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

Blood Product Administration in the Prehospital Setting: A Scoping Review

OBJECTIVES

Implementing prehospital blood products for treating hemorrhagic shock has been utilized globally in military and civilian settings. This review aims to compare various guidelines for using blood products, including the types of blood products, injuries, biomarkers (hemodynamic measurement) to indicate use, associated treatments and risks, and the logistical concerns of storage and wastage in the prehospital setting. Furthermore, it explores whether prehospital blood transfusions are beneficial and a safe treatment option.

METHODS

Data were collected using a systematic search and screening process of online databases CINAHL, Medline, and Scopus, as well as by creating a PRISMA flow diagram to screen articles using inclusion and exclusion criteria. Forty-five articles were screened, with twenty-five excluded, resulting in twenty articles in this scoping review.

RESULTS

The most frequently used blood product used was red blood cells, with twelve studies using either red blood cells alone or in combination with other products. Indications for blood use varied across services, but all aimed to address hemodynamic instability as a primary indication for blood transfusion. Eleven studies recorded no adverse reactions. Only one study reported chills and shivers; however, it was unclear if blood products were the cause. Nine studies avoided logistical issues of storage and wastage to create a feasible rotation system.

CONCLUSIONS

Prehospital blood was used in medical, trauma, and maternity-related hemorrhage. Many types of blood products are in use, ranging from component therapy to whole blood, with each protocol having different indications of use and treatment guidelines aimed at improving hemodynamic stability.

Machine learning in the prediction of massive transfusion in trauma: a retrospective analysis as a proof-of-concept

PURPOSE

Early administration and protocolization of massive hemorrhage protocols (MHP) has been associated with decreases in mortality, multiorgan system failure, and number of blood products used. Various prediction tools have been developed for the initiation of MHP, but no single tool has demonstrated strong prediction with early clinical data. We sought to develop a massive transfusion prediction model using machine learning and early clinical data.

METHODS

Using the National Trauma Data Bank from 2013 to 2018, we included severely injured trauma patients and extracted clinical features available from the pre-hospital and emergency department. We subsequently balanced our dataset and used the Boruta algorithm to determine feature selection. Massive transfusion was defined as five units at 4 h and ten units at 24 h. Six machine learning models were trained on the balanced dataset and tested on the original.

RESULTS

A total of 326,758 patients met our inclusion with 18,871 (5.8%) requiring massive transfusion. Emergency department models demonstrated strong performance characteristics with mean areas under the receiver-operating characteristic curve of 0.83. Extreme gradient boost modeling slightly outperformed and demonstrated adequate predictive performance with pre-hospital data only, as well as 4-h transfusion thresholds.

CONCLUSIONS

We demonstrate the use of machine learning in developing an accurate prediction model for massive transfusion in trauma patients using early clinical data. This research demonstrates the potential utility of artificial intelligence as a clinical decision support tool.

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.

Empiric Cryoprecipitate Transfusion in Patients with Severe Hemorrhage: Results from the US Experience in the International CRYOSTAT-2 Trial

BACKGROUND

Hypofibrinogenemia has been shown to predict massive transfusion and is associated with higher mortality in severely injured patients. However, the role of empiric fibrinogen replacement in bleeding trauma patients remains controversial. We sought to determine the effect of empiric cryoprecipitate as an adjunct to a balanced transfusion strategy (1:1:1).

STUDY DESIGN

This study is a subanalysis of patients treated at the single US trauma center in a multicenter randomized controlled trial. Trauma patients (more than 15 years) were eligible if they had evidence of active hemorrhage requiring emergent surgery or interventional radiology, massive transfusion protocol (MTP) activation, and received at least 1 unit of blood. Transfer patients, those with injuries incompatible with life, or those injured more than 3 hours earlier were excluded. Patients were randomized to standard MTP (STANDARD) or MTP plus 3 pools of cryoprecipitate (CRYO). Primary outcomes included all-cause mortality at 28 days. Secondary outcomes were transfusion requirements, intraoperative and postoperative coagulation laboratory values, and quality-of-life measures (Glasgow outcome score-extended).

