What is the recommended treatment for chronic or non-healing wounds using wound vac (Vacuum-Assisted Closure) therapy?

Negative Pressure Wound Therapy for Chronic and Non-Healing Wounds

Negative pressure wound therapy (NPWT) should be used for post-surgical diabetic foot wounds to reduce wound size and promote healing, but is not recommended as first-line therapy for non-surgical chronic wounds. 1

Mechanism of Action and Benefits

NPWT (also called vacuum-assisted closure or wound VAC) works by:

• Applying continuous or intermittent negative pressure (typically 125 mmHg below ambient pressure)
• Removing excess fluid from the wound bed
• Stimulating granulation tissue formation and wound contraction
• Reducing wound edema and bacterial load
• Improving tissue perfusion and angiogenesis 2

Evidence-Based Recommendations by Wound Type

1. Post-Surgical Wounds

NPWT is most effective for post-surgical wounds, particularly:

• Post-amputation wounds
• Surgical debridement sites
• Wounds after revascularization and minor amputation when primary or delayed secondary closure is not feasible 1

Studies show:

• Greater proportion of foot ulcers achieved complete closure with NPWT than with advanced wound therapy (43.2% vs 28.9%) 1
• Faster healing times compared to standard care 1
• Improved success rates with split skin grafting when combined with NPWT 1

2. Non-Surgical Chronic Wounds

For non-surgical chronic wounds:

• NPWT is not recommended as first-line therapy over best standard of care 1
• Multiple studies comparing NPWT with standard care for non-surgical wounds have high risk of bias 1
• Evidence for effectiveness in non-surgical wounds is limited and inconsistent 1

Application Protocol

1. Wound Preparation:

   • Perform thorough debridement of nonviable tissue
   • Ensure adequate hemostasis
   • Clean wound with appropriate solutions

2. NPWT Application:

   • Apply sterile foam dressing to wound cavity
   • Place fenestrated tube embedded in foam
   • Seal wound with adhesive tape to create airtight environment
   • Connect tube to vacuum pump with fluid collection container
   • Set pressure between 50-125 mmHg (typically 125 mmHg) 2
   • Use continuous or intermittent suction as indicated

3. Maintenance:

   • Change dressings every 3 days 2
   • Regularly assess wound progress
   • Continue until wound is ready for closure, covered with skin graft, or healed

Patient Selection and Considerations

Good Candidates:

• Patients with post-surgical diabetic foot wounds 1
• Post-amputation wounds 1
• Patients with adequate perfusion to the wound area 1

Poor Candidates:

• Patients with non-surgical chronic wounds as primary therapy 1
• Wounds with inadequate debridement
• Wounds with untreated infection
• Patients with poor vascular supply without revascularization 1

Potential Complications and Pitfalls

• Wound maceration
• Retention of dressings
• Potential wound infection
• Pain during therapy
• Cost and patient burden considerations 1

Comprehensive Wound Management

NPWT should be part of a comprehensive approach including:

• Revascularization for adequate perfusion
• Debridement of nonviable tissue
• Management of infection
• Pressure offloading when appropriate
• Medical optimization (glycemic control, smoking cessation)
• Pain control
• Control of edema 1

When to Discontinue NPWT

• When the wound has adequately granulated
• When the wound is ready for surgical closure
• When there is no improvement after 2-3 weeks of therapy
• If complications develop

NPWT represents an important adjunctive therapy for specific wound types, particularly post-surgical wounds, but should be used as part of a comprehensive wound management strategy with careful patient selection.