Debridement of Sulfur Mustard Skin Burns: A Comparison of Three Methods.

Sulfur mustard burns are characterized by delayed symptoms, slow healing, and recurrence after closure. Incomplete debridement at the level of the basement membrane is the postulated cause. Graham pioneered laser debridement of mustard burns. For field or mass-casualty use, saline wet-to-wet or antibiotic-soak debridement is more practical. In this study, we compared laser, saline, and antibiotic debridement in a porcine model of deep partial-thickness injury. Deep-dermal sulfur mustard burns were produced in 18 anesthetized Gottingen minipigs using 10-µl saturated vapor cap exposure time of 90 minutes. Debridement was started 48 hours postinjury and consisted of a single laser treatment; 5 days of 5% aqueous mafenide acetate wet-to-wet dressings; or 7 to 12 days of saline wet-to-wet dressings. Wounds were treated with daily silver sulfadiazine for 30 days and, then, assessed by histopathology, silver-ion analysis, colorimetry, and evaporimetry. All wounds healed well with no sign of infection. Antibiotic debridement showed no advantage over saline debridement. There were no significant differences between groups for colorimetry or evaporimetry. Histopathology was graded on a mustard-specific scale of 1 to 15 where higher values indicate better healing. Mean histology scores were 13.6 for laser, 13.9 for mafenide, and 14.3 for saline. Saline debridement statistically outperformed laser (P < .05) but required the longest debridement time. Laser debridement had the benefit of requiring a single treatment rather than daily dressing changes, significantly decreasing need for wound care and personnel resources. Development of a ruggedized laser for field use is a countermeasures priority.

Safety evaluation of silver-ion dressings in a porcine model of deep dermal wounds: A GLP study.

INTRODUCTION: Silver ion has strong antimicrobial properties and is used in a number of wound dressings. In burn models, silver-nylon dressings produce elevated silver levels in the wound along with minimal systemic effect. We evaluated systemic toxicity in a non-burn wound model to see if a similar pattern of silver ion distribution would occur. METHODS: Eight deep partial-thickness wounds each were created on the dorsum of 40 Gottingen minipigs using a Er-YAG Laser. Half were treated with a 21-day course of silver-nylon dressings (Silverlon®) and half were treated with moist gauze dressings. Wound, blood, liver and kidney silver levels, along with blood chemistry and hematology data were obtained at appropriate intervals. RESULTS: All wounds healed well with healing enhanced by silver-nylon dressings. Silver ion was demonstrable in all wounds treated with silver-nylon at day 21 and after 14 days of no further treatment. Silver ion was not detected in blood, liver or kidney of any animal treated with silver-nylon or control dressings. Liver and kidney function remained normal in all animals. CONCLUSION: A 21-day application of silver-nylon dressings to a non-burn dermal wound produces no systemic or local toxicity in Gottingen minipigs.

Blood and Tissue Silver Levels Following Application of Silver-Based Dressings to Sulfur Mustard Chemical Burns.

Silver-based dressings are commonly used in burn care. Silver sulfadiazine use is associated with elevated blood, urine, and tissue levels of silver ion. We examined wound and tissue levels of silver ion in a two-species model of sulfur mustard chemical burn injury treated with two different silver-based dressings. Superficial dermal and moderate thickness dermal chemical burns were induced in 16 hairless guinea pigs and in 16 Gottingen minipigs by exposure to sulfur mustard vapor. After debridement, silver-nylon burn dressings or silver-calcium alginate dressings were applied and changed every 7 days until wound healing or a maximum of 60 days post exposure. At autopsy, liver, spleen, and wound samples were harvested. Silver ion was measured using inductively coupled plasma-mass spectrography with a lower level of detection of 0.02 parts per billion. Negligible silver ion levels were found in the liver (mean < 0.003 µg/g of tissue) and spleen (mean < 0.05 µg/g) of all 32 animals. Wound biopsies showed silver ion levels ranging from 0.07 to 19.5 µg/g of tissue. Wound levels were higher in minipigs than in hairless guinea pigs and were higher in animals treated with silver-nylon burn wound dressings than with silver-calcium alginate dressings. Silver ion could be detected in some wounds 40 days after dressings were removed. In a chemical burn model, application of silver-nylon or silver-calcium alginate dressings is associated with elevated wound levels but negligible tissue levels of silver ion.

