Will Simultaneous Irrigation Become New Trend for NPWT?

  Decades prior to the first negative pressure wound therapy (NPWT) device being cleared by the US Food and Drug Administration in 1997, Pal Svedman, PhD, MD, reported the use of simultaneous irrigation in conjunction with NPWT to treat infected wounds. The process of irrigating a wound consists of delivering a topical solution to the wound bed to cleanse and eliminate infectious materials. The use of simultaneous irrigation allows continuous wound irrigation without sacrificing negative pressure therapy.

  Although the most recent advancements in NPWT have shown profound healing effects for chronic wounds in particular, there have been no controlled, preclinical, or clinical studies that have evaluated the effectiveness of NPWT with and without irrigation, or that have compared the efficacy of different irrigation solutions.

  To close this gap, a team of academic researchers at the University of Texas (UT) Southwestern Medical Center in Dallas set out to investigate a new wound therapy system that couples NPWT with simultaneous irrigation therapy while maintaining constant negative pressure. The study aimed to determine the effectiveness of simultaneous irrigation therapy to heal wounds and reduce bioburden. The study results represent the first set of randomized, controlled data confirming the effectiveness of simultaneous irrigation.

  This article offers a review of the study.

Enhancing Healing, Reducing Bioburden

  For this study, the research team (which, besides the author, included Jenny Barker, PhD; Paul Kim, DPM; Lawrence Lavery, DPM, MPH; and Jessica Bills, BS) used a porcine model where full-thickness excisional wounds were placed on the dorsum of six pigs. (See Figure 1.) Each site was inoculated with 500 colony-forming units (see Figure 2) of Pseudomonas aeruginosa and left to establish for three days prior to the initiation of therapy. Therapy was applied for 21 days and consisted of (see Figure 3) either NPWT, NPWT with simultaneous irrigation therapy using normal saline or polyhexanide biguanide (Prontosan,® B. Braun) at low or high flow rates, or control (no NPWT). NPWT was administered using the Quantum™ NPWT system (Innovative Therapies Inc.) at -125 mmHg of pressure. (See Figure 4.)

  The data from this study demonstrate two significant findings: 1) NPWT with all irrigation conditions improved wound healing rates over control-treated wounds by at least 20% and 2) NPWT with simultaneous irrigation with saline or Prontosan further reduced bioburden over the control and NPWT-treated wounds. However, flow rate did not affect these outcomes. Together, these data show that NPWT with simultaneous irrigation therapy with either normal saline or an antiseptic, such as Prontosan, has a positive effect on bioburden in a porcine model.

Clinical Impact

  When embarking on new research to explore unchartered territory, it’s important to start at the “ground level” with controlled, preclinical work. For wound care research, the ground level typically starts at the porcine level. Although the next step for our research team has been to apply the same methodology to an ongoing clinical trial, the porcine results helped us to better define the parameters of that trial currently underway at UT Southwestern.

  In this study, the porcine wound model used represents acute wounds in healthy young animals, the healing of which differs from the complex chronic wounds in humans with multiple comorbidities that are typically seen in the outpatient clinic setting. Pigs are also highly resistant to infection, suggesting the data presented may understate the potential effects that could be observed in chronic wound patients. Ultimately, the results will likely translate clinically to improved wound healing outcomes in humans and more efficient care.

Improved Economics

  Wound care is very cost intensive and providers in all care settings are looking for technology advancements that offer improved economics alongside effective clinical outcomes. There are a number of cost drivers for treating wound care patients, with the two most common being infection and hospitalization.

  Reducing wound bioburden can help improve healing time, which can lead to shorter hospital stays and lower the overall cost of care. This study has shown, for the first time, that simultaneous irrigation reduces bioburden, which has been demonstrated clinically to result in faster healing time.

  Another profound finding from an economic standpoint is that saline was found to be just as effective as the more expensive antimicrobial Prontosan at reducing bioburden. Unlike antimicrobial irrigant solutions, saline doesn’t have to be administered through a pharmacy, thus eliminating more total care costs. Further, saline administered at low or high flow rates demonstrated similar efficacy to reduce bioburden without significantly affecting the outcome, suggesting that irrigation solution can be just as effective when administered at a lower flow rate, reducing the labor involved in administering therapy. In addition, the application of simultaneous irrigation using this particular device requires minimal accessory modifications over negative pressure therapy alone.

  Dr. Lavery, a professor of plastic surgery at UT Southwestern and study co-author, states, “Our work further establishes the effectiveness of NPWT and coupling NPWT with simultaneous irrigation converts the system into a dynamic drug-delivery system. This will save the legs of many of my patients with diabetes and foot wounds.”

Translating Results to Clinic

  This study is the first to demonstrate the benefits of simultaneous irrigation along with negative pressure treatment.

   “The device also provides a new cost-efficient purchase model in which hospitals, wound clinics, and long-term care facilities pay only for therapy hours used,” Lavery said. “This is a stark contrast to the current industry standard rental model and may provide more financial predictability for providers.”

  In addition to these economic benefits, Lavery said there are other ease-of-use attributes that will translate to the wound care clinic as well. “A defining attribute of the Quantum device allows for uninterrupted therapy as the same device can be used in a variety of care settings, including at the clinic and home,” he said. “Because there’s no need to switch devices when being discharged from the hospital, patients have to deal with less paperwork and can count on continuity of care. The device may be particularly appealing for wound care clinic patients, as it is also the lightest NPWT device on the market (15 oz without carrying case) and is easy to use.”

NPWT’s Future

  In the wake of sweeping healthcare changes, one key new reality for wound care providers is providing “more with less.” Studies like this are critical in showing how a device, technique, or approach is equivalent or superior to today’s standard, as more decisions will be based on the full cost of care delivery. Because outcomes will be so vital to making healthcare decisions, the study’s authors predict simultaneous irrigation with NPWT will become the standard of care in drug delivery to accelerate healing of the wound bed.

Kathryn Davis is on staff at UT Southwestern Medical Center.