Negative Pressure Wound Therapy (NPWT): A Complete Guide to Types, Benefits & Best Practice

What Is Negative Pressure Wound Therapy (NPWT)?

When NPWT is compared to traditional wound care, it consistently demonstrates superior outcomes in healing rates and reduction of complications.

History and Development of NPWT

Negative pressure wound therapy (NPWT) has transformed the landscape of wound healing since its introduction in the 1990s. The initial concept was based on the use of subatmospheric pressure to accelerate wound closure and reduce complications, particularly in chronic wounds and pressure wounds.

Early clinical experience and research demonstrated that applying negative pressure to a wound bed could effectively remove exudate, decrease edema, and promote wound healing by stimulating tissue formation and blood vessel growth.

As NPWT technology advanced, it became a cornerstone in the treatment of complex wounds, diabetic foot ulcers, and other challenging cases where traditional wound therapy often fell short.

The development of portable, user-friendly devices has expanded the reach of NPWT beyond the hospital, allowing for effective wound management in outpatient and home settings. Today, NPWT is supported by a robust body of clinical evidence and is widely recognised as a safe, effective, and cost-efficient therapy for a broad range of wounds.

How Does Negative Pressure Wound Therapy Work?

NPWT systems use a porous foam dressing, sealed with an occlusive film and connected to a suction pump, which removes exudate and creates negative pressure across the wound bed. It is essential to ensure an airtight seal with the occlusive film to maintain effective negative pressure and therapy delivery.

This process:

• Removes excess fluid
• Encourages granulation tissue and angiogenesis
• Promotes wound contraction, although in deep wounds, granulation is prioritised⁶

These steps promote healing and help prevent infection. NPWT promotes healing by creating an optimal wound environment that supports tissue regeneration and recovery.

Note: Suction temporarily reduces perfusion due to tissue compression, but long-term use stimulates new blood vessel formation.⁶

Wound Assessment and Management

Effective wound assessment and management are essential for successful NPWT outcomes. Before initiating negative pressure wound therapy, clinicians must conduct a comprehensive evaluation of the wound, including its size, depth, location, and the condition of the wound bed.

Identifying factors such as the presence of nonviable tissue, infection, or underlying health conditions is crucial for tailoring the treatment plan.

Wound management begins with preparing the wound bed to promote wound healing. This may involve debridement to remove nonviable tissue, thorough cleaning to reduce infectious materials, and selecting the appropriate dressing to optimise the wound environment.

The goal is to create conditions that support granulation tissue formation, minimise complications, and enhance patient healing. Ongoing assessment and adjustment of the treatment plan ensure that the wound continues to progress toward complete healing.

Indications for NPWT

Negative pressure wound therapy is indicated for a wide range of wounds where promoting wound healing is a priority. NPWT is commonly used for chronic wounds, such as diabetic foot ulcers and pressure wounds, as well as for wounds with significant exudate or debris that require advanced wound management.

It is also an effective option for complex wounds, including those in patients with multiple comorbidities or after surgical procedures.

NPWT can be applied in both acute and chronic care settings, from the operating room to the patient’s home. The decision to use NPWT should be based on a thorough assessment of the wound and the patient’s overall health, ensuring that the therapy is appropriate and that the necessary resources are available to support optimal healing.

Types of Negative Pressure Wound Therapy

Traditional NPWT (tNPWT)

Recommended for:

• Deep wounds requiring granulation⁶

• Requires power source
• Larger, less mobile units¹¹
• Fluid collected in a canister²

NPWT Foams

• Standard black foam: Polyurethane, large pores, repels fluid
• Silver foam: Antimicrobial for infected wounds¹⁵
• White PVA foam: Delicate tissue, tunnelling, hypergranulation¹⁵

Tip: Layer white or silver foam beneath black foam to optimise suction.¹⁵

NPWT Instillation (NPWTi)

Combines suction with fluid delivery (e.g., saline or antiseptic) for 10–20 minutes, then removes it via suction.

Recommended for:

• Infected wounds needing cleansing and exudate control²

Single-Use NPWT (sNPWT)

Compact, battery-powered devices for greater mobility and outpatient use.

