Understanding Negative Pressure Wound Therapy (NPWT)

Oct 29, 2023

Dr Tan Yih Kai

Negative Pressure Wound Therapy (NPWT) also commonly known as Vacuum-Assisted Closure (VAC) therapy for wounds, is an innovative approach to wound healing. It’s not just about closing wounds; it’s about facilitating quicker and more efficient healing using controlled air pressure. Here’s everything you need to know.

NPWT is a technique wherein a device reduces air pressure on a wound, accelerating its healing process. The atmospheric gases exert pressure on our body surfaces, and the wound vacuum removes this pressure specifically over the wound area. This action expedites healing by:

  • Draws fluid from the wound, reducing swelling.
  • Maintaining warmth and moisture in the wound environment to facilitate healing.
  • It helps bring the wound edges closer.
  • Increases blood flow to the wound.
  • Removes bacterial content in the wound.
  • Stimulates new tissue growth for wound closure.
  • Reduces wound inflammation.


A typical NPWT system consists of:

  • A foam or gauze dressing placed directly over the wound.
  • An adhesive film to seal the wound and dressing.
  • A drainage tube connected to a portable vacuum pump, which removes air pressure from the wound either continuously or in cycles.

Patients undergoing this therapy carry the portable pump with them, with dressing changes required every 2-4 days.

NPWT is appropriate for the following types of wounds:

  • Acute surgical wounds
  • Traumatic wounds
  • Non-healing or chronic open wounds (e.g., venous ulcers, and diabetic foot wounds)
  • Pressure ulcers
  • Assisting integration of skin graft

Moreover, NPWT can potentially reduce overall discomfort with dressings that are stable and require less frequent changes.

  • Wounds with exposure of blood vessels and nerves
  • Infected wounds
  • Contaminated wounds
  • Wounds with poor blood supply (Ischaemic wounds)
  • Bleeding from the wound.
  • Injury to the skin around the wound
  • Infection, especially when NPWT is applied prematurely before the wound is deemed clean.

However, with proper training and suitable candidate selection, these risks can be minimized.

When effectively applied, NPWT can offer numerous advantages, such as:

  • Quicker hospital release.
  • Reduced frequency of dressing replacements.
  • Minimized surgical interventions.
  • Decreased expenses related to nursing care.
  • Transition to more affordable healthcare environments.
  • Enhanced overall well-being and quality of life.

The Procedure: A foam or gauze dressing is placed over the wound, sealed with adhesive film. The foam connects to a portable vacuum pump via a drainage tube. The pump, when activated, draws fluid from the wound. Dressing changes are typically daily, though frequency may vary. Pain medication might be prescribed to mitigate discomfort during dressing changes.



Post-Therapy Considerations: It’s crucial to maintain good nutrition, ample rest, and abstain from smoking during the therapy duration, as these factors directly influence wound healing.

Negative Pressure Wound Therapy is revolutionising wound care, offering hope to patients with both acute and chronic wounds. By understanding its mechanism, benefits, and potential risks, patients and caregivers can make informed decisions about wound management.

  1. How long is vacuum-assisted closure therapy typically administered?
    • The therapy duration can vary, often spanning several weeks to months.
  2. Can I administer NPWT at home?
    • Yes, with proper training, NPWT can be administered at home.
  3. What should I do if there’s blood in the device’s tubing?
    • Report immediately to your healthcare provider the presence of blood or clots in the device’s tubing or collection chamber.
  4. How often do dressings need to be changed?
    • Dressings are generally changed every 2–4 days, but the frequency might differ based on the wound’s condition.
  5. Are there conditions that make VAC therapy unsuitable?
    • Yes, conditions like exposed organs, bone infections, cancerous tissue, and very poor wound blood flow may contraindicate NPWT. Always consult with your healthcare provider.

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