Validation of the BATT score for prehospital risk stratification of traumatic haemorrhagic death: usefulness for tranexamic acid treatment criteria

Evaluation of the prehospital administration of tranexamic acid for injured patients: a state-wide observational study with sex and age-disaggregated analysis

BACKGROUND

Tranexamic acid (TXA) decreases mortality in injured patients and should be administered as soon as possible. Despite international guidelines recommending TXA in the prehospital setting, its use remains low. The aim of this study was to assess the prehospital administration of TXA for injured patients in a Swiss region.

METHODS

We conducted a retrospective observational study in Switzerland between 2018 and 2021. Inclusion criteria were injured patients ≥18 years for whom an ambulance or helicopter was dispatched. The exclusion criterion was minor injury defined by a National Advisory Committee for Aeronautics score <3. The primary outcome was the proportion of patients treated with TXA according to guidelines. The European guidelines were represented by the risk of death from bleeding (calculated retrospectively using the Bleeding Audit for Trauma and Triage (BATT) score). Factors impacting the likelihood of receiving TXA were assessed by multivariate analysis.

RESULTS

Of 13 944 patients included in the study, 2401 (17.2%) were considered at risk of death from bleeding. Among these, 257 (11%) received prehospital TXA. This represented 38% of those meeting US guidelines. For European guidelines, the treatment rate increased with the risk of death from bleeding: 6% (95% CI 4.4% to 7.0%) for low risk (BATT score 3-4); 13% (95% CI 11.1% to 15.9%) for intermediate risk (BATT score 5-7); and 21% (95% CI 17.6% to 25.6%) for high risk (BATT score ≥8) (p<0.01). Women and the elderly were treated less often than men and younger patients, irrespective of the risk of death from bleeding and the mechanism of injury.

CONCLUSION

The proportion of injured patients receiving TXA in the prehospital setting of the State of Vaud in Switzerland was low, with even lower rates for women and older patients. The reasons for this undertreatment are probably multifactorial and would require specific studies to clarify and correct them.

The predictive value of four traumatic hemorrhage scores for early massive blood transfusion in trauma patients in the pre-hospital setting

OBJECTIVES

We aimed to explore the predictive value of four traumatic hemorrhage scores for early massive blood transfusion in trauma patients in the pre-hospital setting.

METHODS

Trauma patients admitted to Shenzhen University General Hospital from July 2018 to December 2022 were included in this study. They were divided into the massive transfusion group and the non-massive transfusion group according to the blood transfusion volume within 24 h. Basic information about patients was collected. Glasgow Coma Scale (GCS), focused assessment with sonography for trauma (FAST), and injury severity score (ISS) were performed. The receiving operating characteristic (ROC) curve was used to compare the predictive value of four trauma transfusion scores for early massive blood transfusion in the pre-hospital setting.

RESULTS

A total of 475 patients were enrolled, 43 received massive blood transfusions and 29 died within 24 h. The sensitivity and specificity of the four trauma hemorrhage scores in predicting the need for massive blood transfusions in trauma patients at their recommended cutoff points were all high. Among the four scores, the area under the ROC curve was larger for the assessment of blood consumption (ABC) score (0.864) and smaller for the trauma-induced coagulopathy clinical score (TICCS) score (0.795, p > 0.05).

CONCLUSIONS

All four pre-hospital trauma hemorrhage scores have a high predictive value in assessing massive blood transfusion in trauma patients.

The use of whole body computed tomography does not lead to increased 24-h mortality in severely injured patients in circulatory shock

The Advanced Trauma Life Support (ATLS) approach is generally accepted as the standard of care for the initial management of severely injured patients. While whole body computed tomography (WBCT) is still considered a contraindication in haemodynamically unstable trauma patients, there is a growing amount of data indicating the absence of harm from cross sectional imaging in this patient group. Our study aimed to compare the early mortality of unstable trauma patients undergoing a WBCT during the initial workup with those who did not. Single-center retrospective observational study based on the local trauma registry including 3525 patients with an ISS > 15 from January 2008 to June 2020. We compared the 24-h mortality of injured patients in circulatory shock undergoing WBCT with a control group undergoing standard workup only. Inclusion criteria were the simultaneous presence of a systolic blood pressure < 100 mmHg, lactate > 2.2 mmol/l and base excess < - 2 mmol/l as surrogate markers for circulatory shock. To control for confounding, a propensity score matched analysis with conditional logistic regression for adjustment of residual confounders and a sensitivity analysis using inverse probability weighting (IPW) with and without adjustment were performed. Of the 3525 patients, 161 (4.6%) fulfilled all inclusion criteria. Of these, 132 (82%) underwent WBCT and 29 (18%) standard work-up only. In crude and matched analyses, no difference in early (24 h) mortality was observed (WBCT, 23 (17.4%) and no-WBCT, 8 (27.6%); p = 0.21). After matching and adjustment for main confounders, the odds ratio for the event of death at 24 h in the WBCT group was 0.36 (95% CI 0.07-1.73); p = 0.20. In the present study, WBCT did not increase the risk of death at 24 h among injured patients in shock. This adds to the growing data indicating that WBCT may be offered to trauma patients in circulatory shock without jeopardizing early survival.

