'Indirect VAC': a novel technique of applying vacuum-assisted closure dressing.
Vacuum-assisted closure (VAC) wound dressing is increasingly used
to assist closure in various wounds ranging from simple finger pulp
defect to complex wounds such as laparostomy or infected sternotomy. The
traditional application of direct vacuum therapy can cause discomfort
and put the patient at risk of injuring the affected area while
mobilising. We describe a novel technique of applying VAC therapy
indirectly which is much more comfortable and convenient for the patient
KEYWORDS Dressing / Vacuum / Wound
Davies, Tony W.
|Publication:||Name: Journal of Perioperative Practice Publisher: Association for Perioperative Practice Audience: Academic Format: Magazine/Journal Subject: Health; Health care industry Copyright: COPYRIGHT 2008 Association for Perioperative Practice ISSN: 1750-4589|
|Issue:||Date: Oct, 2008 Source Volume: 18 Source Issue: 10|
VAC wound dressings are increasingly used (Jerome 2007) in the management of various wounds ranging from finger pulp defects (Attar et al 2007) to laparotomy (Bettschart et al 2002, Penn & Rayment 2004) and sternotomy with deep wound infection (Ibrahim & Refaat 2007). VAC therapy improves blood flow, reduces local tissue oedema and removes excess fluid and bacteria from the wound (Venturi et al 2005). It also alters the cytoskeleton of the cells causing increased cellular mitosis (Venturi et al 2005). It is common for the device to be applied straight on to the sponge covering the wound (Direct VAC). When the VAC dressing is applied particularly to a sacral bed sore or diabetic foot, the Therapeutic Regulated Accurate Care (TRAC[R]) pad tubes protrude from the surface and can cause discomfort to the patient. The patient could be injured at the wound site while mobilising.
Here, the authors describe a convenient method of applying VAC, which we call 'Indirect VAC application technique', which we have found to be more comfortable for the patient. It also avoids the VAC TRAC[R] pad tubing protruding from the surface and will be useful for routine use in all types of wounds requiring VAC dressing.
Indirect VAC therapy
The VAC dressing kit comprises of a sponge (Figure 1), two big airproof adhesive films, a canister, TRAC[R] pad tubes for connecting the sponge and the canister and a machine for producing a vacuum. A long thin strip of sponge is required for indirect VAC therapy (or tail VAC). Such a strip can be cut from the main sponge (Figure 1d). Then the remaining main sponge is cut to the correct size to match the contour of the wound. The big sheet of adhesive polyfilm that comes with the kit may be cut into several small strips (Figure 1B). It enables the physician to apply the VAC dressing comfortably in difficult areas without any leaks.
[FIGURE 1 OMITTED]
The main sponge is applied to the wound and covered with polyfilm strips (Figure 2A). Near the main sponge covering the wound, a strip of polyfilm is applied on to the bare normal skin away from bony prominences and areas subject to pressure. A small aperture is made in the polyfilm covering the wound and the thin strip of sponge that was excised at the beginning is applied on to the aperture and spread out on to the polyfilm on the bare skin (Figure 2B). The strip of sponge is covered with polyfilm strips (Figure 2B). Another aperture is made on to the polyfilm covering the sponge strip and the VAC TRAC[R] pad (Figure 1A) is applied. Figure 2C shows the functioning indirect VAC dressing in place.
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
Vacuum dressings help in rapid wound healing. The reticulated cells of the sponge evenly distribute the negative pressure. The VAC dressing is changed every three days, reducing nursing time, and the canister is changed once a week or when full. The VAC dressing also shrinks the size of the wound reducing the need for skin grafting. If a skin graft is required, VAC prepares the bed of the wound so that the uptake will be optimised (Espensen et al 2002). In diabetic foot sepsis, VAC may be applied after toe amputation or wound debridement to allow the patient home using the VAC dressing (Figure 3) and therefore reducing hospital stay. The diabetic foot wound is usually not suitable for immediate skin grafting but the VAC is of immense help in preparing the field for future grafting (Valenta 1994). Although the vacuum is used extensively in various situations (Lemaire et al 2008, Petzina et al 2008, Zwillinger et al 2008) and allows the patient to go home early (Wu & Armstrong 2008), recent systematic reviews did not find enough evidence to support its use in wound healing (Gregor et al 2008, Ubbink et al 2008). VAC removes tissue fluid, thereby decreasing local oedema and shrinks the wound. It also facilitates increased formation of new blood vessels and granulation tissue which is optimal at 125 mmHg (Thomas 2001). Experiments show that intermittent vacuum therapy may work better than continuous negative pressure settings (Philbeck 1999). At the cellular level VAC, using the sponge, caused increased cellular growth, chemotaxis and proliferation without increasing the apoptosis (death) of the cells (McNulty et al 2007). VAC therapy may or may not affect the bacterial load in the tissues (Muller 1997, Ubbink et al 2008). For efficient therapy, any eschar and slough should be debrided prior to application of VAC because they can block the pores of the sponge.
