Succinate Activation of SUCNR1 Predisposes Severely Injured Patients to Neutrophil-mediated ARDS.

OBJECTIVES: Identify the metabolites that are increased in the plasma of severely injured patients that developed ARDS versus severely injured patients that did not, and assay if these increased metabolites prime pulmonary sequestration of neutrophils (PMNs) and induce pulmonary sequestration in an animal model of ARDS. We hypothesize that metabolic derangement due to advanced shock in critically injured patients leads to the PMNs, which serves as the first event in the ARDS. Summary of Background Data: Intracellular metabolites accumulate in the plasma of severely injured patients. METHODS: Untargeted metabolomics profiling of 67 critically injured patients was completed to establish a metabolic signature associated with ARDS development. Metabolites that significantly increased were assayed for PMN priming activity in vitro. The metabolites that primed PMNs were tested in a 2-event animal model of ARDS to identify a molecular link between circulating metabolites and clinical risk for ARDS. RESULTS: After controlling for confounders, 4 metabolites significantly increased: creatine, dehydroascorbate, fumarate, and succinate in trauma patients who developed ARDS ( P < 0.05). Succinate alone primed the PMN oxidase in vitro at physiologically relevant levels. Intravenous succinate-induced PMN sequestration in the lung, a first event, and followed by intravenous lipopolysaccharide, a second event, resulted in ARDS in vivo requiring PMNs. SUCNR1 inhibition abrogated PMN priming, PMN sequestration, and ARDS. Conclusion: Significant increases in plasma succinate post-injury may serve as the first event in ARDS. Targeted inhibition of the SUCNR1 may decrease ARDS development from other disease states to prevent ARDS globally.

The Extremity/Mechanism/Shock Index/GCS (EMS-G) score: A novel pre-hospital scoring system for early and appropriate MTP activation.

BACKGROUND: Numerous in-hospital scoring systems to activate massive transfusion protocols (MTP) have been proposed; however, to date, pre-hospital scoring systems have not been robustly validated. Many trauma centers do not have blood or pre-thawed plasma available in the trauma bay, leading to delays in balanced transfusion. This study aims to assess pre-hospital injury and physiologic parameters to develop a pre-hospital scoring system predictive of need for massive transfusion (MT) prior to patient arrival. METHODS: A retrospective review of all adult full and partial trauma team activations from July 2014-July 2018 from an urban level 2 trauma center was performed utilizing our trauma registry. Stepwise logistic regression analysis was performed to develop a new scoring system, with point totals assigned proportional to the odds ratios of requiring MT for each variable. Internal validation of the EMS-G score was performed using a subset of the data which was not utilized for development of the scoring system, and sensitivity and specificity were compared to previously validated in-hospital scoring systems applied in the pre-hospital setting. RESULTS: 763 patients were included with 94 patients (12.3%) receiving early MT, defined as 4 units pRBC in 4 h or ED death. In-hospital models for predicting MT such as Assessment of Blood Consumption (ABC) or Shock Index (SI) have sensitivities and specificities of 46/85% and 94/79% respectively for early MTP utilization based on pre-hospital data. Pre-hospital variables found to be predictive of MT were used to develop the EMS-G (Extremity, Mechanism, Shock Index, GCS) score. This system assigns obvious extremity injury-1-point, penetrating mechanism -2 points, shock index ≥0.9-2 points, GCS ≤8-3 points. A score of 3 or greater was chosen to maximize sensitivity and specificity for pre-hospital MT activation. EMS-G score based on pre-hospital report is 89% sensitive, 84% specific, with a PPV of 44% and NPV of 98% for early MT. Using this system, 25% of full and partial trauma team activations met criteria for pre-hospital MTP activation. CONCLUSION: The EMS-G Score has increased sensitivity and specificity compared to the ABC Score in the pre-hospital setting and appears more appropriate than shock index alone at predicting massive transfusion. This scoring system allows trauma centers to activate MTP prior to patient arrival to ensure early and appropriate blood product administration without blood product wastage.

Evaluation of a water-soluble contrast protocol for small bowel obstruction: A southwestern surgical congress multicenter trial.

