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

When is enough enough? Odds of survival by unit transfused

BACKGROUND

Balanced transfusion is lifesaving for hemorrhagic shock. The American Red Cross critical blood shortage in 2022 threatened the immediate availability of blood. To eliminate waste, we reviewed the utility of transfusions per unit to define expected mortality at various levels of balanced transfusion.

METHODS

A retrospective study of 296 patients receiving massive transfusion on presentation at a level 1 trauma center was performed from January 2018 to December 2021. Units of packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets received in the first 4 hours were recorded. Patients were excluded if they died in the emergency department, died on arrival, received <2 U PRBCs or FFP, or received PRBC/FFP >2:1. Primary outcomes were mortality and odds of survival to discharge. Subgroups were defined as transfused if receiving 2 to 9 U PRBCs, massive transfusion for 10 to 19 U PRBCs, and ultramassive transfusion for ≥20 U PRBCs.

RESULTS

A total of 207 patients were included (median age, 32 years; median Injury Severity Score, 25; 67% with penetrating mechanism). Mortality was 29% (61 of 207 patients). Odds of survival is equal to odds of mortality at 11 U PRBCs (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.50-1.79). Beyond 16 U PRBCs, odds of mortality exceed survival (OR, 0.36; 95% CI, 0.16-0.82). Survival approaches zero >36 U PRBCs (OR, 0.09; 95% CI, 0.00-0.56). Subgroup mortality rates increased with unit transfused (16% transfused vs. 36% massive transfusion, p = 0.003; 36% massive transfusion vs. 67% ultramassive transfusion, p = 0.006).

CONCLUSION

Mortality increases with each unit balanced transfusion. Surgeons should view efforts heroic beyond 16 U PRBCs/4 hours and near futile beyond 36 U PRBCs/4 hours. While extreme outliers can survive, consider cessation of resuscitation beyond 36 U PRBCs. This is especially true if hemostasis has not been achieved or blood supplies are limited.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level IV.

Predictors of transfusion in trauma and their utility in the prehospital environment: a scoping review

Background: Hemorrhage is a leading cause of preventable mortality from trauma, necessitating resuscitation through blood product transfusions. Early and accurate identification of patients requiring transfusions in the prehospital setting may reduce delays in time to transfusion upon arrival to hospital, reducing mortality. The purpose of this study is to characterize existing literature on predictors of transfusion and analyze their utility in the prehospital context.Objectives: The objectives of this study are to characterize the existing quantity and quality of literature regarding predictor scores for transfusion in injured patients, and to analyse the utility of predictor scores for massive transfusions in the prehospital setting and identify prehospital predictor scores for future research.Methods: A search strategy was developed in consultation with information specialists. A literature search of OVID MEDLINE from 1946 to present was conducted for primary studies evaluating the predictive ability of scoring systems or single variables in predicting transfusion in all trauma settings.Results: Of the 5824 studies were identified, 5784 studies underwent title and abstract screening, 94 studies underwent full text review, and 72 studies were included in the final review. We identified 16 single variables and 52 scoring systems for predicting transfusion. Amongst single predictor variables, fluids administered and systolic blood pressure had the highest reported sensitivity (100%) and specificity (89%) for massive transfusion protocol (MTP) activation respectively. Amongst scoring systems for transfusion, the Shock Index and Modified Shock Index had the highest reported sensitivity (96%), while the Pre-arrival Model had the highest reported specificity (95%) for MTP activation. Overall, 20 scores were identified as being applicable to the prehospital setting, 25 scores were identified as being potentially applicable, and seven scores were identified as being not applicable.Conclusions: We identified an extensive list of predictive single variables, validated scoring systems, and derived models for massive transfusion, presented their properties, and identified those with potential utility in the prehospital setting. By further validating applicable scoring tools in the prehospital setting, we may begin to administer more timely transfusions in the trauma population.

Accuracy of risk tools to predict critical bleeding in major trauma: A systematic review with meta-analysis

BACKGROUND

Early detection of critical bleeding by accurate tools can help ensure rapid delivery of blood products to improve outcomes in major trauma patients. We conducted a systematic review to evaluate the accuracy of risk tools to predict critical bleeding in patients with major trauma.

METHODS

PubMed, Embase, and CENTRAL were searched up to February 2021 for studies investigating risk tools to predict critical bleeding for major trauma people in prehospital and emergency department. We followed the Preferred Reporting Items for Systematic Review and Meta-Analysis of Diagnostic Test Accuracy study guidelines. Two independent authors included studies, extracted data, appraised the quality using the Quality Assessment of Diagnostic Accuracy Studies 2 and assessed the certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development and Evaluation methodology. Sensitivity, specificity, and the receiver operating characteristics curve for all selected triage tools.