The antimicrobial spectrum of Xeroform®.

INTRODUCTION/BACKGROUND: Xeroform® is a petrolatum-based fine mesh gauze containing 3% bismuth tribromophenate. Bismuth, similar to other metals, has antimicrobial properties. Xeroform® has been used for decades in burn and plastic surgery as a donor site dressing and as a covering for wounds or partial thickness burns. Despite this, the antimicrobial spectrum of Xeroform® remains largely unknown. We examined the in-vitro efficacy of Xeroform® against common burn pathogens using zone-of-inhibition methodology in a commercial research facility. METHODS/DESIGN: Pure strains of 15 common burn pathogens including Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-sensitive Staphylococcus aureus (MSSA), Staphylococcus epidermidis, Pseudomonas aeruginosa, Enterobacter cloacae, Escherichia coli, Candida albicans, Vancomycin resistant Enterococcus, Acinetobacter baumennii, Klebsiella pneumonia, Extended spectrum beta-lactamase producing Klebsiella, Beta hemolytic Streptococcus pyogenes, Proteus mirabilis, Serratia marcescens, and Salmonella enterica ssp. Enterica were inoculated at a strength of 106-1010 CFU/ml onto appropriate agar plates. A sterile 1 in2 Xeroform® square was placed in the center of each plate, and the Zone of Inhibition (ZOI) was measured following 18-24h of incubation at 37°C. A second bismuth pharmaceutical (bismuth subsalicylate, Pepto-Bismol®) was then tested using the same methodology against the same strains of MRSA, MSSA, E. coli, K. pneumonia and S. marcescens. Finally, 3% w/v bismuth tribromophenate in glycerol suspension was tested against 13 burn pathogens for antimicrobial activity independent of the Xeroform® dressing by measure of Zone of Inhibition. RESULTS/FINDINGS: For Xeroform®, none of the fifteen pathogens had a measurable zone of inhibition on any plate. Bismuth subsalicylate showed a zone of inhibition for MSSA in 3 plates (mean of 47.2mm), in one of three plates for MRSA (13.8mm), and in one of three plates for S. marcesens (89.6mm). There was no zone of inhibition seen for K. pneumonia or E. coli. Bismuth tribromophenate, when not bound to Xeroform® showed activity against 12 of 13 pathogens. CONCLUSIONS/IMPLICATIONS: While bismuth subsalicylate, and bismuth tribromophenate unbound to Xeroform® demonstrate antimicrobial activity, it appears that Xeroform® dressings do not. The utility of Xeroform® in burn medicine may relate more to use as an impervious dressing than to antimicrobial effect. Donor sites are clean surgical wounds and clean partial thickness burns may have minimal colonization present. In such circumstances, an inactive and impervious dressing may be all that is necessary to promote wound healing.

A literature review of the military uses of silver-nylon dressings with emphasis on wartime operations.

Medical support of military operations involves treatment of massive soft tissue wounds, thermal burns, open fractures, blast injuries and traumatic amputations under conditions that are often austere and far from supply lines. Military hospitals, as recently deployed in Iraq and Afghanistan, are designed and equipped for stabilization and rapid transfer of injured patients back to their home nation. These austere facilities are often tasked with the emergency or long-term treatment of local populations when injured or burned, further stressing the medical resupply system. Pathogens encountered in contemporary wartime practice are increasingly resistant to antibiotics. Ionic silver is bactericidal against a broad spectrum of bacteria, yeasts and fungi, has been utilized as a topical antiseptic for over 100 years, and has no known clinically-relevant resistance. Silver-nylon dressings, initially stocked in US military hospitals as a burn dressing, are now finding utility as a universal dressing for all types of combat wounds. Compared to conventional burn dressings, they are easier to transport and store, easier to use, and do not need to be changed as frequently, allowing for conservation of nursing resources. In this literature review, the recent military uses of silver-nylon dressings are examined. The stockpiling and use of silver-nylon as a universal military burn and wound dressing is advocated.

Silver in medicine: a brief history BC 335 to present.

