Efficacy of prehospital administration of fibrinogen concentrate in trauma patients bleeding or presumed to bleed (FIinTIC): A multicentre, double-blind, placebo-controlled, randomised pilot study

Does an early, balanced resuscitation strategy reduce the incidence of hypofibrinogenemia in hemorrhagic shock?

Objectives

Some centers have recommended including concentrated fibrinogen replacement in massive transfusion protocols (MTPs). Given our center's policy of aggressive early balanced resuscitation (1:1:1), beginning prehospital, we hypothesized that our rates of hypofibrinogenemia may be lower than those previously reported.

Methods

In this retrospective cohort study, patients presenting to our trauma center November 2017 to April 2021 were reviewed. Patients were defined as hypofibrinogenemic (HYPOFIB) if admission fibrinogen <150 or rapid thrombelastography angle <60. Univariate and multivariable analyses assessed risk factors for HYPOFIB. Inverse probability of treatment weighting analyses assessed the relationship between cryoprecipitate administration and outcomes.

Results

Of 29 782 patients, 6618 level 1 activations, and 1948 patients receiving emergency release blood, <1%, 2%, and 7% were HYPOFIB. HYPOFIB patients were younger, had higher head Abbreviated Injury Scale value, and had worse coagulopathy and shock. HYPOFIB had lower survival (48% vs 82%, p<0.001), shorter time to death (median 28 (7, 50) vs 36 (14, 140) hours, p=0.012), and were more likely to die from head injury (72% vs 51%, p<0.001). Risk factors for HYPOFIB included increased age (OR (95% CI) 0.98 (0.96 to 0.99), p=0.03), head injury severity (OR 1.24 (1.06 to 1.46), p=0.009), lower arrival pH (OR 0.01 (0.001 to 0.20), p=0.002), and elevated prehospital red blood cell to platelet ratio (OR 1.20 (1.02 to 1.41), p=0.03). Among HYPOFIB patients, there was no difference in survival for those that received early cryoprecipitate (within 2 hours; 40 vs 47%; p=0.630). On inverse probability of treatment weighted analysis, early cryoprecipitate did not benefit the full cohort (OR 0.52 (0.43 to 0.65), p<0.001), nor the HYPOFIB subgroup (0.28 (0.20 to 0.39), p<0.001).

Conclusions

Low rates of hypofibrinogenemia were found in our center which treats hemorrhage with early, balanced resuscitation. Previously reported higher rates may be partially due to unbalanced resuscitation and/or delay in resuscitation initiation. Routine empiric inclusion of concentrated fibrinogen replacement in MTPs is not supported by the currently available data.

Level of evidence

Level III.

Prehospital transfusion of allogeneic blood products

PURPOSE OF REVIEW

The purpose of this article is to provide a structural and practical analysis of the currently available data concerning prehospital transfusion of allogeneic blood products in cases of trauma and severe bleeding.

RECENT FINDINGS

Prehospital transfusion of allogeneic blood products is a very early intervention, which may offer the potential to improve outcome, but that also comes with challenges including resource allocation, blood product storage, logistics, patient selection, legal and ethical considerations, adverse effects, and costs. Potential benefits including improved stability and reduction in coagulopathy and blood loss have not yet been clearly demonstrated.

SUMMARY

The questionable efficacy and challenges in clinical practice may outweigh the potential benefits of prehospital allogeneic transfusion.

The nature and timing of coagulation dysfunction in a cohort of trauma patients in the Australian pre-hospital setting

BACKGROUND

Acute Traumatic Coagulopathy (ATC) is a complex pathological process that is associated with patient mortality and increased blood transfusion requirements. It is evident on hospital arrival, but there is a paucity of information about the nature of ATC and the characteristics of patients that develop ATC in the pre-hospital setting. The objective of this study was to describe the nature and timing of coagulation dysfunction in a cohort of injured patients and to report on patient and pre-hospital factors associated with the development of ATC in the field.

METHODS

This was a prospective observational study of a convenience sample of trauma patients. Patients had blood taken during the pre-hospital phase of care and evaluated for derangements in Conventional Coagulation Assays (CCA) and Rotational Thromboelastometry (ROTEM). Associations between coagulation derangement and pre-hospital factors and patient outcomes were evaluated.

RESULTS

A total of 216 patients who had either a complete CCA or ROTEM were included in the analysis. One hundred and eighty (83 %) of patients were male, with a median injury severity score of 17 [interquartile range (IQR) 10-27] and median age of 34 years [IQR = 25.0-52.0]. Hypofibrinogenemia was the predominant abnormality seen, (CCA Hypofibrinogenemia: 51/193, 26 %; ROTEM hypofibrinogenemia: 65/204, 32 %). Increased CCA derangement, the presence of ROTEM coagulopathy, worsening INR, worsening FibTEM and decreasing fibrinogen concentration, were all associated with both mortality and early massive transfusion.

CONCLUSION

Clinically significant, multifaceted coagulopathy develops early in the clinical course, with hypofibrinogenemia being the predominant coagulopathy. In keeping with the ED literature, pre-hospital coagulation dysfunction was associated with mortality and early massive transfusion. Further work is required to identify strategies to identify and guide the pre-hospital management of the coagulation dysfunction seen in trauma.

Treatments for Trauma-Induced Coagulopathy: Protocol for a Systematic Review and Meta-Analysis

BACKGROUND

Trauma-induced coagulopathy (TIC) is a common and potentially life-threatening coagulopathy as a result of traumatic injury, characterized by abnormal blood clotting and bleeding. Although several treatments have been proposed for TIC, their effectiveness and safety remain unclear. Further, numerous systematic reviews and meta-analyses on trauma have been conducted; however, to our knowledge, there is no systematic review and meta-analysis that specifically focuses on TIC management. Therefore, a comprehensive synthesis of the available evidence on interventions for TIC is needed.

OBJECTIVE

This systematic review and meta-analysis aim to evaluate the effectiveness and safety of interventions for the management of TIC.

