Plasminogen Degradation by Neutrophil Elastase in Pleural Infection, Not High Plasminogen Activator Inhibitor-1 (PAI-1), is the Cause of Intrapleural Lytic Failure.

BACKGROUND: Complex pleural space infections often require treatment with multiple doses of intrapleural tissue-plasminogen activator(tPA) and deoxyribonuclease(DNase), with treatment failure frequently necessitating surgery. Pleural infections are rich in neutrophils, and neutrophil elastase degrades plasminogen, the target substrate of tPA, that is required to generate fibrinolysis. We hypothesized that pleural fluid from patients with pleural space infection would have high elastase activity, evidence of inflammatory plasminogen degradation, and low fibrinolytic potential in response to tPA that could be rescued with plasminogen supplementation. RESEARCH QUESTION: Does neutrophil elastase degradation of plasminogen contribute to intrapleural fibrinolytic failure? STUDY DESIGN AND METHODS: We obtained infected pleural fluid and circulating plasma from hospitalized adults(n=10) with IRB approval from a randomized trial evaluating intrapleural fibrinolytics versus surgery for initial management of pleural space infections. Samples were collected pre-intervention, post-intervention day-1(PID1), PID2, and PID3. Activity assays, enzyme-linked immunosorbent assays, and western blot(WB) analysis were performed, and turbidometric measurements of fibrinolysis were performed on pleural fluid +/- exogenous plasminogen supplementation. Results are reported as median(Q1, Q3) or n(%) as appropriate, with alpha set at 0.05. RESULTS: Pleural fluid elastase activity was >4-fold higher(p=0.02) and plasminogen antigen levels >3-fold lower(p=0.04) than their corresponding plasma. Pleural fluid WB analysis demonstrated abundant plasminogen degradation fragments consistent with elastase degradation patterns. We found that plasminogen-activator inhibitor-1(PAI-1), the native tPA inhibitor, had high antigen levels pre-intervention but the overwhelming majority of this PAI-1(82%) was not active(p=0.003), and all PAI-1 activity was lost by PID2 in patients receiving intrapleural tPA/DNase. Finally, using turbidity clot lysis assays we found that 9 of 10 patients' pleural fluid was unable to generate a significant fibrinolytic response when challenged with tPA and that plasminogen supplementation rescued fibrinolysis in all patients. INTERPRETATION: Inflammatory plasminogen deficiency, not high PAI-1 activity, is a significant contributor to intrapleural fibrinolytic failure.

RESUSCITATIVE ENDOVASCULAR BALLOON OCCLUSION OF THE AORTA: ZONE 1 REPERFUSION-INDUCED COAGULOPATHY.

ABSTRACT: Objective: We sought to identify potential drivers behind resuscitative endovascular balloon occlusion of the aorta (REBOA) induced reperfusion coagulopathy using novel proteomic methods. Background: Coagulopathy associated with REBOA is poorly defined. The REBOA Zone 1 provokes hepatic and intestinal ischemia that may alter coagulation factor production and lead to molecular pathway alterations that compromises hemostasis. We hypothesized that REBOA Zone 1 would lead to reperfusion coagulopathy driven by mediators of fibrinolysis, loss of coagulation factors, and potential endothelial dysfunction. Methods: Yorkshire swine were subjected to a polytrauma injury (blast traumatic brain injury, tissue injury, and hemorrhagic shock). Pigs were randomized to observation only (controls, n = 6) or to 30 min of REBOA Zone 1 (n = 6) or REBOA Zone 3 (n = 4) as part of their resuscitation. Thromboelastography was used to detect coagulopathy. ELISA assays and mass spectrometry proteomics were used to measure plasma protein levels related to coagulation and systemic inflammation. Results: After the polytrauma phase, balloon deflation of REBOA Zone 1 was associated with significant hyperfibrinolysis (TEG results: REBOA Zone 1 35.50% versus control 9.5% vs. Zone 3 2.4%, P < 0.05). In the proteomics and ELISA results, REBOA Zone 1 was associated with significant decreases in coagulation factor XI and coagulation factor II, and significant elevations of active tissue plasminogen activator, plasmin-antiplasmin complex complexes, and syndecan-1 (P < 0.05). Conclusion: REBOA Zone 1 alters circulating mediators of clot formation, clot lysis, and increases plasma levels of known markers of endotheliopathy, leading to a reperfusion-induced coagulopathy compared with REBOA Zone 3 and no REBOA.

Fibrinolysis Resistance After Injury Is a Risk Factor for a Hospital-Acquired Pneumonia-Like Disease Pattern.

