Variations Between Level I Trauma Centers in 24-Hour Mortality in Severely Injured Patients Requiring a Massive Transfusion

Collecting data on organizational structures of trauma centers: the CAFE web service

Background

During the past several decades, the American College of Surgeons has led efforts to standardize trauma care through their trauma center verification process and Trauma Quality Improvement Program. Despite these endeavors, great variability remains among trauma centers functioning at the same level. Little research has been conducted on the correlation between trauma center organizational structure and patient outcomes. We are attempting to close this knowledge gap with the Comparative Assessment Framework for Environments of Trauma Care (CAFE) project.

Methods

Our first action was to establish a shared terminology that we then used to build the Ontology of Organizational Structures of Trauma centers and Trauma systems (OOSTT). OOSTT underpins the web-based CAFE questionnaire that collects detailed information on the particular organizational attributes of trauma centers and trauma systems. This tool allows users to compare their organizations to an aggregate of other organizations of the same type, while collecting their data.

Results

In collaboration with the American College of Surgeons Committee on Trauma, we tested the system by entering data from three trauma centers and four trauma systems. We also tested retrieval of answers to competency questions.

Discussion

The data we gather will be made available to public health and implementation science researchers using visualizations. In the next phase of our project, we plan to link the gathered data about trauma center attributes to clinical outcomes.

Prediction of critical haemorrhage following trauma: A narrative review

Introduction: Traumatic haemorrhagic shock can be difficult to diagnose. Models for predicting critical bleeding and massive transfusion have been developed to aid clinicians. The aim of this review is to outline the various available models and report on their performance and validation. Methods: A review of the English and non-English literature in Medline, PubMed and Google Scholar was conducted from 1990 to September 2015. We combined several terms for i) haemorrhage AND ii) prediction, in the setting of iii) trauma. We included models that had at least two data points. We extracted information about the models, their developments, performance and validation. Results: There were 36 different models identified that diagnose critical bleeding, which included a total of 36 unique variables. All models were developed retrospectively. The models performed with variable predictive abilities–the most superior with an area under the receiver operating characteristics curve of 0.985, but included detailed findings on imaging and was based on a small cohort. The most commonly included variable was systolic blood pressure, featuring in all but five models. Pattern or mechanism of injury were used by 16 models. Pathology results were used by 15 models, of which nine included base deficit and eight models included haemoglobin. Imaging was utilised in eight models. Thirteen models were known to be validated, with only one being prospectively validated. Conclusions: Several models for predicting critical bleeding exist, however none were deemed accurate enough to dictate treatment. Potential areas of improvement identified include measures of variability in vital signs and point of care imaging and pathology testing.

The use of higher platelet: RBC transfusion ratio in the acute phase of trauma resuscitation: a systematic review

OBJECTIVE

With the recognition of early coagulopathy, trauma resuscitation has shifted toward liberal platelet transfusions. The overall benefit of this strategy remains controversial. Our objective was to compare the effects of a liberal use of platelet (higher platelet:RBC ratios) with a conservative approach (lower ratios) in trauma resuscitation.

DATA SOURCES

We systematically searched Medline, Embase, Web of Science, Biosis, Cochrane Central, and Scopus.

STUDY SELECTION

Two independent reviewers selected randomized controlled trials and observational studies comparing two or more platelet:RBC ratios in trauma resuscitation. We excluded studies investigating the use of whole blood or hemostatic products.

DATA EXTRACTION

Two independent reviewers extracted data and assessed the risk of bias. Primary outcomes were early (in ICU or within 30 d) and late (in hospital or after 30 d) mortality. Secondary outcomes were multiple organ failure, lung injury, and sepsis.

DATA SYNTHESIS

From 6,123 citations, no randomized controlled trials were identified. We included seven observational studies (4,230 patients) addressing confounders through multivariable regression or propensity scores. Heterogeneity of studies precluded meta-analysis. Among the five studies including exclusively patients requiring massive transfusions, four observed a lower mortality with higher ratios. Two studies considering nonmassively bleeding patients observed no benefit of using higher ratios. Two studies evaluated the implementation of a massive transfusion protocol; only one study observed a decrease in mortality with higher ratios. Of the two studies at low risk of survival bias, one study observed a survival benefit. Three studies assessed secondary outcomes. One study observed an increase in multiple organ failure with higher ratios, whereas no study demonstrated an increased risk in lung injury or sepsis.

