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Introduction: Risk stratification for poor outcomes is not currently age-specific. Risk stratification of older patients based on observational cohorts primarily composed of young patients may result in suboptimal clinical care and inaccurate quality benchmarking. We assessed two hypotheses. First, we hypothesized that risk factors for poor outcomes after trauma are age-dependent and, second, that the relative importance of various risk factors are also age-dependent., Methods: A cohort study of severely injured adult trauma patients admitted to the intensive care unit 2014-2018 was performed using trauma registry data. Random forest algorithms predicting poor outcomes (death or complication) were built and validated using three cohorts: (1) patients of all ages, (2) younger patients, and (3) older patients. Older patients were defined as aged 55 y or more to maintain consistency with prior trauma literature. Complications assessed included acute renal failure, acute respiratory distress syndrome, cardiac arrest, unplanned intubation, unplanned intensive care unit admission, and unplanned return to the operating room, as defined by the trauma quality improvement program. Mean decrease in model accuracy (MDA), if each variable was removed and scaled to a Z-score, was calculated. MDA change ≥4 standard deviations between age cohorts was considered significant., Results: Of 5489 patients, 25% were older. Poor outcomes occurred in 12% of younger and 33% of older patients. Head injury was the most important predictor of poor outcome in all cohorts. In the full cohort, age was the most important predictor of poor outcomes after head injury. Within age cohorts, the most important predictors of poor outcomes, after head injury, were surgery requirement in younger patients and arrival Glasgow Coma Scale in older patients. Compared to younger patients, head injury and arrival Glasgow Coma Scale had the greatest increase in importance for older patients, while systolic blood pressure had the greatest decrease in importance., Conclusions: Supervised machine learning identified differences in risk factors and their relative associations with poor outcomes based on age. Age-specific models may improve hospital benchmarking and identify quality improvement targets for older trauma patients., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Little is known about patient-reported outcomes (PROs) following abdominal trauma. We hypothesized that patients undergoing definitive laparotomy (DEF) would have better PROs compared to those treated with damage control laparotomy (DCL)., Methods: The DCL Trial randomized DEF versus DCL in abdominal trauma. PROs were measured using the European Quality of Life-5 Dimensions-5 Levels (EQ-5D) questionnaire at discharge and six months postdischarge (1 = perfect health, 0 = death, and <0 = worse than death) and Posttraumatic Stress Disorder (PTSD) Checklist-Civilian. Unadjusted Bayesian analysis with a neutral prior was used to assess the posterior probability of achieving minimal clinically important difference., Results: Of 39 randomized patients (21 DEF versus 18 DCL), 8 patients died (7 DEF versus 1 DCL). Of those who survived, 28 completed the EQ-5D at discharge (12 DEF versus 16 DCL) and 25 at 6 mo (12 DEF versus 13 DCL). Most patients were male (79%) with a median age of 30 (interquartile range (IQR) 21-42), suffered blunt injury (56%), and were severely injured (median injury severity score 33, IQR 21 - 42). Median EQ-5D value at discharge was 0.20 (IQR 0.06 - 0.52) DEF versus 0.31 (IQR -0.03 - 0.43) DCL, and at six months 0.51 (IQR 0.30 - 0.74) DEF versus 0.50 (IQR 0.28 - 0.84) DCL. The posterior probability of minimal clinically important difference DEF versus DCL at discharge and six months was 16% and 23%, respectively., Conclusions: Functional deficits for trauma patients persist beyond the acute setting regardless of laparotomy status. These deficits warrant longitudinal studies to better inform patients on recovery expectations., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Reliable, accurate, and non-invasive hemoglobin measurements would be useful in the trauma setting. The aim of this study was to re-examine the ability of the Masimo Radical 7 in this setting after recent hardware and software improvements., Methods: Level 1 Trauma patients were prospectively enrolled in the study over a 9-mo period with the goal of obtaining 3 paired data points from 150 patients admitted