Elucidating the clinical characteristics of patients captured using different definitions of massive transfusion

Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management: Management of critical bleeding

The management of major bleeding is a critical aspect of modern healthcare and it is imperative to emphasize the importance of applying Patient Blood Management (PBM) principles. Although transfusion support remains a vital component of bleeding control, treating severe bleeding goes beyond simply replacing lost blood. A more comprehensive, multidisciplinary approach is essential to optimize patient outcomes and minimize the risks associated with excessive transfusions.

Patient blood management guideline for adults with critical bleeding

INTRODUCTION

The management of patients with critical bleeding requires a multidisciplinary approach to achieve haemostasis, optimise physiology, and guide blood component use. The 2011 Patient blood management guidelines: module 1 - critical bleeding/massive transfusion were updated and published. Systematic reviews were conducted for pre-specified research questions, and recommendations were based on meta-analyses of included studies.

MAIN RECOMMENDATIONS

The critical bleeding/massive transfusion guideline includes seven recommendations and 11 good practice statements addressing: major haemorrhage protocols (MHPs) facilitating a multidisciplinary approach to haemorrhage control, correction of coagulopathy and normalisation of physiological derangement; measurement of physiological, biochemical and metabolic parameters in critical bleeding/massive transfusion; the optimal ratio of red blood cells to other blood components; the use of tranexamic acid; viscoelastic haemostatic assays; and cell salvage.

CHANGES IN MANAGEMENT AS A RESULT OF THE GUIDELINE

The new guideline recommends MHPs be established as standard of care in all institutions managing patients with critical bleeding. In addition to routine physiological markers, the new guideline recommends temperature, biochemistry and coagulation profiles be measured early and frequently, providing parameters that define critical derangements. Ratio-based MHPs should include no fewer than four units of fresh frozen plasma and one adult unit of platelets for every eight units of red blood cells. In the setting of trauma and obstetric haemorrhage, administration of tranexamic acid within three hours of bleeding onset is recommended. The use of recombinant activated factor VII (rFVIIa) is not recommended. There was insufficient evidence to make recommendations on the use of viscoelastic haemostatic assays or cell salvage as part of MHPs.

Prediction of intraoperative red blood cell transfusion in valve replacement surgery: machine learning algorithm development based on non-anemic cohort

Background

Our study aimed to develop machine learning algorithms capable of predicting red blood cell (RBC) transfusion during valve replacement surgery based on a preoperative dataset of the non-anemic cohort.

Methods

A total of 423 patients who underwent valvular replacement surgery from January 2015 to December 2020 were enrolled. A comprehensive database that incorporated demographic characteristics, clinical conditions, and results of preoperative biochemistry tests was used for establishing the models. A range of machine learning algorithms were employed, including decision tree, random forest, extreme gradient boosting (XGBoost), categorical boosting (CatBoost), support vector classifier and logistic regression (LR). Subsequently, the area under the receiver operating characteristic curve (AUC), accuracy, recall, precision, and F1 score were used to determine the predictive capability of the algorithms. Furthermore, we utilized SHapley Additive exPlanation (SHAP) values to explain the optimal prediction model.

Results

The enrolled patients were randomly divided into training set and testing set according to the 8:2 ratio. There were 16 important features identified by Sequential Backward Selection for model establishment. The top 5 most influential features in the RF importance matrix plot were hematocrit, hemoglobin, ALT, fibrinogen, and ferritin. The optimal prediction model was CatBoost algorithm, exhibiting the highest AUC (0.752, 95% CI: 0.662-0.780), which also got relatively high F1 score (0.695). The CatBoost algorithm also showed superior performance over the LR model with the AUC (0.666, 95% CI: 0.534-0.697). The SHAP summary plot and the SHAP dependence plot were used to visually illustrate the positive or negative effects of the selected features attributed to the CatBoost model.

Conclusions

This study established a series of prediction models to enhance risk assessment of intraoperative RBC transfusion during valve replacement in no-anemic patients. The identified important predictors may provide effective preoperative interventions.

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.

The nature and timing of coagulation dysfunction in a cohort of trauma patients in the Australian pre-hospital setting

BACKGROUND

Acute Traumatic Coagulopathy (ATC) is a complex pathological process that is associated with patient mortality and increased blood transfusion requirements. It is evident on hospital arrival, but there is a paucity of information about the nature of ATC and the characteristics of patients that develop ATC in the pre-hospital setting. The objective of this study was to describe the nature and timing of coagulation dysfunction in a cohort of injured patients and to report on patient and pre-hospital factors associated with the development of ATC in the field.