METHODS

We will conduct a systematic review and meta-analysis of randomized and nonrandomized controlled trials as well as observational studies regarding severe trauma in patients with TIC. The interventions will include administration of coagulation factor concentrates, tranexamic acid, and blood component products. The control group will be managed with an ordinal transfusion or administered placebo. The primary outcome will be in-hospital mortality. We will search the electronic databases of MEDLINE (PubMed), Web of Science, and the Cochrane Central Register of Controlled Trials. Two reviewers will independently screen the titles and abstracts, retrieve the full text of the selected articles, and extract essential data. We will apply uniform criteria for evaluating the risk of bias associated with individual randomized controlled trials and nonrandomized trials based on the Cochrane risk-of-bias tool. Risk ratio values will be expressed as point estimates with 95% CIs. Continuous variables will be expressed as the mean difference along with their 95% CIs and P values. We will assess the strength of evidence using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. This review will be the first systematic review and meta-analysis providing information on the effectiveness and safety of interventions for the management of TIC, including the administration of coagulation factor concentrates, tranexamic acid, and blood component products. Ethics approval and patient consent were not required for this study protocol, as we conducted a systematic review and meta-analysis of publicly available data, without any direct involvement of human participants.

RESULTS

We will summarize the selection of the eligible studies using a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart. The results will be presented in a table summarizing the evidence. The results of the meta-analysis will be depicted using figures and forest plots.

CONCLUSIONS

This systematic review will provide updated information on the efficacy and safety of using coagulation factor concentrates, tranexamic acid, and blood component products for patients with TIC. To our knowledge, there is no systematic review and meta-analysis that specifically focuses on treatments for TIC.

TRIAL REGISTRATION

UMIN registry UMIN000050170; https://tinyurl.com/yr8pcrj6.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/49582.

Early and Empirical High-Dose Cryoprecipitate for Hemorrhage After Traumatic Injury: The CRYOSTAT-2 Randomized Clinical Trial

Importance

Critical bleeding is associated with a high mortality rate in patients with trauma. Hemorrhage is exacerbated by a complex derangement of coagulation, including an acute fibrinogen deficiency. Management is fibrinogen replacement with cryoprecipitate transfusions or fibrinogen concentrate, usually administered relatively late during hemorrhage.

Objective

To assess whether survival could be improved by administering an early and empirical high dose of cryoprecipitate to all patients with trauma and bleeding that required activation of a major hemorrhage protocol.

Design, Setting, and Participants

CRYOSTAT-2 was an interventional, randomized, open-label, parallel-group controlled, international, multicenter study. Patients were enrolled at 26 UK and US major trauma centers from August 2017 to November 2021. Eligible patients were injured adults requiring activation of the hospital's major hemorrhage protocol with evidence of active hemorrhage, systolic blood pressure less than 90 mm Hg at any time, and receiving at least 1 U of a blood component transfusion.

Intervention

Patients were randomly assigned (in a 1:1 ratio) to receive standard care, which was the local major hemorrhage protocol (reviewed for guideline adherence), or cryoprecipitate, in which 3 pools of cryoprecipitate (6-g fibrinogen equivalent) were to be administered in addition to standard care within 90 minutes of randomization and 3 hours of injury.

Main Outcomes and Measures

The primary outcome was all-cause mortality at 28 days in the intention-to-treat population.

Results

Among 1604 eligible patients, 799 were randomized to the cryoprecipitate group and 805 to the standard care group. Missing primary outcome data occurred in 73 patients (principally due to withdrawal of consent) and 1531 (95%) were included in the primary analysis population. The median (IQR) age of participants was 39 (26-55) years, 1251 (79%) were men, median (IQR) Injury Severity Score was 29 (18-43), 36% had penetrating injury, and 33% had systolic blood pressure less than 90 mm Hg at hospital arrival. All-cause 28-day mortality in the intention-to-treat population was 26.1% in the standard care group vs 25.3% in the cryoprecipitate group (odds ratio, 0.96 [95% CI, 0.75-1.23]; P = .74). There was no difference in safety outcomes or incidence of thrombotic events in the standard care vs cryoprecipitate group (12.9% vs 12.7%).

Conclusions and Relevance

Among patients with trauma and bleeding who required activation of a major hemorrhage protocol, the addition of early and empirical high-dose cryoprecipitate to standard care did not improve all cause 28-day mortality.

Trial Registration

ClinicalTrials.gov Identifier: NCT04704869; ISRCTN Identifier: ISRCTN14998314.

Early Fibrinogen Replacement to Treat the Endotheliopathy of Trauma: Novel Resuscitation Strategies in Severe Trauma

The authors provide a comprehensive review of the endothelial glycocalyx, the components that may be targeted to improve clinical outcomes, and the next steps for evaluation in human subjects.

Pre-Hospital Blood Products for the Care of Bleeding Trauma Patients

BACKGROUND

Controversy surrounds the administration of blood products to severely traumatized patients before they arrive in the hospital in order to compensate for early blood loss and/or to correct coagulation disturbances that arise shortly after the traumatic event. A number of terrestrial and air rescue services have begun to provide this kind of treatment.

METHODS

This review is based on articles using the PICO framework, published from January 2001 to January 2021, that were retrieved by a selective search, with structured searching strategies and searching bundles in Medline (OVIDSP), the Cochrane Central Register of Controlled Trials (CENTRAL), and Epistemonikos. A demand analysis was carried out on the basis of data from the trauma registry of the German Society of Trauma Surgery (TR-DGU) and practical experience from program development and implementation was provided by the Bundeswehr Hospital Ulm.

