Effect of Pre-Hospital Use of the Assessment of Blood Consumption Score and Pre-Thawed Fresh Frozen Plasma on Resuscitation and Trauma Mortality

Prehospital Validation of the Assessment of Blood Consumption (ABC) Score

INTRODUCTION

The Assessment of Blood Consumption (ABC) score is a previously validated scoring system designed to predict which severely injured trauma patients will require massive transfusion. When the ABC score is used in the prehospital setting to activate massive transfusion at the receiving hospital, a 23% decrease in mortality has been demonstrated. However, the ABC score was developed and validated using hospital data from the emergency department (ED). The sensitivity and specificity of the ABC score when calculated using data from the prehospital setting are unknown. We hypothesized that the sensitivity and specificity of the prehospital ABC score will be similar to the sensitivity and specificity of the ED ABC score.

METHODS

A 5-year retrospective analysis (2015-2019) of highest-activation adult trauma patients arriving to a quaternary Level I trauma center by hospital-based helicopter air medical service (HEMS) was performed. Demographic, prehospital, ED triage, and blood product utilization data were collected. Prehospital ABC score was calculated using the highest heart rate, lowest systolic blood pressure, and focused assessment with sonography for trauma (FAST) exam results obtained prior to arrival at the trauma center. ED ABC score was calculated using ED triage vital signs and ED FAST results. Sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristics (AUROC) curve were calculated for each ABC score.

RESULTS

2,067 patients met inclusion criteria. Mean age 39 (±17) years, 76% male, 22% penetrating mechanism. Of these, 128 patients (6%) received massive transfusion using the definition from the original study. Prehospital ABC score at a cutoff of 2 was 51% sensitive and 85% specific for predicting massive transfusion, with 83% correctly classified and an AUROC = 0.73. ED ABC score at the same cutoff was 60% sensitive and 84% specific, with 83% correctly classified and an AUROC = 0.81. By logistic regression, the odds of massive transfusion increased by 2.76 for every 1-point increase in prehospital ABC score (95%CI 2.25-3.37, p < 0.001).

CONCLUSIONS

The ABC score is a useful prehospital tool for identifying who will require massive transfusion. Future studies to evaluate the effect of the prehospital ABC score on clinical care and mortality are necessary.

Ex vivo hemostatic and immuno-inflammatory profiles of freeze-dried plasma

BACKGROUND

Hemorrhage is a leading cause of preventable death in civilian and military trauma. Freeze-dried plasma is promising for hemostatic resuscitation in remote prehospital settings, given its potential benefits in reducing blood loss and mortality, long storage at ambient temperatures, high portability, and rapid reconstitution for transfusion in austere environments. Here we assess the ex vivo characteristics of a novel Terumo's freeze-dried plasma product (TFDP).

STUDY DESIGN AND METHODS

Rotational thromboelastometry (ROTEM) tests (INTEM, EXTEM, and FIBTEM) were conducted on plasma samples at 37°C with a ROTEM delta-machine using standard reagents and procedures. The following samples were analyzed: pooled plasma to produce TFDP, TFDP reconstituted, and stored immediately at -80°C, reconstituted TFDP stored at 4°C for 24 h and room temperature (RT) for 4 h before freezing at -80°C. Analysis of plasma concentrations of selected cytokines, chemokines, and vascular molecules was performed using a multiplex immunoassay system. One-way ANOVA with post hoc tests assessed differences in hemostatic and inflammatory properties.

RESULTS

No significant differences in ROTEM variables (coagulation time [CT], clot formation time, α-angle, maximum clot firmness, and lysis index 30) between the TFDP-producing plasma and reconstituted TFDP samples were observed. Compared to control plasma, reconstituted TFDP stored at 4°C for 24 h or RT for 4 h showed a longer INTEM CT. Levels of immuno-inflammatory mediators were similar between frozen plasma and TFDP.

CONCLUSIONS

TFDP is equivalent to frozen plasma with respect to global hemostatic and immuno-inflammatory mediator profiles. Further investigations of TFDP in trauma-induced coagulopathy models and bleeding patients are warranted.

Prehospital ABC Score Accurately Forecasts Patients Who Will Require Immediate Resource Utilization

OBJECTIVES

Scoring systems, such as the Assessment of Blood Consumption (ABC) Score, are used to identify patients at risk for massive transfusion (MT, ≥10 U red blood cells in 24 hours). Our aeromedical transport helicopter uses ultrasound to perform the Focused Assessment with Sonography for Trauma (FAST) examination. Our objective was to evaluate the ability of the Prehospital ABC (PhABC) Score to predict blood transfusions and the need for emergent laparotomy.

METHODS

Post hoc analysis of a prospective observational study of trauma patients who underwent an in-flight FAST during aeromedical transport during a 7-month period. PhABC Score was positive if ≥2 of the following were present in flight: penetrating trauma, heart rate >120 bpm, systolic blood pressure <90 mm Hg, or a positive abdominal FAST. The PhABC Score was evaluated by area under the receiver operating characteristic (AUROC) curves and logistic regression.