Silver is a naturally occurring element. Similar to other metals, the ionized form of silver (Ag(+1)) has known antimicrobial properties. A number of wound dressings incorporating silver ion or silver compounds have recently been developed and marketed. In addition, the antimicrobial effects of silver are currently being promoted in consumer products such as clothing and household appliances. The present use of silver in medical and consumer products has prompted concerns for potential toxicity and ecological effects, including induction of microbial resistance to antibiotics. These concerns ignore the fact that silver has been used for medicinal purposes for several thousand years. A historical review of the uses of silver in medicine is presented.

Silver in medicine: the basic science.

Silver compounds are increasingly used in medical applications and consumer products. Confusion exists over the benefits and hazards associated with silver compounds. In this article, the biochemistry and physiology of silver are reviewed with emphasis on the use of silver for wound care.

High-frequency percussive ventilation for intercontinental aeromedical evacuation.

High-frequency percussive ventilation (HFPV) has been used for the management of patients with smoke inhalation injury for more than 20 years and is considered a standard of care at many burn centers. Because the ventilator is powered by air and oxygen rather than electricity, prehospital use has been limited by large-volume medical gas requirements. Since 2003, Operations Iraqi Freedom and Enduring Freedom have created a need for long-range aeromedical transfer of service members with severe burn and inhalation injuries. Unique to these conflicts is the availability of US Air Force C-17 cargo aircraft as the primary long-distance airframe. Because C-17 aircraft have a built-in medical oxygen supply, transcontinental patient transport using HFPV has become feasible. In this study, the authors report their initial experiences with the aeromedical transportation of 33 burn patients over a combined distance of 174,145 air miles using HFPV. HFPV is safe and efficacious for transcontinental flight when used by an experienced medical transport team.

Simple derivation of the initial fluid rate for the resuscitation of severely burned adult combat casualties: in silico validation of the rule of 10.

BACKGROUND: In practice, current burn resuscitation formulas, designed to estimate 24-hour fluid resuscitation needs, provide only a starting point for resuscitation. To simplify this process, we devised the "rule of 10" to derive the initial fluid rate. METHODS: We performed an in silico study to determine whether the rule of 10 would result in acceptable initial fluid rates for adult patients. A computer application using Java (Sun Microsystems Inc., Santa Clara, CA) generated a set of 100,000 random weights and percentage of total body surface area (%TBSA) values with distributions matching the model characteristics with which the initial fluid rate was calculated using the rule of 10. The initial rate for 100,000 simulations was compared with initial rates calculated by using either the modified Brooke (MB, 2 mL/kg/%TBSA) or the Parkland (PL, 4 mL/kg/%TBSA) formulas. RESULTS: Analysis of calculated initial fluid rates using the rule of 10 showed that 87.8% (n = 87,840) of patients fell between the initial rates derived by the MB and the PL formulas. Less than 12% (n = 11,502) of patients had rule of 10 derived initial rates below the MB. Among these patients, the median difference of the initial rate was 14 mL/hr (range, 2-212 mL/hr). Among those who had initial rule of 10 calculated rates greater than the PL formula (<1%, n = 658), the median difference in rate was 33 mL/hr (range, 1-213 mL/hr), with a mean %TBSA of 21% +/- 1% and mean weight of 130 kg +/- 11 kg. CONCLUSION: For the majority of adult burn patients, the rule of 10 approximates the initial fluid rate within acceptable ranges.

Deployment and operation of a transportable burn intensive care unit in response to a burn multiple casualty incident.

In many hospitals, intensive care units (ICUs) operate at or above capacity on a daily basis. Multiple casualty incidents will create a sudden need for additional ICU beds and hospital planning for disaster response must anticipate the need for rapid ICU expansion. In this article, the authors describe the management of 6 patients who were burned in Guam and successfully transported a distance of 7,268 miles to San Antonio, TX, for tertiary burn center care. The mission required creation of a temporary burn ICU at Tripler Army Medical Center in Hawaii, approximately midway between the referring hospital and the receiving burn center. A method of creating a temporary burn center is described. Lessons learned, including the need to standardize equipment, and to cross-train and cross-credential medical personnel, are applicable to both military and civilian mass casualty management.

Contribution of bacterial and viral infections to attributable mortality in patients with severe burns: an autopsy series.

