What is the recommended protocol for applying negative pressure (NP) dressing for wound management?

Negative Pressure Wound Therapy Application Protocol

Essential First Step: Interface Layer Placement

Always apply a non-adherent interface layer directly to the wound bed before placing foam—this is mandatory to prevent fistula formation and organ adhesions. 1

• Place the interface layer as widely as possible: laterally into paracolic gutters, cranially onto the diaphragm, and caudally into the pelvic cavity for abdominal wounds 1
• The interface layer prevents bowel damage during dressing changes and reduces adhesion formation between exposed organs and the abdominal wall 1
• Failure to use an interface layer significantly increases fistula risk, particularly with multiple re-explorations 1

Wound Filler Selection and Placement

Use specialized polyurethane foam-based dressings from commercial NPWT kits rather than improvised materials. 1

• Commercial foam compresses under negative pressure, providing constant medial traction that prevents lateral retraction and loss of abdominal domain 1
• Foam-based NPWT is an independent predictor of early fascial closure compared to surgical towel-based systems (vac-pack), which do not compress effectively 1
• Place foam within the wound boundaries, not on surrounding intact skin, to preserve skin integrity 1

Pressure Settings

Apply continuous negative pressure at 75-80 mmHg for most applications. 1, 2

• Continuous pressure up to 80 mmHg is recommended for open abdomen management 1
• Lower pressures (75-80 mmHg) are appropriate for vulnerable anatomic areas 3, 4
• Standard pressure ranges of 75-125 mmHg can be used, but err toward lower settings for safety 4, 5
• Never disconnect or clamp tubing between scheduled changes—intermittent pressure severely compromises therapeutic efficacy 2

Dressing Change Frequency

Change dressings every 2-3 days (48-72 hours). 3, 4, 5

• This interval applies regardless of wound drainage volume 4, 2
• An average of 5 dressing changes is typically required for optimal granulation tissue formation 3
• For small, non-draining wounds, extended intervals may be considered, but vulnerable anatomic locations require maintaining the standard 3-day interval 2
• Fewer dressing changes reduce patient discomfort and analgesia requirements 2

Critical Prerequisites for Infected Wounds

Complete surgical debridement of all necrotic and infected tissue must be performed before applying NPWT—never apply to wounds with residual necrosis. 3, 4

• Debridement must continue into healthy-looking tissue before NPWT application 3
• After adequate debridement, NPWT enhances antibiotic delivery through increased blood flow, removes bacterial load through exudate drainage, and promotes granulation tissue 3
• NPWT should not be used for non-surgical diabetic foot ulcers due to lack of supporting evidence 3

Dynamic Closure Technique (When Applicable)

For open abdomen cases where delayed primary closure is the goal, combine NPWT with sequential dynamic closure techniques. 1

• Dynamic closure (using mesh, clips, or suturing techniques) alongside NPWT achieves 82% fascial closure rates versus 72% with NPWT alone 1
• Apply small amounts of tension sequentially at each dressing change to gradually approximate fascial edges without causing ischemia 1
• This approach extends the window for successful fascial closure up to 3 weeks following initial surgery 1

Sealing and Connection

• Cover the foam with semi-occlusive adhesive drape to create an airtight seal 5
• Embed fenestrated tubing into the foam before sealing 5
• Connect tubing to vacuum pump with fluid collection container 5
• Ensure complete seal—air leaks compromise negative pressure delivery 5

Common Pitfalls to Avoid

• Never skip the interface layer—this single omission dramatically increases fistula risk 1
• Never use improvised materials (surgical towels, gauze) when commercial foam kits are available—they reduce fascial closure rates from 72% to 58% 1
• Never apply NPWT before complete debridement of infected/necrotic tissue 3, 4
• Never disconnect pressure between changes—even brief interruptions negate therapeutic benefits 2
• Be aware that certain interface dressings (petroleum jelly-impregnated gauze) can reduce pressure transmission by up to 41 mmHg, making machine readings unreliable 6