Products and systems
Authors: Christian Kaare Paaskesen Stud. Med, Magnus Balslev Avnstorp, MD, & Hasan Gökcer Tekin MD.
Multiple systems have been developed to preformed NPWT, in this chapter V.A.C and PICO V.A.C will be described.
V.A.C is a negative pressure wound therapy system used in inpatient and outpatient settings (the outpatient setting requires a portable bag). V.A.C can be used multiple times and is commonly used in combination with different types of foams. Black foam has a pore size of 400-600mm, whereas white foam has a pore size of 250mm. White foam has a higher tensile strength and is preferable for undermining wounds compared with black foam, to avoid small pieces of cut foam in the wound. Black foam does not clot as easy as white foam and can transport larger amounts of exudate and generate more granulation tissue. Although, caution is advised in low exuding wounds if the wound dries out and leads to ischemia and necrosis.
The function of foam dressings in NPWT is to distribute an even negative pressure over the whole wound bed. A silver foam is also available for wounds that needs an antibacterial component to ensure healing.
To prevent the foam from sticking to the wound, a silicone dressing (Cuticerin®) can be used as a primary dressing.
When the foam dressing is applied, a fenestrated evacuation tube is applied, and the site is covered with an adhesive drape. To ensure a water- and airtight site, secure the drape in a 3-5 cm peri wound distance on healthy tissue. The V.A.C. system provides the therapist with a selection of modes to choose from, either a continuous or intermittent (2 – 5 minutes) negative pressure ranging from 50 mmHg to 125 mmHg. Large and heavily exudating wounds may require a higher pressure(>150mmHg) (1, 2). Intermittent mode is recommended as it generates more blood flow in periods where the vacuum is off. Studies suggest that wound contraction and the formation rate of granulation tissue is improved using intermittent pressure settings on NPWT systems (3).
- Low – heavily exuding wounds
V.A.C treatment reduces the need of dressing changes and promote patient comfort. It also reduces bacterial load and edema while still maintaining an optimal closed moist environment. Ultimately resulting in faster healing and as a result reduces hospital stay. V.A.C has proven to create granulation tissue, and is widely used to fill out wound cavities. (2)
Some V.A.C. systems also have the ability to perform NPWTi-d and should be used according to manufacture and international guidelines. (4)
Air leak in the dressing can result in an air flow over the wound, desiccating the wound and forming eschar. Eschar seals the wound with retained exudate and leads to worsening of the wound. Once started, NPWT should not be terminated abruptly after one session, as it may result in what is called “rebound phenomenon” which leads to worsening of the wound. 2-3 sessions should always be planned. V.A.C. requires health-care professionals to ensure right and optimal treatment without technical failures. After 2-3 weeks, the formation of granulation tissue will stop, this is an indication to pause the treatment.
- KCI wound VAC system
- Acti V.A.C
- V.A.C. VERAFLO(NPWTi-d)
- Acti V.A.C ulta (NPWTi-d)
PICO is a onetime use negative pressure wound therapy system. It consists of a pocket-sized pump attached to special developed dressing. PICO is used in an outpatient setting and operates at an 80mmHg negative pressure.
- Low – moderate exuding wounds
PICO makes it possible to discharge patient earlier while still maintaining active treatment of a wound. This makes it easier for patients to maintain normal day to day activities. Dressing changes are easy and can be performed by patients at home. The PICO is usually to last 14 days before running out of battery, dressing changes are usually indicated after 5-7 days. PICO also removes wound odor through a unique combination of absorption and vaporization.
If necessary, materials like white and black foam can still be used in combination with the PICO. (5)
The PICO device is pocketsize, and easy for patients to carry around.
Compliance is very important when discharging patients. Information about hygiene and dressing changes must be understood properly, to ensure that the wound bed and peri wound skin do not take damage. The PICO has no cannister for wound exudate, this makes the PICO dependent on the dressing for the maximum exudate absorbance (multiple dressing sizes are available).
- Smith and Nephew PICO®
- Agarwal P, Kukrele R, Sharma D. Vacuum assisted closure (VAC)/negative pressure wound therapy (NPWT) for difficult wounds: A review. J Clin Orthop Trauma. 2019 Sep-Oct;10(5):845-848. doi: 10.1016/j.jcot.2019.06.015. Epub 2019 Jun 20. PMID: 31528055; PMCID: PMC6739293.
- Téot, Luc, Paul E. Banwell, Ulrich E. Ziegler, et al. , ‘Surgery in Wounds’, Anonymous Translator(, Berlin, Heidelberg, Springer Berlin Heidelberg, 2004).
- Malmsjö M, Gustafsson L, Lindstedt S, Gesslein B, Ingemansson R. The effects of variable, intermittent, and continuous negative pressure wound therapy, using foam or gauze, on wound contraction, granulation tissue formation, and ingrowth into the wound filler. Eplasty. 2012;12:e5. Epub 2012 Jan 24. PMID: 22292101; PMCID: PMC3266212
- Kim PJ, Attinger CE, Constantine T, Crist BD, Faust E, Hirche CR, Lavery LA, Messina VJ, Ohura N, Punch LJ, Wirth GA, Younis I, Téot L. Negative pressure wound therapy with instillation: International consensus guidelines update. Int Wound J. 2020 Feb;17(1):174-186. doi: 10.1111/iwj.13254. Epub 2019 Oct 30. PMID: 31667978; PMCID: PMC7003930.
- Payne C, Edwards D. Application of the Single Use Negative Pressure Wound Therapy Device (PICO) on a Heterogeneous Group of Surgical and Traumatic Wounds. Eplasty. 2014 Apr 28;14:e20. PMID: 24917894; PMCID: PMC4006427.