to the ICU or IMU. Hospital laboratory hemoglobin values were compared with cyanomethemoglobin (HiCN) and Masimo device hemoglobin (SpHb) values using comparison plots and Bland-Altman analysis., Results: A total of 380 patients were enrolled in the study with 150 of those being admitted to the ICU or IMU. Comparison of hospital lab hemoglobin and HiCN (n = 494) found a correlation of R2 = 0.92. Comparison of hospital lab hemoglobin and Masimo device hemoglobin (n = 218) found a correlation of R2 = 0.27. Bland-Altman analysis of the 218 of the comparable hospital hemoglobin and Masimo device hemoglobin values had a bias of 0.505 g/dL with 95% of values within the limits of agreement of 4.06 g/dL to -3.60 g/dL., Conclusions: The Masimo Radical 7 device has the potential to provide timely, useful clinical information, but it is not currently able to serve as an initial noninvasive diagnostic tool for trauma patients. There was poor correlation between clinical Hgb and SpHb, and because of that, SpHb should not be used to evaluate hemoglobin levels in trauma patients., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Protocols for expediting critical trauma patients directly from the helipad to the operating room tend to vary by center, rely heavily on physician gestalt, and lack supporting evidence. We evaluated a population of severely injured trauma patients with the aim of determining objective factors associated with the need for immediate surgical intervention., Methods: All highest-activation trauma patients transported by air ambulance between 1/1/16 and 12/31/17 were enrolled retrospectively. Transfer, pediatric, isolated burn, and isolated head trauma patients were excluded. Patients who underwent emergency general surgery within 30 min of arrival without the aid of cross-sectional imaging were compared to the remainder of the cohort., Results: Of the 863 patients who were enrolled, 85 (10%) spent less than 30 min in the emergency department (ED) before undergoing an emergency operation. The remaining 778 patients (90%) formed the comparison group. The ED ≤ 30 min group had a higher percentage of penetrating injuries, lower blood pressure, and was more likely to have a positive FAST exam. The "Direct to Operating Room" (DTOR) score is a predictive scoring system devised to identify patients most likely to benefit from bypassing the ED. The odds ratio of emergency operation within 30 min of hospital arrival increased by 2.71 (95% confidence interval 2.23-3.29; P < 0.001) for every 1-point increase in DTOR score., Conclusions: Trauma patients with profound hypotension or acidosis and positive FAST were more likely to require surgery within 30 min of hospital presentation. Use of a scoring system may allow early identification of these patients in the prehospital setting by nonphysician providers., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Platelet function tests such as thrombelastography platelet mapping and impedance aggregometry have demonstrated universal platelet dysfunction in trauma patients. In this study, we introduce the measurement of platelet contraction force as a test of platelet function. We hypothesize that force will correlate with established coagulation tests such as thrombelastography, demonstrate significant differences between healthy subjects and trauma patients, and identify critically ill trauma patients., Methods: Blood samples were prospectively collected from level 1 trauma patients at initial presentation, assayed for force of and time to contraction and compared with thrombelastography. Blood from healthy subjects was assayed to establish a reference range. Results from trauma patients were compared with healthy controls and trauma patients that died., Results: The study includes one hundred trauma patients with mean age 45 y, 74% were male, and median injury severity score of 14 ± 12. Patients that survived (n = 90) demonstrated significantly elevated platelet contraction force compared with healthy controls (n = 12) (6390 ± 2340 versus 4790 ± 470 μN, P = 0.043) and trauma patients that died (n = 10) (6390 ± 2340 versus 2860 ± 1830 μN, P = 0.0001). Elapsed time to start of platelet contraction was faster in trauma patients that survived compared with healthy controls (660 ± 467 versus 1130 ± 140 s, P = 0.0022) and those that died (660 ± 470 versus 1460 ± 1340 s, P < 0.0001)., Conclusions: In contrast with all existing platelet function tests reported in the literature, which report platelet dysfunction in trauma