Use of Negative Pressure Wound Therapy With Automated, Volumetric Instillation for the Treatment of Extremity and Trunk Wounds

Clinical Outcomes and Potential Cost-Effectiveness

Allen Gabriel, MD; Kevin Kahn, MD; Riyad Karmy-Jones, MD


ePlasty. 2014;14 

In This Article

Abstract and Introduction


Objective A growing body of literature supports use of negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d) with positive clinical outcomes and potential cost savings. A retrospective analysis was performed to compare clinical outcomes of wounds treated with NPWTi-d versus NPWT and to estimate cost-differences between treatments based on clinical outcomes.

Methods Data were extracted from records of patients with extremity or trunk wounds treated with NPWT (n = 34) or NPWTi-d using saline or polyhexanide (n = 48). On the basis of outcomes data, a hypothetical economic model using cost assumptions was created to calculate cost savings for NPWTi-d (related to) number of debridements and length of therapy. Operating room debridement cost was $3393 according to Granick et al. Daily therapy cost for each modality was $194.80 (NPWTi-d) and $106.08 (NPWT) based on internal company information.

Results Results showed significant differences (P < 0.0001) between NPWTi-d and NPWT patients, respectively, for the following: mean operating room debridements (2.0 vs 4.4), mean hospital stay (8.1 vs 27.4 days), mean length of therapy (4.1 vs 20.9 days), and mean time to wound closure (4.1 vs 20.9 days). Hypothetical economic model showed potential average reduction of $8143 for operating room debridements between NPWTi-d ($6786) and NPWT ($14,929) patients. There was a $1418 difference in average therapy costs between groups ($799/NPWTi-d vs $2217/NPWT).

Conclusions In this study, NPWTi-d appeared to assist in wound cleansing and exudate removal, which may have allowed for earlier wound closure compared to NPWT. Hypothetical economic model findings illustrate potential cost-effectiveness of NPWTi-d compared to NPWT.


Direct and indirect costs of wound care contribute to overall health care expenditures in the United States[1] and may increase when complications, such as infection or edema, cause healing delays. Balancing the benefits of lower cost versus higher cost wound healing technologies is a challenging, yet critical, component of determining cost-effectiveness. While negative pressure wound therapy (NPWT) is often associated with higher-cost advanced wound care therapies, overall savings in direct and indirect cost have been reported with NPWT due to resulting decreases in operating room (OR) visits, earlier wound closure, reduced hospital stay, fewer required dressing changes, and improved limb salvage rates.[2–8]

While reduced rates of infection have been reported with use of adjunctive NPWT in acute and chronic infected and critically colonized wounds, results have been somewhat mixed. NPWT has been reported to reduce nonfermentative gram-negative bacilli, yet wounds culturing Staphylococcus aureus have shown increased bacterial levels over time with NPWT.[9] Additional limitations of NPWT have included inability to clear thick exudates through the foam, as well as painful dressing removal. A next-generation NPWT system is now available that facilitates automated, volumetric control of instilled topical wound solutions in combination with NPWT. This NPWT system with instillation and a dwell time (NPWTi-d) differs from other irrigation and instillation systems in that a timed, predetermined volume of topical solution is intermittently delivered, versus continuously fed, and allowed to dwell in the wound bed while NPWT is paused, for a user-selected period of time before NPWT is resumed.[10] Although NPWT systems with intermittent instillation or continuous irrigation have been commercially available since 2004, they have historically been considered cumbersome and time-consuming to use. The new volumetrically controlled NPWTi-d system is fully automated with consistent, controlled fluid instillation.

In addition to providing the labeled therapeutic benefits of the delivered solution, the addition of an instilled solution assists with wound cleansing and lowers wound fluid viscosity, which in turn facilitates more efficient removal of exudates and infectious material utilizing NPWT.[11–13] Positive results have been reported with the combined use of adjunctive NPWT and instillation of topical solutions in wounds at risk for compromised healing, such as noninfected open fractures, infections of bone and/or soft tissue, and chronic ulcers, which made lead to a potential cost benefit.[11,14–18]

Therefore, we conducted a retrospective data analysis to compare the outcomes of patients with extremity and trunk wounds treated with standard NPWT versus NPWTi-d with volumetric fluid instillation and to estimate differences in costs for the 2 treatment arms based on the outcomes. Variables included in the comparative analysis were number of surgical debridements, hospital stay, length of therapy (LOT) and time to wound closure.