Differentiation between SBO that will resolve with supportive measures and those requiring surgery remains challenging. WSC administration may be diagnostic and therapeutic. The purpose of this study was to evaluate use of a SBO protocol using WSC challenge. A protocol was implemented at five tertiary care centers. Demographics, prior surgical history, time to operation, complications, and LOS were analyzed. 283 patients were admitted with SBO; 13% underwent immediate laparotomy; these patients had a median LOS of 7.5 days. The remaining 245 were candidates for WSC challenge. Of those, 80% received contrast. 139 (71%) had contrast passage to the colon. LOS in these patients was 4 days. Sixty-five patients (29%) failed contrast passage within 24 h and underwent surgery. LOS was 9 days. 8% of patients in whom contrast passage was observed at 24 h nevertheless subsequently underwent surgery. 4% of patients who failed WSC challenge did not proceed to surgery. Our multicenter trial revealed that implementation of a WSC protocol may facilitate early recognition of partial from complete obstruction.

Female platelets have distinct functional activity compared with male platelets: Implications in transfusion practice and treatment of trauma-induced coagulopathy.

BACKGROUND: Females are hypercoagulable and have survival benefit in trauma-induced coagulopathy (TIC). The mechanism for this sex-specific hypercoagulability is unknown. Platelets and platelet function are central in providing hemostatic potential and are the largest contributor to clot strength. Ligands (adenosine diphosphate [ADP] and platelet-activating factor [PAF]) bind distinct platelet receptors to potentiate activation and aggregation. We hypothesize that female platelets have a differential response to ADP and PAF, resulting in greater aggregation and activation compared to males, and that estradiol pretreatment of male or female platelets enhances this activity. METHODS: Platelets were collected from healthy volunteers: premenopausal/postmenopausal females (≤54 years, >54 years) and similarly aged males. Platelet aggregometry and flow cytometry (fibrinogen binding capacity) were examined. After treatment with ADP or PAF, platelet aggregation was assessed with Chronolog and activation assessed by CD41 receptor surface expression using flow cytometry. Aggregation and activation were again assessed after platelet pretreatment with estradiol. RESULTS: Healthy volunteers included 12 premenopausal and 13 postmenopausal females and 18 similarly aged males. Female platelets (combined premenopausal and postmenopausal) had increased aggregation with ADP stimulation, as compared to male platelets. Male and female platelets had differential fibrinogen receptor expression, with female platelets (combined premenopausal and postmenopausal) demonstrating robust activation with ADP versus male platelets with PAF. In the presence of estradiol incubation, male platelets' activation with PAF approximated that of females (combined premenopausal and postmenopausal) and activation with PAF was enhanced in both male and female platelets. CONCLUSION: Male and female platelets have differential response to stimuli, suggesting sex-dependent signaling and cellular activation. Female platelets have both increased aggregation and activation potential, and estradiol pretreatment feminizes male platelets to approximate female platelet activation with PAF. These findings offer potential explanation for sex-based differences in hemostatic potential in TIC and question whether donor sex of transfused platelets should be considered in resuscitation. Estradiol may also serve as a novel therapeutic adjunct in TIC.

Preventable death and interpersonal violence in the United States: Who can be saved?

BACKGROUND: Public health initiatives to reduce mortality from penetrating trauma have largely developed from patterns of injury observed in military casualties, with a focus on hemorrhage control and use of tourniquets. Recent efforts show that injury patterns differ between civilian mass casualty events and combat settings, and no studies characterize wounding patterns in all types of civilian homicide. We hypothesize that many homicide deaths are due to nonsurvivable injuries, and that an effective strategy to reduce mortality must focus on both primary prevention as well as improvement in trauma prehospital care. METHODS: We analyzed homicides from the National Violent Death Reporting System from 2012 to 2015. We excluded deaths due to poisoning, intentional neglect, or unknown weapon. Deaths were classified as "dead on scene" (DOS), "dead on arrival" (DOA), or "dead at or after hospital" (DAH) if the patient was admitted to a hospital. Injury patterns for penetrating weapons (firearms and sharp instruments) were further categorized. RESULTS: We included 18,051 homicides, the vast majority of which were due to firearms (n = 12,901 or 71.5%) or sharp instruments (n = 2,265 or 12.5%). The most common injury patterns included wounds to the chest or head, with isolated extremity injuries representing a minority of both firearms deaths (n = 397 of 12,901, 3.1%) and deaths from sharp instruments (n = 50 of 2,265, 2.2%). Furthermore, over half of all deaths occurred prehospital, with only 13.3% of victims admitted prior to death. CONCLUSION: The vast majority of deaths from interpersonal violence are due to firearm injuries. Few deaths appear to be related to extremity hemorrhage alone, and over half of all fatally injured died at the scene. Strategies to decrease mortality from interpersonal violence must go beyond treating injuries that have already occurred, and must address violence prevention directly. LEVEL OF EVIDENCE: Epidemiological study, level IV.

