Comparison of Single-use Closed Incision Negative Pressure Therapy (ciNPT) Systems: Evaluation of Appositional Forces and Pressure Delivery in Presence of Dressing Leak

Abstract Body: Introduction Clinical studies have shown that appropriate delivery of ciNPT reduced the incidence of seroma and superficial site infections in patients at high risk for post-operative infections1.  A key therapy component is holding the tissues in apposition until the healing process provides sufficient strength to withstand stress without mechanical support.  The objective of the study was to evaluate and compare various ciNPT systems.   Methods (Therapy Delivery): ciNPT systems (ciNPT1◊, ciNPT2◊◊, ciNPT3◊◊◊) were tested for 12 hours (3 units x 3 dressings each) using a simulated wound environment with induced dressing leak.  Leak rates when CiNPT1 was compared to ciNPT2/ ciNPT3 were 24/ 41 ccm, respectively.      Methods (Appositional Force Testing): ciNPT1 and ciNPT2 dressings (n=10each) were applied to a silicone incision model, loaded on a tensile test machine and maximum apposition force (MAF) was recorded.  All systems were tested at their prescribed pressure setting (-125mmHg (ciNPT1), -80mmHg (ciNPT2/ciNPT3)).   Results: ciNPT1 units consistently delivered therapy for all 12hr tests.  CiNPT2 & ciNPT3 systems exhibited on/off cycling resulting in average therapy delivery of 4.2 hours and 4 hours, respectively.  Average pressures maintained at 21 ccm leak: -126.5mmHg (ciNPT1) and -27.8mmHg (CiNPT2); at 42 ccm leak: -125.5mmHg  (ciNPT1) and -27.1mmHg (ciNPT3). Mean MAFs for ciNPT1 and ciNPT2 were 5.54N and 1.37N, respectively.     Conclusion:  ciNPT systems are not equivalent in performance.  CiNPT1 systems consistently delivered prescribed therapy levels while exposed to a dressing leak. CiNPT2 and CiNPT3 did not. CiNPT1 systems also provided significantly greater appositional force than CiNPT2.