patients, contractile force demonstrates hyperfunction in surviving trauma patients and dysfunction in nonsurvivors. Platelet contraction reflects platelet metabolic reserve and thus may be a potential biomarker for survival after trauma. Contractile force warrants further investigation to predict mortality in severely injured trauma patients., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Exception from informed consent (EFIC) allows clinician scientists to perform much needed emergency research. Obtaining this exception, however, requires many meetings with community groups for consultation, which can make the process time-consuming and expensive. We aim to determine the impact of using social media in lieu of some community meetings in an effort to obtain an EFIC., Materials and Methods: An economic analysis of four randomized clinical trials was performed. Costs were conservatively estimated using personnel costs, social media costs, and adjusted to 2016 US dollars. People were considered reached if they attended a community meeting or were directed to the study website by social media and spent ≥1 min., Results: The Early Whole Blood study required 14 meetings, reached 272 people, and cost $8260 ($30/person reached). The Pragmatic, Randomized Optimal Platelet and Plasma Ratios study required 14 meetings, reached 260 people, and cost $7479 overall ($29/person reached). The Prehospital Tranexamic Acid Use for Traumatic Brain Injury study required 12 meetings, reached 198 people, and cost $6340 ($32/person reached). Only the damage control laparotomy trial utilized social media in lieu of some community meetings. The damage control laparotomy trial required six meetings at which 137 people were reached. The $1000 social media campaign reached 229 people. The cost was $3977 overall and $11/person reached., Conclusions: Including a social media campaign during the EFIC process increased the number of potential patients reached and reduced total and per person costs reached costs. Obtaining an EFIC for future emergency clinical trials may be facilitated by the inclusion of a social media campaign., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Reductions in platelet (PLT) count and function are associated with poor outcomes in trauma patients. We proposed to determine if patients expected to receive blood products have a decrease in PLT function higher than expected based on the reduction in PLT count, and if the reduction in function could be associated with the donor plasma/supernatant received., Methods: PLT count and function were measured on admission to the emergency department and intensive care unit in severely injured patients expected to receive a transfusion. PLT function was measured by Multiplate aggregometry in response to five agonists. Function was corrected for alterations in count. In vitro studies were conducted in the blood of normal subjects to assess the effect of dilutions with AB donor plasma on PLT function., Results: Forty-six patients were enrolled, with 87% requiring a transfusion. Median Injury Severity Score was 23 (13, 29) and mortality 15%. PLT count and function were decreased from emergency department to intensive care unit admission by 25% and 58%, respectively. Decreases in function persisted after adjustment for count. Patients requiring large volumes of blood products had reductions in function that were disproportionately greater. Reductions in PLT function were greatest after transfusion of PLTs. In in vitro studies with a 30% dilution by autologous plasma caused a relational reduction in function, whereas allogenic plasma resulted in greater decreases that were highly variable between donors., Conclusions: Within hours of injury a decrease in both PLT count and function occurs, that is aggravated with the administration of blood products, with transfusion of PLTs showing the greatest effect. The effect on PLT function of allogenic transfused plasma appears to be highly donor related., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Energy drink consumption in the United States has more than doubled over the last decade and has been implicated in cardiac arrhythmias, myocardial infarction, and even sudden cardiac death. We hypothesized that energy drink consumption may increase the risk of adverse cardiovascular events by increasing platelet aggregation, thereby resulting in a relatively hypercoagulable state and increased risk of thrombosis., Methods: Thirty-two healthy volunteers aged 18-40 y were given 16 oz of