Since I began working in a reconstructive surgery clinic several years ago, I have been exposed to a myriad of complex acute and chronic wounds that require advanced treatment modalities, such as Negative Pressure Wound Therapy (NPWT), in order to heal. These devices were new to me, and I quickly realized that they can be a source of great anxiety for both patient and clinician. I decided I needed more information and education on the topic. In Part 1 of this blog series, I will discuss the basics of NPWT, what it is, how it works, as well as risks and benefits. 

What is Negative Pressure Wound Therapy (NPWT)?
Also known as vacuum-assisted wound closure (VAC), NPWT is the distribution of negative pressure across a wound1. The therapy, which emerged in the early 1980’s, includes the placement of a dressing (foam or gauze) onto the wound and is connected to a vacuum pump via tubing¹. A clear occlusive dressing is placed on top, forming an air tight closed system. Gentle, controlled suction is applied pulling wound debris into a collection chamber. The Food and Drug Administration (FDA) approved the first device for NPWT in 1997. Currently, there are over a dozen FDA approved devices available on the market1, many of which are small and lightweight, allowing patients full mobility³. Due to varying designs, it is important that you become familiar with the manufacturer instructions for the specific device in use.
 
Which types of wounds benefit most from NPWT?

• Surgical wounds, especially those which need to heal by secondary intention¹
• Open abdominal incisions¹
• Dehisced surgical wounds¹
• Burns
• Skin flaps and preparation for skin graft sites¹
• Traumatic wounds¹
• Chronic wounds, such as venous insufficiency ulcers, diabetic foot ulcers, and pressure ulcers^1,4
• Wounds at high risk for infection⁴
• Wounds with copious drainage⁴
• Meshed grafts, to either secure the graft in place or improve epithelialization⁴
• Adjunct to skin graft/flap procedure⁴

How effective is NPWT? Compared to traditional forms of wound therapy, advantages of NPWT include:

• Improved healing of transplanted skin and decreased length of hospital stay for patients receiving split thickness skin grafts.⁴
• Decreased wound infections in patients following orthopedic trauma and open fractures.⁴
• Improved wound healing, shorter length of stay, lower hospital mortality in patients with mediastinitis and unsuccessful wound healing following sternotomy.⁴
• Improved wound healing in patients with diabetes mellitus and gangrene that might require amputation.⁴

 
What are the factors that increase a patient’s risk for adverse events with NPWT:

• Increased risk for bleeding and hemorrhage^2,3
• Anticoagulant or platelet aggregation inhibitor therapy^2,3
• Friable or infected blood vessels^2,3
• Vascular anastomosis³
• Infected wounds³
• Osteomyelitis³
• Spinal cord injury²
• Enteric fistulas²
• Exposed organs, vessels, nerves, tendons, and ligaments³

Are there any contraindications for NPWT?

• Inadequately debrided wounds²
• Necrotic tissue with eschar
• Untreated osteomyelitis^2,3
• Cancer in the wound^2,3
• Untreated coagulopathy²
• Unexplored fistulas
• Exposed vasculature, nerves³, anastomotic site³, vital organs²
• Osteomyelitis⁴

While great strides have been made to improve the safety of NPWT devices, serious adverse events may still occur. Clinicians should take time to review specific device instructions for use, indications, and contraindications and adequate staff training should be provided. Healthcare providers that understand the principles of NPWT can then collaborate to ensure that each patient is selected appropriately for therapy based on wound type, risk profile and care setting. In Part 2 of this series, I will review the procedure for applying a NPWT dressing, general patient care, and tips to trouble-shoot the device.
 

References:
1. Centers for Medicare and Medicaid Services. (2014) Negative Pressure Wound Therapy Technologies for Chronic Wound Care in the Home Setting. Retrieved from the Centers for Medicare and Medicaid Services: https://www.cms.gov/Medicare/Coverage/DeterminationProcess/Downloads/id96ta.pdf
2. Rock, R. (2014). Guidelines for Safe Negative-Pressure Wound Therapy: Rule of Thumb: Assess Twice, Dress Once. Wound Care Advisor, 3(2), 29 – 33.
3. Federal Drug Administration. (2009). FDA Preliminary Public Health Notification: Serious Complications Associated with Negative Pressure Wound Therapy Systems. Retrieved from the Federal Drug Administration: http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm190658.htm#table1
4. Wound Care Centers. (2016) Negative Pressure Wound Therapy. Retrieved from Wound Care Centers: http://www.woundcarecenters.org/article/wound-therapies/negative-pressure-wound-therapy

 Myrna B. Schnur, RN, MSN