Vacuum-assisted wound closure (VAC) was introduced by Argenta and Morykwas1



 VAC is wound management technique that  exposes the wound bed to mechanically induced negative pressure, thereby removing fluid from the extravascular space, improving circulation, and enhancing the proliferation of reparative granulation tissue.


Elements of the VAC System

A VAC system consists of several essential elements –

1) A sterile reticulated polyurethane sponge is cut to conform to the surface of the wound and then is placed into the wound to make contact with the entire wound surface.

2) A plastic egress tube runs from the sponge to another tube, which is connected to a reservoir and programmable vacuum pump.

3) An adherent plastic sheet with adhesive on one side is placed over the sponge around the tubing. The sheet passes onto and into the sponge and adheres to the surrounding skin to seal it and thereby form a closed system for the wound.

4) The settings for the vacuum pump are adjustable for levels of negative pressure from 50 mm Hg to 200 mm Hg.

5) The pump settings can be adjusted for either continuous or intermittent operation.


Pre-requsites for applying vac

1) All devitalized and contaminated material are removed, this material is a focus for bacterial

Growth, which impedes the wound-healing process.

2) Also, thorough débridement is critical before application of VAC.


Key points in application of VAC

 1)The sponge can be cut to match the shape of the wound. It should be placed so that it has direct contact with the entire wound surface, particularly at its depth . If this is not done, the wound tissue can proliferate above the deepest part of the wound and possibly

wall off a “dead space,” which could cause abscess formation and ultimately prolong time to healing.

2)The sponge should be loose and expanded, not tightly packed.

3)the end opposite the reservoir and is either inserted into the sponge

through a hole cut with scissors or placed on its surface

4). The sponge and tube are then sealed to each other and anchored to the skin with the clear flexible plastic sheet cut to an appropriate size, preferably with a mesentery between the tube (where it lifts from the sponge)and the corresponding skin.

5) When the components are properly placed, a closed system is created consisting of the wound, the sponge, the lumen of the tube, and the collecting

reservoir. The reservoir is then placed into the receiving slot on the vacuum pump, and negative pressure is generated .

6) A continuous pressure of 125 mm Hg below ambient pressure is the most

commonly used setting. The intermittent setting was originally designed

into the system because of the animal experiments that showed beneficial effects on blood flow, granulation tissue formation, and random flap survival with an intermittent 3-minutes-on, 5-minutes-off cycle. However, when the ambient

pressure cycles back to 0 mm Hg, the sponge re-expands. This causes some motion at the wound surface, which creates pain. Therefore, the intermittent setting is seldom used. For a weeping wound, a lower negative pressure setting (−50 mm Hg) is used to minimize the irritation of the intact skin at the wound margin.

7) The sponge is usually changed at 48-hour intervals as a bedside procedure

if this schedule is tolerated by the patient and the wound size is limited. Local anesthetic (topical 1% lidocaine placed in the sponge after the vacuum has been turned off) has successfully alleviated pain during sponge changes.

8) For patients with extensive wounds with large surface areas in locations characterized by regional edema or in patients with systemic edema, careful monitoring of fluid volume, hemodynamics, and electrolyte balance may best be conducted in an intensive care unit, an intermediate care unit, or a burn unit. Anticoagulated patients should be monitored carefully.

Indications by Wound Classification

Wounds treated with the VAC technique can be grouped into nine descriptive categories:

(1) Wounds to which a split-thickness skin graft is applied,

(2) Infected wounds (after debridement),

(3) open fracture wounds,

(4) Acute soft-tissue wounds (with exposed tendon, hardware, bone, and/or     joint),

(5) Fasciotomy wounds after compartment syndrome,

(6) Chronic wounds (>3 months’ duration),

(7) Surgical wounds that are difficult to close because of tension,

(8) Wounds with external fixation pins or tubes or catheter sites with irritation and drainage, and

(9) Surgical wounds that weep serous fluid after the second postoperative day.


Key settings specific for wound type-

1) For wound types 1 through 7, the pressure setting is −125 mm Hg and the sponge is changed at 48-hour intervals. For wound types 2, 3, 4, and 6, the VAC technique is appropriate only after complete débridement. In infected wounds or severely contaminated acute wounds, it may be appropriate to wait for a “second look” débridement to be confident that all of the devitalized tissue has been removed.

2) For wound type 8 (external fixation pin irritation), the pressure setting is −50 mm Hg and the sponge at the base of the pin can be changed about once per week. Sterile hydrocolloid gel is useful circumferentially around the pin a short distance (1 in) above the skin to aid in sealing the sponge with the adhesive sheet.

3) For wound type 9 (weeping surgical wounds), the sponge is also applied with the pressure setting lowered to −50 mm Hg so as not to irritate the skin.

When used to bolster a split thickness skin graft (wound type 1), the sponge is applied directly over the split graft, which covers the entire wound surface. The pressure is set at −125 mm Hg and the sponge left in place for 4 days. (If a portion of the graft lifts from the recipient bed at the time of sponge removal, the graft and sponge are reapplied to the bed and sealed, and the negative pressure is re-established for 48 hours.)



-The granulation is often exuberant and will cover small areas of exposed hardware, bone, fascia, and tendon, provided these structures are clean.

 -The VAC method is not a substitute for débridement, however, and with infected wounds, contaminated and devitalized tissues and/or retained implants ordinarily will require removal. Split-thickness skin grafts have been observed to heal more predictably with this technique.This may be because of the evacuation of the serous fluid that forms on the surface of the wound.

-When the VAC system is used as a dressing for fasciotomy wounds after compartment syndrome, edema can be minimized and viable muscle preserved.

-For weeping wounds with confirmed drainage beyond the second postoperative day, a successful transition to a clean, dry wound free of infection is the desired end point.

-Other advantages

1)The ability to directly inspect the vacuum tube and reservoir allows the surgeon to assess the character and volume of the drainage fluid.

2)In addition, the VAC system allows wound fluid to be collected for future analysis.

Complications and Contraindications

1) The most common is a rash on the skin resulting from contact with the suction Sponge , which usually resolves in 24 hours. To minimize this complication, care Should be taken to confine the sponge to the wound and avoid any Overlap onto the normal skin. If overlap of the skin is unavoidable, such as with application over a surgical wound, a setting of −50 mm Hg can be used. The technique is therefore contraindicated in individuals who are intolerant (for either allergic or mechanical reasons) of adhesives on the skin.

2) The effects of the VAC technique on neoplasm are unknown; accordingly, VAC should not be used when neoplasm is part of the wound. 

Principles of VAC

The VAC technique acts to pull off the fluid from the tissue space, thereby lowering capillary afterloadin the zone of stasis. Because the embarrassment to microcirculation is removed, delivery of oxygen and nutrients is enhanced while removal of inhibitory factors and toxins is facilitated. Because bacterial colonization hampers wound healing, the effect of lowering the wound bacterial count may give vacuum treatment an advantage over other methods for management of open contaminated wounds or wounds with a history of infection. VAC appears to offer some distinct advantages over traditional wound closure methods. These include evacuation of wound edema, hastening and promoting the formation of hypervascular wound granulation, and rapid and complete incorporation of meshed split-thickness skin grafts. The system is closed, which lowers the likelihood of wound contamination by resistant hospital organisms.