bottled water or a standardized, sugar-free energy drink on two separate occasions, 1-wk apart. Beverages were consumed after an overnight fast over a 30-min period. Coagulation parameters and platelet function were measured before and 60 min after consumption using thrombelastography and impedance aggregometry., Results: No statistically significant differences in coagulation were detected using kaolin or rapid thrombelastography. In addition, no differences in platelet aggregation were detected using ristocetin, collagen, thrombin receptor-activating peptide, or adenosine diphosphate-induced multiple impedance aggregometry. However, compared to water controls, energy drink consumption resulted in a significant increase in platelet aggregation via arachidonic acid-induced activation (area under the aggregation curve, 72.4 U versus 66.3 U; P = 0.018)., Conclusions: Energy drinks are associated with increased platelet activity via arachidonic acid-induced platelet aggregation within 1 h of consumption. Although larger clinical studies are needed to further address the safety and health concerns of these drinks, the increased platelet response may provide a mechanism by which energy drinks increase the risk of adverse cardiovascular events., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Muscle loss is a sequela of severe burn and critical illness with bed rest contributing significantly to atrophy. We hypothesize that exercise will mitigate muscle loss after burn with bed rest., Materials and Methods: Male rats were assigned to sham ambulatory (S/A), burn ambulatory (B/A), sham hindlimb unloading (S/H), or burn hindlimb unloading (B/H). Rats received a 40% scald burn or sham and were ambulatory or placed in hindlimb unloading, a model of bed rest. Half from each group performed twice daily resistance climbing. Hindlimb isometric forces were measured on day 14., Results: Soleus mass and muscle function were not affected by burn alone. Mass was significantly lower in hindlimb unloading (79 versus 139 mg, P < 0.001) and no exercise (103 versus 115 mg, P < 0.01). Exercise significantly increased soleus mass in B/H (86 versus 77 mg, P < 0.01). Hindlimb unloading significantly decreased muscle force in the twitch (12 versus 31 g, P < 0.001), tetanic (55 versus 148 g, P < 0.001), and specific tetanic measurements (12 versus 22 N/cm(2), P < 0.001). Effects of exercise on force depended on other factors. In B/H, exercise significantly increased twitch (14 versus 8 g, P < 0.05) and specific tetanic force (14 versus 7 N/cm(2), P < 0.01). Fatigue index was lower in ambulatory (55%) and exercise (52%) versus hindlimb (69%, P = 0.03) and no exercise (73%, P = 0.002)., Conclusions: Hindlimb unloading is a significant factor in muscle atrophy. Exercise increased the soleus muscle mass, twitch, and specific force in this model. However, the fatigue index decreased with exercise in all groups. This suggests exercise contributes to functional muscle change in this model of disuse and critical illness., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Identifying hypofibrinogenemia in trauma is important. The optimal method of fibrinogen determination is unknown. We therefore evaluated fibrinogen levels determined by two whole blood viscoelastic hemostatic assays, thrombelastography functional fibrinogen (FF) and rotational thromboelastometry FIBTEM in trauma patients and compared these with the plasma-based Clauss method., Materials and Methods: Prospective study of consecutive adult trauma patients admitted to a level I trauma center. Levels of fibrinogen were analyzed by Clauss, FF, and FIBTEM on arrival. These methods were compared, and we then investigated whether specific cutoffs of fibrinogen levels were indicative for an increased risk of receiving a transfusion within the initial 6 h., Results: A total of 182 patients with an Injury Severity Score of 17 (9-26) were enrolled. Functional fibrinogen maximum amplitude (FF MA) and FIBTEM maximum clot firmness (MCF) had identical correlation coefficients when compared with those of Clauss fibrinogen (both ρ = 0.64, P < 0.001), and FF MA and FIBTEM MCF correlated with each other (ρ = 0.71, P < 0.001). By logistic regression, the following cutoffs of fibrinogen levels were associated with increased odds of receiving a transfusion, red blood cell concentrates: Clauss <2.5 g/L, FF MA <14.9 mm, FIBTEM MCF <10 mm; fresh frozen plasma and platelets: Clauss <2.5 g/L, FF MA <16.9 mm, FIBTEM MCF <14 mm., Conclusions: The viscoelastic