TWO Negative Pressure Wound Therapy (NPWT) System Abilities are Compared for Accurate Pressure Delivery and Efficient Fluid Removal, Is there a Difference?

INTRODUCTION: Negative pressure wound therapy (NPWT) systems must have certain technical capabilities to effectively deliver therapy. The International Consensus Review for NPWT Systems, by the European Wound Management Association (EWMA) states that NPWT systems containing an electronically-controlled feedback loop ensure maintenance of set pressure, guarantee the effectiveness of therapy and provide higher patient safety.1

PURPOSE: Not all NPWT systems have the technical capability to meet all these standards, which can lead to complications in wound healing. 2,3 The objective of this investigation was to use a simulated wound model to compare the ability of 2 commercially available NPWT systems to (1) maintain set pressure in a simulated wound bed when placed at different heights in relation to the “wound” and (2) to efficiently remove a 150 ml of simulated wound fluid. Testing was conducted at an independent third-party laboratory.

RESULTS: The experimental results supported that System M* consistently maintained the selected pressures (-125 & -75 mmHg) at the wound bed at various levels of the system height relative to the wound. System C+ was 30 mmHg below target pressure (-120 mmHg) when placed 1m higher than the wound and was unable to maintain set pressure in the wound bed. When a 150ml fluid bolus was introduced, System M* efficiently cleared 89% of the 150ml bolus of simulated wound fluid in 20 minutes which resulted in System M* consistently delivering set pressure (-125 mmHg) upon the efficient removal of simulated wound fluid.4,5 System C+ failed to remove any detectable level of fluid throughout the two hour evaluation period and was unable to maintain the target pressure (-120 mmHg) at the wound bed.5

CONCLUSION: It is critical that NPWT Systems deliver on fundamentals of NPWT (A set pressure at wound, B efficient fluid removal, C maintain seal). Systems that are unable to deliver set pressure to the wound bed (Fundamental A) and efficiently remove wound fluid (Fundamental B), may negatively impact the six mechanisms of action and hinder healing. NPWT systems that don’t efficiently remove fluid may lead to pooling of exudate and compromise maintaining a sealed wound environment (Fundamental C).