Bacterial infections are a common cause of mortality in burn patients and viral infections, notably herpes simplex virus (HSV) and cytomegalovirus (CMV) have also been associated with mortality. This study is a retrospective review of all autopsy reports from patients with severe thermal burns treated at the US Army Institute of Research (USAISR) burn unit over 12 years. The review focused on those patients with death attributed to a bacterial or viral cause by autopsy report. Of 3751 admissions, 228 patients died with 97 undergoing autopsy. Death was attributed to bacteria for 27 patients and to virus for 5 patients. Bacterial pathogens associated with mortality included Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. This association with mortality was independent of % total body surface area burn, % full-thickness burn, inhalation injury, and day of death post-burn. Bloodstream infection was the most common cause of bacteria related death (50%), followed by pneumonia (44%) and wound infection (6%). Time to death following burn was < or =7 days in 30%, < or =14 days in 59% and < or =21 days in 67%. All of the viral infections associated with mortality involved the lower respiratory tract, HSV for 4 and CMV for 1. Four of these 5 patients had evidence of inhalation injury by bronchoscopy, all had facial and neck burns, and 2 had concomitant Staphylococcus pneumonia. Time to death following burn ranged from 14 to 42 days for the 5 patients. Despite advances in care, gram negative bacterial infections and infection with S. aureus remain the most common cause of bacteria related mortality early in the hospital course. Viral infections are also associated with mortality and numbers have remained stable when compared to data from prior years.

Resuscitation of severely burned military casualties: fluid begets more fluid.

BACKGROUND: In November 2005, institution of a military-wide burn resuscitation guideline requested the documentation of the initial 24-hour resuscitation of severely burned military casualties on a burn flow sheet to provide continuity of care. The guidelines instruct the providers to calculate predicted 24-hour fluid requirements and initial fluid rate based on the American Burn Association Consensus recommendation of 2 (modified Brooke) mL x kg(-1) x % total body surface area (TBSA)(-1) to 4 (Parkland) mL x kg(-1) x %TBSA(-1) burn. The objective of this study was to evaluate the relationship between the estimated fluid volumes calculated, either by the Modified Brooke or the Parkland formulas, and actual volumes received. METHODS: From November 2005 to December 2008, 105 patients were globally evacuated with >20% TBSA burns, of whom 73 had burn flow sheets initiated. Of these, 58 had completed burn flow sheets. Total fluids administered in the first 24-hour period for each patient were recorded. Chart reviews were performed to extract demographic and clinical outcomes data. RESULTS: Of the 58, the modified Brooke formula was used in 31 patients (modified Brooke group) to estimate 24-hour fluid requirements and the Parkland formula was used in 21 (Parkland group). In six, 3 mL x kg(-1) x %TBSA(-1) was used and were excluded from analysis. No significant difference was detected between the two groups for age, %TBSA burned, inhalation injury, or Injury Severity Score. Actual 24-hour resuscitation in the modified Brooke group was significantly lower than in the Parkland group (16.9 L +/- 6.0 L vs. 25.0 L +/- 11.2 L, p = 0.003). A greater percentage of patients exceeded the Ivy index (250 mL/kg) in the Parkland group compared with the modified Brooke group (57% vs. 29%, p = 0.026). On average, those who had 24-hour fluid needs estimated by the modified Brooke formula received a 3.8 mL x kg(-1) x %TBSA(-1) +/- 1.2 mL x kg(-1) x %TBSA(-1) resuscitation, whereas the Parkland group received a 5.9 mL x kg(-1) x %TBSA(-1) +/- 1.1 mL x kg(-1) x %TBSA(-1) resuscitation (p < 0.0001). No differences in measured outcomes were detected between the two groups. On multivariate logistic regression, exceeding the Ivy index was an independent predictor of death (area under the curve [AUC], 0.807; CI, 0.66-0.95). CONCLUSION: In severely burned military casualties undergoing initial burn resuscitation, the modified Brooke formula resulted in significantly less 24-hour volumes without resulting in higher morbidity or mortality.

Abdominal complications after severe burns.