Obstruction reduction: Use of water-soluble contrast challenge to differentiate between partial and complete small bowel obstruction.

Differentiating SBO that will resolve conservatively from those requiring surgery remains challenging. Water-soluble contrast administration may be diagnostic and therapeutic. Our study evaluated use of a WSC challenge protocol. We hypothesize that protocol use discriminates between surgical SBO and obstructions which can be managed non-operatively. Demographics, prior surgeries, time to operation, complications, and LOS were analyzed. 108 patients were admitted with SBO. 13% underwent immediate laparotomy with concern for bowel compromise; these had a median LOS of 8.5 days. 91 received WSC protocol. Of these, 77% had contrast passage to the colon. Of the 48 in whom contrast passed between 0 and 12 h, LOS was 2 days. Of the 22 patients in whom contrast passed between 12 and 24 h, LOS was 4.5 days. 21 had failure of contrast passage; 18 of those underwent surgery after 24 h as a result. Of the 21 patients who failed WSC challenge, median LOS was 8 days. WSC protocol implementation facilitates early recognition of partial from complete obstruction and may decrease LOS. Our findings warrant further evaluation with a multicenter trial.

The why and how our trauma patients die: A prospective Multicenter Western Trauma Association study.

BACKGROUND: Historically, hemorrhage has been attributed as the leading cause (40%) of early death. However, a rigorous, real-time classification of the cause of death (COD) has not been performed. This study sought to prospectively adjudicate and classify COD to determine the epidemiology of trauma mortality. METHODS: Eighteen trauma centers prospectively enrolled all adult trauma patients at the time of death during December 2015 to August 2017. Immediately following death, attending providers adjudicated the primary and contributing secondary COD using standardized definitions. Data were confirmed by autopsies, if performed. RESULTS: One thousand five hundred thirty-six patients were enrolled with a median age of 55 years (interquartile range, 32-75 years), 74.5% were male. Penetrating mechanism (n = 412) patients were younger (32 vs. 64, p < 0.0001) and more likely to be male (86.7% vs. 69.9%, p < 0.0001). Falls were the most common mechanism of injury (26.6%), with gunshot wounds second (24.3%). The most common overall primary COD was traumatic brain injury (TBI) (45%), followed by exsanguination (23%). Traumatic brain injury was nonsurvivable in 82.2% of cases. Blunt patients were more likely to have TBI (47.8% vs. 37.4%, p < 0.0001) and penetrating patients exsanguination (51.7% vs. 12.5%, p < 0.0001) as the primary COD. Exsanguination was the predominant prehospital (44.7%) and early COD (39.1%) with TBI as the most common later. Penetrating mechanism patients died earlier with 80.1% on day 0 (vs. 38.5%, p < 0.0001). Most deaths were deemed disease-related (69.3%), rather than by limitation of further aggressive care (30.7%). Hemorrhage was a contributing cause to 38.8% of deaths that occurred due to withdrawal of care. CONCLUSION: Exsanguination remains the predominant early primary COD with TBI accounting for most deaths at later time points. Timing and primary COD vary significantly by mechanism. Contemporaneous adjudication of COD is essential to elucidate the true understanding of patient outcome, center performance, and future research. LEVEL OF EVIDENCE: Epidemiologic, level II.

Trauma Resuscitation Consideration: Sex Matters.

