How does the PICO single‑use negative‑pressure wound therapy (sNPWT) system function, where should it be placed relative to surgical drains, how frequently should the dressing be changed, and what is its maximum treatment duration?

PICO Single-Use Negative Pressure Wound Therapy System Function

The PICO system delivers continuous negative pressure at -80 mmHg through a canisterless design that manages wound exudate primarily through evaporative loss (up to 85%) via a highly breathable film, eliminating the need for fluid collection canisters while maintaining therapeutic pressure levels equivalent to traditional NPWT systems. 1, 2

Mechanism of Action and Core Technology

Pressure Delivery and Fluid Management

• The PICO device operates at a single preset pressure of -80 mmHg continuously, which is lower than traditional NPWT systems that typically use 125 mmHg 2, 3
• The system manages exudate through evaporative loss rather than canister collection, with the highly breathable adhesive film allowing up to 85% of fluid entering the dressing to evaporate 1
• Real-time pressure monitoring in clinical studies demonstrated continuous delivery of therapeutic negative pressure throughout the entire wear period without significant pressure loss 2
• The canisterless design maintains the same therapeutic effects on wound edge contraction and microvascular blood flow as traditional NPWT systems 1

Structural Components

• The dressing consists of specialized polyurethane foam covered by an airtight adhesive film that creates the sealed environment necessary for negative pressure 1
• A non-adherent interface layer must be placed between the foam and wound bed to prevent direct contact and maintain moisture balance 3, 4
• The lightweight, portable pump unit attaches directly to the dressing without external tubing or canisters 2

Placement Relative to Surgical Drains

Critical Positioning Guidelines

• The PICO dressing should be applied directly over the closed surgical incision after standard wound closure, with surgical drains exiting through separate stab incisions away from the primary incision line 4
• The foam dressing must be placed within the wound cavity for open wounds, not on top of surrounding intact skin, to preserve skin integrity 3
• For closed incisions, the dressing covers the entire incision line plus 2-3 cm of surrounding skin to create an adequate seal 4

Technical Considerations

• Surgical drains should exit the body through separate puncture sites at least 5 cm away from the incision edges to avoid compromising the PICO seal 4
• The adhesive film must create an airtight seal around the entire perimeter; any breach will result in loss of negative pressure 4
• When drains are present, ensure the PICO dressing does not overlap drain exit sites, as this will prevent proper seal formation 4

Dressing Change Frequency

Standard Protocol for Closed Incisions

• Dressing changes should occur every 2-3 days for optimal performance, with most patients requiring an average of 5 dressing changes during the treatment course 5
• For closed surgical incisions, the typical dressing wear time per individual patient averages 4.6 days (range 2-11 days) based on clinical trial data 2
• The dressing should be changed immediately if the seal is compromised, if strike-through occurs (visible fluid on the outer surface), or if signs of infection develop 4

Monitoring Between Changes

• Inspect the seal regularly to ensure the dressing remains adherent and negative pressure is maintained 4
• Monitor for signs of infection including redness, swelling, foul drainage, increased pain, or fever despite the reduced infection risk with NPWT 4
• If malodor develops, discontinue NPWT immediately and perform wound inspection, as foul odor signals residual necrosis or active infection 5

Maximum Treatment Duration

Evidence-Based Time Limits

• The maximum treatment period for the PICO system is 14 days for closed surgical incisions, based on clinical trial protocols and manufacturer guidelines 2
• In clinical studies, the mean study duration was 10.7 days (range 5-14 days), with 55% of wounds achieving closure by the end of the 14-day period 2
• For open wounds managed with traditional NPWT principles, treatment can extend beyond 14 days, with some studies reporting successful fascial closure as late as 21 days, though this applies to traditional systems rather than single-use devices 6

Clinical Outcomes Within Treatment Window

• By 14 days of PICO therapy, 55% of closed surgical wounds had completely healed, with an additional 40% progressing toward closure 2
• The PICO system demonstrated significant reduction in surgical site infection rates from 12.5% to 5.2% (58% reduction) when used prophylactically on closed incisions 6
• Meta-analysis showed reduction in wound dehiscence from 17.4% to 12.8% and decreased hospital length of stay by 0.47 days with PICO therapy 6

Important Clinical Caveats

Contraindications and Prerequisites

• Never apply PICO to infected wounds until complete surgical debridement of all necrotic tissue has been performed 5
• The International Working Group on the Diabetic Foot provides a strong recommendation against using NPWT (including PICO) for chronic non-surgical diabetic foot ulcers due to lack of benefit over standard care 5
• Absolute contraindications include exposed vessels without soft tissue coverage, malignancy in the wound bed, and untreated osteomyelitis 5

Technical Pitfalls to Avoid

• Never place foam directly on exposed tendon without a protective non-adherent interface layer, as this causes tendon damage 5
• Do not increase pressure settings if desiccation occurs; instead, lower pressure to 50 mmHg and verify proper interface layer placement 3
• Avoid using PICO on wounds with minimal exudate, as the system works best when adequate drainage is present 3

Optimal Patient Selection

• PICO therapy is most beneficial for high-risk surgical incisions in patients with obesity, diabetes, contamination, or emergency surgery 4
• The system is particularly valuable when patient mobility is a priority, as the lightweight design (no canister) facilitates early ambulation 4, 2
• Consider PICO for procedures with historically high complication rates, where the number needed to treat is lower and cost-effectiveness is maximized 6