hemostatic assays for determining fibrinogen levels, FIBTEM and FF, are both correlated with the Clauss fibrinogen level, and there are no differences in the strength of these correlations. In this study, specific fibrinogen levels at arrival to the emergency department were indicative, although not necessarily causal, of increased odds of receiving a transfusion., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Fibrinogen is the first coagulation factor to reach critical levels during hemorrhage. Consequently, reestablishing normal fibrinogen levels is necessary to achieve adequate hemostasis. Fibrinogen is supplemented through administration of fresh frozen plasma, cryoprecipitate, or human fibrinogen concentrate, RiaSTAP. RiaSTAP is potentially the most advantageous fibrinogen replacement product because it offers the highest fibrinogen concentration, lowest volume, and most consistent dose. Unfortunately, RiaSTAP is limited by a protocol reconstitution time of 15 min. Conversely, physicians in emergency settings frequently resort to a forceful and rapid reconstitution, which causes foaming and possible protein loss and/or damage. This study aims to address the in vitro effectiveness of protocol-reconstituted RiaSTAP versus rapidly reconstituted RiaSTAP versus cryoprecipitate., Methods: Three fibrinogen treatments were prepared: protocol-reconstituted RiaSTAP, rapidly reconstituted RiaSTAP, and thawed cryoprecipitate. Each treatment was added in theoretical doses of 0-600 mg/dL to fibrinogen-depleted plasma (normal fibrinogen level is 150-450 mg/dL). Samples were generated in triplicate, and each sample was subjected to rapid thrombelastography and Clauss assays. The rapid thrombelastography assay measures the hemostatic potential of a blood and/or plasma sample. The maximum amplitude (MA) parameter indicates overall clot strength and is a reflection of fibrinogen efficacy. The Clauss assay measures the time to clot formation in response to a known concentration of thrombin, and the amount of functional fibrinogen is then determined from a standard curve., Results: For all fibrinogen treatments, increasing fibrinogen dose resulted in an increase in MA. There was no significant difference in MA between both RiaSTAP reconstitutions (slope of RiaSTAP [protocol], 10.85 mm/[100 mg/dL] and slope of RiaSTAP [rapid], 10.54 mm/[100 mg/dL]). However, both protocol-reconstituted RiaSTAP and rapidly reconstituted RiaSTAP have higher MA values than cryoprecipitate in doses of ≥100 mg/dL. Moreover, each replicate of cryoprecipitate showed a higher variance in fibrinogen efficacy (coefficient of variance [CV] = 44.7%) at a fibrinogen dose of 300 mg/dL. RiaSTAP, however, showed a lower variance in fibrinogen efficacy for both reconstitutions (RiaSTAP [protocol], CV = 3.3% and RiaSTAP [rapid], CV = 2.7%), indicating a consistent fibrinogen dose., Conclusions: RiaSTAP (either reconstitution method) has greater hemostatic potential and less variability in fibrinogen concentration compared with cryoprecipitate. Rapidly reconstituted RiaSTAP does not compromise hemostatic potential and can be used to potentially facilitate hemostasis in rapidly bleeding patients., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Sepsis is a deleterious systemic response to an infection with a high incidence of morbidity and mortality, affecting more than a million patients a year in the US. The purpose of this study was to develop a screening tool for the early identification of sepsis in emergency department patients using readily available information at triage., Materials and Methods: This prospective, observational study took place at an academic tertiary referral hospital. Over a period of 10 wk, all patients who were seen at triage were screened for study enrollment. Inclusion criteria were adult (age≥18 y) nontrauma patients and exclusion criteria were prisoners and pregnant women. Using a Spot Check StO2 device to measure StO2 value, heart rate, respiratory rate, and temperature, these values were used to generate a cumulative screening score indicating whether a patient may have sepsis., Results: A total of 500 patients were screened. The incidence of sepsis in the present study population was 8.4%. The screening tool yielded a sensitivity of 85.7%, a specificity of 78.4%, a positive predictive value of 26.7%, and a negative predictive value of 98.4%., Conclusions: Heart rate, respiratory rate, and temperature have good diagnostic potential for the early identification of sepsis among