Background: Pneumonia is associated with increased morbidity and costs in the intensive care unit (ICU). Its early identification is key for optimal outcomes, but early biomarkers are lacking. Studies suggest that fibrinolysis resistance (FR) after major abdominal surgery is linked to an increased risk of infection. Patients and Methods: Patients in a randomized controlled trial for hemorrhagic shock were evaluated for FR. Fibrinolysis resistance was quantified by thrombelastography with exogenous tissue plasminogen activator (tPA-TEG) at 24- and 48-hours post-injury and measuring LY30 (%). A receiver-operating characteristics (ROC) curve analysis was used to identify a cutoff for increased risk of pneumonia, which was then validated in ICU patients at risk for venous thromboembolism (VTE). Multivariable logistic regression was used to control for confounders. Results: Forty-nine patients in the hemorrhagic shock cohort had tPA-TEGs at 24- and 48-hours (median ISS, 27; 7% pneumonia). A composite tPA-TEG LY30 of less than 4% at 24 and 48 hours was found to be the optimal cutoff for increased risk of pneumonia. This cohort had a seven-fold increased rate of pneumonia (4% vs. 28%; p = 0.048). Eighty-eight patients in the VTE cohort had tPA-TEGs at 24 and 48 hours post-ICU admission (median ISS, 28; 6% pneumonia). The tPA-TEG LY30 of less than 4% was associated with a 10-fold increased rate of pneumonia (19% vs. 1.5%; p = 0.002). In patients with traumatic brain injury, the same association was found (33% vs. 3.2%; p = 0.006). Adjusting for confounders, the tPA-TEG persisted as a substantial risk factor for pneumonia (adjusted odds ratio [OR], 35.7; 95% confidence interval [CI], 1.9-682; p = 0.018). Conclusions: Fibrinolysis resistance quantified by tPA-TEG within 48 hours of ICU admission is associated with an increased risk of pneumonia in patients in hemorrhagic shock and those at risk for VTE. Prospective validation of the tPA-TEG LY30 optimal cutoff for pneumonia and further investigation into whether endogenous FR is a cause of an altered immunity is warranted.

Differentiating Pathologic from Physiologic Fibrinolysis: Not as Simple as Conventional Thrombelastography.

BACKGROUND: Conventional rapid-thrombelastography (rTEG) cannot differentiate fibrinolysis shutdown from hypofibrinolysis, as both of these patient populations have low fibrinolytic activity. Tissue plasminogen activator (tPA) TEG can identify depletion of fibrinolytic inhibitors, and its use in combination with rTEG has the potential to differentiate all three pathologic fibrinolytic phenotypes following trauma. We hypothesize tPA-TEG and rapid TEG (rTEG) in combination can further stratify fibrinolysis phenotypes post-injury to better stratify risk for mortality. STUDY DESIGN: Adult trauma patients (n=981) with both rTEG and tPA-TEG performed <2 hours post-injury were included. rTEG LY30 was used to initially define fibrinolysis phenotypes (Hyperfibrinolysis >3%, Physiologic 0.9-3%, Shutdown <0.9%), with Youden Index then used to define pathologic extremes of tPA-TEG LY30 [tPA sensitive (depletion of fibrinolytic inhibitors) versus resistant] resulting in 9 groups that were assessed for risk of death. RESULTS: The median NISS was 22, 21% were female, 45% had penetrating injury, and overall mortality was 13%. The tPA-TEG LY30 inflection point for increased mortality was>35.5% (tPA sensitive, OR mortality 9.2 P<0.001) and <0.3% (tPA resistance, OR mortality 6.3 p=0.04). Of the nine potential fibrinolytic phenotypes, five were associated with increased mortality. Overall, the 9 phenotypes provided a significantly better prediction of mortality than rTEG or tPA-TEG alone (AUROC=0.80 vs 0.63 and 0.75, respectively, p<0.0001). These could be condensed to three pathologic phenotypes (true hyperfibrinolysis, early fibrinolysis shutdown, and hypofibrinolysis). CONCLUSIONS: The combination of rTEG and tPA-TEG increases the ability to predict mortality and suggests patient specific strategies for improved outcome.

Mitigation of trauma-induced endotheliopathy by activated protein C: A potential therapeutic for postinjury thromboinflammation.

BACKGROUND: Activated Protein C (aPC) plays dual roles after injury, driving both trauma-induced coagulopathy (TIC) by cleaving, and thus inactivating, factors Va and VIIIa and depressing fibrinolysis while also mediating an inflammomodulatory milieu via protease activated receptor-1 (PAR-1) cytoprotective signaling. Because of this dual role, it represents and ideal target for study and therapeutics after trauma. A known aPC variant, 3K3A-aPC, has been engineered to preserve cytoprotective activity while retaining minimal anticoagulant activity rendering it potentially ideal as a cytoprotective therapeutic after trauma. We hypothesized that 3K3A-aPC would mitigate the endotheliopathy of trauma by protecting against endothelial permeability. METHODS: We used electric cell-substrate impedance sensing to measure permeability changes in real time in primary endothelial cells. These were cultured, grown to confluence, and treated with a 2 µg/mL solution of 3K3A-aPC at 180 minutes, 120 minutes, 60 minutes, 30 minutes prior to stimulation with ex vivo plasma taken from severely injured trauma patients (Injury Severity Score > 15 and BD < -6) (trauma plasma [TP]). Cells treated with thrombin and untreated cells were included in this study as control groups. Permeability changes were recorded in real time via electric cell-substrate impedance sensing for 30 minutes after treatment with TP. We quantified permeability changes in the control and treatment groups as area under the curve (AUC). Rac1/RhoA activity was also compared between these groups. Statistical significance was determined by one-way ANOVA followed by a post hoc analysis using Tukey's multiple comparison's test. RESULTS: Treatment with aPC mitigated endothelial permeability induced by ex vivo trauma plasma at all pre-treatment time points. The AUC of the 30-minute 3K3A-aPC pretreatment group was higher than TP alone (mean diff. 22.12 95% CI [13.75, 30.49], p < 0.0001) (Figure). Moreover, the AUC of the 60-minute, 120-minute, and 180-minute pretreatment groups was also higher than TP alone (mean diff., 16.30; 95% confidence interval [CI], 7.93-24.67; 19.43; 95% CI, 11.06-27.80, and 18.65; 95% CI, 10.28-27.02;, all p < 0.0001, respectively). Rac1/RhoA activity was higher in the aPC pretreatment group when compared with all other groups ( p < 0.01). CONCLUSION: Pretreatment with 3K3A-aPC, which retains its cytoprotective function but has only ~5% of its anticoagulant function, abrogates the effects of trauma-induced endotheliopathy. This represents a potential therapeutic treatment for dysregulated thromboinflammation for injured patients by minimizing aPC's role in trauma-induced coagulopathy while concurrently amplifying its essential cytoprotective function. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level III.

