Lippincott Nursing Pocket Card - January 2021

Guide to Negative Pressure Wound Therapy (NPWT)

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Guide to Negative Pressure Wound Therapy (NPWT)

Also known as vacuum-assisted wound closure (VAC), NPWT is a dressing system that continuously or intermittently applies negative pressure across the surface of wounds that are acute, chronic, complex, or difficult-to-heal (Gestring, 2020). NPWT devices support a moist wound healing environment, pull wound edges together, promote blood flow and granulation tissue formation, decrease edema, remove extracellular fluid and bacteria, and increase tissue oxygenation (Tamir et al., 2018). Many of these devices are small and lightweight, allowing patients full mobility. Due to varying designs, it is important that you become familiar with the manufacturer instructions for the specific device in use.

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Indications

Wounds that benefit most from NPWT (Wound Care Centers, n.d.)

  • Diabetic ulcers
  • Venous ulcers
  • Arterial ulcers
  • Pressure injuries
  • First- and second-degree burns
  • Chronic wounds
  • Wounds at high risk for infection
  • Open abdominal incisions or dehisced surgical wounds
  • Following surgical debridement of acute or chronic wounds (i.e., orthopedic, necrotizing infection)
  • Skin flaps and preparation for skin graft sites in reconstructive surgery
  • Wounds with copious drainage
  • Meshed grafts, to either secure the graft in place or improve epithelialization
  • Prophylactic therapy to prevent surgical wound infections

Advantages of NPWT Compared to Traditional Forms of Wound Therapy (Gestring, 2020)

  • Dressing changes are required less frequently (i.e. every two to five days).

  • Customizable to almost all types of wounds including circumferential extremity wounds and wounds located close to orthopedic fixation frames.
  • Accelerates wound healing and significantly decreases the time to wound closure in diabetic patients, improving quality of life.
  • Reduces the need for complex, subsequent reconstructive procedures.
Disadvantages of NPWT (Gestring, 2020)
  • The patient is required to carry a portable pump.
  • NPWT systems cost significantly more than traditional wound dressings.

General Procedure (Gestring, 2020)

NPWT systems include an open-pore polyurethane ether foam sponge, semiocclusive adhesive cover, fluid collection system, and suction pump. The following steps outline the general procedure, however please consult your institution’s specific policies regarding NPWT.
  • Trim the foam sponge to fit the size of the open wound and place it into the wound; the foam should not extend beyond the wound margin.
  • Apply the adhesive sheet to the foam dressing.
  • Cut a hole in the adhesive sheet and apply the suction port with tubing which is connected to a disposable collection cannister.
  • Connect the portable pump to the suction tubing and apply settings, typically -20 to -175 mmHg of continuous or intermittent suction; the polyurethane foam evenly distributes subatmospheric pressure throughout the foam creating positive pressure across the surface of the wound.
  • If fragile structures are present within the wound, place an additional layer beneath the foam, such as Vicryl or petrolatum gauze.

Dressing Changes (Gestring, 2020)

Change dressing and tubing every 48 to 120 hours (two to five days), as ordered or based on your institution’s policy.
  • Pre-medicate patient with analgesia prior to dressing change as ordered.
  • Turn off the device.
  • Remove the semiocclusive dressing and carefully remove the foam sponge. If the sponge adheres to the underlying tissue, soak it with saline and let it sit for a few minutes prior to removal.
  • If patient experiences excessive pain during sponge removal, the sponge may be soaked with topical Xylocaine without epinephrine.

Risks and Complications (Gestring, 2020)

  • Pain – Premedicate prior to dressing changes.
  • Bleeding – Apply firm pressure to the wound surface if minor bleeding occurs during dressing changes; for severe hemorrhage, apply direct pressure and contact provider as surgery may be needed to control bleeding, based on the source (i.e. exposed vessel or vascular graft).
  • Infection – Discontinue NPWT dressing, irrigate and debride the wound, obtain wound cultures, and initiate empiric antibiotics as prescribed.
  • Enterocutaneous fistula – While NPWT may assist with the closure of postoperative fistulas, they may also cause enteric fistulas to form.

