Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical Warfareing the epidermis for autotransplantation.) The roofsof HD blisters, however, are not expected to reattachto the blister floor because of HD-induced damageto basal cells and basement membrane zone (BMZ)components. Sloughing will eventually occur. Weakattachment of the neoepidermis to the underlyingdermis (fragile skin) has been noted in human HD casualtiesand experimentally exposed weanling pigs. 131Once the lesions have fully reepithelialized, protectivedressings may initially be needed to avoid or minimizedamage from friction with clothing or bedding.For patients presenting with ruptured HD-inducedblisters, careful removal of the blister roof with scissors,application of an antibiotic ointment, and placementof a sterile dressing is warranted. For both of thesescenarios, more complete debridement is necessaryfor large lesions.In hospital settings, vesicles that have coalesced orbecome confluent, as well as larger intact blisters canbe unroofed and cleansed by gently rubbing the affectedareas with a saline soaked course mesh gauze orlaparotomy pad under general anesthesia or conscioussedation. Alternately, sharp scissor debridement can becarried out. In field settings, sharp debridement may bemore practical. Following debridement or unroofing,the wounds will require protection from infection anddesiccation. Options include various topical antimicrobials,or the use of biologic or synthetic dressings.Intact vesicles or blisters that are debrided in cleanhospital settings may benefit from the application ofbiologic dressings, such as porcine heterograft (pigskin);collagen-laminated nylon dressings such asBiobrane (Dow Hickam Pharmaceuticals Inc, SugarLand, Tex); or silver-containing dressings such asActicoat (Smith and Nephew, Largo, Fla); Silverlon(Argentum, Lakemont, Ga); or Silvasorb (MedlineIndustries, Mundelein Ill). 131–137 These dressings createa moist healing environment, decrease pain, andobviate the need for daily dressing changes. Biobranehas the added advantage of flexibility, facilitatingmovement. If adherent, pigskin and Biobrane maybe left in place until reepithelialization occurs. Silvercontainingdressings need to be changed every fewdays, following manufacturers’ recommendations.Biologic, synthetic, or silver dressings that are not adheredto the wound bed should be promptly removed,followed by wound cleansing and application of anappropriate topical antibiotic. Fluid could build upunderneath dressings that do not remain in completecontact with the wound bed, resulting in masceration.Dressings should also be removed if infection or cellulitisdevelops. Field application of these dressingsis usually impractical because the appropriate levelof cleanliness cannot be maintained.Wounds that are not freshly debrided, are dirtyor contaminated, or contain blisters already brokenshould be unroofed or debrided and cleansed withsoap and water or appropriate surgical detergents,such as chlorhexidine gluconate solution. Extrapolatingfrom burn experience, iodine-containing surgicaldetergents or prep solutions have poor coverageagainst Pseudomonas species and should be avoided.Following cleansing, the area should be liberallycovered with a topical antibiotic (eg, 1% silver sulfadiazinecream, aqueous 5% mafenide acetate solution,Dakin solution, 0.5% silver nitrate solution, bacitracinantibiotic ointment, or Neosporin ointment [Pfizer Inc,New York, NY]), and a sterile dressing should thenbe applied. Biologic or synthetic dressings shouldnot be used in this setting. The choice of antibiotic islargely a matter of personal experience and hospital orbattlefield availability, for there is little scientific datain actual HD injuries to strongly advocate one agentover another. The use of bacitracin and Neosporinointments should be limited to small wounds (lessthan 1% TBSA) and employed for very brief periods(3–5 days) because of their high capacity to provokeallergic cutaneous reactions. 138 Bacitracin is only effectiveagainst Gram-positive bacteria, but Neosporin hasa broader antimicrobial spectrum. The use of 11.1%mafenide acetate cream should be avoided because ofthe severe pain it causes when applied to partial-thicknesswounds and the possibility of metabolic acidosis.Mafenide acetate cream would be appropriate overinsensate full thickness injuries caused by liquid HDexposure; over superficial (partial thickness) injuriesthat become infected and convert to full thickness; orover wounds that are visibly infected (see below). Followingapplication of any topical antibiotic, a steriledressing should be put in place.Several antimicrobials are available in liquid form,facilitating wound debridement and inspection. Theseinclude 0.5% silver nitrate solution, Dakin solution(0.25%–0.5% sodium hypochlorite), and 5% mafenideacetate solution. 140 Silver nitrate 0.5% solution is inexpensive,readily available, and has bacteriostaticcoverage against a broad spectrum of Gram-positiveand Gram-negative bacteria and yeast-like organisms.Silver nitrate solution is a primary topical therapyfor toxic epidermal necrosis; silver sulfadiazene is apoor choice because sulfa drugs are often the incitingagent. Silver nitrate solution does not penetrate deepwounds and works best on minimally colonized, debrided,or superficial injury. 139 It has the disadvantagesof staining instruments, clothing, and bed linens andcauses hypochloremia, hypocalcemia, and hyponatremiawith prolonged use. Dakin solution is likewiseinexpensive and readily available, with bacteriocidal280