METHODS

This was a prospective observational study of a convenience sample of trauma patients. Patients had blood taken during the pre-hospital phase of care and evaluated for derangements in Conventional Coagulation Assays (CCA) and Rotational Thromboelastometry (ROTEM). Associations between coagulation derangement and pre-hospital factors and patient outcomes were evaluated.

RESULTS

A total of 216 patients who had either a complete CCA or ROTEM were included in the analysis. One hundred and eighty (83 %) of patients were male, with a median injury severity score of 17 [interquartile range (IQR) 10-27] and median age of 34 years [IQR = 25.0-52.0]. Hypofibrinogenemia was the predominant abnormality seen, (CCA Hypofibrinogenemia: 51/193, 26 %; ROTEM hypofibrinogenemia: 65/204, 32 %). Increased CCA derangement, the presence of ROTEM coagulopathy, worsening INR, worsening FibTEM and decreasing fibrinogen concentration, were all associated with both mortality and early massive transfusion.

CONCLUSION

Clinically significant, multifaceted coagulopathy develops early in the clinical course, with hypofibrinogenemia being the predominant coagulopathy. In keeping with the ED literature, pre-hospital coagulation dysfunction was associated with mortality and early massive transfusion. Further work is required to identify strategies to identify and guide the pre-hospital management of the coagulation dysfunction seen in trauma.

Seeking a Relevant Description of Major Trauma Bleeding: Comparison of Four Major Bleeding Definitions

BACKGROUND

The traditional definition of massive transfusion is 10 red blood cell units transfused within 24 hr. This definition has been faulted for excluding patients who die early from exsanguination. Alternative major bleeding definitions in the trauma literature include time-based (e.g., Resuscitation Intensity) and event based (e.g., Sharpe) transfusion thresholds.

OBJECTIVE

The study objective was to compare four definitions of major bleeding, including a modification to the Sharpe definition, on clinically relevant processes and outcomes.

METHODS

This is a retrospective cohort study of adult trauma patients admitted from the field to a Level I trauma center from 2014 to 2019. Data sources were the trauma registry, blood bank, and electronic medical records. Transfusion thresholds were defined as follows: Resuscitation Intensity-4 units of any combination of crystalloids, colloids, or blood products within the first 30 min of arrival; Sharpe-10 red blood cell units from trauma bay presentation to inpatient admission (a proxy for the interval of hemorrhage control); Modified Sharpe-10 units of any combination of blood products during the same interval. The study analysis consisted of descriptive statistics.

RESULTS

The cohort contained 187 subjects. Of 39 deaths, 28 (72%) occurred within 6 hr following arrival. Modified Sharpe captured 27 (96%) of these 28 subjects, whereas Resuscitation Intensity captured 20 (71%). Sharpe and the traditional definition each captured 22 subjects (79%). Modified Sharpe captured 17%-25% of deaths missed by the other definitions.

CONCLUSION

Modified Sharpe may optimally indicate major bleeding during trauma resuscitation.

Clinical decision support versus a paper-based protocol for massive transfusion: Impact on decision outcomes in a simulation study

BACKGROUND

Management of major hemorrhage frequently requires massive transfusion (MT) support, which should be delivered effectively and efficiently. We have previously developed a clinical decision support system (CDS) for MT using a multicenter multidisciplinary user-centered design study. Here we examine its impact when administering a MT.

STUDY DESIGN AND METHODS

We conducted a randomized simulation trial to compare a CDS for MT with a paper-based MT protocol for the management of simulated hemorrhage. A total of 44 specialist physicians, trainees (residents), and nurses were recruited across critical care to participate in two 20-min simulated bleeding scenarios. The primary outcome was the decision velocity (correct decisions per hour) and overall task completion. Secondary outcomes included cognitive workload and System Usability Scale (SUS).

RESULTS

There was a statistically significant increase in decision velocity for CDS-based management (mean 8.5 decisions per hour) compared to paper based (mean 6.9 decisions per hour; p .003, 95% CI 0.6-2.6). There was no significant difference in the overall task completion using CDS-based management (mean 13.3) compared to paper-based (mean 13.2; p .92, 95% CI -1.2-1.3). Cognitive workload was statistically significantly lower using the CDS compared to the paper protocol (mean 57.1 vs. mean 64.5, p .005, 95% CI 2.4-12.5). CDS usability was assessed as a SUS score of 82.5 (IQR 75-87.5).