RESULTS

Forty-nine patients (23 in the CRYO group and 26 in the STANDARD group) were enrolled between May 2021 and October 2021. Time to randomization was similar between groups (14 vs 24 minutes, p = 0.676). Median time to cryoprecipitate was 41 minutes (interquartile range 37 to 48). There were no differences in demographics, arrival physiology, laboratory values, or injury severity. Intraoperative and ICU thrombelastography values, including functional fibrinogen, were similar between groups. There was no benefit to CRYO with respect to post-emergency department transfusions (intraoperative and ICU through 24 hours), complications, Glasgow outcome score, or mortality.

CONCLUSIONS

In this study of severely injured, bleeding trauma patients, empiric cryoprecipitate did not improve survival or reduce transfusion requirements. Cryoprecipitate should continue as an "on-demand" addition to a balanced transfusion strategy, guided by laboratory values and should not be given empirically.

Is a Positive Prehospital FAST Associated with Severe Bleeding? A Multicenter Retrospective Study

INTRODUCTION

Severe hemorrhage is the leading cause of early preventable death in severe trauma patients. Delayed diagnosis is a poor prognostic factor, and severe hemorrhage prediction is essential. The aim of our study was to investigate if there was an association between the detection of peritoneal or pleural fluid on prehospital sonography for trauma and posttraumatic severe hemorrhage.

METHODS

We retrospectively studied data from records of thoracic or abdominal trauma patients managed in mobile intensive care units from January 2017 to December 2021 in four centers in France. Severe hemorrhage was defined as a condition necessitating transfusion of at least four packed red blood cells or surgical intervention/radioembolization for hemostasis within the first 24 h. Using a multivariate analysis, we investigated the predictive performance of focused assessment with sonography for trauma (FAST) alone or in combination with the five Red Flags criteria validated by Hamada et al.

RESULTS

Among the 527 patients analyzed, 371 (71%) were men, the mean age was 41 ± 19 years, and the Injury Severity Score was 11 (Interquartile range = [5; 22]). Seventy-three (14%) patients had severe hemorrhage - of whom 28 (38%) had a positive FAST, compared to 61 (13%) without severe hemorrhage (p < 0.01). For severe hemorrhage prediction, FAST had a sensitivity of 38% (95%CI = [27%; 50%]) and a specificity of 87% (95%CI = [83%; 90%]) (AUC = 0.62, 95%CI = [0.57; 0.68]). The comparison of the other outcomes between positive and negative FAST was: hemostatic procedure, 22 (25%) vs 28 (6%), p < 0.01; intensive care unit admission 71 (80%) vs 190 (43%), p < 0.01; mean length of hospital stay 11 [4; 27] vs 4 [0; 14] days, p = 0.02; 30-day mortality 13 (15%) vs 22 (5%), p < 0.01.

CONCLUSION

A positive FAST performed in the prehospital setting is associated with severe hemorrhage and all prognostic criteria we studied.

The reports of my death are greatly exaggerated: An evaluation of futility cut points in massive transfusion

BACKGROUND

Following COVID and the subsequent blood shortage, several investigators evaluated futility cut points in massive transfusion. We hypothesized that early aggressive use of damage-control resuscitation, including whole blood (WB), would demonstrate that these cut points of futility were significantly underestimating potential survival among patients receiving >50 U of blood in the first 4 hours.

METHODS

Adult trauma patients admitted from November 2017 to October 2021 who received emergency-release blood products in prehospital or emergency department setting were included. Deaths within 30 minutes of arrival were excluded. Total blood products were defined as total red blood cell, plasma, and WB in the field and in the first 4 hours after arrival. Patients were first divided into those receiving ≤50 or >50 U of blood in the first 4 hours. We then evaluated patients by whether they received any WB or received only component therapy. Thirty-day survival was evaluated for all included patients.

RESULTS

A total of 2,299 patients met the inclusion criteria (2,043 in ≤50 U, 256 in >50 U groups). While there were no differences in age or sex, the >50 U group was more likely to sustain penetrating injury (47% vs. 30%, p < 0.05). Patients receiving >50 U of blood had lower field and arrival blood pressure and larger prehospital and emergency department resuscitation volumes ( p < 0.05). Patients in the >50 U group had lower survival than those in the ≤50 cohort (31% vs. 79%; p < 0.05). Patients who received WB (n = 1,291) had 43% increased odds of survival compared with those who received only component therapy (n = 1,008) (1.09-1.87, p = 0.009) and higher 30-day survival at transfusion volumes >50 U.

