Study Says NPWT More Effective Than Moist Dressings For DFUs
- Volume 21 - Issue 4 - April 2008
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Negative pressure wound therapy (NPWT) is more effective than advanced moist wound therapy in facilitating the closure of diabetic foot ulcers and reducing secondary amputations. These are the findings of researchers who recently published the largest randomized, multicenter, controlled trial on NPWT.
In the study, which was published in Diabetes Care, researchers randomized 169 patients to VAC Therapy (KCI) and 166 patients to advanced moist wound therapy (primarily hydrogels and alginates). Patients had stage 2 or 3 (as per the Wagner scale) calcaneal, dorsal or plantar ulcers. Researchers determined that within the 112-day active treatment phase, 43.2 percent of NPWT patients achieved wound closure in comparison to 28.9 percent of patients who received moist dressings.
Furthermore, NPWT patients underwent significantly fewer amputations, with researchers citing a 4.1 percent amputation rate for the NPWT patients in comparison to 10.2 percent for the moist dressings group.
Lee Rogers, DPM, has found that NPWT can simplify complicated wounds. In a matter of days, Dr. Rogers says the technology can convert deep wounds with exposed subcutaneous structures into shallow wounds with granular tissue. He adds that the granular tissue is “extremely vascular and of high quality.
“I would argue that NPWT is the ‘standard of care’ for deep, complicated wounds,” says Dr. Rogers, the Director of the Amputation Prevention Center at Broadlawns Medical Center in Des Moines, Iowa.
Luis Leal, DPM, has found NPWT to be more effective than moist dressings. He also notes the increased promotion of granulation tissue, which permits him to plan definitive closure of the wound.
As far as advantages, he notes the shorter nursing time and the ability to transition patients to a subacute setting, reducing the length of hospital stays. Dr. Leal, the Director of the Wound and Limb Healing Institute at Palisades Medical Center in North Bergen, N.J., also cites the reduced number of secondary amputations.
Some Caveats To Keep In Mind
Dr. Rogers says physicians should avoid using NPWT to the point of complete wound closure, noting that this is a problem in several studies. Ideally, Dr. Rogers says it is best to use NPWT to promote granular tissue formation. After achieving granulation tissue, he says podiatrists can close the wound easily with a skin graft, surgical flap or skin substitute.
As for disadvantages to NPWT, Dr. Rogers notes there are few. However, one can mitigate any maceration, odor or pain during therapy, according to Dr. Rogers.
“The benefits of use far exceed the risks of not using NPWT,” maintains Dr. Rogers.
Dr. Leal notes a tendency of more infections in VAC therapy patients in comparison to patients who use moist dressings. He also says there is an inherent danger due to improperly placed devices. Cost is another downside, notes Dr. Leal.
“In my eyes, a major issue with NPWT remains the lack of basic science and research concerning (the modality),” continues Dr. Leal. “We know it works. However, we do not know why it works at the gross or cellular level, and many of the theories espoused are counterintuitive.”
Patient compliance is usually not a problem with NPWT, according to Dr. Rogers, who says patients generally change the dressing every three days. If the patient uses negative pressure at home, he says this requires either a home care nurse with experience in NPWT or the patient must have the dressing changed in the clinic.