RESULTS

The currently available evidence on the pre-hospital administration of blood products in the early treatment of severely injured patients is based largely on retrospective, single-center case series. Two randomized controlled trials (RCTs) concerning the early use of fresh frozen plasma concentrates have yielded partly conflicting results. Three further RCTs on the use of lyophilized plasma (lyplas), lyplas plus erythrocyte concentrate, or whole blood likewise revealed non-uniform effects on short-term and intermediate-term mortality. Our demand analysis based on data from the TR-DGU showed that 300 to 1800 patients per year in Germany could benefit from the pre-hospital administration of blood products. This might be indicated in patients who have systolic hypotension (<100 mmHg) in combination with a suspected or confirmed hemorrhage, as well as pathological shock parameters in the point-of-care diagnostic testing performed on the scene (serum base excess ≤ -2.5 mmol/L and/or serum lactate concentration >4 mmol/L).

CONCLUSION

The studies that have been published to date yield no clear evidence either for or against the early pre-hospital administration of blood products. Any treatment of this kind should be accompanied by scientific evaluation.

Emergency administration of fibrinogen concentrate for haemorrhage: systematic review and meta-analysis

INTRODUCTION

The occurrence of massive haemorrhages in various emergency situations increases the need for blood transfusions and increases the risk of mortality. Fibrinogen concentrate (FC) use may increase plasma fibrinogen levels more rapidly than fresh-frozen product or cryoprecipitate use. Previous several systematic reviews and meta-analyses have not effectively demonstrated FC efficacy in significantly improving the risk of mortality and reducing transfusion requirements. In this study, we investigated the use of FC for haemorrhages in emergency situations.

METHODS AND ANALYSIS

In this systematic review and meta-analysis, we included controlled trials, but excluded randomized controlled trials (RCTs) in elective surgeries. The study population consisted of patients with haemorrhages in emergency situations, and the intervention was emergency supplementation of FC. The control group was administered with ordinal transfusion or placebo. The primary and secondary outcomes were in-hospital mortality and the amount of transfusion and thrombotic events, respectively. The electronic databases searched included MEDLINE (PubMed), Web of Science, and the Cochrane Central Register of Controlled Trials.

RESULTS

Nine RCTs in the qualitative synthesis with a total of 701 patients were included. Results showed a slight increase in in-hospital mortality with FC treatment (RR 1.24, 95% CI 0.64-2.39, p = 0.52) with very low certainty of the evidence. There was no reduction in the use of red blood cells (RBC) transfusion in the first 24 h after admission with FC treatment (mean difference [MD] 0.0 Unit in the FC group, 95% CI - 0.99-0.98, p = 0.99) with very low certainty of the evidence. However, the use of fresh-frozen plasma (FFP) transfusion significantly increased in the first 24 h after admission with FC treatment (MD 2.61 Unit higher in the FC group, 95% CI 0.07-5.16, p = 0.04). The occurrence of thrombotic events did not significantly differ with FC treatment.

CONCLUSIONS

The present study indicates that the use of FC may result in a slight increase in in-hospital mortality. While FC did not appear to reduce the use of RBC transfusion, it likely increased the use of FFP transfusion and may result in a large increase in platelet concentrate transfusion. However, the results should be interpreted cautiously due to the unbalanced severity in the patient population, high heterogeneity, and risk of bias.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Resonant Acoustic Rheometry to Measure Coagulation Kinetics in Hemophilia A and Healthy Plasma: A Novel Viscoelastic Method

Compared with conventional coagulation tests and factor-specific assays, viscoelastic hemostatic assays (VHAs) can provide a more thorough evaluation of clot formation and lysis but have several limitations including clot deformation. In this proof-of-concept study, we test a noncontact technique, termed resonant acoustic rheometry (RAR), for measuring the kinetics of human plasma coagulation. Specifically, RAR utilizes a dual-mode ultrasound technique to induce and detect surface oscillation of blood samples without direct physical contact and measures the resonant frequency of the surface oscillation over time, which is reflective of the viscoelasticity of the sample. Analysis of RAR results of normal plasma allowed defining a set of parameters for quantifying coagulation. RAR detected a flat-line tracing of resonant frequency in hemophilia A plasma that was corrected with the addition of tissue factor. Our RAR results captured the kinetics of plasma coagulation and the newly defined RAR parameters correlated with increasing tissue factor concentration in both healthy and hemophilia A plasma. These findings demonstrate the feasibility of RAR as a novel approach for VHA, providing the foundation for future studies to compare RAR parameters to conventional coagulation tests, factor-specific assays, and VHA parameters.

Shock Index for Early Detection of Low Plasma Fibrinogen in Trauma: A Prospective Observational Cohort Pilot Study

Shock index (a ratio between heart rate and systolic blood pressure) predicts transfusion requirements and the need for haemostatic resuscitation in severe trauma patients. In the present study, we aimed to determine whether prehospital and on-admission shock index values can be used to predict low plasma fibrinogen in trauma patients. Between January 2016 and February 2017, trauma patients admitted from the helicopter emergency medical service into two large trauma centres in the Czech Republic were prospectively assessed for demographic, laboratory and trauma-associated variables and shock index at scene, during transport and at admission to the emergency department. Hypofibrinogenemia defined as fibrinogen plasma level of 1.5 g·L^-l was deemed as a cut-off for further analysis. Three hundred and twenty-two patients were screened for eligibility. Of these, 264 (83%) were included for further analysis. The hypofibrinogenemia was predicted by the worst prehospital shock index with the area under the receiver operating characteristics curve (AUROC) of 0.79 (95% CI 0.64-0.91) and by the admission shock index with AUROC of 0.79 (95% CI 0.66-0.91). For predicting hypofibrinogenemia, the prehospital shock index ≥ 1 has 0.5 sensitivity (95% CI 0.19-0.81), 0.88 specificity (95% CI 0.83-0.92) and a negative predictive value of 0.98 (0.96-0.99). The shock index may help to identify trauma patients at risk of hypofibrinogenemia early in the prehospital course.

Raising the bar on fibrinogen: a retrospective assessment of critical hypofibrinogenemia in severely injured trauma patients

Objectives

Fibrinogen depletion may occur at higher levels than historically referenced. We evaluated hypofibrinogenemia and associated mortality and multiple organ failure (MOF) after severe injury.