RESULTS

Eighty-nine observational studies for adults and 12 observational studies for children met our inclusion criteria. In adults, we found 23 externally validated and 28 unvalidated tools; in children, 3 externally validated tools and 5 unvalidated. In the externally validated tools, we identified those including clinical, laboratory, and ultrasound assessments. Among tools including only a clinical assessment, the Shock Index showed high sensitivity and specificity with the CoE ranging from very low to moderate in adults, as well as Shock Index Pediatric Age adjusted with a moderate CoE. We found that tools using clinical, laboratory, and ultrasound assessments were overall more accurate than those tools without all three components.

CONCLUSION

Clinicians should consider risk tools to predict critical bleeding in a time-sensitive setting like major life-threatening trauma. The Shock Index and Shock Index Pediatric Age adjusted are easy and handy tools to predict critical bleeding in the prehospital setting. In the emergency department, however, many other tools can be used, which include laboratory and ultrasound assessments, depending on staff experience and resources.

LEVEL OF EVIDENCE

Systematic Review and Meta-Analysis; Level III.

Derivation and Validation of a Score Using Prehospital Data to Identify Adults With Trauma Requiring Early Laparotomy

IMPORTANCE

A scoring tool to identify which adults with traumatic injury will require early laparotomy could help improve prehospital triage and system readiness.

OBJECTIVE

To develop and validate a prediction model using prehospital information for early laparotomy following trauma.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study analyzed data from the 2017 version of the American College of Surgeons Trauma Quality Improvement Program database. All adult patients with traumatic injury aged 18 years or older who were admitted to a US trauma center in 2017 were included. Patients were randomly assigned to a derivation or validation cohort. Data were collected and analyzed between July 2020 and September 2020.

MAIN OUTCOMES AND MEASURES

The primary outcome was laparotomy within 2 hours of hospital arrival. A scoring system was developed to predict early laparotomy using a logistic regression model in the derivation cohort. This was validated in the validation cohort using the area under the receiver operating characteristic curve.

RESULTS

A total of 379 890 US adults with traumatic injury were included; 190 264 patients were in the derivation cohort and 189 626 patients were in the validation cohort. The cohorts had the same proportion of laparotomy within 2 hours of hospital arrival (1.1%). The median (IQR) age was 32 (25-46) years in the early laparotomy group and 54 (33-72) years in the group with no early laparotomy. The early laparotomy group contained 113 776 of 188 211 (60.5%) male patients, while the group with no early laparotomy contained 1702 of 2053 (82.9%) male patients. The variable most strongly associated with early laparotomy was penetrating injury to the head, neck, torso, or extremities proximal to the elbow or knee (odds ratio, 13.47; 95% CI, 12.22-14.86) with a point value of 10 (maximum overall score 20). Other variables included in the scoring system were the male sex, a systolic blood pressure less than 90 mm Hg, a Glasgow Coma Scale of less than or equal to 13, having chest wall instability or deformity, pelvic fracture, and high-risk blunt mechanism. In the validation cohort, the C statistic of the scoring system was 0.78 (95% CI, 0.77-0.79).

CONCLUSIONS AND RELEVANCE

In this study, a novel scoring tool using prehospital information was derived and validated to identify which adults with traumatic injury will require laparotomy within 2 hours of hospital arrival. This tool may help trauma professionals allocate operative team resources before patient arrival.

Blunt Trauma Massive Transfusion (B-MaT) Score: A Novel Scoring Tool

BACKGROUND

Multiple tools predicting massive transfusion (MT) in trauma have been developed but utilize variables that are not immediately available. Additionally, they only differentiate blunt from penetrating trauma and do not account for the large range of blunt mechanisms and their difference in force. We aimed to develop a Blunt trauma Massive Transfusion (B-MaT) score that accounts for high-risk blunt mechanisms and predicts MT needs in blunt trauma patients (BTPs) prior to arrival.

MATERIALS AND METHODS

The adult 2017 Trauma Quality Improvement Program database was used to identify BTPs who were divided into 2 sets at random (derivation/validation). First, multiple logistic regression models were created to determine risk factors of MT (≥6 units of PRBCs within 4-hours or ≥10 units within 24-hours). Next, the weighted average and relative impact of each independent predictor was used to derive a B-MaT score. Finally, the area under the receiver-operating curve (AROC) was calculated.

RESULTS

Of 172,423 patients in the derivation-set, 1,160 (0.7%) required MT. Heart rate ≥ 120bpm, systolic blood pressure ≤ 90mmHg, and high-risk blunt mechanisms were identified as independent predictors for MT. B-MaT scores were derived ranging from 0 -9, with scores of 6, 7, and 9 yielding a MT rate of 11.7%, 19.4%, and 32.4%, respectively. The AROC was 0.86. The validation-set had an AROC of 0.85.

CONCLUSIONS

B-MaT is a novel scoring tool that predicts need for MT in BTPs and can be calculated prior to arrival. B-MaT warrants prospective validation to confirm its accuracy and assess its ability to improve patient outcomes and blood product allocation.