Nationwide analysis of prehospital tranexamic acid for trauma demonstrates systematic bias in adherence to treatment guidelines: a retrospective cohort study

BACKGROUND

Prehospital (PH) tranexamic acid (TXA) improves survival from trauma haemorrhage. Injury mechanism, physiology, and sex demographics vary with patient age. The authors hypothesised that these factors influence TXA guideline compliance and examined national trends in PH use to identify any systematic biases in bleeding management.

MATERIALS AND METHODS

The UK Trauma Audit and Research Network data for TXA eligible patients admitted to major trauma centres were divided into two cohorts: 2013-2015 ( n =32 072) and 2017-2019 ( n =14 974). Patients were stratified by PH, emergency department or no TXA use. Logistic regression models explored interaction between PH variables and TXA administration. Results are presented as odds ratios with a 95% CI.

RESULTS

PH TXA use increased from 8% to 27% over time ( P <0.001). Only 3% of eligible patients who fell less than 2 m received PH TXA versus 63% with penetrating injuries ( P <0.001). Older patients eligible for PH TXA were less likely to receive it compared to younger patients [≥65 years old: 590 (13%) vs. <65 years old: 3361 (33%), P <0.001]. There was a significant interaction between age and sex with fewer older women receiving PH TXA. In shocked patients, one third of females compared to a fifth of men did not receive TXA ( P <0.001). There was a decrease in PH TXA use as age increased ( P <0.001).

CONCLUSIONS

Despite a threefold increase in use, treatment guidance for PH TXA is not universally applied. Older people, women, and patients with low energy injury mechanisms appear to be systematically under treated. Training and education for PH providers should address these potential treatment biases.

Explainable Prediction Model of the Need for Emergency Hemostasis Using Field Information During Physician-Staffed Helicopter Emergency Medical Service Interventions: A Single-Center, Retrospective, Observational Pilot Study

OBJECTIVE

Early recognition of hemostasis is important to prevent trauma-related deaths. We conducted a pilot study of a predictive model of hemostatic need using factors that can be collected during helicopter emergency medical service (HEMS) interventions until transport hospital selection using cases from our institution.

METHODS

This single-center, retrospective, observational pilot study included 251 trauma patients aged ≥ 18 years treated with HEMS between April 2017 and March 2022, in Nara Medical University. Cardiac arrest and pre-HEMS treatment patients were excluded. Emergency hemostatic surgery prediction models were constructed using the light gradient boosting machine cross-validation method using objective data that could be collected before hospital determination. The accuracy of this model was compared with that of the ground emergency medical service-based model, and factors influencing outcome were visualized using Shapley additive explanations.

RESULTS

The predictive accuracy of the model with HEMS intervention factors was an area under the receiver operating characteristic curve of 0.80, superior to the 0.73 accuracy area under the receiver operating characteristic curve for ground emergency medical services constructed with contact information. Clinically important factors, such as shock index, blood pressure changes, and ultrasound findings, had a significant impact on outcomes, with nonmonotonic effects observed across factors.

CONCLUSION

This pilot study suggests that predictive models of emergency hemostasis can be built using limited prehospital information. To validate this model, a larger, multicenter study is recommended.

Factors that influence the administration of tranexamic acid (TXA) to trauma patients in prehospital settings: a systematic review

OBJECTIVE

In the UK there are around 5400 deaths annually from injury. Tranexamic acid (TXA) prevents bleeding and has been shown to reduce trauma mortality. However, only 5% of UK major trauma patients who are at risk of haemorrhage receive prehospital TXA. This review aims to examine the evidence regarding factors influencing the prehospital administration of TXA to trauma patients.

DESIGN

Systematic literature review.

DATA SOURCES

AMED, CENTRAL, CINAHL, Cochrane Database of Systematic Reviews, Conference Proceedings Citation Index-Science, Embase and MEDLINE were searched from January 2010 to 2020; searches were updated in June 2022.