Methods

Retrospective investigation including 417 adult patients with Injury Severity Score (ISS) >15. Demographics and injury characteristics were collected. Fibrinogen within 30 minutes of admission was described: <150 mg/dL, 150 mg/dL to 200 mg/dL and >200 mg/dL. Primary outcome: 28-day mortality. Secondary outcomes: 28-day MOF and blood product transfusion. Multivariable logistic regression model evaluated association of fibrinogen categories on risk of death, after controlling for confounding variables. Results presented as OR and 95% CIs.

Results

Fibrinogen <150 mg/dL: 4.8%, 150 mg/dL to 200 mg/dL: 18.2%, >200 mg/dL: 77.0%. 28-day mortality: 15.6%. Patients with <150 mg/dL fibrinogen had over fourfold increased 28-day mortality risk (OR: 4.9, 95% CI 1.53 to 15.7) after adjusting for age, ISS and admission Glasgow Coma Scale. Patients with lower fibrinogen were more likely to develop MOF (p=0.04) and receive larger red blood cell transfusion volumes at 3 hours and 24 hours (p<0.01).

Conclusions

Fibrinogen <150 mg/dL is significantly associated with increased 28-day mortality. Patients with fibrinogen <150 mg/dL were more likely to develop MOF and required increased administration of blood products. The optimal threshold for critically low fibrinogen, the association with MOF and subsequent fibrinogen replacement requires further investigation.

Level of evidence

Level III.

Characterization of 2 Different Prothrombin Complex Concentrates by Different Hemostatic Assays in an In Vitro Hemodilution Model

BACKGROUND

Viscoelastically guided coagulation factor concentrate-based algorithms for the treatment of trauma-induced coagulopathy include the administration of prothrombin complex concentrates (PCCs). However, the exact role of PCC preparations in this context is a matter of debate. Particularly, the ideal diagnostic trigger for their administration and potential differences between heparin-containing and heparin-free preparations remain unclear. We investigated the hypothesis that 2 different PCCs might have distinct influences on in vitro blood coagulation.

METHODS

We conducted a direct comparison of 2 commercially available PCC preparations (the heparin-containing Beriplex P/N and the heparin-free Cofact) in an in vitro hemodilution model. Sole fibrinogen substitution served as the control group. To characterize the hemostatic changes, we utilized conventional coagulation tests, a thrombin generation assay (TGA), and 2 different viscoelastic hemostatic assays (VHAs; ROTEM delta and ClotPro).

RESULTS

Irrespective of the diagnostic assay used, no significant differences between the 2 PCC groups were observed. Fibrinogen levels remained stable from the baseline throughout every dilution level. The control group already showed an increased endogenous thrombin potential (ETP; nM·L -1 ·min -1 ) at all dilution levels compared to baseline (baseline, 2829.4 (432.8); 40% dilution, 4211.7 (391.6); 60% dilution, 4290.9 (300.8); 80% dilution, 3861.4 (303.5); all P < .001). Spiking with both PCC preparations led to a further-pronounced thrombin elevation in comparison to the control group (ETP at 40% dilution, PCC1: 4913.3 [370.2], PCC2: 4988.1 [265.7]; 60% dilution, PCC1: 5174.5 [234.7], PCC2: 5390.4 [334.9]; 80% dilution, PCC1: 5253.8 [357.9], PCC2: 5392.6 [313.4]; all P < .001). Conventional coagulation tests did not mirror the TGA results. Despite increased thrombin generation, prothrombin time was significantly prolonged at all dilution levels for the control group, and both PCC groups exhibited significant prolongations at the 60% and 80% dilution levels (all P < .001) compared to baseline. Similarly, VHA did not depict the thrombin elevation. Furthermore, descriptive analyses revealed relevant differences between the 2 VHA devices, particularly at baseline.

CONCLUSIONS

Both PCC preparations (ie, irrespective of heparin content) induced significant elevation of thrombin generation, which was not depicted by conventional coagulation tests or VHA. Our in vitro results suggest that diagnostic assays routinely used to guide PCC administration might not adequately reflect thrombin generation in bleeding patients.

Coagulopathy management of multiple injured patients - a comprehensive literature review of the European guideline 2019

The European guideline on the management of trauma-induced major bleeding and coagulopathy summarises the most relevant recommendations for trauma coagulopathy management. The management of trauma-induced major bleeding should interdisciplinary follow algorithms which distinguish between life-threatening and non-life-threatening bleeding. Point-of-care viscoelastic methods (VEM) assist target-controlled haemostatic treatment. Neither conventional coagulation assays nor VEM should delay treatment in life-threatening trauma-induced bleeding. Adjustments may be rational due to local circumstances, including the availability of blood products, pharmaceuticals, and employees.

Operability of a Resonance-Based Viscoelastic Haemostatic Analyzer in the High-Vibration Environment of Air Medical Transport

Trauma and bleeding are associated with a high mortality, and most of these deaths occur early after injury. Viscoelastic haemostatic tests have gained increasing importance in goal-directed transfusion and bleeding management. A new generation of small-sized and thus portable ultrasound-based viscoelastic analysers have been introduced in clinical practice. We questioned whether a promising candidate can be used in emergency helicopters, with a focus on the susceptibility to vibration stress. We investigated whether the high vibration environment of an emergency helicopter would affect the operability of an ultrasound-based viscoelastic analyser and would yield reproducible results in flight and on the ground. We drew blood from 27 healthy volunteers and performed simultaneous analyses on two TEG 6s. Each measurement was performed in-flight on board an Airbus H135 emergency helicopter and was repeated on the ground, close to the flight area. Results from both measurements were compared, and the recorded tracings and numeric results were analysed for artifacts. Vibratometric measurements were performed throughout the flight in order to quantify changes in the magnitude and character of vibrations in different phases of helicopter operation. The high vibration environment was associated with the presence of artifacts in all recorded tracings. There were significant differences in citrated Kaolin + Heparinase measurements in-flight and on the ground. All other assays increased in variability but did not show significant differences between the two time points. We observed numerous artifacts in viscoelastic measurements that were performed in flight. Some parameters that were obtained from the same sample showed significant differences between in-flight and on-ground measurements. Performing resonance-based viscoelastic tests in helicopter medical service is prone to artifacts. However, a 10 min delay between initiation of measurement and take-off might produce more reliable results.