Combination of aspirin and rosuvastatin for reduction of venous thromboembolism in severely injured patients: a double-blind, placebo-controlled, pragmatic randomized phase II clinical trial (The STAT Trial).

INTRODUCTION: Venous thromboembolism (VTE) remains a significant source of postinjury morbidity and mortality. Beta-hydroxy beta-methylglutaryl-CoA (HMG-CoA) reductase inhibitors (rosuvastatin) significantly reduced pathologic clotting events in healthy populations in a prior trial. Furthermore, acetylsalicylic acid (ASA) has been shown to be noninferior to prophylactic heparinoids for VTE prevention following orthopedic surgery. We hypothesized that a combination of rosuvastatin/ASA, in addition to standard VTE chemoprophylaxis, would reduce VTE in critically ill trauma patients. METHODS: This was a double-blind, placebo-controlled, randomized trial, evaluating VTE rates in two groups: ASA + statin (Experimental) and identical placebos (Control). Injured adults, 18-65 years old, admitted to the surgical intensive care unit without contraindications for VTE prophylaxis were eligible. Upon initiation of routine VTE chemoprophylaxis (i.e. heparin/heparin-derivatives), they were randomized to the Experimental or Control group. VTE was the primary outcome. RESULTS: Of 112 potentially eligible patients, 33% (n = 37, median new injury severity scale = 27) were successfully randomized, of whom 11% had VTEs. The Experimental group had no VTEs, while the Control group had 6 VTEs (4 PEs and 2 DVTs) in 4 (22%) patients (P = 0.046). The Experimental treatment was not associated with any serious adverse events. Due to the COVID-19 pandemic, the study was interrupted at the second interim analysis at <10% of the planned enrollment, with significance declared at P < 0.012 at that stage. DISCUSSION: The combination of ASA and rosuvastatin with standard VTE prophylaxis showed a favorable trend toward reducing VTEs with no serious adverse events. An appropriately powered phase III multicenter trial is needed to further investigate this therapeutic approach. LEVEL OF EVIDENCE: Level II, Therapeutic.

Does tranexamic acid increase venous thromboembolism risk among trauma patients? A prospective multicenter analysis across 17 level I trauma centers.

IMPORTANCE: The early use of tranexamic acid (TXA) has demonstrated benefit among some trauma patients in hemorrhagic shock. The association between TXA administration and thromboembolic events (including deep vein thrombosis (DVT), pulmonary embolism (PE) and pulmonary thrombosis (PT)) remains unclear. We aimed to characterize the risk of venous thromboembolism (VTE) subtypes among trauma patients receiving TXA and to determine whether TXA is associated with VTE risk and mortality. METHODS: We analyzed a prospective, observational, multicenter cohort data from the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. The study was conducted across 17 US level I trauma centers between January 1, 2018, and December 31,2020. We studied trauma patients ages 18-40 years, admitted for at least 48 h with a minimum of 1 VTE risk factor and followed until hospital discharge or 30 days. We compared TXA recipients to non-recipients for VTE and mortality using inverse probability weighted Cox models. The primary outcome was the presence of documented venous thromboembolism (VTE). The secondary outcome was mortality. VTE was defined as DVT, PE, or PT. RESULTS: Among the 7,331 trauma patients analyzed, 466 (6.4%) received TXA. Patients in the TXA group were more severely injured than patients in the non-TXA group (ISS 16+: 69.1% vs. 48.5%, p < 0.001) and a higher percentage underwent a major surgical procedure (85.8% vs. 73.6%, p < 0.001). Among TXA recipients, 12.5% developed VTE (1.3% PT, 2.4% PE, 8.8% DVT) with 5.6% mortality. In the non-TXA group, 4.6% developed VTE (1.1% PT, 0.5% PE, 3.0% DVT) with 1.7% mortality. In analyses adjusting for patient demographic and clinical characteristics, TXA administration was not significantly associated with VTE (aHR 1.00, 95%CI: 0.69-1.46, p = 0.99) but was significantly associated with increased mortality (aHR 2.01, 95%CI: 1.46-2.77, p < 0.001). CONCLUSION: TXA was not clearly identified as an independent risk factor for VTE in adjusted analyses, but the risk of VTE among trauma patients receiving TXA remains high (12.5%). This supports the judicious use of TXA in resuscitation, with consideration of early initiation of DVT prophylaxis in this high-risk group.

