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Before sulfur mustard (HD) injuries can be effectively treated, assessment of lesion depth must occur. Accurate depth assessment is important because it dictates how aggressive treatment needs to be to minimize or prevent cosmetic and functional deficits. Depth of injury typically is assessed by physical examination. Diagnosing very superficial and very deep lesions is relatively easy for the experienced burn surgeon. Lesions of intermediate depth, however, are often problematic in determining the need for grafting. This study was a preliminary evaluation of two noninvasive bioengineering methodologies, laser Doppler perfusion imaging (LDPI) and indocyanine green fluorescence imaging (ICGFI), to determine their ability to accurately diagnose depth of sulfur mustard lesions in a weanling swine model. Histological evaluation was used to assess the accuracy of the imaging techniques in determining burn depth. Six female weanling swine (8-12 kg) were exposed to 400 microl of neat sulfur mustard on six ventral sites for 2, 8, 30, or 60 minutes. This exposure regimen produced lesions of varying depths from superficial to deep dermal. Evaluations of lesion depth using the bioengineering techniques were conducted at 24, 48, and 72 hours after exposure. After euthanasia at 72 hours after exposure, skin biopsies were taken from each site and processed for routine hematoxylin and eosin histological evaluation to determine the true depth of the lesion. Results demonstrated that LDPI and ICGFI were useful tools to characterize skin perfusion and provided a good estimate of HD lesion depth. Traditional LDPI and the novel prototype ICGFI instrumentation used in this study produced images of blood flow through skin lesions, which provided a useful assessment of burn depth. LDPI and ICGFI accurately predicted the need for aggressive treatment (30- and 60-minute HD lesions) and nonaggressive treatment (2- and 8-minute HD lesions) for the lesions generated in this study. Histological evaluation confirmed the accuracy of the assessment. The ICGFI instrument offers several advantages over LDPI including real-time blood flow imaging, low cost, small size, portability, and not requiring the patient to be repositioned. A negative, however, is the need for intravenous dye injection. Although this would not be an issue in a hospital, it may be problematic in a mass casualty field setting. Additional experiments are required to determine the exposure time necessary to produce a graded series of partial-thickness HD lesions and to optimize instrumental parameters. The data generated in this follow-on study will allow for a full assessment of the potential LDPI and ICGFI hold for predicting the need for aggressive treatment after HD exposure. The lasting message is that objective imaging techniques can augment the visual judgment of burn depth.

Background Sulfur mustard (2,2′-dichlorodiethyl sulfide; HD) is a potent vesicating chemical warfare agent that poses a continuing threat to both military and civilian populations. Significant cutaneous HD injuries can take several months to heal, necessitate lengthy hospitalizations, and result in long-term complications. There are currently no standardized or optimized methods of casualty management. New strategies are needed to provide for optimal and rapid wound healing. Objective The primary aim of this research was to develop improved clinical strategies (treatment guidelines) for optimal treatment of superficial dermal (second degree) cutaneous HD injuries, with the goal of returning damaged skin to optimal appearance and normal function in the shortest period of time. Methods Superficial dermal HD injuries were created on the ventral abdominal surface of weanling pigs. At 48 h post-exposure, lesions were laser debrided and a treatment adjunct applied. Cultured epithelial allografts and 11 commercial off-the-shelf (COTS) products were examined for their efficacy in improving wound healing of these injuries. Clinical evaluations and a variety of non-invasive bioengineering methods were used at 7 and 14 days post-surgery to follow the progress of wound healing and evaluate various cosmetic and functional properties of the wounds. Measurements included reflectance colorimetry to measure erythema; evaporimetry to examine transepidermal water loss as a method of evaluating barrier function; torsional ballistometry to evaluate the mechanical properties of skin firmness and elasticity; and two-dimensional high frequency ultrasonography (HFU) to monitor skin thickness (e.g., edema, scar tissue). Histopathology and immunohistochemistry were performed 14 days following surgery to examine structural integrity and quality of healing. Logical Decisions® for Windows was used to rank the 12 treatment adjuncts that were studied. Results The most efficacious treatment adjuncts included (1) Vacuum Assisted Closure™, V.A.C.®, involving application of topical negative pressure, (2) Amino-Plex® Spray (biO2 Cosmeceuticals International, Inc., Beverly Hills, CA), a nutritive cosmeceutical product that is designed to increase oxygen in cells, stimulate ATP synthesis, improve glucose transportation, stimulate collagen formation, and promote angiogenesis, and (3) ReCell® Autologous Cell Harvesting Device (Clinical Cell Culture Americas LLC, Coral Springs, Florida), an innovative medical device that was developed to allow rapid harvesting of autologous cells from a thin split-thickness biopsy followed by spray application of a population of skin cells onto wounds within 30 min of collecting the biopsy, without the need of culturing the keratinocytes in a clinical laboratory. Conclusions Complete re-epithelialization of debrided HD injuries in 7 days is possible. In general, shallow laser debridement through the basement membrane zone (100 μm) appears to provide better results than deeper debridement (400 μm) with respect to early re-epithelialization, cosmetic appearance, functional restoration, and structural integrity. Of the 12 treatment adjuncts examined, the most promising included Vacuum Assisted Closure™, Amino-Plex® Spray, and ReCell® Autologous Cell Harvesting Device.