BACKGROUND: Sex dimorphisms in coagulation have been recognized, but whole blood assessment of these dimorphisms and their relationship to outcomes in trauma have not been investigated. This study characterizes the viscoelastic hemostatic profile of severely injured patients by sex, and examines how sex-specific coagulation differences affect clinical outcomes, specifically, massive transfusion (MT) and death. We hypothesized that severely injured females are more hypercoagulable and therefore, have lower rates of MT and mortality. STUDY DESIGN: Hemostatic profiles and clinical outcomes from all trauma activation patients from 2 level I trauma centers were examined, with sex as an experimental variable. As part of a prospective study, whole blood was collected and thrombelastography (TEG) was performed. Coagulation profiles were compared between sexes, and association with MT and mortality were examined. Poisson regression with robust standard errors was performed. RESULTS: Overall, 464 patients (23% female) were included. By TEG, females had a more hypercoagulable profile, with a higher angle (clot propagation) and maximum amplitude (MA, clot strength). Females were less likely to present with hyperfibrinolysis or prolonged activating clotting time than males. In the setting of depressed clot strength (abnormal MA), female sex conferred a survival benefit, and hyperfibrinolysis was associated with higher case-fatality rate in males. CONCLUSIONS: Severely injured females have a more hypercoagulable profile than males. This hypercoagulable status conferred a protective effect against mortality in the setting of diminished clot strength. The mechanism behind these dimorphisms needs to be elucidated and may have treatment implications for sex-specific trauma resuscitation.

Effect of Pre-Hospital Use of the Assessment of Blood Consumption Score and Pre-Thawed Fresh Frozen Plasma on Resuscitation and Trauma Mortality.

BACKGROUND: Early blood product resuscitation reduces trauma patient mortality from hemorrhage. This mortality benefit depends on a system that can rapidly identify actively bleeding patients, initiate massive transfusion protocol (MTP), and mobilize resources to the bedside. We hypothesized that process improvement efforts that identify patients early and mobilize appropriate blood products to the bedside for immediate use would improve mortality. STUDY DESIGN: Pre-implementation, MTP activation was at the discretion of the trauma surgeon, and only PRBCs were immediately available. In June 2016, the Assessment of Blood Consumption (ABC) score was incorporated in our pre-hospital triage process, and a process for thawed plasma to be available was developed. We performed a retrospective review of patients who were hypotensive on arrival or had MTP activated. We compared mortality and MTP component ratios 15 months pre- vs 15 months post-implementation. RESULTS: Activations of MTP increased 6-fold, while the specificity of the process remained the same. In patients receiving MTP, appropriate blood product transfusion ratios increased 44%. Overall and penetrating trauma mortality improved by 23% and 41%, respectively. When divided by the Injury Severity Score (ISS), penetrating trauma mortality decreased by 65% for the ISS subgroup 15 to 24 and by 38% for ISS subgroup ≥ 25. Length of stay, ICU length of stay, and readmission rates were not significantly different. CONCLUSIONS: Delivery of balanced blood product resuscitation is essential to confer mortality benefits. Process improvement directed at early recognition of the hemorrhagic patient, immediate product availability, and product delivery to the bedside for transfusion allows for mortality reduction without increased resource use.

The Metabolopathy of Tissue Injury, Hemorrhagic Shock, and Resuscitation in a Rat Model.

INTRODUCTION: The metabolic consequences of trauma induce significant clinical pathology. In this study, we evaluate the independent, metabolic contributions of tissue injury (TI) and combined tissue injury and hemorrhagic shock (TI/HS) using mass spectrometry (MS) metabolomics in a controlled animal model of critical injury. METHODS: Sprague-Dawley rats (n = 14) underwent TI alone or TI/HS, followed by resuscitation with normal saline and shed blood. Plasma was collected (baseline, post-laparotomy, post-HS, post-resuscitation) for ultra-high pressure liquid chromatography MS-metabolomics. Repeated-measures ANOVA with Tukey multiple column comparison test compared the fold change of metabolite concentration among the animal groups at corresponding time points. RESULTS: Four hundred forty metabolites were identified. TI alone did not change the metabolite levels versus baseline. TI/HS induced changes in metabolites from glycolysis, the tricarboxylic acid cycle, the pentose phosphate, fatty acid and glutathione homeostasis pathways, sulfur metabolism, and urea cycle versus TI alone. Following resuscitation many metabolites normalized to TI alone levels, including lactate, most tri-carboxylic acid metabolites, most urea cycle metabolites, glutathione disulfide, and some metabolites from both the pentose phosphate pathway and sulfur metabolism. CONCLUSIONS: Significant changes occur immediately following TI/HS versus TI alone. These metabolic changes are not explained by dilution as a number of metabolites remained unchanged or even increased following resuscitation. The differential metabolic changes resulting from TI alone and TI/HS provide foundation for future investigations severe injury in humans, where TI and HS are often concurrent. This investigation provides a foundation to evaluate metabolic-related outcomes and design-targeted resuscitation strategies.