METABOLOMIC AND PROTEOMIC CHANGES IN TRAUMA-INDUCED HYPOCALCEMIA.

ABSTRACT: Background: Trauma-induced hypocalcemia is common and associated with adverse outcomes, but the mechanisms remain unclear. Thus, we aimed to characterize the metabolomic and proteomic differences between normocalcemic and hypocalcemic trauma patients to illuminate biochemical pathways that may underlie a distinct pathology linked with this clinical phenomenon. Methods: Plasma was obtained on arrival from injured patients at a Level 1 Trauma Center. Samples obtained after transfusion were excluded. Multiple regression was used to adjust the omics data for injury severity and arrival base excess before metabolome- and proteome-wide comparisons between normocalcemic (ionized Ca 2+ > 1.0 mmol/L) and hypocalcemic (ionized Ca 2+ ≤ 1.0 mmol/L) patients using partial least squares-discriminant analysis. OmicsNet and Gene Ontology were used for network and pathway analyses, respectively. Results: Excluding isolated traumatic brain injury and penetrating injury, the main analysis included 36 patients (n = 14 hypocalcemic, n = 22 normocalcemic). Adjusted analyses demonstrated distinct metabolomic and proteomic signatures for normocalcemic and hypocalcemic patients. Hypocalcemic patients had evidence of mitochondrial dysfunction (tricarboxylic acid cycle disruption, dysfunctional fatty acid oxidation), inflammatory dysregulation (elevated damage-associated molecular patterns, activated endothelial cells), aberrant coagulation pathways, and proteolytic imbalance with increased tissue destruction. Conclusions: Independent of injury severity, hemorrhagic shock, and transfusion, trauma-induced hypocalcemia is associated with early metabolomic and proteomic changes that may reflect unique pathology in hypocalcemic trauma patients. This study paves the way for future experiments to investigate mechanisms, identify intervenable pathways, and refine our management of hypocalcemia in severely injured patients.

Prehospital ETCO2 is predictive of death in intubated and non-intubated patients.

BACKGROUND: Prehospital identification of shock in trauma patients lacks accurate markers. Low end tidal carbon dioxide (ETCO2) correlates with mortality in intubated patients. The predictive value of ETCO2 obtained by nasal capnography cannula (NCC) is unknown. We hypothesized that prehospital ETCO2 values obtained by NCC and in-line ventilator circuit (ILVC) would be predictive of mortality. METHODS: This was a prospective, observational, multicenter study. ETCO2 values were collected by a NCC or through ILVC. AUROCs were compared with prehospital systolic blood pressure (SBP) and shock index (SI). The Youden index defined optimal cutoffs. RESULTS: Of 550 enrolled patients, 487 (88.5%) had ETCO2 measured through an NCC. Median age was 37 (27-52) years; 76.5% were male; median ISS was 13 (5-22). Mortality was 10.4%. Minimum prehospital ETCO2 significantly predicted mortality with an AUROC of 0.76 (CI 0.69-0.84; Youden index â€‹= â€‹22 â€‹mmHg), outperforming SBP with an AUROC of 0.68; (CI 0.62-0.74, p â€‹= â€‹0.04) and shock index with an AUROC of 0.67 (CI 0.59-0.74, p â€‹= â€‹0.03). CONCLUSION: Prehospital ETCO2 measured by non-invasive NCC or ILVC may be predictive of mortality in injured patients.

Use of Tranexamic Acid With Resuscitative Endovascular Balloon Occlusion of the Aorta is Associated With Higher Distal Embolism Rates: Results From the American Association of Surgery for Trauma Aortic Occlusion and Resuscitation for Trauma and Acute Care Surgery Trial.

INTRODUCTION: Tranexamic acid (TXA) use has been associated with thrombotic complications. OBJECTIVE: We aim to investigate outcomes associated with TXA use in the setting of high- (HP) and low-profile (LP) introducer sheaths for resuscitative endovascular balloon occlusion of the aorta (REBOA). PARTICIPANTS: The Aortic Occlusion and Resuscitation for Trauma and Acute Care Surgery (AORTA) database was queried for patients who underwent REBOA using a low-profile 7 French (LP) or high-profile, 11-14 French (HP) introducer sheaths between 2013 and 2022. Demographics, physiology, and outcomes were examined for patients who survived beyond the index operation. RESULTS: 574 patients underwent REBOA (503 LP, 71 HP); 77% were male, mean age was 44 ± 19 and mean injury severity score (ISS) was 35 ± 16. 212 patients received TXA (181 [36%] LP, 31 [43.7%] HP). There were no significant differences in admission vital signs, GCS, age, ISS, SBP at AO, CPR at AO, and duration of AO among LP and HP patients. Overall, mortality was significantly higher in the HP (67.6%) vs the LP group (54.9%; P = .043). Distal embolism was significantly higher in the HP group (20.4%) vs the LP group (3.9%; P < .001). Logistic regression demonstrated that TXA use was associated with a higher rate of distal embolism in both groups (OR = 2.92; P = .021). 2 LP patients (one who received TXA) required an amputation. CONCLUSION: Patients who undergo REBOA are profoundly injured and physiologically devastated. Tranexamic acid was associated with a higher rate of distal embolism in those who received REBOA, regardless of access sheath size. For patients receiving TXA, REBOA placement should be accompanied by strict protocols for immediate diagnosis and treatment of thrombotic complications.