Cryoprecipitate use during massive transfusion: A propensity score analysis

INTRODUCTION

Cryoprecipitate is frequently administered as an adjunct to balanced transfusion in the setting of traumatic hemorrhage. However, civilian studies have not demonstrated a clear survival advantage, and prior observational studies noted selection bias when analyzing cryoprecipitate use. Additionally, due to the logistics involved in cryoprecipitate administration, it is inconsistently implemented alongside standardized massive transfusion protocols. This study aims to evaluate the effects of early cryoprecipitate administration on inpatient mortality in the setting of massive transfusion for exsanguinating trauma and to use propensity score analysis to minimize selection bias.

METHODS

The registry of an urban level 1 trauma center was queried for adult patients who received at least 6 units of packed red blood cells within 4 h of presentation. Univariate analysis, multiple logistic regression, and propensity score matching were performed.

RESULTS

562 patients were identified. Patients with lower median RTS (6.86 (IQR 4.09-7.84) vs 7.6 (IQR 5.97-7.84), P<0.01), decreased Glasgow coma scale (12 (IQR 4-15) vs 15 (IQR 10-15), P<0.01), and increased lactate (7.5 (IQR 4.3-10.2) vs 4.9 (IQR 3.1-7.2), P<0.01) were more commonly administered cryoprecipitate. Mortality was greater among those who received cryoprecipitate (40.2% vs 23.7%, p<0.01) on univariate analysis. Neither multiple logistic regression (OR 0.917; 95% confidence interval 0.462-1.822; p = 0.805) nor propensity score matching (average treatment effect on the treated 2.3%, p = 0.77) revealed that cryoprecipitate administration was associated with a difference in inpatient mortality.

CONCLUSIONS

Patients receiving cryoprecipitate within 4 h of presentation were more severely injured at presentation and had increased inpatient mortality. Multivariable logistic regression and propensity score analysis failed to show that early administration of cryoprecipitate was associated with survival benefit for exsanguinating trauma patients. The prospect of definitively assessing the utility of cryoprecipitate in exsanguinating hemorrhage warrants prospective investigation.

Multicentre observational study on practice of prehospital management of hypotensive trauma patients: the SPITFIRE study protocol

INTRODUCTION

Major haemorrhage after injury is the leading cause of preventable death for trauma patients. Recent advancements in trauma care suggest damage control resuscitation (DCR) should start in the prehospital phase following major trauma. In Italy, Helicopter Emergency Medical Services (HEMS) assist the most complex injuries and deliver the most advanced interventions including DCR. The effect size of DCR delivered prehospitally on survival remains however unclear.

METHODS AND ANALYSIS

This is an investigator-initiated, large, national, prospective, observational cohort study aiming to recruit >500 patients in haemorrhagic shock after major trauma. We aim at describing the current practice of hypotensive trauma management as well as propose the creation of a national registry of patients with haemorrhagic shock.

PRIMARY OBJECTIVE

the exploration of the effect size of the variation in clinical practice on the mortality of hypotensive trauma patients. The primary outcome measure will be 24 hours, 7-day and 30-day mortality. Secondary outcomes include: association of prehospital factors and survival from injury to hospital admission, hospital length of stay, prehospital and in-hospital complications, hospital outcomes; use of prehospital ultrasound; association of prehospital factors and volume of first 24-hours blood product administration and evaluation of the prevalence of use, appropriateness, haemodynamic, metabolic and effects on mortality of prehospital blood transfusions.

INCLUSION CRITERIA

age >18 years, traumatic injury attended by a HEMS team including a physician, a systolic blood pressure <90 mm Hg or weak/absent radial pulse and a confirmed or clinically likely diagnosis of major haemorrhage. Prehospital and in-hospital variables will be collected to include key times, clinical findings, examinations and interventions. Patients will be followed-up until day 30 from admission. The Glasgow Outcome Scale Extended will be collected at 30 days from admission.

ETHICS AND DISSEMINATION

The study has been approved by the Ethics committee 'Comitato Etico di Area Vasta Emilia Centro'. Data will be disseminated to the scientific community by abstracts submitted to international conferences and by original articles submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04760977.

Prehospital activation of a coordinated multidisciplinary hospital response in preparation for patients with severe hemorrhage. A state-wide data linkage study of the New South Wales "Code Crimson" pathway

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma. Prehospital medical teams can streamline access to massive transfusion and definitive hemorrhage control by alerting in-hospital trauma teams of suspected life-threatening bleeding in unstable patients. This study reports the initial experience of an Australian "Code Crimson" pathway facilitating early multidisciplinary care for these patients.

METHODS

This data-linkage study combined prehospital databases with a trauma registry of patients with an ISS > 12 between 2017 and 2019. Four groups were created; prehospital Code Crimson (CC) activation with and without in-hospital links and patients with inpatient treatment consistent with CC, without one being activated. Diagnostic accuracy was estimated using capture-recapture methodology to replace the missing cell (no prehospital CC and ISS < 12).

RESULTS

Of 72 prehospital CC patients, 50 were linked with hospital data. Of 154 potentially missed patients, 42 had a prehospital link. Most CC patients were young males who sustained blunt trauma and required more prehospital interventions than non-CC patients. CC patients had more multisystem trauma, especially complex thoracic injuries (80%), while missed-CC patients more frequently had single organ injuries (59%). CC patients required fewer hemorrhage control procedures (60% vs 86%). Lower mortality was observed in CC patients despite greater hospital and ICU length of stay. Despite a low sensitivity (0.49, 95%CI 0.38-0.61) and good specificity (0.92, 95%CI 0.86-0.96), the positive likelihood ratio was acceptable (6.42, 95%CI 3.30-12.48).

