Publications

BACKGROUND: Prehospital blood transfusion is increasingly recognized as an important early resuscitation intervention for patients with hemorrhagic shock. However, comprehensive evaluations of such programs have been limited by heterogeneity in data collection, outcome definitions, and reporting methodologies. This impedes effective benchmarking, quality improvement initiatives, research efforts, and the creation of protocols and policies. The Standardized Emergency Medical Service (EMS) Metrics for Survival in Transfusion and Advanced Resuscitation (SEMSTAR) project sought to develop consensus-driven data elements and standardized outcome definitions to facilitate consistent reporting of prehospital blood transfusion programs.

METHODS: Initial data metrics were identified through a literature review and surveyed across US EMS systems that perform prehospital transfusions. A modified Delphi methodology was then used by a multidisciplinary panel of 28 subject-matter experts in EMS, trauma surgery, transfusion medicine, and resuscitation science. Predefined thresholds analyzed metric inclusion, classification as either core or expanded elements, and endorsement of standardized outcome definitions.

RESULTS: 89 EMS systems completed the initial survey of 208 potential data elements. Of these, 193 (93%) advanced to expert review. Experts reached consensus on 168 data elements: 86 core metrics for universal reporting and 82 expanded metrics for comprehensive analysis. Consensus was also achieved on standardized definitions for hemorrhagic circulatory collapse, including stratification by pretransfusion circulatory collapse status and survival after prehospital transfusion. Wherever possible, the resulting framework draws from existing data infrastructure, including the National Emergency Medical Services Information System and trauma registry variables.

CONCLUSION: SEMSTAR establishes the first national, consensus-driven framework for standardized data collection and outcome reporting among prehospital blood transfusion programs. By defining core and expanded metrics with standardized survival definitions, this framework enables benchmarking, quality improvement, and multicenter research across diverse EMS systems. SEMSTAR adoption will enable rigorous program evaluation and support the development of a national registry to advance evidence-based care for patients with hemorrhagic shock.

LEVEL OF EVIDENCE: IV.

BACKGROUND: Blood transfusion and hemorrhage control procedures can be unreliable surrogates for bleeding requiring intervention in children. Some receive unnecessary blood transfusions or lack intraoperative findings for hemorrhage, while others die before an intervention occurs. Standardized criteria for adjudicating the presence of actionable hemorrhage are needed. We aimed to define expert consensus criteria for retrospectively identifying actionable hemorrhage within 6 hours of emergency department (ED) arrival.

METHODS: Experts from six specialties involved in pediatric trauma care participated in a modified Delphi study. Panelists were prompted to consider "actionable hemorrhage" as "severe bleeding or injuries at risk of progression to class III or IV shock without prompt intervention." In Round 1, panelists answered five free-response questions identifying criteria for actionable hemorrhage, including indicators for transfusion and hemorrhage control procedures, postmortem findings, and other relevant factors. Responses were consolidated and rated on a five-point strength-of-indication scale in subsequent rounds. Consensus was defined a priori as ≥70% agreement among panelists. Stability of consensus (p>0.05) between rounds was assessed using the Wilcoxon Signed-Rank Test.

RESULTS: Three Delphi rounds were required to achieve a stable consensus. Twenty-nine of 32 participating panelists participated in all three rounds. Thirteen statements achieved stable consensus as strong indicators of actionable hemorrhage. Criteria with the highest agreement included partial/total resection of intrathoracic/abdominal bleeding solid organs (96.4%), hemoglobin<6 g/dL (93.1%), and resuscitative thoracotomy/sternotomy with hilar or thoracic/abdominal aortic cross-clamp, cardiac massage, or cardiorrhaphy (92.9%). No statements reached a stable consensus as weak indicators of actionable hemorrhage.

CONCLUSIONS: We established expert consensus criteria for adjudication of actionable hemorrhage in injured children within 6 hours of ED arrival. These criteria reflect strong indicators that an intervention or death was due to an actionable hemorrhage. Prospective validation of these criteria is needed. (J Trauma Acute Care Surg. 2026;00:00-00. Copyright © 2026 Wolters Kluwer Health, Inc. All rights reserved.).

LEVEL OF EVIDENCE: Diagnostic Test/Criteria; Level III.

IMPORTANCE: Tranexamic acid (TXA) is associated with improved survival following trauma in prior prehospital trials, shaping clinical practice. The Study of Tranexamic Acid During Air and Ground Medical Prehospital Transport (STAAMP) trial did not find a difference in mortality between TXA and placebo. A bayesian approach that incorporates prior clinical evidence may better characterize the impact of TXA.

OBJECTIVE: To evaluate the probability of mortality benefit associated with prehospital TXA in trauma.

DESIGN, SETTING, AND PARTICIPANTS: This quality improvement study used a post hoc bayesian analysis of data from the STAAMP trial, a prospective, multicenter, double-masked, placebo-controlled, phase 3 randomized clinical trial conducted at level I trauma centers in the US from May 1, 2015, to October 31, 2019. Patients at risk for hemorrhage within approximately 2 hours of injury were randomized to receive prehospital TXA or placebo. The data analysis was performed between January 1, 2024, and December 31, 2025.