Red blood cells in hemorrhagic shock: a critical role for glutaminolysis in fueling alanine transamination in rats.

Red blood cells (RBCs) are the most abundant host cell in the human body and play a critical role in oxygen transport and systemic metabolic homeostasis. Hypoxic metabolic reprogramming of RBCs in response to high-altitude hypoxia or anaerobic storage in the blood bank has been extensively described. However, little is known about the RBC metabolism following hemorrhagic shock (HS), the most common preventable cause of death in trauma, the global leading cause of total life-years lost. Metabolomics analyses were performed through ultra-high pressure liquid chromatography-mass spectrometry on RBCs from Sprague-Dawley rats undergoing HS (mean arterial pressure [MAP], <30 mm Hg) in comparison with sham rats (MAP, >80 mm Hg). Steady-state measurements were accompanied by metabolic flux analysis upon tracing of in vivo-injected 13C15N-glutamine or inhibition of glutaminolysis using the anticancer drug CB-839. RBC metabolic phenotypes recapitulated the systemic metabolic reprogramming observed in plasma from the same rodent model. Results indicate that shock RBCs rely on glutamine to fuel glutathione (GSH) synthesis and pyruvate transamination, whereas abrogation of glutaminolysis conferred early mortality and exacerbated lactic acidosis and systemic accumulation of succinate, a predictor of mortality in the military and civilian critically ill populations. Glutamine is here identified as an essential amine group donor in HS RBCs, plasma, liver, and lungs, providing additional rationale for the central role glutaminolysis plays in metabolic reprogramming and survival following severe hemorrhage.

Glutamine metabolism drives succinate accumulation in plasma and the lung during hemorrhagic shock.

BACKGROUND: Metabolomic investigations have consistently reported succinate accumulation in plasma after critical injury. Succinate receptors have been identified on numerous tissues, and succinate has been directly implicated in postischemic inflammation, organ dysfunction, platelet activation, and the generation of reactive oxygen species, which may potentiate morbidity and mortality risk to patients. Metabolic flux (heavy-isotope labeling) studies demonstrate that glycolysis is not the primary source of increased plasma succinate during protracted shock. Glutamine is an alternative parent substrate for ATP generation during anaerobic conditions, a biochemical mechanism that ultimately supports cellular survival but produces succinate as a catabolite. We hypothesize that succinate accumulation during hemorrhagic shock is driven by glutaminolysis. METHODS: Sprague-Dawley rats were subjected to hemorrhagic shock for 45 minutes (shock, n = 8) and compared with normotensive shams (sham, n = 8). At 15 minutes, animals received intravenous injection of C5-N2-glutamine solution (iLG). Blood, brain, heart, lung, and liver tissues were harvested at defined time points. Labeling distribution in samples was determined by ultrahigh-pressure liquid chromatography-mass spectrometry metabolomic analysis. Repeated-measures analysis of variance with Tukey comparison determined significance of relative fold change in metabolite level from baseline. RESULTS: Hemorrhagic shock instigated succinate accumulation in plasma and lungs tissues (8.5- vs. 1.1-fold increase plasma succinate level from baseline, shock vs. sham, p = 0.001; 3.2-fold higher succinate level in lung tissue, shock vs. sham, p = 0.006). Metabolomic analysis identified labeled glutamine and labeled succinate in plasma (p = 0.002) and lung tissue (p = 0.013), confirming glutamine as the parent substrate. Kinetic analyses in shams showed constant total levels of all metabolites without significant change due to iLG. CONCLUSION: Glutamine metabolism contributes to increased succinate concentration in plasma during hemorrhagic shock. The glutaminolytic pathway is implicated as a therapeutic target to prevent the contribution of succinate accumulation in plasma and the lung-to-postshock pathogenesis.

Trauma/hemorrhagic shock instigates aberrant metabolic flux through glycolytic pathways, as revealed by preliminary (13)C-glucose labeling metabolomics.