Recommended for:

• Shallow wounds prioritising epithelialisation
• Closed surgical incisions to reduce infection risk⁶

Canister-free options available, using absorption and evaporation to manage fluid.⁶

Equipment and Personnel

A successful NPWT program relies on specialised equipment and skilled personnel. The core components of an NPWT system include a negative pressure device, dressings designed to conform to the wound, and tubing that transmits subatmospheric pressure to the wound bed.

These elements work together to remove exudate, reduce edema, and promote wound healing.

Healthcare professionals such as nurses, physicians, and wound care specialists play a vital role in delivering NPWT.

Their responsibilities include assessing the wound, developing and implementing a treatment plan, and providing ongoing patient care. Proper training in the use of NPWT equipment is essential to ensure safe and effective therapy, troubleshoot potential issues, and achieve the best possible outcomes for wound healing.

Clinical Benefits of NPWT

• Stimulates angiogenesis and collagen production (especially type I)
• Encourages fibroblast migration and tissue repair⁶
• Reduces oedema and exudate⁴
• Minimises periwound maceration and infection risk⁶
• Improves seal and odour control with fewer dressing changes⁹
• Maintains an optimal moist wound environment¹⁴

NPWT promotes wound healing by creating an optimal environment for tissue repair. The effectiveness of NPWT is influenced by several factors, such as wound type, location, and patient health.

Best practice involves a step-down approach: start with tNPWT, transition to sNPWT as healing progresses.²

Risks & Contraindications of NPWT

Cautions:

• Periwound skin damage
• Vascular impairment
• Autonomic dysreflexia (especially in spinal cord injury patients)¹⁵
• Environmental factors impacting canister-free systems⁶

Contraindications:

• Full-thickness burns²
• Exposed vasculature, nerves, organs ²
• Untreated osteomyelitis or eschar-covered wounds
• Malignant wounds (unless palliative)
• Bleeding risks including anticoagulant use
• Unexplored or non-enteric fistulas

NPWT must be removed before MRI, defibrillation, or HBOT.

Best Practice Tips for Safe NPWT Use

General Setup

• Follow facility policy and manufacturer instructions
• Change dressing if therapy is interrupted >2 hours
• Keep pump dry
• Use adhesive remover to reduce trauma²
• Turn off suction 10 minutes before dressing change

Periwound Skin Protection

• Apply liquid barrier film⁷
• Use hydrocolloids or stoma powder for damaged skin⁷
• Avoid creams under adhesive film

Foam Handling Best Practice

• Trim foam outside the wound bed
• Document number of foam pieces used
• Use a contact layer (silicone or mesh) over exposed tendon/muscle
• Avoid packing tight or into unexplored tracts

Creating an Effective Seal

• Dry skin thoroughly
• Use small drape strips to reduce creases
• Seal edges with paste or rings in challenging areas
• Avoid overlapping drape layers to prevent maceration

Tubing & Port Placement Tips

• tNPWT: Port at lowest point to aid drainage
• sNPWT: Port at highest point to prevent blockage
• Anchor tubing to avoid tension

Optimising NPWT Pressure Settings

Clinical benefits observed within range: 75–125 mmHg¹²

• tNPWT range: 50–175 mmHg8⁸
• sNPWT: ~80 mmHg (non-adjustable)8,2^8,2

• Pain reduction: 50–75 mmHg¹
• High exudate: ~150 mmHg¹
• Bleeding risk: Lower pressures preferred¹⁵

Suction Modes: Continuous vs Intermittent

• Continuous: Ideal for first 48 hours, bleeding risk, high exudate, grafts¹⁵
• Intermittent: Encourages granulation, used after exudate decreases

High-intensity mode helps maintain seal in large wounds.

Enhancing Wound Care with NPWT

Negative pressure wound therapy accelerates healing and reduces complications when integrated with:

• Cleansing protocols (where cleanse choice is critical for optimal results, especially in complex or infected wounds)
• Effective debridement
• Infection control strategies
• Correct foam and pressure settings
• Integration of advanced dressings like Veraflo Cleanse Choice into NPWT protocols enhances wound cleansing and supports healing in complex wounds.

Using a step-down NPWT approach tailored to wound characteristics improves healing and outcomes, particularly in the management of complex wound