Evaluating Efficiency and Complication Rates of Topical Negative Pressure Therapy in the Home Care Setting

Abstract: Background. Topical negative pressure (TNP) therapy has been used since 1995 and growing evidence has facilitated its adoption as the standard of care in wound care. Despite its widespread use, literature on the use of TNP therapy in the home care setting is scarce. Methods. A retrospective study of 140 patients treated with TNP therapy in the outpatient department at a single institution between December 2005 and October 2008 was performed. Results. A total of 140 patients with 146 wounds were treated with TNP therapy. There were 74 male and 66 female patients (mean age was 58 years). In total, 92% of patients had a positive outcome. A total of 38 complications occurred, six of which eventually resulted in a negative outcome. The remaining 32 had positive outcomes. Thirteen complications were considered typical for home care treatment, one of which had a negative outcome. Conclusion. Healing rates in the home care setting seem to be comparable to rates reported for patients treated in the hospital. Complication rates are low in both hospital and home groups.
Address correspondence to: Pascal Steenvoorde, MD, PhD, MSc Medical Spectrum Twente Enschede, The Netherlands Haaksbergerstraat 55 7513 ER Enschede Email: p.steenvoorde@mst.nl
     Topical negative pressure (TNP) therapy is a noninvasive procedure where negative pressure is used to treat acute, subacute, or chronic wounds. The TNP system incorporates a polyurethane or polyvinyl alcohol foam dressing (Kinetic Concepts Inc [KCI], Houten, The Netherlands) that maintains porosity under suction and equalizes the pressure applied across the wound bed.1,2 This procedure is thought to provide various mechanisms that support healing, increase local blood flow, reduce edema, stimulate formation of granulation tissue and cell proliferation, remove soluble healing inhibitors, reduce bacterial load, and draw wound edges together.1,2 However, the reduction of bacterial load has been debated.3      The therapy has been utilized since 1995 and growing evidence caused the adoption of TNP as the standard of care in wound care management.1,2,4,5 TNP is an expensive therapy, especially in a clinical setting. However, it is stated that TNP could prevent high costs because of factors such as faster healing times.1,3,5 Treatment in a home care setting avoids escalating costs associated with hospitalization.5 Complications intrinsic to TNP, such as skin maceration, which occur in the clinical setting will probably also occur in the home care setting. Some complications are exclusive to the home care setting. For instance, a blind patient burned part of the TNP apparatus while cooking at home—fortunately, the patient was not severely harmed. Complications associated with TNP and venous thrombosis is another example, which the authors have addressed previously.6      Published TNP research mainly contains studies performed in a clinical setting. Patients also can be treated in the home with a mobile TNP unit. Evidence regarding the safety and efficiency of TNP therapy in the home care setting is limited.7,8 The aim of this single-center, retrospective study was to investigate if TNP therapy in a home care setting is just as feasible, effective, and safe compared to a clinical setting.

Methods

     Patients. Retrospective data comprised 140 patients who were treated at home with TNP therapy during the period of December 2005 through October 2008 and were treated initially in the Rijnland Hospital (Leiderdorp, The Netherlands). The following patient characteristics were recorded at presentation: diagnosis, age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, smoking behavior, presence of diabetes mellitus, and presence of peripheral arterial disease.      Procedure. Topical negative pressure therapy consisted of black polyurethane foam (GranuFoam™, KCI) or white polyvinyl alcohol foam (WhiteFoam™, KCI) that was applied to the wound. The foam was covered with a transparent adhesive drape, and continuous negative pressure of 125 mmHg was applied. The dressings were changed at the outpatient department of the wound center twice weekly.1,5 Some of the dressing changes were also done in the home care setting; however, this involved only 10 patients. These patients visited the outpatient department once every 2 weeks; the other patients’ dressing changes were all done in the home. In cases where a split-thickness skin graft (SSG) had been performed, white polyvinyl alcohol foam dressing was used and TNP remained in place for 3–5 days with 75 mmHg of continuous negative pressure.      Primary outcome measures consisted of the duration of TNP treatment in the home setting, time to wound healing, and the final outcome that was achieved. Secondary outcome measures were the presence of complications. Wound healing time was calculated from the last day of treatment with TNP therapy to the date of reaching the final outcome. Nine different outcomes were defined according to the outcome definition in the literature and experience with the technique.7 Beneficial outcomes included • Wound fully closed via SSG • Wound spontaneously closed completely • Wound became smaller • Wound appears cleaner • Wound ready for SSG Unsuccessful outcomes included: • No difference observed • Wound worsened • Minor amputation required • Major amputation required