MAIN OUTCOMES AND MEASURES: The primary outcome was 30-day mortality assessed using frequentist statistics. Bayesian hierarchical logistic regression models were built to estimate the posterior probability of mortality associated with TXA. The prior distributions were informed by Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage 2 (CRASH-2) and Prehospital Antifibrinolytics for Traumatic Coagulopathy and Hemorrhage (PATCH-Trauma) trial data, and the influence of prior selection, sample size, and varying risk thresholds was also evaluated.

RESULTS: Of 903 STAAMP patients analyzed (median [IQR] age, 39 [26-55] years; 668 male [74.0%]), 447 received TXA and 456 received placebo. The majority of patients (n = 760 [84.2%]) sustained blunt injuries, with a median injury severity score of 12 (IQR, 5-22). In the frequentist analysis, the 30-day mortality rates were 8.1% and 9.9% for the TXA and placebo groups, respectively (hazard ratio, 0.81; 95% CI, 0.59-1.11). Using bayesian models, the estimated posterior risk ratios were 0.91 (95% credible interval [CrI], 0.85-0.97) with a CRASH-2 prior, 0.80 (95% CrI, 0.65-0.97) with a PATCH-Trauma prior, and 0.82 (95% CrI, 0.52-1.23) under a noninformative prior. The results were robust across confounders, site clustering, and alternative priors. The posterior probability that TXA reduced mortality ranged from 84% to 99%.

CONCLUSIONS AND RELEVANCE: This quality improvement study using a post hoc bayesian reanalysis of the STAAMP trial suggested a high probability that prehospital TXA would improve survival. Bayesian methods may offer refined inference and support clinical decision-making in prehospital trauma care.

BACKGROUND: Both whole blood (WB) and component therapy (CT) are used for hemostatic resuscitation in injured children. We hypothesize that early WB transfusion compared to CT alone is associated with decreased post-traumatic organ dysfunction.

STUDY DESIGN AND METHODS: This single-center observational study included children ages 0-17 years between January 2021 and March 2024 with trauma mechanism and intensive care unit admission. The primary outcome was Pediatric Logistic Organ Dysfunction 2 (PELOD-2) score on post-trauma days 1-7. Data were analyzed using linear regression adjusting for age, sex, race, year, injury mechanism, injury severity score (ISS), shock index pediatric age-adjusted, and total 4-h transfusion volume (mL/kg).

RESULTS: In total, 540 subjects met eligibility criteria; of the 52/540 (10%) who received blood transfusion within 4 h, 11/52 (21%) received RBC alone, 12/52 (23%) received WB alone, 9/52 (17%) of subjects received RBC plus other, and 20/52 (38%) received WB plus other. The cohort was 60% (326/540) male, 83% (449/540) blunt injury mechanism, median (interquartile range [IQR]) age 3 years (0-11), and median (IQR) ISS of 11 (8-18). In adjusted analysis, transfusion of WB + other was an independent predictor of lower PELOD-2 score through post-trauma day 7 in comparison to subjects receiving RBC + other.

DISCUSSION: In subjects who were transfused multiple blood products, receipt of any WB versus CT alone for hemostatic resuscitation after injury was associated with reduced organ dysfunction. Further investigation is needed in large cohorts to fully elucidate clinical benefit and improve mechanistic understanding.

BACKGROUND: Whole blood (WB) is a preferred resuscitation strategy, yet how storage affects hemostasis remains unclear. Prior studies have shown decreased fibrinogen function during storage; however, these were limited by incomplete removal of platelet contributions. Additionally, leukoreduced (LR) versus non-leukoreduced (NLR) status in preserving fibrinogen remains unknown.

STUDY METHODS: WB units (n = 15, 7 NLR, 8 nLR) were evaluated at serial time points through day 35. ROTEM EXTEM was performed. Platelet-poor plasma (PPP) from WB at day 0, day 21, and day 35 underwent western blot for fibrinogen. Functional fibrinogen was measured using the Clauss assay after freeze-thaw cycles of WB PPP to minimize platelet contribution.

RESULTS: As WB aged, there was a progressive decrease in alpha angle and maximum clot firmness. Platelet count dropped sharply by day 7. Western blot demonstrated no evidence of fibrinogen degradation in either LR or NLR WB. Clauss fibrinogen concentrations were unchanged from day 0 to day 35, with a modest non-significant decline by day 35 driven primarily by NLR units.

DISCUSSION: Fibrinogen did not undergo detectable proteolysis during storage of WB and had preserved function through day 35 after freeze-thaw cycles to minimize platelet contributions. NLR appeared to impact fibrinogen function with medians below 200 for day 21 and 35 but was not statistically significant. This suggests that previously reported reductions in fibrinogen function may be based on leukoreduction status, but that early changes in fibrinolysis sensitivity are more likely due to residual platelet contributions to the assays rather than loss of fibrinogen function itself.