Vacuum-assisted closure (VAC) therapy has been used to manage wounds for 20 years and has taken wound treatment to a higher level. Clinical applications include chronic and acute wounds. Wound treatment has become easier with VAC. It improves the quality of life of the patient and reduces hospitalization time and expenses.
With the development of a portable vacuum device, treating patients with wounds is possible even in the home. We have been treating admitted and home care patients with VAC for five years in our Wound Centre. In this article, we discuss our experiences with VAC and review the procedure’s current applications and complications.
Background
Before the introduction of VAC therapy, the treatment and management of difficult wounds mainly belonged in the arena of plastic and reconstructive surgery.1 When Morykwas and colleagues developed VAC, however, they could have hoped only that it would take the treatment of acute and chronic wounds to a higher level.2 VAC is also known as TNP (topical negative pressure), as SPD (sub-atmospheric pressure), as VST (vacuum sealing technique), and as SSS (sealed surface wound suction).3 It is a technique that is easy to use in a clinical setting, and it has a low complication rate.4 The portable VAC system has made wound treatment possible in a home care setting, a development that improves quality of life and reduces hospitalization time.5,6 The portable VAC system (V.A.C. Freedom) is the size of a regular handbag. (See Figure 1, left.)
In this paper, we will discuss the working mechanisms of VAC, its current clinical applications, and the complications that might occur during VAC treatment.
Figure 1: The portable VAC device is the size of a regular handbag. Weighing little more than a kilogram, it is perfect for home care treatment.
How Does It Work?
Normally, wounds heal by approximation of the wound edges—for example, by suturing or by the formation of a matrix of small blood vessels and connective tissue, when wound edges are not opposed, for the migration of keratinocytes across the surface and the re-epithelialization of the defect. This is a complex process; its main objectives can be considered minimization of blood loss, replacement of any defects with new tissue (granulation), and the restoration of an intact epithelial barrier. For this process to occur, healing debris must be removed, infection must be controlled, and inflammation must be cleared.4 Further disturbance of the rate of healing may occur due to inadequate vascular supply and incapacity of the wound to form new capillaries or matrix. Any disruption in the processes involved in wound healing, such as debridement, granulation, and epithelialization, can lead to the formation of a chronic wound. In our Wound Centre, VAC is mainly used in the granulation phase of a wound, as well as for securing split skin grafts.7
VAC uses medical-grade, open cell polyurethane ether foam.2,4 The pore size is generally 400-600 micrometers. This foam is cut to fit the wound bed before it is applied to the wound. If necessary, multiple pieces of foam can be used to connect separate wounds or to fill up any remaining gaps. Adhesive tape is then applied over an additional three to five cm border of intact skin to provide a seal.4 Then a track pad is placed over a small hole in the adhesive tape. A tube connects the track pad to an adjustable vacuum pump and a canister for collecting effluent fluids. The pump can be adjusted for both the timing (intermittent vs. continuous) and the magnitude of the vacuum effect.4 In general, an intermittent cycle (five minutes on, two minutes off) is used; this has been shown to be most beneficial.2 The VAC system is easy to apply, even on difficult wounds like the open abdomen. (See Figure 2, left.)