Fibrinogen on Admission in Trauma score: Early prediction of low plasma fibrinogen concentrations in trauma patients

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.

The conundrum of the definition of haemorrhagic shock: a pragmatic exploration based on a scoping review, experts' survey and a cohort analysis

PURPOSE

Traumatic hemorrhagic shock (THS) is a complex, dynamic process and, no consensual definition of THS is available. This study aims (1) to explore existing definitions of traumatic hemorrhagic shock (THS), (2) to identify essential components of these definitions and (3) to illustrate in a pragmatic way the consequences of applying five of these definitions to a trauma registry.

METHODS

We conducted (1) a scoping review to identify the definitions used for traumatic hemorrhagic shock (THS); (2) an international experts survey to rank by relevance a selection of components extracted from these definitions and (3) a registry-based analysis where several candidate definitions were tested in a large trauma registry to evaluate how the use of different definitions affected baseline characteristics, resources use and patient outcome.

RESULTS

Sixty-eight studies were included revealing 52 distinct definitions. The most frequently used was "a systolic blood pressure (SBP) less than or equal to 70 mmHg or between 71 and 90 mmHg if the heart rate is greater than or equal to 108 beats per min". The expert panel identified base excess, blood lactate concentration, SBP and shock index as the most relevant physiological components to define THS. Five definitions of THS were tested and highlighted significant differences across groups on important outcomes such as the proportion of massive transfusion, the need for surgery, in-hospital length of stay or in-hospital mortality.

CONCLUSIONS

This study demonstrates a large heterogeneity in the definitions of THS suggesting a need for standardization. Five candidate definitions were identified in a three-step process to illustrate how each shapes study cohort composition and impacts outcome. The results inform research stakeholders in the choice of a consensual definition.

Management of Coagulopathy in Bleeding Patients

Early recognition of coagulopathy is necessary for its prompt correction and successful management. Novel approaches, such as point-of-care testing (POC) and administration of coagulation factor concentrates (CFCs), aim to tailor the haemostatic therapy to each patient and thus reduce the risks of over- or under-transfusion. CFCs are an effective alternative to ratio-based transfusion therapies for the correction of different types of coagulopathies. In case of major bleeding or urgent surgery in patients treated with vitamin K antagonist anticoagulants, prothrombin complex concentrate (PCC) can effectively reverse the effects of the anticoagulant drug. Evidence for PCC effectiveness in the treatment of direct oral anticoagulants-associated bleeding is also increasing and PCC is recommended in guidelines as an alternative to specific reversal agents. In trauma-induced coagulopathy, fibrinogen concentrate is the preferred first-line treatment for hypofibrinogenaemia. Goal-directed coagulation management algorithms based on POC results provide guidance on how to adjust the treatment to the needs of the patient. When POC is not available, concentrate-based management can be guided by other parameters, such as blood gas analysis, thus providing an important alternative. Overall, tailored haemostatic therapies offer a more targeted approach to increase the concentration of coagulation factors in bleeding patients than traditional transfusion protocols.

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.

Effect of fibrinogen concentrate administration on early mortality in traumatic hemorrhagic shock: A propensity score analysis

BACKGROUND

Fibrinogen concentrate is widely used in traumatic hemorrhagic shock despite weak evidence in the literature. The aim of the study was to evaluate the effect of fibrinogen concentrate administration within the first 6 hours on 24-hour all-cause mortality in traumatic hemorrhagic shock using a causal inference approach.

METHODS

Observational study from a French multicenter prospective trauma registry was performed. Hemorrhagic shock was defined as transfusion of four or more red blood cell units within the first 6 hours after admission. The confounding variables for the outcome (24-hour all-cause mortality) and treatment allocation (fibrinogen concentrate administration within the first 6 hours) were chosen by a Delphi method. The propensity score was specified with a data-adaptive algorithm and a doubly-robust approach with inverse proportionality of treatment weighting allowed to compute the average treatment effect. Sensitivity analyses were performed.

RESULTS

Of 14,336 patients in the registry during the study period, 1,027 in hemorrhagic shock were analyzed (758 receiving fibrinogen concentrate within 6 hours and 269 not receiving fibrinogen concentrate). The average treatment effect, expressed as a risk difference, was -0.031 (95% confidence interval, -0.084 to 0.021). All sensitivity analysis confirmed the results.

