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Science Behind V.A.C. Therapy

Wound Healing Begins at the Cellular Level

Understanding the Science of V.A.C. Therapy

With more than 918 peer-reviewed articles, the clinical and economic benefits of V.A.C.® (Vacuum Assisted Closure®) Therapy are widely known: faster 20 and more effective5 than gauze11,14, leading to improved patient Quality of Life1 and cost - effectiveness3. However, it is equally important to understand how V.A.C. Therapy works deep inside the wound to achieve the superior clinical outcomes. The following sections describe how V.A.C. Therapy promotes wound healing and how its unique mechanisms of action differentiate it from other Negative Pressure Wound Therapy devices.

What Makes Up the V.A.C. Therapy System

Three Critical Components, One Unique Integrated System

The V.A.C. Therapy System is comprised of three essential components that actively work together to help wound healing through promotion of granulation tissue formation2, 12, 13.



Image of V.A.C. Therapy System




  1. V.A.C. Therapy Units Provides intermittent and continuous therapy with integrated patient safety features, delivering controlled negative (sub-atmospheric) pressure to the wound site
  2. SensaT.R.A.C. Technology Regulates the equal distribution of pressure across the wound area
  3. V.A.C. GranuFoam Dressings Are designed for negative pressure wound therapy, drawing fluid away from the wound site, provide both a microstrain and macrostrain effect for optimal wound healing.

How V.A.C. Therapy Works at the Cellular Level

The Science Behind V.A.C. Therapy: Macrostrain and Microstrain

Under negative pressure, V.A.C. Therapy with proprietary V.A.C. GranuFoam™ Dressings applies both mechanical and biological forces to the wound to create an environment that promotes wound healing. These forces are known as macrostrain and microstrain.


Image of macrostrain



Macrostrain is the visible alteration that occurs when negative pressure contracts the open pore V.A.C. GranuFoam dressing.


  • Draws the wound edges together
  • Provides direct and complete wound bed contact
  • Evenly distributes negative pressure
  • Removes wound exudate and materials which may cause infection


Image of microstrain



Microstrain takes place at the cellular level, leading to cell stretching induced by the open pore V.A.C. GranuFoam contact with the wound bed.


  • Encourages moist wound healing
  • Promotes granulation tissue formation
  • Promotes perfusion through angiogenesis
  • Increases cellular proliferation and migration
  • Reduces oedema

Using V.A.C. Therapy with V.A.C. open pore GranuFoam dressings results in both macrostrain11, 16, 18 and microstrain 11 ,  16 ,  18  working together to give clinically proven results for advanced wound healing.

Watch a video of how V.A.C. Therapy works at the cellular level through macrostrain and microstrain.






  V.A.C. Therapy Mechanisms of Action – Transcription (RTF, 28.7 KB)

How V.A.C. Therapy Removes Barriers to Wound Healing

V.A.C. Therapy Mechanisms of Action

V.A.C. Therapy provides a closed, moist environment that promotes wound healing through the following mechanisms:

Wound Healing Barrier V.A.C. Therapy Mechanism
Excessive bacterial burden Removes infectious materials
Inadequate protection against infection Provides a closed, protected wound healing environment
Excess exudate Removes exudate
Excess oedema (interstitial fluid) Reduces oedema (interstitial fluid)
Absence of moisture Provides a moist wound healing environment
Lack of adequate blood flow Promotes perfusion and angiogenesis
Lack of cellular activity Promotes cellular migration and proliferation during granulation tissue formation

SensaT.R.A.C. Technology

V.A.C. Therapy uses SensaT.R.A.C.™ (Therapeutic Regulated Accurate Care) to:

  • Monitor and maintain target pressure at the wound site for consistent therapy delivery
  •  Reduce tubing blockages and false alarms through enhanced fluid dynamics
  •  Enable use of Smart Alarms for increased patient safety
  • Provide easier and more efficient V.A.C. dressing application
  • Enhance patient comfort

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