Successful Management of Complex Pediatric and Neonatal Wounds With Methylene Blue and Gentian Violet Foam Dressings

Vita Boyar, MD

Disclosures

Wounds. 2021;33(10):253-259. 

In This Article

Discussion

The following dressing attributes are essential in pediatric wound care: effective debridement that is as painless as possible, a nontoxic antibacterial action, inflammation reduction, and moisture sensitivity. Secondary dressing considerations include promotion of healthy edges, wound protection, and atraumatic removal. The MB/GV antibacterial foam dressings fulfilled these desired attributes for the patients described in this case series.

Several reasons for these desired dressing attributes have been hypothesized. The microporous structure of MB/GV PVA foams enhances absorption and creates a capillary action that resembles the pulling action of NPWT.[1,2] Although NPWT often is beneficial clinically, there are many scenarios in which it cannot be used. Negative pressure wound therapy can be challenging to apply in exceedingly small spaces (eg, some wound locations in neonates) or in certain anatomic locations in older children. In addition, hemodynamically unstable neonates may not be appropriate candidates for NPWT given the concern of negative pressure being higher than mean blood pressure and a potential cause of blood pressure instability, a concern described in the literature. In both PVA and PU foams, bacteria in the exudate draw into the foam, where the bacteria come into contact with GV and MB organic dyes. Therefore, using the microporous structure of MB/GV PVA foam as a pulling capillary action resembles NPWT microstrain action, without the hemodynamic instability or risk of granulation tissue ingrowth into the foam or epidermal stripping during adhesive dressing removal associated with NPWT.

In 2014, the United States Food and Drug Administration approved these dressings as antibacterial.[1] This antibacterial action is as follows. The MB/GV dyes work via interference with the oxidation-reduction (redox) potentials in the electron chain transport steps of oxidative metabolism. Bacteria rely on energy generated via this process. By short-circuiting the energy-generating process, the MB/GV dyes create the equivalent of a hypoxic environment, making metabolism impossible.[1] Gram-positive bacteria, gram-negative bacteria, and fungi appear to be susceptible to this action. Both MB and GV dyes are bound to the foam. When bacteria enter the foam, GV has a preferential binding affinity to gram-positive bacteria, and MB has a higher binding affinity to gram-negative bacteria. Upon contact with the exudate, the dyes do not become diluted or systemically absorbed while killing bacteria on contact with the foam.[3,4] The PVA foam has been shown to be effective in eliminating biofilm and suppressing new bacterial growth.[3–7]

The MB/GV PVA foam dressings used in this case series have other advantages, such as effective absorption of exudate, including inflammatory mediators, proteases, bacterial debris, and the wicking away of extra fluid, which likely contributes to decreasing inflammation.[8] Another interesting property of MB/GV PVA foam dressings is the support of wound edges.[5] The PVA dressing activates edge keratinocytes and enhances migration across the wound, although the mechanism of action remains unclear. Polyvinyl alcohol dressing flattens rolled edges or epibole, minimizing the need for aggressive debridement.[5] As dressings, both foams were soft, comfortable, pliable, and easy to remove. Upon dressing removal, the patients' pain scores did not change, regardless of patient age.

All the wounds in this case series improved with MB/GV foam use. Autolytic debridement was achieved along with anti-inflammatory and antibacterial effects, as appearance of wounds improved and cultures were negative. Published studies of adults support these outcomes, especially in the setting of chronic wounds.[3,4] Woo and Heil[3] demonstrated effective debridement and healing of various pressure ulcers and surgical wounds. Some studies have shown synergistic effects of PVA foam with collagenase on wound debridement.[4,9] In 2 separate studies, Sibbald et al[5] and Coutts et al[6] demonstrated effective antibacterial, debriding, anti-inflammatory, and edge action of the dressing in adult wounds. Hill[10] presented results regarding removal of devitalized tissue using MB/GV dressings in a variety of adult wounds, including pressure injury, surgical nonhealing wounds, and dehisced surgical wounds. Furtado[11] described the use of PVA foam in a premature neonate in whom an open abdomen secondary to intestinal perforation developed. In this case, surgery could not close the abdomen to contain the bowel, and MB/GV foam was used to protect the bowel while acting as a mild NPWT and exudate absorber. Granulation tissue developed after 7 days.

Alternative dressings are also available. Silver- and iodine-infused foams, hydrofiber, and alginates are common in adult practice. Pediatric practitioners should be cautious about using silver and iodine applications, because potential side effects include thyroid dysregulation, argyria, leukopenia, agranulocytosis, and kernicterus, none of which is desired in neonatal and critically ill pediatric patients.[12] In this author's personal experience, medical-grade honey gel works well but takes a longer time compared with enzymatic or mechanical debridement to enhance autolytic debridement. The desire for minimal moisture precludes the use of medical-grade honey on the omphalocele wounds and peristomal dermatitis described in this case series. Hydroconductive dressings contribute to excellent moisture wicking but do not provide simultaneous antimicrobial coverage. Alginates are known to donate calcium in exchange for sodium, causing potential concern for hypercalcemia. Concern for hypercalcemia, and therefore use of alginate, would be a particular contraindication in neonates and critically ill pediatric patients with renal abnormalities. Dehydration is another concern in managing large neonatal wounds, as alginates are highly viscous hydrophilic products.[13] Silver-infused hydrofiber was used initially in 3 of the wounds reported herein, with suboptimal outcomes.

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