on the relationship between NPWT and wound infections.…”

“…4,[10][11][12] Previous work has shown that vancomycin effectively penetrates wounds in patients undergoing NPWT, possibly to a greater extent than in normal tissue. 15 These data add to this existing literature and extend it further by showing that vancomycin, ciprofloxacin, piperacillin, and tazobactam all penetrate wounds in patients undergoing NPWT, and suggest that cefazolin may not penetrate wounds as effectively under the NPWT conditions studied here.…”