Negative pressure wound therapy (aka “wound vac” or NPWT) has been being used much more frequently in recent years for managing a variety of wounds. There has always been considerable debate about the strength of evidence for its efficacy and the overall cost-effectiveness. All of us, however, have probably seen individual cases of difficult-to-heal wounds that dramatically improved after initiation of negative pressure therapy. But in recent years a number of adverse events related to these devices has begun to emerge.
In 2009 the FDA issued an alert about potential dangers associated with use of negative pressure wound therapy devices (see our December 2009 What’s New in the Patient Safety World column “FDA Safety Alert on Negative Pressure Wound Therapy Systems”). That preliminary safety alert about negative pressure wound therapy and an associated consumer alert were based on reports of 6 deaths and 77 injuries reported over the period from 2007 to 2009 and were followed by an update in 2010.
Now the FDA has issued yet another update, based upon reports of 6 additional deaths and 97 additional injuries since the 2009 alert, bringing the totals to 12 deaths and 174 injuries related to the NPWT devices. The FDA has emphasized the fact that in many of the cases the adverse events occurred in patients being treated at home or in long-term care facilities.
Serious bleeding continues to be the most serious complication. This was seen in patients with vascular grafts, wound infections, patients on anticoagulants, or during removal of dressings attached to the tissues. However, many of the recent reports also deal with infection related to retention of dressing pieces in the wounds.
The FDA update provides advice for both healthcare professionals and for patients and their families. They list several types of wounds for which NPWT is contraindicated including those with necrotic tissue with eschar present, untreated osteomyelitis, non-enteric and unexplored fistulas, malignancy in the wound, and those with exposed vasculature, nerves, organs or anastomotic sites. They also list risk factors that may predispose to these complications and make recommendations about ensuring that the patient and/or caregiver has been appropriately instructed on use of the system and how to recognize and address complications.
Talk about good timing – there are two new review articles on NPWT. The Pennsylvania Patient Safety Authority has a review article “Improving the Safety of Negative-Pressure Wound Therpy” in it March issue of the Pennsylvania Patient Safety Advisory. This is an excellent review of the evidence base for NPWT, which they admit is weak, the theories about how NPWT works, and economic analyses that suggest it may be a cost-effective alternative to other wound therapies. It highlights the adverse effects noted in the original FDA alert(s) and discusses examples of 419 events reported to the PPSA in 2008-2009. It then provides advice not only about initiation of NPWT but also about when to stop it, and guidelines about assessment of the patients, wound preparation, application of the device, ongoing monitoring and assessment, and education of the patient and family caregiver.
The second new article (Moues 2011) is a critical review of the evidence base for NPWT. It reviews the evidence for the various claimed mechanisms of action for NPWT and reviews the evidence for the clinical utility of NPWT. It points out that many of the uses have been based on consensus statements rather than based in high-level clinical studies and highlights the need for future research in several areas. It also provides an excellent reference list. It does not, however, focus on adverse events associated with NPWT.
FDA. Consumer Alert. Negative Pressure Wound Devices Draw FDA Notice, Advice. 2009
Mirsaidi N. Negative pressure wound therapy: Use with care. Nursing 2010, September issue, p.64-66
FDA. FDA Safety Communication: UPDATE on Serious Complications Associated with Negative Pressure Wound Therapy Systems. Date Issued: February 24, 2011
Pennsylvania Patient Safety Authority. Improving the Safety of Negative-Pressure Wound Therapy. Pa Patient Saf Advis 2011; 8(1): 18-25.
Mouës CM, Heule F, Hovius SER. A review of topical negative pressure therapy in wound healing: sufficient evidence? American Journal of Surgery 2011; 201(4): 544-556, April 2011