BACKGROUND: Abdominal catastrophe in the severely burned patient without abdominal injury has been described. We perceived an alarming recent incidence of this complication in our burn center, both during acute resuscitation and later in the hospital course. We sought to define incidence, outcomes, and associated factors, such as excessive resuscitation volume and treatment issues. STUDY DESIGN: We examined all severely burned military and civilian patients with abdominal pathology between March 2003 and February 2008. Data included age, gender, total body surface area burn, inhalation injury, Injury Severity Score, disposition, resuscitation volume, time from injury to diagnosis, use of recombinant factor VIIa, vasopressors, and early tube feedings. We assembled a Delphi panel of surgeons experienced in abdominal catastrophes to review these data. RESULTS: Among 1,825 patients admitted to the US Army Institute of Surgical Research Burn Center, 120 (6.6%) were diagnosed with abdominal pathology (burn size 48% +/- 19%), of which 51 (2.8%) had abdominal catastrophe. The majority of these occurred in the first days after injury with associated abdominal compartment syndrome (32 of 51) and increased linearly to burn size. We noted another group of patients who presented primarily with ischemic bowel later in the course, with the same clinical presentation. Resuscitation volume was 6.02 mL/kg/percent total body surface area burned. Vasopressors were used in 71% of patients and tube feedings in 57% before diagnosis. CONCLUSIONS: Abdominal catastrophe without abdominal trauma occurs in 2.8% of our population. Associated mortality was 78% without obvious cause. Delphi panel experts recommended more aggressive monitoring of abdominal compartment pressures and earlier operative management to improve outcomes.

Continuous venovenous hemofiltration in severely burned patients with acute kidney injury: a cohort study.

INTRODUCTION: Acute kidney injury (AKI) is a common and devastating complication in critically ill burn patients with mortality reported to be between 80 and 100%. We aimed to determine the effect on mortality of early application of continuous venovenous hemofiltration (CVVH) in severely burned patients with AKI admitted to our burn intensive care unit (BICU). METHODS: We performed a retrospective cohort study comparing a population of patients managed with early and aggressive CVVH compared with historical controls managed conservatively before the availability of CVVH. Patients with total body surface area (TBSA) burns of more than 40% and AKI were treated with early CVVH and their outcomes compared with a group of historical controls. RESULTS: Overall, the 28-day mortality was significantly lower in the CVVH arm (n = 29) compared with controls (n = 28) (38% vs. 71%, P = 0.011) as was the in-hospital mortality (62% vs. 86%, P = 0.04). In a subgroup of patients in shock, a dramatic reduction in the pressor requirement was seen after 24 and 48 hours of treatment. Compared with controls (n = 19), significantly fewer patients in the CVVH group (n = 21) required vasopressors at 24 hours (100% vs 43%, P < 0.0001) and at 48 hours (94% vs 24%, P < 0.0001). In those with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), there was a significant increase from baseline in the partial pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2) ratio at 24 hours in the CVVH group (n = 16, 174 +/- 78 to 327 +/- 122, P = 0.003) but not the control group (n = 20, 186 +/- 64 to 207 +/- 131, P = 0.98). CONCLUSIONS: The application of CVVH in adult patients with severe burns and AKI was associated with a decrease in 28-day and hospital mortality when compared with a historical control group, which largely did not receive any form of renal replacement. Clinical improvements were realized in the subgroups of patients with shock and ALI/ARDS. A randomized controlled trial comparing early CVVH to standard care in this high-risk population is planned.

Military return to duty and civilian return to work factors following burns with focus on the hand and literature review.

Functional recovery and outcome from severe burns is oftentimes judged by the time required for a person to return to work (RTW) in civilian life. The equivalent in military terms is return to active duty. Many factors have been described in the literature as associated with this outcome. Hand function, in particular, is thought to have a great influence on the resumption of preburn activities. The purpose of this investigation was to compare factors associated with civilian RTW with combat injured military personnel. A review of the literature was performed to assimilate the many factors reported as involved with RTW or duty. Additionally, a focus on the influence of hand burns is included. Thirty-four different parameters influencing RTW have been reported inconsistently in the literature. In a military population of combat burns, TBSA burn, length of hospitalization and intensive care and inhalation injury were found as the most significant factors in determining return to duty status. In previous RTW investigations of civilian populations, there exists a scatter of factors reported to influence patient disposition with a mixture of conflicting results. In neither military nor civilian populations was the presence of a hand burn found as a dominant factor. Variety in patient information collected and statistical approaches used to analyze this information were found to influence the results and deter comparisons between patient populations. There is a need for a consensus data set and corresponding statistical approach used to evaluate RTW and duty outcomes after burn injury.