How should I manage a foul-smelling wound that is currently being treated with negative-pressure wound therapy (NPWT)?

Management of Malodorous Wound Despite Negative Pressure Wound Therapy

The most critical action is to immediately remove the NPWT, perform complete surgical debridement of all necrotic and infected tissue into healthy margins, obtain wound cultures, and only then consider reapplying NPWT—a foul odor indicates residual necrosis or active infection, both absolute contraindications to continued vacuum therapy. 1, 2

Why Malodor Indicates NPWT Failure

Foul smell signals one of two problems that make NPWT inappropriate:

• Residual necrotic tissue remains in the wound bed, which NPWT cannot remove and will only seal under the dressing 1, 2
• Active uncontrolled infection is present, creating purulent discharge and bacterial overgrowth 1, 2
• The 2018 WSES/SIS-E consensus provides only a conditional 1C recommendation for NPWT after complete necrosis removal—meaning the evidence supporting NPWT even in ideal conditions is weak 1

Immediate Management Algorithm

Step 1: Discontinue NPWT and Assess the Wound

• Remove the vacuum dressing completely and inspect the entire wound bed 2
• Look specifically for: gray/black necrotic tissue, purulent exudate, undermining edges, exposed structures, and signs of spreading infection 1
• Obtain wound cultures from tissue (not swab) during debridement to guide antibiotic therapy 1

Step 2: Perform Aggressive Surgical Debridement

• Debride radically into healthy-looking tissue—this is the single most important intervention for both infection control and wound healing 1
• Continue debridement until you reach bleeding, viable tissue with no remaining necrosis 1, 2
• Plan for serial debridements every 24-48 hours if needed, as one procedure is often insufficient 1

Step 3: Control Contamination Sources

• If the wound is perineal or near the rectum, consider fecal diversion with a rectal tube device rather than colostomy, which can be used in combination with NPWT once infection is controlled 1
• Protect the wound from ongoing contamination (urine, stool, saliva depending on location) 1

Step 4: Initiate Appropriate Wound Care

After complete debridement, choose between:

• NPWT with instillation (NPWTi) using 0.125% sodium hypochlorite solution, which reduces both planktonic bacteria by 48% and biofilm-protected organisms in infected wounds 3, 4

  • Instill solution, dwell for 10-20 minutes, then apply negative pressure 3
  • This addresses both infection and provides NPWT benefits 4

• Standard moist wound dressings with antimicrobial agents (e.g., polyhexanide spray for wound cleansing and antisepsis) if NPWT infrastructure is unavailable 5

  • Change dressings daily or twice daily to manage exudate and odor 1

Modified NPWT Protocol If Reapplying

Only restart NPWT after complete debridement and infection control:

• Use reduced pressure of 75-80 mmHg instead of standard 125 mmHg to prevent tissue desiccation and allow better perfusion 6, 7
• Place a large fenestrated non-adherent interface layer over any exposed structures (tendon, bone, vessels) to prevent damage 6, 2
• Change dressings every 2-3 days (average 5 changes needed) to monitor for recurrent infection 6, 7
• Use continuous pressure mode only—avoid intermittent cycling which impairs moisture control 6
• Measure evacuated fluid volume at each change; increasing purulent drainage indicates treatment failure 1, 6

Common Pitfalls to Avoid

• Never reapply NPWT to a malodorous wound without debridement—this seals infection under an occlusive dressing and can lead to sepsis or fistula formation 1, 2
• Do not assume NPWT reduces bacterial burden—evidence shows NPWT does not significantly decrease wound bacteria and may paradoxically increase planktonic counts 8
• Avoid using standard NPWT for chronic non-surgical diabetic foot ulcers—the IWGDF issues a strong recommendation against this due to lack of benefit over standard care 1, 2
• Do not apply foam directly to exposed tendons—always use a protective interface layer first 6, 2

When NPWT Should Not Be Restarted

Absolute contraindications even after debridement:

• Chronic non-surgical diabetic foot ulcers (strong evidence against use) 1, 2
• Exposed vessels without adequate soft tissue coverage 6
• Malignancy in the wound bed 6
• Untreated osteomyelitis 6
• Patient unable to tolerate frequent dressing changes or lacks access to trained personnel 1, 6

Alternative Management Strategy

If modified NPWT fails again or malodor persists:

• Transition to advanced moist wound therapy with silver-impregnated dressings or medical-grade honey 7
• Consider NPWTi with antimicrobial instillation as described above if not already tried 3, 4
• Reassess for deeper infection (abscess, osteomyelitis) requiring further surgical intervention 1
• Ensure adequate systemic antibiotic coverage based on culture results 1