Wound healing occurs by three methods:
* primary intention
* secondary intention
* tertiary intention.
Healing by primary intention occurs when the wound is closed primarily, for example, after excision of a cutaneous lump and closure of the wound. When a wound is left open to heal by nature, the mechanism is called healing by secondary intention. Granulation tissue and fibroblast fills the gap and the fibroblasts shrink the wound. This happens in abscesses after incision and drainage. VAC increases the granulation tissue formation and also reduces the size of the wound by negative pressure and removal of tissue oedema.
Here the wound heals faster than simple secondary wound healing alone, i.e. open wounds without VAC. When a wound is left open for a few days and subsequently sutured, the process of healing is called healing by tertiary intention or delayed primary closure.
We have found indirect VAC technique very useful in healing pressure ulcers. Over the past six years, we have used this method of VAC dressing in at least 200 patients. The types of wounds in which Indirect VAC was used varied from diabetic foot to necrotising fasciitis wounds after debridement. We have found this technique to be much more comfortable to the patients. Within the time period of observation, no incidents of trauma from VAC were observed from this indirect technique.
Two similar techniques have been described which also decrease patient discomfort. The 'bridging technique' (Banwell et al 2002, Venturi et al 2005) and 'heel dressing' (Schneider et al 1998) are similar to our VAC dressing and usually applied to the foot alone. The polyfilm is used as a single piece whereas we describe the adhesive polyfilm being cut into small pieces and applied as required. Additional pieces of sponges can be added to the second (indirect) sponge to extend the application site of the TRAC[R] pad to a convenient and comfortable place. This is useful in sacral pressure ulcers. In a custom made VAC GranuFoam[R] Heel Dressing (KCI, Kidlington, UK), the extension sponge (Heel) comes with the kit itself. The dressing TRAC[R] pad is placed on top of the foot. In the Heel dressing, VAC is often applied to the heel over a skin graft and the patient can be allowed to mobilise early without losing the skin graft. In our technique, we cut the heel shape from the main sponge ourselves and therefore reduced the cost of the dressing without the need for a special heel dressing.
Close proximity to large vessels is a contraindication to VAC therapy. Other contraindications include the risk of haemorrhage, extensive necrotic tissue, osteomyelitis, malignant wounds and an underlying entero-cutaneous fistula.
Direct application of the VAC TRAC[R] pad may cause significant discomfort and there is a potential risk of causing injury. The authors believe that the new technique (Indirect VAC) will improve patient comfort and may avoid potential injuries.
Provenance and Peer review: Unsolicited submission; Peer reviewed.