CLINICALTRIALS

gov and OpenGrey were also searched and forward and backwards citation chasing performed.

ELIGIBILITY CRITERIA

All primary research reporting factors influencing TXA administration to trauma patients in the prehospital setting was included.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers performed the selection process, quality assessment and data extraction. Data were tabulated, grouped by setting and influencing factor and synthesised narratively.

RESULTS

Twenty papers (278 249 participants in total) were included in the final synthesis; 13 papers from civilian and 7 from military settings. Thirteen studies were rated as 'moderate' using the Effective Public Health Practice Project Quality Assessment Tool. Several common factors were identified: knowledge and skills; consequences and social influences; injury type (severity, injury site and mechanism); protocols; resources; priorities; patient age; patient sex.

CONCLUSIONS

This review highlights an absence of high-quality research. Preliminary evidence suggests a host of system and individual-level factors that may be important in determining whether TXA is administered to trauma patients in the prehospital setting.

FUNDING AND REGISTRATION

This review was supported by Research Capability Funding from the South Western Ambulance Service NHS Foundation Trust and the National Institute for Health Research Applied Research Collaboration South West Peninsula.

PROSPERO REGISTRATION NUMBER

CRD42020162943.

Early identification of bleeding in trauma patients: external validation of traumatic bleeding scores in the Swiss Trauma Registry

BACKGROUND

Early identification of bleeding at the scene of an injury is important for triage and timely treatment of injured patients and transport to an appropriate facility. The aim of the study is to compare the performance of different bleeding scores.

METHODS

We examined data from the Swiss Trauma Registry for the years 2015-2019. The Swiss Trauma Registry includes patients with major trauma (injury severity score (ISS) ≥ 16 and/or abbreviated injury scale (AIS) head ≥ 3) admitted to any level-one trauma centre in Switzerland. We evaluated ABC, TASH and Shock index (SI) scores, used to predict massive transfusion (MT) and the BATT score and used to predict death from bleeding. We evaluated the scores when used prehospital and in-hospital in terms of discrimination (C-Statistic) and calibration (calibration slope). The outcomes were early death within 24 h and the receipt of massive transfusion (≥ 10 Red Blood cells (RBC) units in the first 24 h or ≥ 3 RBC units in the first hour).

RESULTS

We examined data from 13,222 major trauma patients. There were 1,533 (12%) deaths from any cause, 530 (4%) early deaths within 24 h, and 523 (4%) patients who received a MT (≥ 3 RBC within the first hour). In the prehospital setting, the BATT score had the highest discrimination for early death (C-statistic: 0.86, 95% CI 0.84-0.87) compared to the ABC score (0.63, 95% CI 0.60-0.65) and SI (0.53, 95% CI 0.50-0.56), P < 0.001. At hospital admission, the TASH score had the highest discrimination for MT (0.80, 95% CI 0.78-0.82). The positive likelihood ratio for early death were superior to 5 for BATT, ABC and TASH. The negative likelihood ratio for early death was below 0.1 only for the BATT score.

CONCLUSIONS

The BATT score accurately estimates the risk of early death with excellent performance, low undertriage, and can be used for prehospital treatment decision-making. Scores predicting MT presented a high undertriage rate. The outcome MT seems not appropriate to stratify the risk of life-threatening bleeding.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT04561050 . Registered 15 September 2020.

Effects of tranexamic acid treatment in severely and non-severely injured trauma patients

BACKGROUND

Urgent treatment with tranexamic acid (TXA) reduces bleeding deaths but there is disagreement about which patients should be treated. We examine the effects of TXA treatment in severely and non-severely injured trauma patients.

STUDY DESIGN AND METHODS

We did an individual patient data meta-analysis of randomized trials with over 1000 trauma patients that assessed the effects of TXA on survival. We defined the severity of injury according to characteristics at first assessment: systolic blood pressure of less than 90 mm Hg and a heart rate greater than 120 beats per minute or Glasgow Coma Scale score of less than nine or any GCS with one or more fixed dilated pupils. The primary measure was survival on the day of the injury. We examined the effect of TXA on survival in severely and non-severely injured patients and how these effects vary with the time from injury to treatment.

RESULTS

We obtained data for 32,944 patients from two randomized trials. Tranexamic acid significantly increased survival on the day of the injury (OR = 1.22, 95% CI 1.11-1.34; p < .01). The effect of tranexamic acid on survival in non-severely injured patients (OR = 1.25, 1.03-1.50) was similar to that in severely injured patients (OR = 1.22, 1.09-1.37) with no significant heterogeneity (p = .87). In severely and non-severely injured pateints, treatment within the first hour after injury was the most effective.