DISCUSSION

Compared to paper-based management, CDS-based MT supports more time-efficient decision-making by users with limited CDS training and achieves similar overall task completion while reducing cognitive load. Clinical implementation will determine whether the benefits demonstrated translate to improved patient outcomes.

Definitions of massive transfusion in adults with critical bleeding: a systematic review

BACKGROUND

Definitions for massive transfusion (MT) vary widely between studies, contributing to challenges in interpretation of research findings and practice evaluation. In this first systematic review, we aimed to identify all MT definitions used in randomised controlled trials (RCTs) to date to inform the development of consensus definitions for MT.

METHODS

We systematically searched the following databases for RCTs from inception until 11 August 2022: MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Cumulative Index to Nursing and Allied Health Literature, and Transfusion Evidence Library. Ongoing trials were sought from CENTRAL, ClinicalTrials.gov, and World Health Organisation International Clinical Trials Registry Platform. To be eligible for inclusion, studies had to fulfil all the following three criteria: (1) be an RCT; (2) include an adult patient population with major bleeding who had received, or were anticipated to receive, an MT in any clinical setting; and (3) specify a definition for MT as an inclusion criterion or outcome measure.

RESULTS

Of the 8,458 distinct references identified, 30 trials were included for analysis (19 published, 11 ongoing). Trauma was the most common clinical setting in published trials, while for ongoing trials, it was obstetrics. A total of 15 different definitions of MT were identified across published and ongoing trials, varying greatly in cut-offs for volume transfused and time period. Almost all definitions specified the number of red blood cells (RBCs) within a set time period, with none including plasma, platelets or other haemostatic agents that are part of contemporary transfusion resuscitation. For completed trials, the most commonly used definition was transfusion of ≥ 10 RBC units in 24 h (9/19, all in trauma), while for ongoing trials it was 3-5 RBC units (n = 7), with the timing for transfusion being poorly defined, or in some trials not provided at all (n = 5).

CONCLUSIONS

Transfusion of ≥ 10 RBC units within 24 h was the most commonly used definition in published RCTs, while lower RBC volumes are being used in ongoing RCTs. Any consensus definitions should reflect the need to incorporate different blood components/products for MT and agree on whether a 'one-size-fits-all' approach should be used across different clinical settings.

Clinical presentation and in-hospital outcomes of intraoperative red blood cell transfusion in non-anemic patients undergoing elective valve replacement

Background

Intraoperative transfusion is associated with adverse clinical outcomes in cardiac surgery. However, few studies have shown the impact of intraoperative red blood cell (RBC) transfusion on non-anemic patients undergoing cardiac surgery. We assessed the in-hospital clinical outcomes of non-anemic patients undergoing isolated valve replacements and investigated the predictors associated with intraoperative RBC transfusion.

Methods

We enrolled 345 non-anemic patients undergoing isolated valve replacements in our department from January 2015 to December 2019. The patients were stratified by the receipt of intraoperative RBC transfusion. Baseline characteristics were compared between groups and multiple logistic regression was used to identify the predictors for intraoperative RBC transfusion. The association between intraoperative RBC transfusion and in-hospital outcomes was also evaluated.

Results

Intraoperative RBC transfusion developed in 84 of the 345 enrolled patients (24.3%). Three independent predictors for intraoperative RBC transfusion of non-anemic patients undergoing isolated valve replacements were identified by multivariate logistic analysis, including female, iron deficiency and hemoglobin level. When the two groups were compared, a significant tendency of higher in-hospital mortality (6.0% vs. 1.1%, P = 0.033) and higher incidence of postoperative hypoxemia (9.5% vs. 2.7%, P = 0.007) were observed in the intraoperative RBC transfusion group. After adjustment, the presence of intraoperative RBC transfusion was associated with an increase in postoperative hypoxemia (OR = 3.36, 95% CI: 1.16–9.71, P = 0.026).

Conclusion

Intraoperative RBC transfusion was associated with poorer clinical outcomes in non-anemic adults undergoing isolated valve replacements, which significantly increased the risk of postoperative hypoxemia. The independent predictors of intraoperative RBC transfusion, such as iron deficiency and female, were identified, which may be helpful for risk assessment and perioperative management.

