When is negative pressure dressing (NPWT) recommended for chronic wounds?

Negative Pressure Wound Therapy for Chronic Wounds

Direct Recommendation

Consider NPWT only for post-operative diabetic foot wounds to reduce wound size, but avoid it for non-surgical chronic wounds where evidence does not support its use. 1

Clinical Algorithm for NPWT Use

When to Use NPWT

Post-Surgical Wounds (Recommended with Caution)

• Apply NPWT after foot amputations in diabetic patients, where studies show 43.2% complete closure versus 28.9% with standard therapy 2
• Use after complete surgical debridement of infected wounds, once all necrotic tissue is removed 3
• Consider for post-operative wounds following hindfoot/ankle reconstructions or total ankle replacements 4
• Apply to improve split-thickness skin graft success, though evidence quality is limited 1

Critical Prerequisites Before Application

• Complete surgical removal of all necrotic and infected tissue must be accomplished first, continuing into healthy-looking tissue 3
• Never apply NPWT to wounds with residual necrotic tissue or uncontrolled infection 3
• Ensure adequate lower-extremity arterial flow is present 1

When NOT to Use NPWT

Non-Surgical Chronic Wounds (Not Recommended)

• Do not use NPWT for non-surgical diabetic foot ulcers, as the International Working Group on the Diabetic Foot provides a weak recommendation against this practice due to conflicting and methodologically flawed studies 1, 3
• Avoid in venous leg ulcers where the evidence base is weakest 5
• Do not select NPWT in preference to standard care for chronic pressure ulcers without surgical intervention 1

Technical Specifications

Pressure Settings

• Use standard pressure of 80-125 mmHg for most applications 6
• Reduce to 75-80 mmHg for vulnerable anatomic areas, exposed structures, or fragile tissue 2, 7

Dressing Management

• Change dressings every 2-3 days, with an average of 5 dressing changes required for optimal granulation 3, 7
• Use white foam over exposed structures, fragile tissue, or when frequent assessment is needed, as it creates a non-adherent interface preventing excessive tissue ingrowth 2
• Apply a non-adherent wound contact layer beneath foam to prevent excessive fluid removal and desiccation 2

Evidence Quality and Limitations

Strength of Evidence

• All recommendations for NPWT carry weak strength with low-to-moderate quality evidence 1
• Studies in post-operative wounds show benefit but have high risk of bias, high dropout rates, and methodological flaws 1
• The evidence base is strongest for non-ischemic diabetic foot ulcers post-surgery and weakest for venous leg ulcers 5

Cost-Effectiveness Concerns

• Cost-effectiveness remains unproven even in post-surgical applications where some benefit exists 2
• Significant resource requirements include specialized equipment, trained personnel, and frequent monitoring 2
• Patient burden includes frequent clinic visits, potential adverse effects like wound maceration, dressing retention, and wound infection 1, 2

Mechanism of Action

NPWT works by extracting wound exudate, stimulating granulation tissue formation, promoting wound contraction, increasing local blood flow and tissue perfusion (which enhances antibiotic delivery), removing inflammatory fluids and reducing bacterial load, and managing edema 1, 3, 8

Common Pitfalls to Avoid

• Do not apply NPWT expecting complete epithelialization—it stimulates healing but does not result in complete wound closure alone 1
• Never apply foam directly to wound bed without protective interface in vulnerable wounds 2
• Do not use in wounds with inadequate arterial perfusion 1
• Avoid in patients who cannot tolerate frequent clinic visits or dressing changes 2