BACKGROUND: Metabolic derangement is a key hallmark of major traumatic injury. The recent introduction of mass spectrometry-based metabolomics technologies in the field of trauma shed new light on metabolic aberrations in plasma that are triggered by trauma and hemorrhagic shock. Alteration in metabolites associated with catabolism, acidosis and hyperglycemia have been identified. However, the mechanisms underlying fluxes driving such metabolic adaptations remain elusive. METHODS: A bolus of U-(13)C-glucose was injected in Sprague-Dawley rats at different time points. Plasma extracts were analyzed via ultra-high performance liquid chromatography-mass spectrometry to detect quantitative fluctuations in metabolite levels as well as to trace the distribution of heavy labeled carbon isotopologues. RESULTS: Rats experiencing trauma did not show major plasma metabolic aberrations. However, trauma/hemorrhagic shock triggered severe metabolic derangement, resulting in increased glucose levels, lactate and carboxylic acid accumulation. Isotopologue distributions in late Krebs cycle metabolites (especially succinate) suggested a blockade at complex I and II of the electron transport chain, likely due to mitochondrial uncoupling. Urate increased after trauma and hemorrhage. Increased levels of unlabeled mannitol and citramalate, metabolites of potential bacterial origin, were also observed in trauma/hemorrhagic shock rats, but not trauma alone or controls. CONCLUSIONS: These preliminary results are consistent with observations we have recently obtained in humans, and expand upon our early results on rodent models of trauma and hemorrhagic shock by providing the kinetics of glucose fluxes after trauma and hemorrhage. Despite the preliminary nature of this study, owing to the limited number of biological replicates, results highlight a role for shock, rather than trauma alone, in eliciting systemic metabolic aberrations. This study provides the foundation for tracing experiments in rat models of trauma. The goal is to improve our understanding of substrate specific metabolic derangements in trauma/hemorrhagic shock, so as to design resuscitative strategies tailored toward metabolic alterations and the severity of trauma.

Pathologic metabolism: an exploratory study of the plasma metabolome of critical injury.

BACKGROUND: Severe trauma is associated with massive alterations in metabolism. Thus far, investigations have relied on traditional bioanalytic approaches including calorimetry or nuclear magnetic resonance. However, recent strides in mass spectrometry (MS)-based metabolomics present enhanced analytic opportunities to characterize a wide range of metabolites in the critical care setting. METHODS: MS-based metabolomics analyses were performed on plasma samples from severely injured patients' trauma activation field blood and plasma samples obtained during emergency department thoracotomy. These were compared against the metabolic profiles of healthy controls. RESULTS: Few significant alterations were observed between trauma activation field blood and emergency department thoracotomy patients. In contrast, we identified trauma-dependent metabolic signatures, which support a state of hypercatabolism, driven by sugar consumption, lipolysis and fatty acid use, accumulation of ketone bodies, proteolysis and nucleoside breakdown, which provides carbon and nitrogen sources to compensate for trauma-induced energy consumption and negative nitrogen balance. Unexpectedly, metabolites of bacterial origin (including tricarballylate and citramalate) were detected in plasma from trauma patients. CONCLUSION: In the future, the correlation between metabolomics adaptation and recovery outcomes could be studied by MS-based approaches, and this work can provide a method for assessing the efficacy of alternative resuscitation strategies.

Dynamic changes in rat mesenteric lymph proteins following trauma using label-free mass spectrometry.

Early events triggered by posttrauma/hemorrhagic shock currently represent a leading cause of morbidity and mortality in these patients. The causative agents of these events have been associated with increased neutrophil priming secondary to shock-dependent alterations of mesenteric lymph. Previous studies have suggested that unknown soluble components of the postshock mesenteric lymph are main drivers of these events. In the present study, we applied a label-free proteomics approach to further delve into the early proteome changes of the mesenteric lymph in response to hemorrhagic shock. Time-course analyses were performed by sampling the lymph every 30 min after shock up until 3 h (the time window within which a climax in neutrophil priming was observed). There are novel, transient early post-hemorrhagic shock alterations to the proteome and previously undocumented postshock protein alterations. These results underlie the triggering of coagulation and proinflammatory responses secondary to trauma/hemorrhagic shock, metabolic deregulation and apoptosis, and alterations to proteases/antiproteases homeostasis, which are suggestive of the potential implication of extracellular matrix proteases in priming neutrophil activation. Finally, there is a likely correlation between early postshock mesenteric lymph-mediated neutrophil priming and proteomics changes, above all protease/antiproteases impaired homeostasis (especially of serine proteases and metalloproteases).

