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Quantifying Bacterial Bioburden During Negative Pressure Wound Therapy: Does the Wound VAC Enhance Bacterial Clearance?

Weed, Tonja MD; Ratliff, Catherine RN, PhD; Drake, David B. MD

Original Article

The bacterial colonization of a wound is a recognized detrimental factor in the multifactorial process of wound healing. The harmful effects on wound healing are recognized to correspond to a level of >105 colonies of bacteria per gram of tissue. Negative pressure wound therapy has become an accepted treatment modality for acute and chronic wounds with accelerated healing rates observed. It has been previously reported that this therapy enhances bacterial clearance, which may account for the wound healing effects noted. We retrospectively reviewed 25 patients’ charts undergoing Wound VAC (Vacuum Assisted Closure Device; KCI International, San Antonio, TX) therapy with serial quantitative cultures and found that there is not a consistent effect of bacterial clearance with the Wound VAC. Furthermore, bacterial colonization increased significantly with Wound VAC therapy and remained in a range of 104–106. Despite this finding, the beneficial effects of this treatment modality on wound healing were noted in most cases.

The purpose of this study was to quantitatively assess and monitor the degree of bacterial bioburden during negative pressure wound therapy for both acute and chronic wounds. The Wound VAC is a closed dressing system that applies negative pressure to a wound bed through an open cell sponge covered with an occlusive dressing. This dressing is connected by tubing to a pump that supplies negative pressure. The sponge and tubing system are changed every 3–5 days as recommended by the manufacturer. The VAC is currently in use for both inpatients and outpatients to optimize the wound environment and promote wound healing. Traditionally, occlusive dressings over contaminated wounds are thought to be detrimental to wound healing due to the effect of promoting increased levels of bacteria in the wound. Excellent healing rates have been reported with the VAC system, but heretofore the clinical level of bacterial bioburden has not been defined during the use of this dressing system.

A review of 25 patients undergoing VAC treatment demonstrated increased quantitative bacterial colonization of wound exudate during use of the VAC device. The wounds nevertheless showed beneficial effects of healing during treatment.

From the Department of Plastic Surgery, University of Virginia Health System, Charlottesville, VA.

Received September 28, 2003 and accepted for publication September 29, 2003.

Reprints: David B. Drake, MD, FACS, Associate Professor, Department of Plastic Surgery, P.O. Box 800376, University of Virginia Health System, Charlottesville, VA 22908

Presented at the Southeastern Society of Plastic and Reconstructive Surgeons, Palm Beach, FL, June 2, 2003.

© 2004 Lippincott Williams & Wilkins, Inc.