emergency department triage personnel. Additionally, early evidence suggests StO2 may play a complementary and synergistic role in the early identification of sepsis by triage personnel., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Hemodynamic status and coagulation capacity affect blood loss after injury. The most advantageous fluid and blood pressure to optimize resuscitation and minimize perturbation of coagulation are unclear. We investigated interactions of isovolumic hemodilution on hemodynamics, coagulation, and blood loss after injury., Methods: Twenty-five male rats were randomized into three groups (Whole Blood Uncontrolled Blood Pressure [WBU], n = 7; Lactated Ringers Uncontrolled Blood Pressure [LRU], n = 10; Whole Blood Controlled Blood Pressure [WBC], n = 8) with isovolumic hemodilution of 50% blood volume, with and without control of pre-injury blood pressure. All rats underwent uniform grade IV liver injury 30 min after serial exchanges. Post-injury blood loss and coagulation function were measured., Results: Dilution occurred, determined by hematocrit, with LRU having a greater reduction. Pre-injury mean arterial pressure (MAP) decreased compared with baseline (98 ± 7 mmHg) with LRU (62 ± 14 mmHg) and WBC (61 ± 10 mmHg), resulting in WBU (101 ± 13 mmHg) being significantly higher and not changed from baseline. Post-injury, MAP decreased from pre-injury, with LRU significantly lower than the other two groups. No differences were observed in prothrombin time/international normalized ratio or thromboelastography. Bleed volume was significantly different between groups: WBU < WBC < LRU and associated with the pre-injury MAP. Controlling baseline MAP, dilution with Lactated Ringers (LR) resulted in greater blood loss than whole blood (3.0 ± 0.4 versus 1.9 ± 0.3 mL)., Conclusions: In this rat model of liver injury, blood loss was associated with baseline MAP and type of fluid used for dilution. Hemodilution with LR did not produce coagulopathy based on laboratory values. When controlling baseline MAP, dilution with LR increased bleeding, confirming a functional coagulopathic state., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Hyperglycemia in critically ill patients has been associated with increased morbidity and mortality. It is unclear to what degree hyperglycemia should be regulated in a mixed surgical population., Study Design: A retrospective chart review of 210 surgical patients in the intensive care unit (ICU) was performed. All patients were placed on an intravenous insulin protocol targeted to a blood glucose (BG) of 80-140 mg/dL. Outcomes were compared between surgical patients with controlled BG levels (80-140 mg/dL) versus uncontrolled levels (>140 mg/dL)., Results: The mortality rate of this population was 12%, 5% in the controlled BG group compared with 18% in the uncontrolled BG group (P < 0.01). After adjusting for covariates, the mortality rate of the uncontrolled blood glucose group was significantly greater (OR = 4.8, 95% CI 1.4-20; P = 0.02). The overall hypoglycemic rate was <1%, and was not associated with a higher mortality, P = 0.60. A greater mortality rate was associated with patients who spent a greater time with blood glucose values >181 mg/dL (OR = 1.3, 95% CI 1.1-1.6; P = 0.01)., Conclusions: Increased mortality was associated with surgical patients in the uncontrolled blood glucose group compared with patients who were well controlled with insulin therapy. These results are comparable to previous studies and indicate that surgical patients are a population who may benefit from tighter glycemic control. Further investigations through prospective randomized studies are needed to fully evaluate the effects of hyperglycemia in a diverse surgical population as well as specific surgical subspecialties., (Copyright © 2012. Published by Elsevier Inc.)

