Treatment of Acute Necrotizing Fasciitis Using Negative Pressure Wound Therapy and Adjunctive NeutroPhase Irrigation Under the Foam Author(s):  John R. Crew, MD; Randell Varilla, RN, MSN; Thomas Allandale Rocas III, RN, BSN, CWCN; Suriani Abdul Rani, MS; Dmitri Debabov, PhD Index: WOUNDS. 2013;25(10):272-277.   Abstract: Necrotizing fasciitis is a complication of a bacterial infection that activates the immune system in perifascial planes. This case report highlights initial diagnostic failures that delay early treatment, which causes profoundly negative consequences. Antimicrobial control with abolition of the inciting bacteria does not neutralize the subsequent endopathologic ravages. A new therapeutic technique, which combines negative pressure wound therapy (NPWT) and a pure hypochlorous acid solution 0.01% (NeutroPhase, NovaBay Pharmaceuticals Inc, Emeryville, CA) along with debridement and antibiotics is described in this study. It is believed that the combination of neutralization of the toxins produced by bacteria with NeutroPhase along with the NPWT action of removing exudates is effective in saving the patient.

Key words: negative pressure, NPWT pumps,  necrotizing fasciitis, hypochlorous acid, debridement, tissue repair, flesh eating

Introduction   Necrotizing fasciitis, commonly known as flesh-eating disease, is an infection of the deeper layers of skin and subcutaneous tissues which easily spreads across the fascial planes under the subcutaneous tissue. Necrotizing fasciitis is a quickly progressing and severe disease of sudden onset. It is best treated immediately with high doses of intravenous antibiotics. Type I necrotizing fasciitis is classified as a polymicrobial infection, whereas type II is classified as a monomicrobial infection. Many types of bacteria can cause necrotizing fasciitis (eg, Group A Streptococcus [GAS], Streptococcus pyogenes, Group B Streptococcus [GBS], Streptococcus agalactiae, Staphylococcus aureus, Vibrio vulnificus, Clostridium perfringens, and Bacteroides fragilis). Such infections are more likely to occur in people with compromised immune systems.1 Historically, GAS made up most cases of type II infections. However, since as early as 2001, another serious form of monomicrobial necrotizing fasciitis has been observed with increasing frequency.2 In these cases, the bacterium causing it is methicillin-resistant Staphylococcus aureus (MRSA). Group B Streptococcus has recently emerged as a causative agent of necrotizing fasciitis.3

Due to its subtle symptoms, the early diagnosis of necrotizing fasciitis can be difficult, unless triggered by toxic shock syndrome or organ failure, which present with acute symptoms. When the onset occurs, early diagnosis is what is needed to minimize the morbidity and mortality rate of 10%-70%, which occurs even in younger patients. The toxicity caused by GAS or Staphylococcal superantigen release results in nonspecific T-cell activation and massive cytokine release, and can dramatically change the patient’s situation from acute to critical, requiring surgical incision and drainage.

While the virulence factors that enable GBS to cause necrotizing fasciitis have not yet been established, horizontal transfer of DNA encoding virulence factors is common among different strains of GAS and a similar process may have occurred between Group A and Group B streptococci, conferring the virulent strain of GBS.3

Pure hypochlorous acid (HOCl) is a naturally occurring, well-known, broad-spectrum, fast-acting antimicrobial agent produced as part of the innate immune system’s response to infection during oxidative burst by neutrophils and monocytes.4 Pure HOCl has been shown to have activity against both gram-positive and gram-negative bacteria without toxicity to human cells, and to control the tissue bioburden in a rodent model of infected granulating wound without inhibiting the wound healing process.5,6 The active species in all hypochlorite solutions is undissociated HOCl.7 This is because pure HOCl, unlike diluted bleach/Dakin solution, is an uncharged molecule and can penetrate microbial cell walls and spores with ease. NeutroPhase (NovaBay Pharmaceuticals Inc, Emeryville, CA) is pure 0.01% hypochlorous acid (ie, > 97% relative molar distribution of active chlorine species as HOCl) in a 0.9% saline solution at pH 4-5. It is believed that neutralization of the superantigens occurs with frequent irrigation of pure HOCl under the negative pressure wound therapy (NPWT) foam and removal of exudates, helping in the management of necrotizing fasciitis.

Materials and Methods   A combination of pure hypochlorous acid solution 0.01% as the irrigation solution and NPWT was used to treat a patient with acute necrotizing fasciitis. A line diagram of the equipment is shown on Figure 1. Before treatment, the wound area was cleansed, the wound debrided, and the skin dried. A foam dressing (V.A.C. GranuFoam, KCI, San Antonio, TX) was sized and placed in the wound. A separate inflow tube (ie, an intravenous extension with a port) was placed on and through the foam. The adhesive drape was attached and placed over the entire area, including the foam. The area around the tubing was sealed with a skin barrier ointment (Stomadhesive Paste, ConvaTec, Skillman, NJ). The NPWT device was then turned on and adjusted from 50-125 mm Hg suction. The irrigation solution (5 mL) was instilled via syringe through the inlet-port into the wound bed with the vacuum turned on (Figure 2).

Activity of the irrigation solution against alpha-hemolysin toxin of S. aureus was tested by cytotoxicity assay. Human lung epithelial cells (A549, ATCC CCL 185) were grown in F12K cell culture medium supplemented with 10% fetal bovine serum (Life/Invitrogen, Carlsbad, CA) and 100 IU/mL penicillin/100 µg/mL streptomycin (Mediatech Inc, a Corning subsidiary, Manassas, VA). Assays were performed using F12K medium with different concentrations of purified toxin by measuring the reduction of MTS tetrazolium compound into formazan that is soluble in cell culture medium. On the day before the assay, 5000 cells/well were seeded in a flat-bottom 96-well plate. One ug/mL alpha-hemolysin toxin (Sigma Aldrich, St. Louis, MO) from S. aureus was incubated with a series of irrigation solution dilutions for 1 hour.

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