Mechanisms of Action of Instillation and Dwell Negative Pressure Wound Therapy with Case Reports of Clinical Applications

Negative pressure wound therapy (NPWT) has revolutionized the care of complex wounds since 1997. The addition of instillation (NPWTi-d) adds several potential benefits and challenges to clinicians dealing with complex wounds in a hospital setting. We surveyed the literature regarding the mechanism of action of these devices and reviewed our clinical experience to date. Potential mechanisms of action include the removal of microorganisms from the wound surface, dilution of cytotoxic molecules, upregulation of angiogenesis pathways, and maintenance of a moist wound environment. As we have extended our use of these devices to more complex wounds, we have taken advantage of and observed potential mechanisms of action, including facilitated removal of microorganisms, dilution of inflammatory and cytotoxic macromolecules, additional wound hydration, and enhanced angiogenesis through an intermittent application of NPWT. We have also observed complications, including bleeding, loss of a seal along the wound, and pain. NPWTi-d provides additional options for clinicians caring for complex wounds with favorable responses in wounds with significant contamination and those with poor inherent vascularity. Further studies to clarify the mechanisms of action, better define the wound types that would benefit, and techniques to manage complications using this device should further advance this field.