Tissue plasminogen activator challenge thrombelastography is the most accurate assay in predicting the need for massive transfusion in hypotensive trauma patients.

BACKGROUND: Tissue plasminogen activator (tPA) added to thrombelastography (TEG) detects hyperfibrinolysis by measuring clot lysis at 30 min (tPA-challenge-TEG). We hypothesize that tPA-challenge-TEG is a better predictor of massive transfusion (MT) than existing strategies in trauma patients with hypotension. METHODS: Trauma activation patients (TAP, 2014-2020) with 1) systolic blood pressure <90 mmHg (early) or 2) those who arrived normotensive but developed hypotension within 1H postinjury (delayed) were analyzed. MT was defined as >10 RBC U/6H postinjury or death within 6H after ≥1 RBC unit. Area under the receiver operating characteristics curves were used to compare predictive performance. Youden index determined optimal cutoffs. RESULTS: tPA-challenge-TEG was the best predictor of MT in the early hypotension subgroup (N = 212) with positive (PPV) and negative predictive values (NPV) of 75.0%, and 77.6%, respectively. tPA-challenge-TEG was a better predictor of MT than all but TASH (PPV = 65.0%, NPV = 93.3%) in the delayed hypotension group (N = 125). CONCLUSIONS: The tPA-challenge-TEG is the most accurate predictor of MT in trauma patients arriving hypotensive and offers early recognition of MT in patients with delayed hypotension.

Early venous thromboembolism prophylaxis in patients with trauma intracranial hemorrhage: Analysis of the prospective multicenter Consortium of Leaders in Traumatic Thromboembolism study.

BACKGROUND: The optimal time to initiate venous thromboembolism prophylaxis (VTEp) for patients with intracranial hemorrhage (ICH) is controversial and must balance the risks of VTE with potential progression of ICH. We sought to evaluate the efficacy and safety of early VTEp initiation after traumatic ICH. METHODS: This is a secondary analysis of the prospective multicenter Consortium of Leaders in the Study of Thromboembolism study. Patients with head Abbreviated Injury Scale score of > 2 and with immediate VTEp held because of ICH were included. Patients were divided into VTEp ≤ or >48 hours and compared. Outcome variables included overall VTE, deep vein thrombosis (DVT), pulmonary embolism, progression of intracranial hemorrhage (pICH), or other bleeding events. Univariate and multivariate logistic regressions were performed. RESULTS: There were 881 patients in total; 378 (43%) started VTEp ≤48 hours (early). Patients starting VTEp >48 hours (late) had higher VTE (12.4% vs. 7.2%, p = 0.01) and DVT (11.0% vs. 6.1%, p = 0.01) rates than the early group. The incidence of pulmonary embolism (2.1% vs. 2.2%, p = 0.94), pICH (1.9% vs. 1.8%, p = 0.95), or any other bleeding event (1.9% vs. 3.0%, p = 0.28) was equivalent between early and late VTEp groups. On multivariate logistic regression analysis, VTEp >48 hours (odds ratio [OR], 1.86), ventilator days >3 (OR, 2.00), and risk assessment profile score of ≥5 (OR, 6.70) were independent risk factors for VTE (all p < 0.05), while VTEp with enoxaparin was associated with decreased VTE (OR, 0.54, p < 0.05). Importantly, VTEp ≤48 hours was not associated with pICH (OR, 0.75) or risk of other bleeding events (OR, 1.28) (both p = NS). CONCLUSION: Early initiation of VTEp (≤48 hours) for patients with ICH was associated with decreased VTE/DVT rates without increased risk of pICH or other significant bleeding events. Enoxaparin is superior to unfractionated heparin as VTE prophylaxis in patients with severe TBI. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Omics Signatures of Tissue Injury and Hemorrhagic Shock in Swine.