DISCUSSION

Early tranexamic acid treatment improves survival in both severely and non-severely injured trauma patients. Its use should not be restricted to the severely injured.

Use of tranexamic acid in major trauma: a sex-disaggregated analysis of the Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH-2 and CRASH-3) trials and UK trauma registry (Trauma and Audit Research Network) data

BACKGROUND

Women are less likely than men to receive some emergency treatments. This study examines whether the effect of tranexamic acid (TXA) on mortality in trauma patients varies by sex and whether the receipt of TXA by trauma patients varies by sex.

METHODS

First, we conducted a sex-disaggregated analysis of data from the Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH)-2 and CRASH-3 trials. We used interaction tests to determine whether the treatment effect varied by sex. Second, we examined data from the Trauma and Audit Research Network (TARN) to explore sex differences in the receipt of TXA. We used logistic regression models to estimate the odds ratio for receipt of TXA in females compared with males. Results are reported as n (%), risk ratios (RR), and odds ratios (OR) with 95% confidence intervals.

RESULTS

Overall, 20 211 polytrauma patients (CRASH-2) and 12 737 patients with traumatic brain injuries (CRASH-3) were included in our analysis. TXA reduced the risk of death in females (RR=0.69 [0.52-0.91]) and in males (RR=0.80 [0.71-0.90]) with no significant heterogeneity by sex (P=0.34). We examined TARN data for 216 364 patients aged ≥16 yr with an Injury Severity Score ≥9 with 98 879 (46%) females and 117 485 (54%) males. TXA was received by 7198 (7.3% [7.1-7.4%]) of the females and 19 697 (16.8% [16.6-17.0%]) of the males (OR=0.39 [0.38-0.40]). The sex difference in the receipt of TXA increased with increasing age.

CONCLUSIONS

Administration of TXA to patients with bleeding trauma reduces mortality to a similar extent in women and men, but women are substantially less likely to be treated with TXA.

Sex discrimination after injury: is inequity in tranexamic acid administration just the tip of the iceberg?

There is emerging evidence of inequalities in healthcare provision between women and men. Trauma care is no exception with a number of studies indicating lower levels of prioritisation for injured female patients. The antifibrinolytic drug tranexamic acid, reduced trauma deaths to a similar extent in females and males in the international Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH) randomised controlled trials, but in real-world practice, national registry data shows females are less likely to receive tranexamic acid than males. Inequity in the provision of tranexamic acid may extend beyond sex (and gender), and further study is required to examine the effect of age and mechanism of injury differences between men and women in the decision to treat.

Barriers and facilitators to the administration of prehospital tranexamic acid: a paramedic interview study using the theoretical domains framework

BACKGROUND

Tranexamic acid (TXA) is an antifibrinolytic drug used to prevent bleeding. It was introduced as an intervention for post-traumatic haemorrhage across emergency medical services (EMS) in the UK during 2012. However, despite strong evidence of effectiveness, prehospital TXA administration rates are low. This study used the theoretical domains framework (TDF) to identify barriers and facilitators to the administration of TXA to trauma patients by EMS providers (paramedics) in the UK.

METHODS

Interviews were completed with 18 UK paramedics from a single EMS provider organisation. A convenience sampling approach was used, and interviews continued until thematic saturation was reached. Semistructured telephone interviews explored paramedics' experiences of administering TXA to trauma patients, including identifying whether or not patients were at risk of bleeding. Data were analysed inductively using thematic analysis (stage 1). Themes were mapped to the theoretical domains of the TDF to identify behavioural theory-derived barriers and facilitators to the administration of TXA to trauma patients (stage 2). Belief statements were identified and assessed for importance according to prevalence, discordance and evidence base (stage 3).

RESULTS

Barriers and facilitators to paramedics' administration of TXA to trauma patients were represented by 11 of the 14 domains of the TDF. Important barriers included a lack of knowledge and experience with TXA (Domain: Knowledge and Skills), confusion and restrictions relating to the guidelines for TXA administration (Domain: Social/professional role and identity), a lack of resources (Domain: Environmental context and resources) and difficulty in identifying patients at risk of bleeding (Domain: Memory, attention and decision processes).

CONCLUSIONS

This study presents a behavioural theory-based approach to identifying barriers and facilitators to the prehospital administration of TXA to trauma patients in the UK. It identifies multiple influencing factors that may serve as a basis for developing an intervention to increase prehospital administration of TXA.