Comparison of Two Methods of Negative Pressure Wound Therapy

Prospective Randomized Control Trial Comparing Two Methods of Negative Pressure Wound Therapy: Gauze Suction Versus Vacuum Assisted Closure Device

The current standard for negative pressure wound therapy is the Vacuum Assisted Closure Device (VAC), a commercial system that utilizes a computerized suction pump to apply negative pressure to an open-cell poly-urethane foam dressing sealed over a wound. The VAC system is effective but has some drawbacks: The system is expensive. There us conflicting data about the effectiveness of VAC therapy for infected wounds. VAC therapy is difficult to use (and frequently fails) in wounds with excess fluid drainage, and in wounds near body orifices. Over the past 4 years, we have accumulated additional experience with negative pressure wound therapy using wall suction applied to sealed gauze dressings with about 30 patients. We call this method G-SUC and have used it when we have been unable to maintain a dressing seal with the VAC system (due to excess drainage or wound location), for management if infected wounds. We have found this method to be effective without any specific negative side effects. Our specific aims are: Compare the effectiveness of G-SUC and standard VAC therapy. Outcomes measured for each method will include the proportional change in wound size over 1 - 2 weeks. Compare the effectiveness of G-SUC and VAC system in controlling wound infections as measured by the number of patients who are able to clear infection by 4 days. Compare the failure of each method of therapy by documenting the number of dressing that cannot be maintained because of fluid or suction. Measure and compare the cost of wound treatment with the two methods including direct cost and time spent at the bed side performing the dressing change. Our hypotheses are: G-SUC and VAC are equivalent for the treatment of uncomplicated wounds in the acute care, in-patient setting. G-SUC is more effective than VAC for management of infected wounds. G-SUC is more versatile than VAC, and functional G-SUC dressings can be maintained in situations where functional VAC dressings cannot. Negative pressure therapy with G-SUC is less costly than VAC.

Gauze suction (G-SUC) Negative Pressure Wound Therapy, continuous wall suction at 75 to 80 mm Hg was applied and dressings were changed daily.

Vacuum Assisted Closure Device (VAC) Negative Pressure Wound Therapy, continuous suction at 75 to 125 mm Hg and the dressing was changed every 48 hours.

Wound surface area was measured daily. The percent change from Day 1 was calculated. A negative value indicates a decrease.

Wound volume was measured daily. The percent change from Day 1 was calculated. A negative value indicates a decrease.

Self-reported pain levels were used to assess pain. Patients were asked to rate their pain level according to the 0 to 10 linear analog scale immediately before, during, and after removal of the dressing. The average number of dressing changes for the G-SUC group was 4.5 (range 2-15) and the average number of dressing changes for the VAC group was 2.8 (range 2-6). The sum of pain intensity differences (SPID) was used to facilitate comparison of pain levels. The SPID score was calculated for each dressing change using the formula: (pain during - pain before) + (pain after - pain during). Higher values indicating greater pain.

Direct costs for each type of dressing were measured. In the VAC group, this included rental charges for the equipment and the cost of supplies. In the G-SUC group, this included the cost of supplies (suction canisters, catheters or drains, tubing, gauze, and adhesive drapes).

Inclusion Criteria: - Hospitalized patients at the University of Chicago Medical Center with acute wounds resulting from ether trauma, dehiscence or surgical complications Exclusion Criteria: Patients with systemic sepsis caused by wound infection Those with grossly necrotic wounds Malignancy in the wound Wounds with untreated osteomyelitis Patients with allergy to sulfamylon and Dakin's (sodium hypochlorite) Patients with 2 first criteria would become eligible once their sepsis resolves and/or necrotic tissue has been debrided from the wound.

Dorafshar AH, Franczyk M, Gottlieb LJ, Wroblewski KE, Lohman RF. A prospective randomized trial comparing subatmospheric wound therapy with a sealed gauze dressing and the standard vacuum-assisted closure device. Ann Plast Surg. 2012 Jul;69(1):79-84. doi: 10.1097/SAP.0b013e318221286c.