CONCLUSIONS

The initiation of a state-wide Code Crimson process was highly specific for the need for hemorrhage control intervention in hospital, but further work is required to improve the sensitivity of prehospital activation. Patients who had a Code Crimson activation sustained more multisystem trauma but had lower mortality than those who did not. These results guide measures to improve this pathway.

LEVEL OF EVIDENCE

Level III, Therapeutic/Care management.

Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices

Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG^® 5000) and rotational thromboelastometry (ROTEM^® delta), have been supplanted not only by cartridge systems (TEG^® 6S and ROTEM^® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot^®, Quantra^®, and ClotPro^®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.

Which injured patients with moderate fibrinogen deficit need fibrinogen supplementation?

Background

In severely injured patients, fibrinogen supplementation is recommended when fibrinogenemia is < 1.5 g L⁻¹, but some teams have suggested to use higher thresholds (fibrinogenemia < 2.0 g L⁻¹ or FIBTEM clot amplitude at 5 min (A5) values < 11 mm). The goal of this study was to specify in patients with a moderate fibrinogen deficit (MFD) whether some admission characteristics would be associated with fibrinogen administration at 24 h.

Methods

Prospective analysis of retrospectively collected data from a trauma registry (01/2011–12/2019). MFD-C was defined by a fibrinogenemia 1.51–1.99 g L⁻¹ or the corresponding FIBTEM-A5 values (MFD-A5) that were determined from linear regression and ROC curve analysis. Administration of fibrinogen were described according to the following admission parameters: shock index (SI) > 1, hemoglobin level < 110 g L⁻¹ (HemoCue®), and base deficit > 5 mEq L⁻¹. Data are expressed as count (%), median [IQR].

Results

1076 patients were included in the study and 266 (27%) had MFD-C, among them, 122/266 (46%) received fibrinogen. Patients with MFD-C who received fibrinogen were more severely injured (ISS: 27 [19–36] vs. 24 [17–29]) and had more impaired vital signs (base deficit: 5.4 [3.6–7.8] vs. 3.8 [2.0–6.0]). Linear regression analysis found a positive correlation between fibrinogen level and FIBTEM-A5 (r: 0.805). For a fibrinogen level < 1.5 g L⁻¹ and < 2.0 g L⁻¹, FIBTEM-A5 thresholds were 6 mm (sensitivity 85%, specificity 83%, AUC: 0.934) and 9 mm (sensitivity 84%, specificity 69%, AUC: 0.874), respectively. MFD-A5 values (185 (27%) patients) were defined as a FIBTEM-A5 between 7 and 9 mm. More than 50% of MFD-C patients presenting a SI > 1, a hemoglobin level < 110 g L⁻¹, or a base deficit > 5.0 mEq L⁻¹ received fibrinogen. The relative risk [95% CI] for fibrinogen administration (SI > 1) were 1.39 [1.06–1.82] for MFD-C, and 2.17 [1.48–3.19] for MFD-A5. Results were not modified after adjustment on the ISS.

Conclusions

We have shown in this study an association between shock parameters and fibrinogen administration. Further studies are needed to determine how these parameters may be used to guide fibrinogen administration in trauma patients with MFD.

Use of Dried Plasma in Prehospital and Austere Environments

More than 1,000,000 units of lyophilized plasma have been used in France, Germany, and South Africa. Recently, numerous other countries have adopted lyophilized plasma for patients with severe bleeding in prehospital and austere settings.

Outcome measures used in clinical research evaluating prehospital blood component transfusion in traumatically injured bleeding patients: A systematic review

BACKGROUND

Trial outcomes should be relevant to all stakeholders and allow assessment of interventions' efficacy and safety at appropriate timeframes. There is no consensus regarding outcome measures in the growing field of prehospital trauma transfusion research. Harmonization of future clinical outcome reporting is key to facilitate interstudy comparisons and generate cohesive, robust evidence to guide practice. The objective of this study was to evaluate outcome measures reported in prehospital trauma transfusion trials.

METHODS

Data Sources, Eligibility Criteria, Participants, and InterventionsWe conducted a scoping systematic review to identify the type, number, and definitions of outcomes reported in randomized controlled trials, and prospective and retrospective observational cohort studies investigating prehospital blood component transfusion in adult and pediatric patients with traumatic hemorrhage. Electronic database searching of PubMed, Embase, Web of Science, Cochrane, OVID, clinical trials.gov, and the Transfusion Evidence Library was completed in accordance with Preferred Reporting Items for Meta-analyses guidelines.Study Appraisal and Synthesis MethodsTwo review authors independently extracted outcome data. Unique lists of salutogenic (patient-reported health and wellbeing outcomes) and nonsalutogenic focused outcomes were established.

RESULTS

A total of 3,471 records were identified. Thirty-four studies fulfilled the inclusion criteria: 4 military (n = 1,566 patients) and 30 civilian (n = 14,398 patients), all between 2000 and 2020. Two hundred twelve individual non-patient-reported outcomes were identified, which collapsed into 20 outcome domains with varied definitions and timings. All primary outcomes measured effectiveness, rather than safety or complications. Sixty-nine percent reported mortality, with 11 different definitions. No salutogenic outcomes were reported.

CONCLUSION

There is heterogeneity in outcome reporting and definitions, an absence of patient-reported outcome, and an emphasis on clinical effectiveness rather than safety or adverse events in prehospital trauma transfusion trials. We recommend stakeholder consultation and a Delphi process to develop a clearly defined minimum core outcome set for prehospital trauma transfusion trials.

LEVEL OF EVIDENCE

Scoping systematic review, level III.

Hypofibrinogenaemia and hypocalcaemia in adult trauma patients receiving pre-hospital packed red blood cell transfusions: Potential for supplementary pre-hospital therapeutic interventions

OBJECTIVE

To report the arrival ionised calcium (iCa) and fibrinogen concentrations in trauma patients treated with packed red blood cells by the road-based high-acuity response units of a metropolitan ambulance service.

