"Homemade" Negative Pressure Wound Therapy

Treatment of Complex Wounds Under Challenging Conditions

Nauman Ahmad Gill, MBBS, MRCS; Abdul Hameed, FRCS, CRCS(Plast); Yawar Sajjad, MBBS, FCPS; Zeeshan Ahmad, MBBS; Mohammad Ali Rafique Mirza, MBBS, FCPS(Plast)

Disclosures

Wounds. 2011;22(4):84-92. 

In This Article

Discussion

The use of NPWT has been established as a promising new technology in the field of wound healing with multiple applications in a variety of wounds, including those that are difficult to heal.[8] Two main factors are considered to be responsible for the dramatic response seen in the wounds: removal of fluid and mechanical deformation.[12] Removal of fluid decreases edema, which decreases the interstitial pressure resulting in increased blood flow. Mechanical deformation causes a wide variety of molecular responses, including changes in ion concentration, permeability of cell membrane, release of second messengers, and stimulation of molecular pathways increasing the mitotic rate of stretched cells. Recently, Scherer et al,[13] in their experimental model on diabetic mice, concluded that vascular response is related to the polyurethane foam, whereas tissue strain induced by NPWT stimulated cell proliferation. Labler et al[14] found increased concentration of local interleukin-8 and vascular endothelial growth factor, which may accelerate neovascularization. This therapy has now been used successfully to treat chronic and acute wounds, burns, envenomations, infiltrations, sternal wound infections, abdominal wall defects, perineal, urologic, and orthopedic wounds.[15] Despite all these reports of success, a recent systematic review has indicated that there is a paucity of randomized, controlled trials in terms of patient allocation concealment, cost of treatment, and follow up.[16]

Contemporary medicine has not only evolved in terms of technological advancement but also in finding cost effective solutions. Expensive equipment with evolving applications cannot be provided at public hospitals with limited budgets, especially in developing countries. The authors devised our own NPWT system based on the same principles as described by Fleischmann et al[5] and Morykwas et al[6] and have found it to be very effective, especially in the treatment of complex and challenging wounds where other options for reconstruction are limited. The cost of commercially available V.A.C is Rs. 600,000 ($7500) for the unit and Rs. 6000 ($75) for each dressing change. The authors' homemade NPWT costs Rs. 1200 ($15) each for initial application and for subsequent dressing changes. In terms of daily expense, this amounts to $12 for an inpatient and $7 for a patient who is managed on an outpatient basis. We have used negative pressure dressings to aid coverage of acute and chronic wounds and have found this therapy to be very effective even for treating difficult wounds where options for reconstruction are limited.

The negative pressure in the present study was maintained at 125 mmHg, as has been found to be most effective for increasing blood flow to the wound.[6] DeFranzo et al[17] treated 75 patients with lower limb wounds and changed the dressings every 2 days, while Banwell and Téot[18] changed dressing every 4 days. Rozen et al[10] used their own NPWT for skin grafts and applied it continuously for 5 to 7 days and reported 100% graft take in chronic ulcers in the presence of comorbidities—what this indicates is that no consensus exists regarding dressing change intervals. In the present study, dressings were changed every 4 days because the authors choose to perform the dressing changes in the theatre under aseptic conditions, mostly via the administration of analgesics, except in patients with large painful wounds that required general anesthesia. This practice has also helped to reduce the number of dressing changes, increase patient comfort and compliance, and reduce overall treatment costs.

Although Argenta et al[8] have discouraged using wall suction stating large controlled volumes might induce wound desiccation,[8] Shalom et al[11] used wall suction successfully for 15 patients with complex wounds. Kiyokawa et al[19] used saline irrigation with continuous negative pressure through a continuous aspirator (Mera Sacume™) after experiencing foam contamination using the V.A.C system. Fenn and Butler[20] used suction drain bottle and wall suction for abdominoplasty wound dehiscence and achieved successful wound closure. Rozen et al[10] used conventional closed suction drain to apply negative pressure to skin grafts of nine patients. In the present study, both wall suction and an ordinary suction machine (locally manufactured) with controlled negative pressure were used and good results were obtained.

Management of full-thickness lower leg and foot wounds can be quite challenging when treatment options are limited (Figures 4A–C, 5A–C). If the patient has concomitant injuries such as a head or chest injury, reconstruction cannot be prioritized in the acute injury phase. Subatmospheric pressure dressing may extend the acute period and acts as a bridge during the time when major flaps and free tissue transfer procedures are not possible.[21] Most of the patients with lower limb wounds included in the present study also had injuries to the chest, abdomen, or head, or had diabetes, and/or hepatic/renal impairment. For this reason, NPWT provided the opportunity to cover the wound with a minimally invasive technique (ie, skin grafting).

Figure 4.

A. IIIC tibia fracture with bone loss after a traffic accident. This patient also suffered a head injury. B. Healthy granulation tissue after two sessions of negative pressure therapy. C. Coverage with skin graft.

Figure 5.

A. Crush injury to the right foot with exposed bones and tendons. B. Application of home-made negative pressure dressing. C. Complete graft take resulting in coverage of the large wound.

Negative pressure wound therapy has also gained popularity as a reliable and superior strategy for patients with postoperative deep sternal wound infections, as compared to conventional dressings.[22] The authors used NPWT to treat two patients with methicillin-resistant Staphylococcus aureus (MRSA) infected sternotomy wounds after cardiac bypass surgery. In both patients, discharge from the wound decreased significantly and wound cultures were negative for MRSA after 12 days (3 dressing changes). One of those patients was treated with NPWT until their wound healed completely. In the other patient's case, a pedicled latissimus dorsi muscle flap was utilized to fill the defect after the wound was cleared of MRSA in order to provide well-vascularized tissue to facilitate healing. She developed wound dehiscence at the inferior and right margin of the wound. She was subsequently treated with NPWT until the wound healed completely. Both these patients have well-healed sternotomy wounds without any fistulae or recurrence of infection at 6-month follow up. Although the number of cases in this study is low to compared to others in the literature, the duration of therapy is longer (23 days) compared to the study conducted by Gustafsson et al[23] (3–34 days, median 10 days) who treated 40 consecutive patients with deep sternal wounds.

The true efficacy of NPWT can be established by flawless randomized controlled trials. The paucity of such trials in the literature is due to the varying nature of wounds in different circumstances, involvement of different tissues, and availability of resources at different places. It is difficult to advocate the use of expensive forms of negative pressure therapy; nevertheless, one cannot deny the effectiveness of this treatment modality. Perez et al[24] compared the homemade vacuum system with conventional saline soaked gauze dressing and found that healing of complex wounds was significantly faster with homemade vacuum system as compared to conventional wound care. The main limitation of the present study is the absence of a control cohort treated with commercially available NPWT, so as to establish non-inferiority of the authors' technique. However, "homemade" solutions like the one presented here can be utilized anywhere, especially in resource challenged, third world countries. The authors recommend such cost effective solutions as the first line of treatment for management of complex wounds under challenging situations.

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