Attar KH, Imran D, Iyer S 2007 Vacuum-assisted closure (VAC) therapy in the management of digital pulp defects Acta Chirurgiae Plasticae 49 (3) 75-76
Banwell PE, Evison D, Whitworth IM 2002 Vacuum therapy in degloving injuries of the foot: technical refinements British Journal of Plastic Surgery 55 (3) 264-266
Bettschart V, Vallet C, Majno P et al 2002 Laparostomy with vacuum dressing after liver transplantation Transplantation Proceedings 34 (3) 777-778
Espensen EH, Nixon BP, Lavery LA, Armstrong DG 2002 Use of subatmospheric (VAC) therapy to improve bioengineered tissue grafting in diabetic foot wounds Journal of the American Podiatric Medical Association 92 (7) 395-397
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Ibrahim MF, Refaat AA 2007 ICVTS on-line discussion B. VAC therapy in post cardiac surgery deep sternal wound infection Interactive Cardiovascular and Thoracic Surgery 6 (4) 527-528
Jerome D 2007 Advances in negative pressure wound therapy: the VAC instill Journal of Wound, Ostomy, and Continence Nursing 34 (2) 191-194
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McNulty AK, Schmidt M, Feeley T, Kieswetter K 2007 Effects of negative pressure wound therapy on fibroblast viability, chemotactic signaling, and proliferation in a provisional wound (fibrin) matrix Wound Repair and Regeneration 15 (6) 838-846
Muller G 1997 Vacuum dressing in septic wound treatment Langenbecks Archiv fur Chirurgie Supplement Kongressband 114, 537-541
Penn E, Rayment S 2004 Management of a dehisced abdominal wound with VAC therapy British Journal of Nursing 13 (4) 194-201
Petzina R, Ugander M, Gustafsson L 2008 Topical negative pressure therapy of a sternotomy wound increases sternal fluid content but does not affect internal thoracic artery blood flow: assessment using magnetic resonance imaging Journal of Thoracic and Cardiovascular Surgery 135 (5) 1007-1013
Philbeck TE, Millsap MH, Briones RB, Wight DG, Schroeder WJ 1999 The clinical and cost-effectiveness of externally applied negative pressure wound therapy in the treatment of wounds in home healthcare Medicare patients Ostomy/Wound Management 45 (11) 41-50
Schneider AM, Morykwas MJ, Argenta LC 1998 A new and reliable method of securing skin grafts to the difficult recipient bed Plastic and Reconstructive Surgery 102 (4) 1195-1198
Thomas S 2001 An introduction to the use of Vacuum-assisted closure (online) Available from: www.worldwidewounds.com [Accessed 14 August 2008]
Ubbink DT, Westerbos SJ, Nelson EA, Vermeulen H 2008 A systematic review of topical negative pressure therapy for acute and chronic wounds British Journal of Surgery 95 (6) 685-692
Valenta AL 1994 Using the vacuum dressing alternative for difficult wounds American Journal of Nursing 94 (4) 44-45
Venturi ML, Attinger CE, Mesbahi AN, Hess CL, Graw S 2005 Mechanisms and clinical applications of the vacuum-assisted closure (VAC) Device: a review American Journal of Clinical Dermatology 6 (3) 185-194
Wu SC, Armstrong DG 2008 Clinical outcome of diabetic foot ulcers treated with negative pressure wound therapy and the transition from acute care to home care International Wound Journal 5 (Suppl 2) 10-16
Zwillinger N, Carette S, Lorenceau B 2008 Salvage of a leg avulsion injury by vacuum negative pressure therapy: a case report Annales de chirurgie plastique et esthetique 53 (1) 74-78
Specialist Registrar, Department of Surgery, Queen Mary's Hospital, Sidcup
Consultant Surgeon, Department of Surgery, Queen Mary's Hospital, Sidcup
Tony W Davies
Consultant Surgeon, Department of Surgery, Queen Mary's Hospital, Sidcup, UK
Correspondence address: Department of Surgery, Queen Mary's Hospital, Sidcup, DA14 6LT. Email: email@example.com
Table 1 Case study: Application Vac dressing when a major vessel is exposed In our reported case (see Figure 2), the patient, an intravenous drug abuser, underwent debridement of necrotic tissue in the left groin. The femoral artery was exposed and there was only thin fascia covering the artery. A Mepitel (Direct Medical, Texas, USA) dressing was used to protect the blood vessel before the VAC was applied (KCI, UK) using a portable vacuum machine. Using the indirect VAC technique and removing the TRAC[R] pad from the groin crease, allowed the wound to granulate while the patient mobilised. Within two weeks, sufficient granulation tissue had formed to protect the vessels and allow standard dressings while the wound healed by secondary intention. Table 2 Tips for successful and comfortable application of VAC dressings Suggestion Reason Turn off the machine and Suction will cause pain disconnect the VAC tubing before changing the dressing Make sure the dressings Otherwise the therapy will not are air tight work Any slough (dead tissue) and Will obstruct the VAC sponge eschar should be excised Make sure VAC sponge does not Vacuum on normal skin is painful contact the normal skin When the wound affects pressure Otherwise the patient may get points such as sacrum, heel etc, further pressure sores from the use the method described by us to VAC tube move the TRAC pad well away from the wound If you suspect an enterocutaneous VAC is contra-indicated fistula or a big blood vessel underneath the VAC dressing inform relevant surgical team Change the canister earlier than VAC will not work when canister is seven days when it is full full
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