METHODS

A retrospective review of trauma patients treated with packed red blood cells by high-acuity response units between January 2012 and December 2016. Patients were identified from databases at southeast Queensland adult trauma centres, Pathology Queensland Central Transfusion Laboratory, Gold Coast University Hospital blood bank and the Queensland Ambulance Service. Patient characteristics, results of laboratory tests within 30 min of ED arrival were analysed.

RESULTS

A total of 164 cases were analysed. The median injury severity score was 33.5 (interquartile range 22-41), with blunt trauma the commonest mechanism of injury (n = 128, 78.0%). Fifty-eight of the 117 patients (24.4%) with fibrinogen measured had a fibrinogen concentration ≤1.5 g/L; 79 of the 123 patients (64.2%) with an international normalised ratio (INR) measurement had an INR >1.2; 97 of 148 patients (63.8%) with an iCa measured, had an iCa below the Pathology Queensland reference range of 1.15-1.32 mmol/L. Arrival fibrinogen concentration ≤1.5 g/L and arrival iCa ≤1.00 were associated with in-hospital mortality with odds ratio 11.90 (95% confidence interval 4.50-31.65) and odds ratio 4.97 (95% confidence interval 1.42-17.47), respectively.

CONCLUSIONS

Hypocalcaemia and hypofibrinogenaemia on ED arrival were common in this cohort. Future work should evaluate whether outcomes improve by correction of these deficits during the pre-hospital phase of trauma care.

Massive Transfusion in trauma: an evolving paradigm

A considerable amount of literature has nurtured the idea that massive transfusion is an independent trauma disease and therapeutic tool. In this opinion paper, the authors expose the evolution and challenge the classic paradigm and historic definition of massive transfusion. Based on current evidence the elements of an evolving strategy in transfusion management and bleeding control are exposed such as use of tranexamic acid, combination and ratios of blood products, use of fluids and viscoelastic testing. The synergy of these elements provides the basis to develop updated strategies and perspectives for transfusion management after trauma and to consider a classic definition of massive transfusion as outdated or the need for massive transfusion as failure. An alternative concept, Time Critical Transfusion may be better placed to take into account modern transfusion management after trauma.

Infrastructure, logistics and clinical practice management of acute trauma hemorrhage and coagulopathy: a survey across German trauma centers

PURPOSE

Early detection and management of acute trauma hemorrhage and coagulopathy have been associated with improved outcomes, but local infrastructure, logistics and clinical strategies may differ.

METHODS

To assess local differences in infrastructure, logistics and clinical management of acute trauma hemorrhage and coagulopathy we have conducted a web-based survey amongst clinicians working in DGU^®-certified supraregional, regional and local trauma centers.

RESULTS

137/1875 respondents completed the questionnaire yielding a response rate of 7.3%. The majority specified to work as head of department or senior consultant (95%) in trauma/orthopedic surgery (80%) of supraregional (38%), regional (34%) or local (27%) trauma centers. Conventional coagulation assays are most frequently used to monitor bleeding trauma patients. Only half of the respondents (53%) rely on extended coagulation tests, e.g. viscoelastic hemostatic assays. Tests to assess preinjury use of direct oral anticoagulants and platelet inhibitors are still not widely available and vary according to level of care. Conventional blood products are widely available but there remain differences between trauma centers of different level of care to access other hemostatic therapies, e.g. coagulation factor concentrates. Trauma centers of higher level of care are more likely to implement treatment protocols.

CONCLUSION

This survey confirms still existing differences in infrastructure, logistics and clinical practice management for the detection of acute trauma hemorrhage and coagulopathy amongst DGU^®-certified supraregional, regional and local trauma centers. Further work is recommended to locally implement diagnostics, therapies and treatment algorithms compliant to current guidelines to ensure the best possible outcomes in bleeding trauma patients.

First-Line Administration of Fibrinogen Concentrate in the Bleeding Trauma Patient: Searching for Effective Dosages and Optimal Post-Treatment Levels Limiting Massive Transfusion-Further Results of the RETIC Study

Fibrinogen supplementation is recommended for treatment of severe trauma hemorrhage. However, required dosages and aimed for post-treatment fibrinogen levels remain a matter of discussion. Within the published RETIC study, adult patients suffering trauma-induced coagulopathy were randomly assigned to receive fibrinogen concentrate (FC) as first-line (n = 50) or crossover rescue (n = 20) therapy. Depending on bodyweight, a single dose of 3, 4, 5, or 6 g FC was administered and repeated if necessary (FibA10 < 9 mm). The dose-dependent response (changes in plasma fibrinogen and FibA10) was analyzed. Receiver operating characteristics (ROC) analysis regarding the need for massive transfusion and correlation analyses regarding fibrinogen concentrations and polymerization were performed. Median FC single doses amounted to 62.5 (57 to 66.66) mg·kg⁻¹. One FC single-dose sufficiently corrected fibrinogen and FibA10 (median fibrinogen 213 mg·dL⁻¹, median FibA10 11 mm) only in patients with baseline fibrinogen above 100 mg·dL⁻¹ and FibA10 above 5 mm, repeated dosing was required in patients with lower baseline fibrinogen/FibA10. Fibrinogen increased by 83 or 107 mg·dL⁻¹ and FibA10 by 4 or 4.5 mm after single or double dose of FC, respectively. ROC curve analysis revealed post-treatment fibrinogen levels under 204.5 mg·dL⁻¹ to predict the need for massive transfusion (AUC 0.652; specificity: 0.667; sensitivity: 0.688). Baseline fibrinogen/FibA10 levels should be considered for FC dosing as only sufficiently corrected post-treatment levels limit transfusion requirements.

Vorbereitung auf eine differenzierte Hämotherapie nach Trauma – Ergebnisse einer Befragung deutscher Kliniken

Hintergrund

Die unkontrollierte Blutung ist weiterhin eine führende potenziell vermeidbare Todesursache im Rahmen schwerer Verletzungen.

