Negative Pressure Wound Therapy With Controlled Saline Instillation (NPWTi): Dressing Properties and Granulation Response In Vivo

Abstract

Negative pressure wound therapy (NPWT) with reticulated open-cell foam (ROCF) dressings (ROCF G, V.A.C.® GranuFoamTM Dress- ing, KCI USA, Inc, San Antonio, TX) creates a healing environment that removes wound exudates, reduces edema, and promotes perfusion and granulation tissue formation. Controlled instillation of saline dur- ing NPWT (NPWTi) may further enhance healing by facilitating auto- matic and contained volumetric wound irrigation and cleansing. A new ROCF dressing (ROCF-V, V.A.C. VeraFloTM Dressing, KCI USA, Inc, San Antonio, TX) has been developed for use with NPWTi; benchtop and in vivo tests compared the properties and performance of both ROCF-G and ROCF-V. Pore size and density (contributors to microdeformation) are similar for both ROCF-G and ROCF-V, while mechanical testing demonstrates ROCF-V is stronger than ROCF-G under both tensile and tear loading. ROCF-V surface energy is higher than ROCF-G, making ROCF-V less hydrophobic. Under wet conditions ROCF-V wicks more fluid and shows less pressure drop than ROCF-G, suggesting ROCF-V may be better suited for NPWTi. After 7 days of therapy in a porcine full-thickness excisional wound model, NPWTi with ROCF-V resulted in a 43% increase (P < 0.05) in granulation tissue thickness compared to NPWT with ROCF-G. These data suggest NPWTi with ROCF-V creates a wound healing environment that provides enhanced granulation tissue formation compared to standard NPWT with ROCF-G. .