OBJECTIVE: Advanced mass spectrometry methods were leveraged to analyze both proteomics and metabolomics signatures in plasma upon controlled tissue injury (TI) and hemorrhagic shock (HS)-isolated or combined-in a swine model, followed by correlation to viscoelastic measurements of coagulopathy via thrombelastography. BACKGROUND: TI and HS cause distinct molecular changes in plasma in both animal models and trauma patients. However, the contribution to coagulopathy of trauma, the leading cause of preventable mortality in this patient population remains unclear. The recent development of a swine model for isolated or combined TI+HS facilitated the current study. METHODS: Male swine (n=17) were randomized to either isolated or combined TI and HS. Coagulation status was analyzed by thrombelastography during the monitored time course. The plasma fractions of the blood draws (at baseline; end of shock; and at 30 minutes, 1, 2, and 4 hours after shock) were analyzed by mass spectrometry-based proteomics and metabolomics workflows. RESULTS: HS-isolated or combined with TI-caused the most severe omic alterations during the monitored time course. While isolated TI delayed the activation of coagulation cascades. Correlation to thrombelastography parameters of clot strength (maximum amplitude) and breakdown (LY30) revealed signatures of coagulopathy which were supported by analysis of gene ontology-enriched biological pathways. CONCLUSION: The current study provides a comprehensive characterization of proteomic and metabolomic alterations to combined or isolated TI and HS in a swine model and identifies early and late omics correlates to viscoelastic measurements in this system.

OUTCOMES FOLLOWING ZONE 3 AND ZONE 1 AORTIC OCCLUSION FOR THE TREATMENT OF BLUNT PELVIC INJURIES.

ABSTRACT: Background: A 2021 report of the Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery multicenter registry described the outcomes of patients treated with Zone 3 resuscitative endovascular balloon occlusion of the aorta (REBOA zone 3). Our study builds upon that report, testing the hypothesis that REBOA zone 3 is associated with better outcomes than REBOA Zone 1 in the immediate treatment of severe, blunt pelvic injuries. Methods: We included adults who underwent aortic occlusion (AO) via REBOA zone 1 or REBOA Zone 3 in the emergency department for severe, blunt pelvic injuries [Abbreviated Injury Score ≥ 3 or pelvic packing/embolization/first 24 hours] in institutions with >10 REBOAs. Adjustment for confounders was accomplished with a Cox proportional hazards model for survival, generalized estimating equations for intensive care unit (ICU)-free days (IFD) and ventilation-free days (VFD) > 0 days, and mixed linear models for continuous outcomes (Glasgow Coma Scale [GCS], Glasgow Outcome Scale [GOS]), accounting for facility clustering. Results: Of 109 eligible patients, 66 (60.6%) underwent REBOA Zone 3 and 43 (39.4%) REBOA Zone 1. There were no differences in demographics, but compared with REBOA Zone 3, REBOA Zone 1 patients were more likely to be admitted to high volume centers and be more severely injured. These patients did not differ in systolic blood pressure (SBP), cardiopulmonary resuscitation in the prehospital/hospital settings, SBP at the start of AO, time to AO start, likelihood of achieving hemodynamic stability or requirement of a second AO. After controlling for confounders, compared with REBOA Zone 3, REBOA Zone 1 was associated with a significantly higher mortality (adjusted hazard ratio, 1.51; 95% confidence interval [CI], 1.04-2.19), but there were no differences in VFD > 0 (adjusted relative risk, 0.66; 95% CI, 0.33-1.31), IFD > 0 (adjusted relative risk, 0.78; 95% CI, 0.39-1.57), discharge GCS (adjusted difference, -1.16; 95% CI, -4.2 to 1.90) or discharge GOS (adjusted difference, -0.67; 95% CI -1.9 to 0.63). Conclusions: This study suggests that compared with REBOA Zone 1, REBOA Zone 3 provides superior survival and is not inferior regarding other adverse outcomes in patients with severe blunt pelvic injuries.

A proteomic analysis of NETosis in trauma: Emergence of serpinB1 as a key player.

BACKGROUND: Release of neutrophil extracellular traps (NETosis) may mediate postinjury organ dysfunction, but mechanisms remain unclear. The intracellular serine protease inhibitor (serpin) B1 is vital to neutrophil function and has been shown to restrict NETosis in inflammatory settings. In this study, we used discovery proteomics to identify the proteomic signature of trauma-induced NETosis. We hypothesized that serpinB1 would be a major component of this NET protein profile and associated with adverse outcomes. METHODS: This was a post hoc analysis of data collected as part of the COMBAT randomized clinical trial. Blood was collected from injured patients at a single Level I Trauma Center. Proteomic analyses were performed through targeted liquid chromatography coupled with mass spectrometry. Abundances of serpinB1 and known NETosis markers were analyzed with patient and injury characteristics, clinical data, and outcomes. RESULTS: SerpinB1 levels on emergency department (ED) arrival were significantly correlated with proteomic markers of NETosis, including core histones, transketolase, and S100A8/A9 proteins. More severely injured patients had elevated serpinB1 and NETosis markers on ED arrival. Levels of serpinB1 and top NETosis markers were significantly elevated on ED arrival in nonsurvivors and patients with fewer ventilator- and ICU-free days. In proteome-wide receiver operating characteristic analysis, serpinB1 was consistently among the top proteins associated with adverse outcomes. Among NETosis markers, levels of serpinB1 early in the patient's course exhibited the greatest separation between patients with fewer and greater ventilator- and ICU-free days. Gene Ontology analysis of top predictors of adverse outcomes further supports NETosis as a potential mediator of postinjury organ dysfunction. CONCLUSION: We have identified a proteomic signature of trauma-induced NETosis, and NETosis is an early process following severe injury that may mediate organ dysfunction. In addition, serpinB1 is a major component of this NET protein profile that may serve as an early marker of excessive NETosis after injury.