Ziel der Arbeit

Die vorliegende Arbeit hat zum Ziel, die Vorbereitung für eine differenzierte Hämotherapie im Rahmen der Schwerstverletztenbehandlung in Kliniken verschiedener Versorgungsstufen innerhalb der Struktur des TraumaNetzwerks der Deutschen Gesellschaft für Unfallchirurgie (DGU)® zu evaluieren.

Material und Methoden

Anhand einer Online-Umfrage wurden gezielt Diagnose- und Therapiestrategien sowie vorhandene Ressourcen innerhalb der Kliniken erfragt. Im Rahmen einer Subgruppenanalyse sollte festgestellt werden, ob es Unterschiede in Bezug auf infrastrukturelle Voraussetzungen und diagnostisches bzw. therapeutisches Vorgehen innerhalb der Versorgungsstufen des TraumaNetzwerks DGU® gibt.

Ergebnisse

Massivtransfusionsprotokolle (MTP) bestehen in 75 % der Kliniken. Die Aktivierung erfolgt i. d. R. durch den Trauma-Leader (62 %). In 63 % erfolgt die Aktivierung aufgrund einer Anforderung aus der Präklinik. Als Transfusionstrigger werden ein positives FAST (80 %) und ein Pulsdruck < 45 mm Hg (60 %) angegeben. In 50 % der Kliniken existiert kein starres Transfusionsverhältnis der einzelnen Blutkomponenten. Überregionale Traumazentren (ÜTZ) bekommen im Vergleich zu regionalen Traumazentren (RTZ) und lokalen Traumazentren (LTZ) angeforderte Blutprodukte frühzeitiger (p 0,025).

Diskussion

Der massive Blutverlust ist ein seltenes Ereignis, welches mit einer hohen Letalität vergesellschaftet sein kann. MTP bilden die Grundlage für eine frühe Therapie der traumainduzierten Koagulopathie und tragen zur Verbesserung der Überlebenschancen der Patienten bei. Es existiert ein deutlicher Unterschied in den diagnostischen und therapeutischen Möglichkeiten in den einzelnen Versorgungsebenen. ÜTZ verfügen mehrheitlich über die umfangreichsten Optionen, gefolgt von RTZ und LTZ.

Prehospital administration of blood and plasma products

PURPOSE OF REVIEW

Posttraumatic bleeding following major trauma is life threatening for the patient and remains a major global health issue. Bleeding after major trauma is worsened by trauma-induced coagulopathy (TIC). TIC consists of acute trauma coagulopathy and resuscitation coagulopathy. The early diagnosis and management of prehospital TIC management are challenging.

RECENT FINDINGS

Concepts for early diagnosis and management of civilian prehospital TIC management are evolving. The feasibility of prehospital blood component as well as coagulation factor transfusion has been proven.

SUMMARY

Due to different national guidelines and regulations of blood component therapies there is a wide heterogeneity in concepts of prehospital damage control resuscitation. Tranexamic acid administration is widely accepted, whereas the transfusion of whole blood, blood components, or coagulations factors needs further examination in the civilian setting.

Fibrinogen in traumatic haemorrhage

PURPOSE OF REVIEW

Recent advances in the understanding of the pathophysiological processes associated with traumatic haemorrhage and trauma-induced coagulopathy (TIC) have resulted in improved outcomes for seriously injured trauma patients. However, a significant number of trauma patients still die from haemorrhage. This article reviews the role of fibrinogen in normal haemostasis, the effect of trauma and TIC on fibrinogen levels and current evidence for fibrinogen replacement in the management of traumatic haemorrhage.

RECENT FINDINGS

Fibrinogen is usually the first factor to reach critically low levels in traumatic haemorrhage and hypofibrinogenaemia after severe trauma is associated with increased risk of massive transfusion and death. It is postulated that the early replacement of fibrinogen in severely injured trauma patients can improve outcomes. There is, however, a paucity of evidence to support this, and in addition, there is little evidence to support or refute the effects of cryoprecipitate or fibrinogen concentrate for fibrinogen replacement.

SUMMARY

The important role fibrinogen plays in haemostasis and effective clot formation is clear. A number of pilot trials have investigated different strategies for fibrinogen replacement in severe trauma. These trials have formed the basis of several large-scale phase III trials, which, cumulatively will provide a firm evidence base to harmonise worldwide clinical management of severely injured trauma patients with major haemorrhage.

Randomised controlled trials in pre-hospital trauma: a systematic mapping review

BACKGROUND

Trauma is a leading cause of morbidity and mortality worldwide with about 5.8 million deaths globally and the leading cause of death in those aged 45 and younger. The pre-hospital phase of traumatic injury is particularly important as care received during this phase has effects on survival. The need for high quality clinical trials in this area has been recognised for several years as a key priority to improve the evidence base and, ultimately, clinical care in prehospital trauma. We aimed to systematically map the existing evidence base for pre-hospital trauma trials, to identify knowledge gaps and inform decisions about the future research agenda.

METHODS

A systematic mapping review was conducted first employing a search of key databases (MEDLINE, CINAHL, EMBASE, and Cochrane Library from inception to March 23rd 2020) to identify randomised controlled trials within the pre-hospital trauma and injury setting. The evidence 'map' identified and described the characteristics of included studies and compared these studies against existing priorities for research. Narrative description of studies informed by analysis of relevant data using descriptive statistics was completed.

RESULTS

Twenty-three eligible studies, including 10,405 participants across 14 countries, were identified and included in the systematic map. No clear temporal or geographical trends in publications were identified. Studies were categorised into six broad categories based on intervention type with evaluations of fluid therapy and analgesia making up 60% of the included trials. Overall, studies were heterogenous with regard to individual interventions within categories and outcomes reported. There was poor reporting across several studies. No studies reported patient involvement in the design or conduct of the trials.

CONCLUSION

This mapping review has highlighted that evidence from trials in prehospital trauma is sparse and where trials have been completed, the reporting is generally poor and study designs sub-optimal. There is a continued need, and significant scope, for improvement in a setting where high quality evidence has great potential to make a demonstrable impact on care and outcomes.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.