Early tracheostomy improves outcomes in severely injured children and adolescents.

BACKGROUND: Early tracheostomy has been advocated for adult trauma patients to improve outcomes and resource utilization. We hypothesized that timing of tracheostomy for severely injured children would similarly impact outcomes. METHODS: Injured children undergoing tracheostomy over a 10-year period (2002-2012) were reviewed. Early tracheostomy was defined as post-injury day ≤ 7. Data were compared using Student's t test, Pearson chi-squared test and Fisher exact test. Statistical significance was set at p<0.05 with 95% confidence intervals. RESULTS: During the 10-year study period, 91 patients underwent tracheostomy following injury. Twenty-nine (32%) patients were < 12 years old; of these, 38% received early tracheostomy. Sixty-two (68%) patients were age 13 to 18; of these, 52% underwent early tracheostomy. Patients undergoing early tracheostomy had fewer ventilator days (p=0.003), ICU days (p=0.003), hospital days (p=0.046), and tracheal complications (p=0.03) compared to late tracheostomy. There was no difference in pneumonia (p=0.48) between early and late tracheostomy. CONCLUSION: Children undergoing early tracheostomy had improved outcomes compared to those who underwent late tracheostomy. Early tracheostomy should be considered for the severely injured child. SUMMARY: Early tracheostomy is advocated for adult trauma patients to improve patient comfort and resource utilization. In a review of 91 pediatric trauma patients undergoing tracheostomy, those undergoing tracheostomy on post-injury day ≤ 7 had fewer ventilator days, ICU days, hospital days, and tracheal complications compared to those undergoing tracheostomy after post-injury day 7.

Proteomic profiling of the mesenteric lymph after hemorrhagic shock: Differential gel electrophoresis and mass spectrometry analysis.

Experiments show that upon traumatic injury the composition of mesenteric lymph changes such that it initiates an immune response that can ultimately result in multiple organ dysfunction syndrome (MODS). To identify candidate protein mediators of this process we carried out a quantitative proteomic study on mesenteric lymph from a well characterized rat shock model. We analyzed three animals using analytical 2D differential gel electrophoresis. Intra-animal variation for the majority of protein spots was minor. Functional clustering of proteins revealed changes arising from several global classes that give novel insight into fundamental mechanisms of MODS. Mass spectrometry based proteomic analysis of proteins in mesenteric lymph can effectively be used to identify candidate mediators and loss of protective agents in shock models.

Proteome and system ontology of hemorrhagic shock: exploring early constitutive changes in postshock mesenteric lymph.

BACKGROUND: Postshock mesenteric lymph (PSML) is the mechanistic link between splanchnic ischemia reperfusion (IR) and remote organ injury. We hypothesize that an unbiased inspection of the proteome of PSML will reveal previously unrecognized aberrations in systems biology provoked by hemorrhage-induced mesenteric IR injury in vivo. METHODS: Shock was induced in male Sprague-Dawley rats by controlled hemorrhage, and the mesenteric duct was cannulated for lymph collection. Preshock and postshock lymph were collected for differential in-gel electrophoresis (DIGE)-based proteomics. Proteins that increased or decreased in relative concentration > or =1.5-fold were selected for trypsin digestion and analysis by mass spectrometry (MS). RESULTS: Evidence of tissue injury was detected by an increase in cell/tissue proteins in PSML. Components of coagulation were depleted, whereas products of hemolysis were increased. Haptoglobin was decreased, which supports an early postshock hemolytic process. Interestingly, several protective protease inhibitors were decreased in PSML. The unexpected findings were an increase in alpha-enolase (a key glycolitic enzyme and cell-surface plasminogen binding receptor, +2.4-fold change) and increased major urinary protein (MUP, a sex-specific lipid-binding protein, +17.1-fold change) in PSML. CONCLUSION: A proteomic evaluation of PSML revealed evidence of several shock-associated processes: protein release from tissue injury, depletion of coagulation factors and evidence of hemolysis, depletion of protective protease inhibitors, and an increase in abundance of lipid carriers. These results suggest that constitutive changes in the proteome of PSML may provide novel insights into the complex pathophysiology of postshock systems biology.