CONCLUSIONS

Fibrinogen concentrate administration within the first 6 hours of a traumatic hemorrhagic shock did not decrease 24-hour all-cause mortality.

LEVEL OF EVIDENCE

Prognostic, level III.

Association of Early, High Plasma-to-Red Blood Cell Transfusion Ratio With Mortality in Adults With Severe Bleeding After Trauma

IMPORTANCE

Optimal transfusion management is crucial when treating patients with trauma. However, the association of an early, high transfusion ratio of fresh frozen plasma (FFP) to packed red blood cells (PRBC) with survival remains uncertain.

OBJECTIVE

To study the association of an early, high FFP-to-PRBC ratio with all-cause 30-day mortality in patients with severe bleeding after trauma.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzes the data included in a multicenter national French trauma registry, Traumabase, from January 2012 to July 2017. Traumabase is a prospective, active, multicenter adult trauma registry that includes all consecutive patients with trauma treated at 15 trauma centers in France. Overall, 897 patients with severe bleeding after trauma were identified using the following criteria: (1) received 4 or more units of PRBC during the first 6 hours or (2) died from hemorrhagic shock before receiving 4 units of PRBC.

EXPOSURES

Eligible patients were divided into a high-ratio group, defined as an FFP-to-PRBC ratio more than 1:1.5, and a low-ratio group, defined as an FFP-to-PRBC ratio of 1:1.5 or less. The ratio was calculated using the cumulative units of FFP and PRBC received during the first 6 hours of management.

MAIN OUTCOMES AND MEASURES

A Cox regression model was used to analyze 30-day survival with the transfusion ratio as a time-dependent variable to account for survivorship bias.

RESULTS

Of the 12 217 patients included in the registry, 897 (7.3%) were analyzed (median [interquartile range] age, 38 (29-54) years; 639 [71.2%] men). The median (interquartile range) injury severity score was 34 (22-48), and the overall 30-day mortality rate was 33.6% (301 patients). A total of 506 patients (56.4%) underwent transfusion with a high ratio and 391 (43.6%) with a low ratio. A high transfusion ratio was associated with a significant reduction in 30-day mortality (hazard ratio, 0.74; 95% CI, 0.58-0.94; P = .01). When only analyzing patients who had complete data, a high transfusion ratio continued to be associated with a reduction in 30-day mortality (hazard ratio, 0.57; 95% CI, 0.33-0.97; P = .04).

CONCLUSIONS AND RELEVANCE

In this analysis of the Traumabase registry, an early FFP-to-PRBC ratio of more than 1:1.5 was associated with increased 30-day survival among patients with severe bleeding after trauma. This result supports the use of early, high FFP-to-PRBC transfusion ratios in patients with severe trauma.

Modelling the association between fibrinogen concentration on admission and mortality in patients with massive transfusion after severe trauma: an analysis of a large regional database

Background

The relationship between fibrinogen concentration and traumatic death has been poorly explored after severe trauma. Existing studies analysed this relationship in unselected trauma population, often considering fibrinogen concentration as a categorical variable. The aim of our study was to model the relationship between fibrinogen concentration and in-hospital mortality in severe trauma patients requiring massive transfusion using fibrinogen on admission as a continuous variable.

Methods

We designed a retrospective observational study based on prospectively collected data from 2009 to 2015 in seven French level-I trauma centres. All consecutive patients requiring a transfusion of at least 10 packed red blood cells (RBC) within 24 h were included. To assess the relationship between in-hospital death and fibrinogen concentration on admission, we performed generalized linear and additive models with death as a dependent variable. We also assessed the relationship between fibrinogen concentration below 1.5 g.L^− 1 and potential predictors.

Results

Within the study period, 366 patients were included. A non-linear relationship was found between fibrinogen concentration and death. Graphical modelling of this relationship depicted a negative association between fibrinogen levels and death below a fibrinogen concentration of 1.5 g.L^− 1. Predictors of low fibrinogen concentration (< 1.5 g.L^− 1) were systolic blood pressure, Glasgow coma scale and haemoglobin concentration on admission.

Conclusions

A complex and robust approach for modelling the relationship between fibrinogen and mortality revealed a critical fibrinogen threshold of 1.5 g.L^− 1 for severe trauma patients requiring massive transfusion. This trigger may guide the administration of procoagulant therapies in this context.