RESULTS

A total of 291 trauma patients met inclusion criteria, 23 underwent emergent laparotomy, and 12 received an MT. A positive PhABC Score predicted emergent laparotomy, with a positive predictive value of 48% and a negative predictive value of 95% (sensitivity 46%, specificity 96%, AUROC curve 0.83). A positive PhABC Score also predicted receipt of an MT with a positive predictive value of 28% and a negative predictive value of 94% (sensitivity 33%, specificity 93%, AUROC curve 0.77). Multiple logistic regression identified FAST as the most powerful contributor of the PhABC Score to the prediction of both emergent laparotomy (odds ratio 8.5, P < 0.001) and MT (odds ratio 5.9, P < 0.001).

CONCLUSIONS

The PhABC Score effectively predicts in-hospital resource utilization. It provides an outstanding undertriage rate from the prehospital setting, and it is helpful to improve trauma team activation, mobilize blood products, and prepare the operating room.

Predicting the need for massive transfusion in the prehospital setting

INTRODUCTION

Massive transfusion (MT) prediction scores allowed for the early identification of patients with massive hemorrhage likely to require large volumes of blood products. Despite their utility, very few MT scoring systems have shown promise in the pre-hospital setting due to their complexity and resource limitations.

AREAS COVERED

Pub med database was utilized to identify supporting literature for this review which discusses the importance of blood-based resuscitation and highlights the utility of scoring systems to predict the need of massive transfusion. MTP scoring systems effective in the prehospital setting are specifically discussed.

EXPERT OPINION

Massive transfusions scores are useful in alerting hospitals to the severity of trauma patients and organizing resources necessary for appropriate patient care but should not completely replace clinical . The opportunity exists to extend their use to the pre-hospital setting to allow for even earlier notification and to triage patients to trauma centers best able to treat severely injured.

Reducing AB plasma utilisation through the AB plasma appropriateness index

OBJECTIVES

We hypothesised that there was inappropriate group AB plasma used in our hospital, identifiable by a novel key quality indicator (KQI) and mitigable through massive transfusion protocol (MTP) modification.

BACKGROUND

Group AB plasma is a scarce resource strained by increasing usage worldwide when used as universal donor plasma in non-group AB patients. To reduce inappropriate use and to promote benchmarking to the best practice, we developed the AB plasma appropriateness index (ABAI). ABAI is the ratio of AB plasma transfused to group AB or unknown blood group patients to all AB plasma utilised, where values closer to 1 are better.

METHODS

Data collected included AB plasma disposition by blood group, indications for transfusion, total blood utilisation, patient clinical characteristics and outcomes. ABAI during a 12-month period was retrospectively assessed, which led to implementation of pre-thawed group A plasma instead of group AB plasma for trauma patients starting in July 2017.

RESULTS

The ABAI retrospectively showed inappropriate use in non-group AB patients in our hospital, the majority used to avoid expiry after thaw. When comparing 1-year pre- and post-implementation periods, ABAI improved from 0·464 to 0·900 (P < 0·0001). After exclusion of therapeutic plasma exchange, ABAI still improved (0·486-0·720, P < 0·0001). No differences in the length of stay or mortality associated in 32 patients receiving group A plasma for emergency release were observed.

CONCLUSION

The ABAI is a novel KQI to indicate inappropriate AB plasma usage for quality improvement. This led to thawed A plasma use for MTPs, reducing inappropriate AB plasma usage.

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

BACKGROUND

Numerous in-hospital scoring systems to activate massive transfusion protocols (MTP) have been proposed; however, to date, pre-hospital scoring systems have not been robustly validated. Many trauma centers do not have blood or pre-thawed plasma available in the trauma bay, leading to delays in balanced transfusion. This study aims to assess pre-hospital injury and physiologic parameters to develop a pre-hospital scoring system predictive of need for massive transfusion (MT) prior to patient arrival.

METHODS

A retrospective review of all adult full and partial trauma team activations from July 2014-July 2018 from an urban level 2 trauma center was performed utilizing our trauma registry. Stepwise logistic regression analysis was performed to develop a new scoring system, with point totals assigned proportional to the odds ratios of requiring MT for each variable. Internal validation of the EMS-G score was performed using a subset of the data which was not utilized for development of the scoring system, and sensitivity and specificity were compared to previously validated in-hospital scoring systems applied in the pre-hospital setting.

RESULTS

763 patients were included with 94 patients (12.3%) receiving early MT, defined as 4 units pRBC in 4 h or ED death. In-hospital models for predicting MT such as Assessment of Blood Consumption (ABC) or Shock Index (SI) have sensitivities and specificities of 46/85% and 94/79% respectively for early MTP utilization based on pre-hospital data. Pre-hospital variables found to be predictive of MT were used to develop the EMS-G (Extremity, Mechanism, Shock Index, GCS) score. This system assigns obvious extremity injury-1-point, penetrating mechanism -2 points, shock index ≥0.9-2 points, GCS ≤8-3 points. A score of 3 or greater was chosen to maximize sensitivity and specificity for pre-hospital MT activation. EMS-G score based on pre-hospital report is 89% sensitive, 84% specific, with a PPV of 44% and NPV of 98% for early MT. Using this system, 25% of full and partial trauma team activations met criteria for pre-hospital MTP activation.

CONCLUSION

The EMS-G Score has increased sensitivity and specificity compared to the ABC Score in the pre-hospital setting and appears more appropriate than shock index alone at predicting massive transfusion. This scoring system allows trauma centers to activate MTP prior to patient arrival to ensure early and appropriate blood product administration without blood product wastage.