Background: Severe burn induces a sustained hypermetabolic response, which causes long-term loss of muscle mass and decrease in muscle strength. In this study, we sought to determine whether muscle disuse has additional impact on muscle atrophy after severe burn using a rat model combining severe cutaneous burn and hindlimb unloading., Methods: Forty Sprague-Dawley rats (≈ 300 g) were randomly assigned to sham ambulatory (S/A), sham hindlimb unloading (S/HLU), burn ambulatory (B/A), or burn hindlimb unloading (B/HLU) groups. Rats received a 40% total body surface (TBSA) full thickness scald burn, and rats with hindlimb unloading were placed in a tail traction system. At d 14, lean body mass (LBM) was determined using DEXA scan, followed by measurement of the isometric mechanical properties in the predominantly fast-twitch plantaris muscle (PL) and the predominantly slow-twitch soleus muscle (SL). Muscle weight (wt), protein wt, and wet/dry wt were determined., Results: At d 14, body weight had decreased significantly in all treatment groups; B/HLU resulted in significantly greater loss compared with the B/A, S/HLU, and S/A. The losses could be attributed to loss of LBM. PL muscle wt and Po were lowest in the B/HLU group (<0.05 versus S/A, S/HLU, or B/A). SL muscle wt and Po were significantly less in both S/HLU and B/HLU compared with that of S/A and B/A; no significant difference was found between S/HLU and B/HLU., Conclusions: Cutaneous burn and hindlimb unloading have an additive effect on muscle atrophy, characterized by loss of muscle mass and decrease in muscle strength in both fast (PL) and slow (SL) twitch muscles. Of the two, disuse appeared to be the dominant factor for continuous muscle wasting after acute burn in this model., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: Clinicians have postulated that decreased atmospheric pressure during air evacuation exacerbates muscle edema and necrosis in injured limbs. The present study investigated whether the mild hypobaric, hypoxic conditions of simulated flight during muscle reperfusion worsened muscle edema and muscle injury in an established animal model., Methods: Twenty male Sprague-Dawley rats underwent tourniquet-induced hind limb ischemia for 2h. After removal of the tourniquet, rats were divided into two groups (n=10/group), and exposed to either (1) hypobaric, hypoxic conditions (HB) of 522 mm Hg (simulating 10,000 feet, the upper limit of normal aircraft cabin pressure), or (2) normobaric, normoxic conditions (NB) of 760 mm Hg (sea level), for 6h. Muscle wet weight, muscle dry:wet weight ratios, viability, and routine histology were measured on the gastrocnemius and tibialis anterior muscles. Blood samples were analyzed for percentage hematocrit, leukocyte count, and coagulation status., Results: Ischemia resulted in significant edema in both groups (P<0.05). Normobaric normoxia caused greater edema in the gastrocnemius compared with hypobaric hypoxia; the tibialis anterior was not significantly different between groups. The decrease in body weight for NB and HB was 3.4+/-1.4 and 10.7+/-1.2g, respectively (P<0.05). Hematocrit was 44.7+/-0.5 and 42.6+/-0.6 (P<0.05)., Conclusions: The hypobaric, hypoxic conditions of simulated medical air evacuation were not associated with increased muscle edema following 2h of ischemic injury. This suggests that other factors, such as resuscitation, may be the cause of muscle edema in flight-evacuated patients., (Published by Elsevier Inc.)

Background: Military burns result from either combat or non-combat causes. We compared these etiologies from patients involved in ongoing conflicts to evaluate their impact and provide prevention recommendations., Methods: All military patients with significant burns treated at the United States Army Institute of Surgical Research from April 2003 to May 2005 were reviewed. Injuries were categorized as having resulted from combat or non-combat causes. Demographics, burn severity and pattern, mortality, and early outcomes were compared., Results: There were 273 burn patients seen with 63% injured in combat. A high early rate of non-combat injuries was noted. Feedback on non-combat burn prevention was provided to the combat theater, and the incidence of non-combat burns decreased. Mean age and time from injury to admission did not differ. The majority of combat injuries resulted from explosive device detonation. Waste burning, ammunition handling, and gasoline caused most non-combat injuries. Combat casualties had more associated and inhalation injuries and greater full-thickness burn size; total body surface area burned was equivalent. The hands and the face were the most frequently burned body areas. Mortality was 5% in combat and 2% in non-combat patients. The majority of survivors in both groups returned to military duty., Conclusions: The disparity in full-thickness burn size and incidence of inhalation and associated injuries resulted from differing mechanisms of injury, with explosions and penetrating trauma more common in combat wounds. Despite the severity of combat burns, mortality was low and outcomes generally good. Non-combat burns are preventable and have decreased in incidence.