V.A.C.Ulta™ NPWT System Made Easy
01/09/12 | Complex wounds, Infection, Pressure ulcers | Rycerz A, Vowden K, Warner V, Jørgensen B.
Negative pressure wound therapy (NPWT) offers clinicians an important option for the advanced management of many wound types. Over the past 15 years NPWT has revolutionised care for many patients with chronic and acute wounds and has prompted the development of new NPWT systems, including portable, single-use and wound-specific devices. This requires a clear understanding of the characteristics of the various NPWT systems and applications. The V.A.C.Ulta™ Therapy System (KCI) is a new device that combines V.A.C.® Therapy (KCI) with the added option of the controlled delivery of topical instillation solutions to the wound bed using V.A.C. VeraFlo™ Therapy (KCI).
What is the V.A.C.Ulta™ NPWT System?
The V.A.C.Ulta™ System is an integrated negative pressure wound therapy (NPWT) system that offers standard NPWT (V.A.C.® Therapy) and an instillation option using V.A.C. VeraFlo™ Therapy (Figure 1). This combination system allows instillation solutions to be delivered to the wound bed to help manage complex, difficult-to-heal wounds, before converting to standard NPWT for further wound therapy. The V.A.C.Ulta™ System eliminates the need for a separate NPWT unit and manual application of a topical instillation solution between NPWT cycles.
How does the V.A.C.Ulta™ System deliver NPWT?
V.A.C.® Therapy is an established method of NPWT and has been used in the treatment of a variety of wounds since mid 1990s. The NPWT delivered by the V.A.C.Ulta™ Therapy System is the same as that provided by all other KCI V.A.C.® Therapy Systems and offers two therapy modes, both of which are monitored by SensaT.R.A.C.™ technology:
- A traditional continuous mode, which delivers negative pressure to the wound bed in the range of -25mmHg to -200mmHg
- Dynamic Pressure Control™ (DPC), which evolved from intermittent therapy and provides cycles of negative pressure to the wound bed. This maintains a low level of negative pressure (-25mmHg) between cycles to minimise the risk of leaks and fluid accumulation at the wound site. DPC may also help minimise patient discomfort from foam expansion that can occur when the negative pressure at the wound bed returns to 0mmHg.
How does the V.A.C.Ulta™ System deliver controlled wound instillation?
The V.A.C.Ulta™ System incorporates V.A.C. VeraFlo™ Therapy. This new technology combines V.A.C.® Therapy with the automated, controlled delivery and removal of topical wound instillation solutions at the wound bed (Figure 2).
This includes the following functions:
- The Fill Assist Tool - this allows the clinician to visually assess the correct instillation volume. Once set, the same amount of solution will be delivered for each subsequent instillation phase
- The Test Cycle Tool - this runs an abbreviated instillation cycle to ensure that the system is set up and functioning as intended
- n The Dressing Soak Tool - this allows the clinician to soak the dressing with instillation solution, making dressing removal easier and increasing patient comfort.
V.A.C. VeraFlo™ Therapy uses specially engineered dressings - the V.A.C. VeraFlo™ Dressing and the V.A.C. VeraFlo Cleanse™ Dressing - which have an open-pore structure that is similar to V.A.C.® GranuFoam™ Dressings. These dressings help to promote wound healing and have reduced hydrophobic properties. They also provide greater mechanical strength for use during instillation therapy, helping to prevent tearing at dressing changes.
The V.A.C. VeraFlo Cleanse™ Dressing is composed of denser material than the V.A.C. VeraFlo™ Dressing and is typically chosen when wound cleansing is the primary goal of therapy. Both dressings enhance fluid delivery and removal when used in combination with the V.A.C.Ulta™ System.
When is wound irrigation indicated?
It is now recognised that wound bed preparation plays a key role in creating an optimal wound healing environment. Regular cleansing of the wound can help to address the barriers to healing by removing devitalised tissue, debris, infectious agents and exudate to help prepare the wound bed for closure.
Wound irrigation is a long-standing practice that has been widely accepted for removal of these barriers to wound healing. Compared with swabbing or bathing, wound irrigation is considered to be the most consistently effective method of wound cleansing.
The role of instillation fluids in wound therapy
Instillation therapy combined with NPWT was introduced in 1998 for the management of septic wounds that had failed to respond to conventional therapy6. Initially, this system was used in infected wounds using antimicrobial solutions. This combined therapy has now been expanded to include cleansing regimens that can help to remove debris, exudate, infectious agents and healing inhibitors[7-8].
Several publications describe various clinical applications of instillation therapy, most of which focus on the treatment of wound infection. Gabriel et al looked at the use of instillation therapy on soft tissue infections, demonstrating that instilling silver nitrate helped reduce bioburden, decreased time to wound closure and allowed early hospital discharge. The instillation of a polyhexanide (PHMB) solution by Schintler et al and Timmers et al showed effective treatment of soft tissue necrotising fasciitis and osteomyelitis, respectively, when used in combination with other treatments. Lehner et al reported that the same regimen was an effective adjunctive therapy for acutely and chronically infected orthopaedic implants.
The role of biofilm management in wound care
It is now widely accepted that many chronic wounds contain biofilms. Biofilms develop when free floating micro-organisms attach to the wound surface, quickly replicating and forming colonies that are tolerant to antibiotics, antiseptics and disinfectants. As a result, systemic antimicrobial therapy may not be effective. Good wound bed preparation and topical antimicrobials are known to play an important role in the management
Evidence for V.A.C VeraFlo™ Therapy in biofilm management
Data using a biofilm model with pig skin explants have shown that V.A.C. VeraFlo™ Therapy, when combined with an appropriate antimicrobial solution (eg 0.1% PHMB), may have the ability to disrupt mature biofilms and to reduce bacterial load after 24 hours. This research needs to be confirmed in human trials, while further work is needed to determine the most appropriate solutions, and optimal concentrations, for use in the management of biofilms. Another bench study has shown that V.A.C. VeraFlo™ Therapy allows for more controlled wound cleansing with less aerosolisation compared with standard techniques, reducing the potential spread of biofilm-producing microorganisms during wound cleansing.