Duration of Antibiotic Therapy for Early VAP Trial: Study Protocol for a Surgical Infection Society Multicenter, Pragmatic, Randomized Clinical Trial of Four versus Seven Days of Definitive Antibiotic Therapy for Early Ventilator-Associated Pneumonia in Surgical Patients.

Background: Current guidelines recommend a seven-day course of antibiotic therapy for patients with ventilator-associated pneumonia (VAP). However, clinical and microbiologic resolution of infection may occur much sooner than seven days, particularly in patients with early VAP. Shortening the course of antibiotic therapy for early VAP likely results in lower antibiotic-associated complications, but it is unclear whether VAP recurrence rates will be higher in patients receiving fewer days of therapy. We propose to compare four days versus seven days of antibiotic therapy for early VAP in surgical patients in a multicenter, pragmatic, randomized clinical trial. Patients and Methods: Eligible patients admitted to a surgical intensive care unit with early VAP, defined as VAP occurring within two to seven days of intubation, will be randomized to receive four or seven days of antibiotic therapy. The two primary outcomes are: VAP recurrence, defined as VAP occurring two to 14 days after completion of initial therapy and antibiotic-free days, defined as the number of days without receiving any antibiotic agents within 30 days from completion of initial therapy. Data will be analyzed using both intention-to-treat and per-protocol strategies. Power analysis was performed assuming non-inferiority of four days vs. seven days for VAP recurrence and superiority of four days versus seven days for antibiotic-free days. The total sample size to detect a 10% difference between groups with 80% power and assuming a 10% dropout rate is 458 patients. Three separate data analyses are planned throughout the trial and sample size will be re-calculated at each interim analysis. Conclusions: The Duration of Antibiotic Therapy for Early VAP (DATE) Trial will enroll surgical patients with early VAP to analyze whether a shorter duration of antibiotic therapy results in similar clinical outcomes while decreasing antibiotic exposure.

REBOA for the Treatment of Blast Polytrauma: Zone 3 Provides Cerebral Perfusion, Attenuates Organ Dysfunction and Reperfusion Coagulopathy Compared to Zone 1 in a Swine Model.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving therapy for hemorrhagic shock following pelvic/lower extremity injuries in military settings. However, Zone 1 aortic occlusion (AO; above the celiac artery), while providing brain/cardiac perfusion, may induce/worsen visceral ischemia and organ dysfunction. In contrast, AO Zone 3 (below the renal arteries) provides abdominal perfusion potentially minimizing ischemia/reperfusion injury. We hypothesized that, compared with AO Zone 1, AO Zone 3 provides neuro/cardioprotection while minimizing visceral ischemia and reperfusion coagulopathy after severe traumatic hemorrhage due to pelvic/lower extremity injuries. METHODS: Fifty-kilogram male Yorkshire swine underwent a blast polytrauma injury followed by a resuscitation protocol with randomization to no AO (No AO, n = 6) or AO with REBOA at Zone 1 (AO Zone 1; n = 6) or Zone 3 (AO Zone 3; n = 4). Vital signs and intracranial pressure (ICP) were monitored for 240 minutes. Citrate native and tissue plasminogen activator challenge thrombelastography, prothrombin time, creatinine, lipase, total bilirubin, troponin, and enzyme-linked immunosorbent assays protein levels were measured at set intervals. RESULTS: Both AO groups had significant increases in mean arterial pressure during aortic occlusion. All three groups had significant increases in ICP, but final ICP in the No AO group (26 ± 5.8 mm Hg) was significantly elevated compared with AO Zone 1 (17 ± 5.2 mm Hg) and AO Zone 3 (16 ± 4.2 mm Hg) ( p < 0.01). The final mean troponin in the No AO group (4.10 ± 5.67 ng/mL) was significantly higher than baseline (0.03 ± 0.02 ng/mL, p < 0.05), while the two AO groups had no significant changes ( p > 0.05). AO Zone 1 was the only group associated with hyperfibrinolysis ( p < 0.05) and significantly increased prothrombin time ( p < 0.05). Only AO Zone 1 group had significantly higher markers of organ damage. CONCLUSION: Compared with AO Zone 1, AO Zone 3 provided similar neuro/cardioprotection but with less organ dysfunction and coagulopathy. This study suggests that Zone 3 REBOA may be preferable over Zone 1 for treating military relevant blast polytrauma with minimal intra-abdominal and chest trauma, but further clinical investigation is warranted.

A proposed clinical coagulation score for research in trauma-induced coagulopathy.

