Adjunct Therapies - negative pressure wound therapy

Negative pressure wound therapy has revolutionized wound care over the past 2 decades, and the technology continues to improve so that more wounds can be safely treated with this adjunct therapy.

Go to the profile of Rose Hamm
Nov 18, 2019
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When negative pressure wound therapy (NPWT) was first introduced in the 1990’s, it truly revolutionized wound care, making many wounds that were previously difficult to treat and closable only by surgery, manageable in a way that improved wound outcomes, but also improved patient function at an earlier stage of treatment.  There were, however, two contraindications that had to be addressed before NPWT could be initiated into the care plan: infection and more than 30% necrotic tissue in the wound bed.  Over the past decade, research and development has introduced changes in the technology that allow application of NPWT on both infected and necrotic wounds – silver impregnated foam, NPWT with instillation, and reticulated open cell foam.  In addition, to address the pain related with removal of the adhesive film placed over NPWT dressings, a silicone acrylic drape is available.  This film combines the properties of maintaining a seal to prevent leakage with a less traumatic removal that reduces damage to the periwound skin and is less painful for the patient.[i]

Silver has long been used as an antimicrobial agent in wound care, and the impregnation of silver ions into polyurethane foam allows the application of NPWT to wounds that may be infected without the use of a silver dressing interface.  It also allows dressing changes to be performed every 2-3 days rather than daily.

NPWT with instillation (NPWTi-d)  also addresses infection by allowing timed automatic instillation of normal saline or antibiotic solutions through a second ingress tube without the removal of the dressing.  Intermittent timing controls the amount and duration of fluid instillation (termed dwell time), alternating with the amount and time of negative pressure.  NPWTi-d provides ongoing removal of infectious and necrotic material, reduction of tissue edema, maintenance of a moist wound environment, and facilitation of wound contraction.[ii]  Herskovitz et al reported on a single-use only fluid delivery NPWT system that provides continuous delivery of fluid at a rate of approximately ¾ mL per day, thus providing “a hydrated wound environment enhanced with specific liquid agents for an extended period of up to 7 days.”[iii] Suggested fluids are anesthetics for painful wounds, antiseptics and antibiotics for infected wounds, steroids for inflammatory-related wounds, topical beta-blockers for recalcitrant wounds, immune modulatory agents for inflammatory dermatologic disorders (e.g. pyoderma gangrenosum), growth factors, and sodium thiosulfate for calciphylaxis. 

Used in conjunction with NPWTi-d, a reticulated open cell foam with through holes (see photo) has been developed to provide more effective wound cleansing by removing thick wound exudate and infectious material when the patient is not a candidate for surgical debridement.[iv]  This special foam can be used on wounds with more than 30% necrotic tissue to facilitate debridement. 

These changes in NPWT technology make it possible, even advantageous, to apply NPWT on almost any wound that has depth or a large surface area.  The wound evaluation, clinical decisions, and artful application require astute knowledge and skill, and the results can be life-changing.  The greatest decrease in wound size usually occurs within the first 3 weeks of treatment, but for a patient with functional impairments, those 3 weeks of being able to participate in mobility, exercise, and functional activities can be critical to the overall outcomes.  With NPWT in place on a large wound, the patient CAN participate in therapies with more ease and comfort, and that exercise can also help improve wound healing – a win/win situation for everyone!

More information is available on NPWT at the following:

Gibbs K, Hamm R. Negative pressure wound therapy.  In Hamm R (Ed), Text and Atlas of Wound Diagnosis and Treatment: 2nd edition.  New York: McGraw Hill Education.  2019, 435-457.  Available at https://accessphysiotherapy.mhmedical.com/book.aspx?bookid=1334

 

[i] Georgoudiou S, Kim P.  Advances in negative pressure wound therapy for the wound clinic.  Today’s Wound Clinic.  2019;13(9):8-10.

[ii] Punch L. Utilizing instillation with negative pressure in the management of large wounds.  Current Dialogues in Wound Management. 2019; Summer edition:7-10.

[iii] Herskovitz I, MacQubae FE, Borda LJ, et al.  A novel topical wound therapy delivery system.  Wounds. 2017;29(9):269-276.

[iv] Blalock L.  Use of negative pressure wound therapy with instillation and a novel reticulated open-cell foam dressing with through holes at a level 2 trauma center.  Wounds. 2019;31(2):55-58.

Go to the profile of Rose Hamm

Rose Hamm

Physical Therapy, University of Southern California

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