CONCLUSIONS

There is insufficient evidence to strongly support the use of a precise platelet:RBC ratio for trauma resuscitation, especially in nonmassively bleeding patients. Randomized controlled trials evaluating both the safety and efficacy of liberal platelet transfusions are warranted.

Toward a better definition of massive transfusion: focus on the interval of hemorrhage control

BACKGROUND

In clinical research, massive transfusion (MT) is commonly defined as transfusion of 10 or more red blood cell (RBC) units within 24 hours. However, the clinical relevance of this definition remains poorly understood. In this study, we evaluated whether patients who reach the MT threshold during hemorrhage control differ clinically from those who reach it after hemorrhage control (i.e., after intensive care unit [ICU] arrival) but before 24 hours.

METHODS

Prospective data were collected on all Level I trauma resuscitations within 5.5 years. Patients transfused 10 or more RBCs in the first 24 hours of hospitalization were identified and stratified according to when the MT threshold was achieved: before ICU arrival (Pre-ICU) versus after ICU arrival but before 24 hours of hospitalization (Post-ICU). Clinical characteristics between groups were compared.

RESULTS

Three hundred five patients received 10 or more units before ICU arrival, and 46 reached the MT threshold after ICU arrival but before 24 hours. Both groups were clinically similar with respect to age, sex, and Injury Severity Score, but the Post-ICU group had a larger proportion of blunt injuries (71 vs. 53%, p < 0.05), lower mean admission lactate (5.9 vs. 8.1 mmol/L, p < 0.05), and higher systolic blood pressure (112 vs. 96 mm Hg, p < 0.05) compared with the Pre-ICU group. Twenty-four-hour mortality was significantly lower in the Post-ICU group compared with the Pre-ICU group (9 vs. 33%, p < 0.05). In-hospital mortality was not significantly different between groups (33 vs. 46%, p = 0.11).

CONCLUSION

Patients reaching the MT threshold after ICU arrival comprise a relatively small proportion of those that would be included by the traditional MT definition. However, they have a significantly decreased mortality risk at 24 hours and the potential to dilute the study cohort. For research purposes, restricting the MT definition to 10 or more RBCs during hemorrhage control may result in study cohorts with relatively more uniform mortality risks.

LEVEL OF EVIDENCE

Prognostic study, level II.

Early resuscitation intensity as a surrogate for bleeding severity and early mortality in the PROMMTT study

BACKGROUND

The classic definition of massive transfusion, 10 or more units of red blood cells (RBCs) in 24 hours, has never been demonstrated as a valid surrogate for severe hemorrhage and can introduce survival bias. In addition, the definition fails to capture other products that the clinician may have immediately available, and may use, during the initial resuscitation. Assuming that units of resuscitative fluids reflect patient illness, our objective was to identify a rate of resuscitation intensity (RI) that could serve as an early surrogate of sickness for patients with substantial bleeding after injury.

METHODS

Adult patients surviving at least 30 minutes after admission and receiving one or more RBCs within 6 hours of admission from 10 US Level 1 trauma centers were enrolled in the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study. Total fluid units were calculated as the sum of the number of crystalloid units (1 L = 1 U), colloids (0.5 L = 1 U), and blood products (1 RBC = 1 U, 1 plasma = 1 U, 6 pack platelets = 1 U). Univariable and multivariable logistic regressions were used to evaluate associations between RI and 6-hour mortality, adjusting for age, center, penetrating injury, weighted Revised Trauma Score (RTS), and Injury Severity Score (ISS).

RESULTS

A total of 1,096 eligible patients received resuscitative fluids within 30 minutes, including 620 transfused with blood products. Despite varying products used, the total fluid RI was similar across all sites (3.2 ± 2.5 U). Patients who received four or more units of any resuscitative fluid had a 6-hour mortality rate of 14.4% versus 4.5% in patients who received less than 4 U. The adjusted odds ratio of 6-hour mortality for patients receiving 4 U or more within 30 minutes was 2.1 (95% confidence interval, 1.2-3.5).

CONCLUSION

Resuscitation with four or more units of any fluid was significantly associated with 6-hour mortality. This study suggests that early RI regardless of fluid type can be used as a surrogate for sickness and mortality in severely bleeding patients.