CONCLUSION

Patient survival rates in patients receiving >50 U of blood in the first 4 hours of care are as high as 50% to 60%, with survival still at 15% to 25% after 100 U. While responsible blood stewardship is critical, futility should not be declared based on high transfusion volumes alone.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

[Trauma team activation-Who should be alerted for which patients?]

INTRODUCTION

It is estimated that in total almost 10 million people are injured in accidents in Germany every year, most of which are in the household milieu and leisure sector. It is estimated that of these more than 32,000 seriously injured patients are admitted to the emergency room every year. It is recommended that the decision of the prehospital treatment team or the first examiner in the hospital as to whether a potentially severely injured patient should be admitted via the emergency room of the hospital should be based on a catalogue of criteria.

MATERIAL AND METHOD

Against the background of the update of the S3 guidelines on the treatment of multiple trauma/severely injured patients and on the basis of the current literature, an overview with respect to the composition of the team and the criteria for which an emergency room team is or should be activated is given.

RESULTS

Alerting the emergency room team is still recommended if a certain injury pattern is present or if a prehospital intervention is necessary. The B‑criteria based on the course of the accident or mechanism, which have recently been the subject of increasing criticism, have been adapted. Recommendations for geriatric patients could also be formulated.

DISCUSSION

Compared to the S3 guidelines from 2016 the emergency room alarm criteria could be revised on the basis of new literature and have been included in the revised guidelines. There is no doubt that further optimization. e.g., based on prehospital algorithms or using point of care diagnostics, are possible and desirable in the future.

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.

Prehospital Ultrasound: A Narrative Review

Background: Point-of-care ultrasound is rapidly becoming more prevalent in the prehospital environment. Though considered a relatively new intervention in this setting, there is growing literature that aims to explore the use of prehospital ultrasound by EMS personnel.Methods: To better understand and report the state of the science on prehospital ultrasound, we conducted a narrative review of the literature.Results: Following a keyword search of MEDLINE in Ovid from inception to August 2, 2022, 2,564 records were identified and screened. Based on review of abstracts and full texts, with addition of seven articles via bibliography review, 193 records were included. Many included studies detail usage in air medical and other critical care transport environments. Clinicians performing prehospital ultrasound are often physicians or other advanced practice personnel who have previous ultrasound experience, which facilitates implementation in the prehospital setting. Emerging literature details training programs for prehospital personnel who are novices to ultrasound, and implementation for some study types appears feasible without prior experience. Unique use scenarios that show promise include during critical care transport, for triage in austere settings, and for thoracic evaluation of patients at risk of life-threatening pathology.Conclusion: There is a growing mostly observational body of literature describing the use of ultrasound by prehospital personnel. Prehospital ultrasound has demonstrated feasibility for specific conditions, yet interventional studies evaluating benefit to patient outcomes are absent.

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.

Prehospital Hemorrhage Assessment Criteria: A Concise Review

OBJECTIVE

Early assessment of the clinical status of trauma patients is crucial for guiding the treatment strategy, and it requires a rapid and systematic approach. The aim of this report is to critically review the assessment parameters currently used in the prehospital setting to quantify blood loss in trauma.

DATA SOURCES

Studies regarding hemorrhagic shock in trauma were pooled from PubMed, EMBASE, and Cochrane databases using key words such as "hemorrhagic shock," "vital signs evaluation," "trauma," "blood loss," and "emergency medical service," alone or combined.

STUDY SELECTION

Articles published since 2009 in English and Italian were considered eligible if containing data on assessment parameters in blood loss in adults.

DATA EXTRACTION

Sixteen articles matching the inclusion criteria were considered in our study.

DATA SYNTHESIS

Current prehospital assessment measures lack precise correlation with blood loss.

CONCLUSIONS

Traditional assessment parameters such as heart rate, systolic blood pressure, shock index, and Glasgow Coma Scale score often lag in providing accurate blood loss assessment. The current literature supports the need for a noninvasive, continuously monitored assessment parameter to identify early shock in the prehospital setting.