Results

     A total of 140 patients with 146 wounds were treated with TNP therapy. The most important indications for TNP therapy were postoperative wound infection (n = 71 [49%]) and wounds with a traumatic origin (n = 33 [23%]). The average age of all patients was 58 years. The number of male patients was 74 (53%).      Various patient factors negatively influenced outcomes. Some data are missing because they were not recorded. Seventy-eight patients (57%) had a BMI above 25 kg/m2 (4 values missing), 30 patients (21%) had diabetes mellitus, 32 patients (24%) smoked (5 values missing), 31 patients (22%) had peripheral arterial disease (1 value missing), and 67 patients (48%) had an ASA class III or IV (indicative of high risk patients if undergoing surgery).      Six patients were treated with TNP therapy and later received a SSG for the same wound, which was considered to be a different wound. Two of the six patients needed a second SSG, which were considered as one SSG. Five patients have had separate periods of TNP therapy for the same indication, which were considered one period.      Out of all of the wounds, 134 demonstrated good outcomes and 11 displayed poor outcomes. One patient died in another hospital due to an acute problem unrelated to the wound. Of all the poor outcome wounds, eight patients were older than 60 years, four were male, five had a BMI > 25 kg/m2, five had diabetes mellitus, five smoked, eight had peripheral arterial disease, and seven had ASA class III/IV. The outcomes were analyzed for the different patient characteristics with the Fisher Exact Probability Test, but only patients with peripheral arterial disease had a significantly worse outcome compared to patients without peripheral arterial disease (P = 0.0002). Table 1 shows the primary outcomes and complications according to different indications. The largest group is the postoperative wound infection group, which showed high success rates and only minor complications. The combined indications show a TNP treatment time of only 19 days, a healing time of 69 days, a success rate of 92%, and only 9% success rate with home care complications.      A total of 38 complications occurred, but only 13 complications were typical for home care treatment while 25 complications also occurred in the clinic setting. In terms of weighing out the complications, six patients with a complication eventually had a bad outcome and 32 patients with a complication had good outcomes. Of the 13 typical home care complications; six patients could not handle the TNP system, because they did not understand how it operated. Despite written and verbal explanation in the outpatient department or information given directly to the patient while he/she was in the clinic prior to discharge. For example, patients accidentally turned the system off, or did not know how to respond to alarm signals. Four patients experienced problems with the functioning of the system because of obstruction or leakage. Two patients with a history of thrombosis, developed venous thromboembolism.6 One patient with a visual impairment accidentally set the system on fire while cooking. Only one of the patients with a typical home-care complication experienced a negative outcome (the wound did not change during the treatment with TNP).

Discussion

     Since its initial use in 1995, TNP has coined the phrase “standard of care” in wound care management. Currently, portable TNP systems are available to use in the home, but based on the literature it remains unknown if this home-based treatment lowers efficiency rates or induces an unacceptably high number of specific complications. Together all wounds have a mean treatment time of 19 days and a mean healing time of 69 days. This is comparable with data of clinical treatment published in the literature.1,2,3,9      Analysis of demographics shows that patients with peripheral arterial disease have a significantly worse outcome than patients without peripheral arterial disease. However, still 73% of patients with peripheral arterial disease had a good outcome with TNP therapy and therefore, in our opinion, peripheral arterial disease is not a contraindication for the therapy. Some wounds never closed or in some cases, only closed after an extensive amount of time. Therefore, it is questionable as to whether or not the healing time is specifically because of TNP treatment or a result of other treatments used after the period of TNP therapy.      There were 13 home care complications and six of which can probably be prevented with a good instruction on handling the TNP system. Two patients developed thrombosis, which can be prevented with anticoagulant treatment. In four cases the TNP system demonstrated technical problems.

Conclusion

     The results in this study show that TNP treatment in a home care setting is equally successful as the TNP systems used within the clinical setting. The complication rate is low and does not seem to influence final patient outcome. Wounds of pressure ulcers and arterial or venous leg ulcers have the lowest success rate and need extended treatment and healing time. Two thirds of those wounds will have a good outcome. Further investigation on effective TNP instructions and perhaps anti-thrombosis medication can provide useful tools to decrease the already low complication rate. Treatment with TNP in the home care setting is both feasible and efficient.