BACKGROUND: Trauma-induced coagulopathy (TIC) has been the subject of intense study for greater than a century, and it is associated with high morbidity and mortality. The Trans-Agency Consortium for Trauma-Induced Coagulopathy, funded by the National Health Heart, Lung and Blood Institute, was tasked with developing a clinical TIC score, distinguishing between injury-induced bleeding from persistent bleeding due to TIC. We hypothesized that the Trans-Agency Consortium for Trauma-Induced Coagulopathy clinical TIC score would correlate with laboratory measures of coagulation, transfusion requirements, and mortality. METHODS: Trauma activation patients requiring a surgical procedure for hemostasis were scored in the operating room (OR) and in the first ICU day by the attending trauma surgeon. Conventional and viscoelastic (thrombelastography) coagulation assays, transfusion requirements, and mortality were correlated to the coagulation scores using the Cochran-Armitage trend test or linear regression for numerical variables. RESULTS: Increased OR TIC scores were significantly associated with abnormal conventional and viscoelastic measurements, including hyperfibrinolysis incidence, as well as with higher mortality and more frequent requirement for massive transfusion ( p < 0.0001 for all trends). Patients with OR TIC score greater than 3 were more than 31 times more likely to have an ICU TIC score greater than 3 (relative risk, 31.6; 95% confidence interval, 12.7-78.3; p < 0.0001). CONCLUSION: A clinically defined TIC score obtained in the OR reflected the requirement for massive transfusion and mortality in severely injured trauma patients and also correlated with abnormal coagulation assays. The OR TIC score should be validated in multicenter studies. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Platelet and cryoprecipitate transfusions from female donors improve coagulopathy in vitro.

BACKGROUND: Females are relatively hypercoagulable compared with males, with increased platelet aggregation and improved clot dynamics. However, sex differences in coagulation have not yet been considered in transfusion guidelines. Therefore, our objective was to evaluate hemostatic differences in sex concordant and sex discordant cryoprecipitate and platelet transfusions. We hypothesized that transfusion of blood products from female donors results in improved coagulopathy compared with male blood products. METHODS: This was a cohort study evaluating sex dimorphisms in coagulation assays and clotting factors in healthy volunteer plasma and cryoprecipitate. Sex dimorphisms in transfusions were evaluated using an in vitro coagulopathy model. Female or male platelets or single-donor cryoprecipitate was added to "recipient" whole blood after dilution of recipient blood with citrated saline to provoke a coagulopathic profile. Citrated native thromboelastography was then performed. Liquid chromatography/mass spectroscopy was performed on single-donor cryoprecipitate to evaluate sex dimorphisms in the proteome of cryoprecipitate. RESULTS: Females have an increased proportion of functional fibrinogen. Transfusion of female-donor platelets and cryoprecipitate induces a larger decrease in R time and greater increase in angle than male-donor platelets or cryoprecipitate. Female-donor cryoprecipitate has increased factor V and factor XIII compared with male cryoprecipitate, and comprehensive proteomics revealed sex differences in several proteins with potential immunological significance. CONCLUSION: Platelets and cryoprecipitate from female donors improve coagulopathy more than male blood products in vitro. Increased factor V and factor XIII activity as well as increased fibrinogen activity in female donors appears to drive this disparity. Sex differences in the proteome of cryoprecipitate may influence how transfusions modulate the thromboinflammation of trauma. The differing hemostatic profiles of female and male blood products suggest the potential role of sex-specific transfusions guidelines in hemostatic resuscitation.

Hemoglobin Concentration Impacts Viscoelastic Hemostatic Assays in ICU Admitted Patients.

OBJECTIVES: Low hemoglobin concentration impairs clinical hemostasis across several diseases. It is unclear whether hemoglobin impacts laboratory functional coagulation assessments. We evaluated the relationship of hemoglobin concentration on viscoelastic hemostatic assays in intracerebral hemorrhage (ICH) and perioperative patients admitted to an ICU. DESIGN: Observational cohort study and separate in vitro laboratory study. SETTING: Multicenter tertiary referral ICUs. PATIENTS: Two acute ICH cohorts receiving distinct testing modalities: rotational thromboelastometry (ROTEM) and thromboelastography (TEG), and a third surgical ICU cohort receiving ROTEM were evaluated to assess the generalizability of findings across disease processes and testing platforms. A separate in vitro ROTEM laboratory study was performed utilizing ICH patient blood samples. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Relationships between baseline hemoglobin and ROTEM/TEG results were separately assessed across patient cohorts using Spearman correlations and linear regression models. A separate in vitro study assessed ROTEM tracing changes after serial hemoglobin modifications from ICH patient blood samples. In both our ROTEM (n = 34) and TEG (n = 239) ICH cohorts, hemoglobin concentrations directly correlated with coagulation kinetics (ROTEM r: 0.46; p = 0.01; TEG r: 0.49; p < 0.0001) and inversely correlated with clot strength (ROTEM r: -0.52, p = 0.002; TEG r: -0.40, p < 0.0001). Similar relationships were identified in perioperative ICU admitted patients (n = 121). We continued to identify these relationships in linear regression models. When manipulating ICH patient blood samples to achieve lower hemoglobin concentrations in vitro, we similarly identified that lower hemoglobin concentrations resulted in progressively faster coagulation kinetics and greater clot strength on ROTEM tracings. CONCLUSIONS: Lower hemoglobin concentrations have a consistent, measurable impact on ROTEM/TEG testing in ICU admitted patients, which appear to be artifactual. It is possible that patients with low hemoglobin may appear to have normal viscoelastic parameters when, in fact, they have a mild hypocoagulable state. Further work is required to determine if these tests should be corrected for a patient's hemoglobin concentration.