The prospective, observational, multicenter, major trauma transfusion (PROMMTT) study: comparative effectiveness of a time-varying treatment with competing risks

OBJECTIVE

To relate in-hospital mortality to early transfusion of plasma and/or platelets and to time-varying plasma:red blood cell (RBC) and platelet:RBC ratios.

DESIGN

Prospective cohort study documenting the timing of transfusions during active resuscitation and patient outcomes. Data were analyzed using time-dependent proportional hazards models.

SETTING

Ten US level I trauma centers.

PATIENTS

Adult trauma patients surviving for 30 minutes after admission who received a transfusion of at least 1 unit of RBCs within 6 hours of admission (n = 1245, the original study group) and at least 3 total units (of RBCs, plasma, or platelets) within 24 hours (n = 905, the analysis group).

MAIN OUTCOME MEASURE

In-hospital mortality.

RESULTS

Plasma:RBC and platelet:RBC ratios were not constant during the first 24 hours (P < .001 for both). In a multivariable time-dependent Cox model, increased ratios of plasma:RBCs (adjusted hazard ratio = 0.31; 95% CI, 0.16-0.58) and platelets:RBCs (adjusted hazard ratio = 0.55; 95% CI, 0.31-0.98) were independently associated with decreased 6-hour mortality, when hemorrhagic death predominated. In the first 6 hours, patients with ratios less than 1:2 were 3 to 4 times more likely to die than patients with ratios of 1:1 or higher. After 24 hours, plasma and platelet ratios were unassociated with mortality, when competing risks from nonhemorrhagic causes prevailed.

CONCLUSIONS

Higher plasma and platelet ratios early in resuscitation were associated with decreased mortality in patients who received transfusions of at least 3 units of blood products during the first 24 hours after admission. Among survivors at 24 hours, the subsequent risk of death by day 30 was not associated with plasma or platelet ratios.

Emergency department blood transfusion: the first two units are free

INTRODUCTION

Studies on blood product transfusions after trauma recommend targeting specific ratios to reduce mortality. Although crystalloid volumes as little as 1.5 L predict increased mortality after trauma, little data is available regarding the threshold of red blood cell (RBC) transfusion volume that predicts increased mortality.

MATERIALS AND METHODS

Data from a level I trauma center between January 2000 and December 2008 were reviewed. Trauma patients who received at least 100 mL RBC in the emergency department (ED) were included. Each unit of RBC was defined as 300 mL. Demographics, RBC transfusion volume, and mortality were analyzed in the nonelderly (<70 y) and elderly (≥70 y). Multivariate logistic regression was performed at various volume cutoffs to determine whether there was a threshold transfusion volume that independently predicted mortality.

RESULTS

A total of 560 patients received ≥100 mL RBC in the ED. Overall mortality was 24.3%, with 22.5% (104 deaths) in the nonelderly and 32.7% (32 deaths) in the elderly. Multivariate logistic regression demonstrated that RBC transfusion of ≥900 mL was associated with increased mortality in both the nonelderly (adjusted odds ratio 2.06, P = 0.008) and elderly (adjusted odds ratio 5.08, P = 0.006).

CONCLUSIONS

Although transfusion of greater than 2 units in the ED was an independent predictor of mortality, transfusion of 2 units or less was not. Interestingly, unlike crystalloid volume, stepwise increases in blood volume were not associated with stepwise increases in mortality. The underlying etiology for mortality discrepancies, such as transfusion ratios, hypothermia, or immunosuppression, needs to be better delineated.

The microcirculation: linking trauma and coagulopathy

Survival after severe traumatic shock can be complicated by a number of pathophysiologic processes that ensue after the initial trauma. One of these is trauma-induced coagulopathy (TIC) whose onset may occur before initial fluid resuscitation. The pathogenesis of TIC has not yet been fully elaborated, but evolving evidence appears to link severe tissue hypoxia and damage to the endothelium as key factors, which evolve into measurable structural and biochemical changes of the endothelium resulting in a coagulopathic state. This paper will provide a general review of these linkages and identify knowledge gaps as well as suggest new approaches and areas of investigation, which may both limit the development of TIC as well as produce insights into its pathophysiology. A better understanding of these issues will be necessary in order to advance the practice of remote damage control resuscitation.