Factors that increase a patient’s risk for adverse events with NPWT

  • Anticoagulant or platelet aggregation inhibitor therapy
  • Any factors that increase patient risk for bleeding and hemorrhage
  • Friable or infected blood vessels
  • Vascular anastomosis
  • Infected wounds
  • Osteomyelitis
  • Spinal cord injury
  • Enteric fistulas
  • Exposed organs, vessels, nerves, tendons, and ligaments

Contraindications (Gestring, 2020)

  • Exposed vital organs, blood vessels, or vascular grafts
  • Cancer tissue within the wound is more friable and prone to bleeding 
Relative Contraindications (Gestring, 2020)
  • Ischemic wounds, necrotic tissue with eschar
  • Ongoing infection – Wounds should be adequately debrided of devitalized tissue and infections should be treated prior to NPWT.
  • Fragile skin – Shearing force at the wound margin can result in skin avulsion and necrosis.
  • Adhesive allergy

What should the NPWT orders include?

  • Wound dressing material (foam or gauze) and wound adjunct (protective non-adherent, petroleum or silver dressing) (Rock, 2014)
  • Negative pressure setting (-20 to -175 mmHg)
  • Therapy setting (continuous, intermittent or variable)
  • Frequency of dressing change; varies between 1 and 7 days or as needed (Wound Care Centers, n.d.; Gestring, 2020)

Wound Care Tips (Rock, 2014)

  • Use protective barriers, such as non-adherent or petroleum gauze, to protect sutured blood vessels or organs near areas being treated with NPWT.
  • Avoid over packing the wound too tightly with foam; this prevents negative pressure from reaching the wound bed, causing exudate to accumulate.
  • Avoid placing the tubing over bony prominences, skinfolds, creases, and weight-bearing surfaces to prevent tubing-related pressure ulcers.
  • Count and document all pieces of foam or gauze on the outer dressing and in the medical record, to help prevent retention of materials in the wound; whenever possible, apply foam dressing as a single piece.
  • With a heavily colonized or infected wound, consider changing the dressing every 12 to 24 hours as directed by the prescribing clinician.

Nursing Considerations

  • Assess your patient for wound healing issues, such as poor nutrition (low protein levels), diminished oxygenation, decreased circulation, diabetes, smoking, obesity, foreign bodies, infection and low hemoglobin levels (Rock, 2014).
  • Assess and manage your patient’s pain; be sure to premedicate as needed before each dressing change.
  • Provide patient education on:
    • Alarms and device ‘noise’
    • Dressing changes
    • Signs of complications, and to seek medical care immediately if bleeding occurs
  • Advise patients to seek medical care if they notice:
    • Significant change in the color of the drainage (cloudy or bright red)
    • Excessive bleeding under the clear dressing, in the tubing or in the canister
    • Increased redness or odor from the wound
    • Increased pain
    • The device has been left off for more than 2 hours
    • Signs of infection, such as fever, redness or swelling of the wound, itching/rash, warmth, pus or foul-smelling drainage
    • Signs of allergic reaction to the drape/dressing including redness, swelling, rash, hives, or severe itching
    • Patient should seek immediate medical assistance if they have trouble breathing.

Troubleshooting the Device

  • Confirm that the unit is on and set to the appropriate negative pressure, that the foam is collapsed, and the NPWT device is maintaining the prescribed therapy (Rock, 2014).
  • Be sure the negative pressure seal has not been broken and leaks are minimal.
  • Ensure there are no kinks in the tubing and that all clamps are open.
  • Address and resolve alarm issues; reasons for the unit to alarm include: canister is full, there is a leak in the system, battery is low/dead, or therapy is not activated.
  • Do not leave the device off for more than two hours; if the device is off for more than two hours, apply a moist dressing (Rock, 2014) and notify the prescribing clinician immediately.
  • Avoid getting the electrical device wet; educate the patient to disconnect the unit from the tubing and clamp the tubing before bathing.
  • Check the drainage chamber to make sure it is filling correctly and does not need changing.
References:
Gestring, M. (2020, July 22). Negative pressure wound therapy. UpToDate. https://www.uptodate.com/contents/negative- pressure-wound-therapy
 
Rock, R. (2014). Guidelines for Safe Negative-Pressure Wound Therapy: Rule of Thumb: Assess Twice, Dress Once. Wound Care Advisor, 3(2), 29-33.
 
Tamir, E., Finestone, A.S., Wiser, I., Anekstein, Y. and Agar, G. (2018). Outpatient negative-pressure wound therapy following surgical debridement: Results and complications. Advances in Skin & Wound Care: The Journal for Prevention and Healing, 31(8), 365-369. https://doi.org/10.1097/01.ASW.0000531352.93490.24
 
Wound Care Centers. (n.d.) Negative Pressure Wound Therapy. Retrieved January 28, 2021 from http://www.woundcarecenters.org/article/wound-therapies/negative-pressure-wound-therapy