Resuscitation Patterns and Massive Transfusion for the Critical Bleeding Dog-A Multicentric Retrospective Study of 69 Cases (2007-2013)

Objective: To describe resuscitation patterns of critically bleeding dogs, including those receiving massive transfusion (MT). Design: Retrospective study from three universities (2007-2013). Animals: Critically bleeding dogs, defined as dogs who received ≥ 25 ml/kg of blood products for treatment of hemorrhagic shock caused by blood loss. Measurements and Main Results: Sixty-nine dogs were included. Sources of critical bleeding were trauma (26.1%), intra/perioperative surgical period (26.1%), miscellaneous (24.6%), and spontaneous hemoabdomen (23.1%). Median (range) age was 7 years (0.5-18). Median body weight was 20 kg (2.6-57). Median pre-transfusion hematocrit, total protein, systolic blood pressure, and lactate were 25% (10-63), 4.1 g/dl (2-7.1), 80 mm Hg (20-181), and 6.4 mmol/L (1.1-18.2), respectively. Median blood product volume administered was 44 ml/kg (25-137.4). Median plasma to red blood cell ratio was 0.8 (0-4), and median non-blood product resuscitation fluid to blood product ratio was 0.5 (0-3.6). MT was given to 47.8% of dogs. Survival rate was 40.6%. The estimated odds of survival were higher by a factor of 1.8 (95% CI: 1.174, 3.094) for a dog with 1 g/dl higher total protein above reference interval and were lower by a factor of 0.6 (95% CI: 0.340, 0.915) per 100% prolongation of partial thromboplastin time above the reference interval. No predictors of MT were identified. Conclusions: Critical bleeding in dogs was associated with a wide range of resuscitation patterns and carries a guarded to poor prognosis.

Epidemiology of Massive Transfusion - A Common Intervention in Need of a Definition

While massive transfusion (MT) recipients account for a small proportion of all transfused patients, they account for approximately 10% of blood products issued. Furthermore, MT events pose organizational and logistical challenges for health care providers, laboratory and transfusion services. Overall, the majority of MT events are to support major bleeding in surgical patients, trauma and gastrointestinal hemorrhage. The clinical context in which the bleeding event occurred, the number of blood products required, patient age and comorbidities are the most important predictors of outcomes for short- and long-term survival. These data are important to inform blood services, clinicians and health care providers in order to improve care and outcomes for patients with major bleeding. There is no standard accepted definition of MT, with most definitions based on number of blood components administered within a certain time-period or activation of MT protocol. The type of definition used has implications for the clinical characteristics of MT recipients included in epidemiological and interventional studies. In order to understand trends in incidence of MT, variation in blood utilization and patient outcomes, and to harmonize research outcomes, a standard and universally accepted definition of MT is urgently required.

Incidence, trends and risk factors for obstetric massive blood transfusion in China from 2012 to 2019: an observational study

OBJECTIVES

This study aims to use the high-quality national monitoring data from the China's National Maternal Near Miss Surveillance System (NMNMSS) to ascertain the incidence, trends and risk factors of obstetric massive blood transfusion (MBT) from 2012 to 2019 in China and determine its clinical outcomes.

SETTINGS

Observational study of hospitalised pregnancies who had given birth or ended their pregnancy among member hospitals of NMNMSS.

PARTICIPANTS

11 667 406 women were included in this study.

PRIMARY AND SECONDARY OUTCOME MEASURES

We screened for the incidence, trends, risk factors and main reasons for obstetric MBT, and the outcomes after obstetric MBT. MBT was defined as the transfusion of ≥5 units of red blood cells or ≥1000 mL of whole blood. The incidence of MBT was defined as the MBT cases per 10 000 pregnancies.

RESULTS

Obstetric MBT occurred in 27 626 cases, corresponding to an incidence of 23.68 per 10 000 maternities, which exhibited an increasing trend in China during 2012-2019 (14.03-29.59 per 10 000 maternities, p for trend <0.001). Obstetric MBT was mainly associated with amniotic fluid embolism, uterine atony, abnormal placenta, severe anaemia, ectopic pregnancy, abortion, caesarean section, advanced maternal age and multiparous from biological effect. While from sociological effects, uterine atony, severe anaemia and placenta previa are the top three complications which more likely to undergo obstetric MBT in the Chinese population. Overall, the secular trends of hysterectomy incidence (25.07%-9.92%) and MMR during hospitalisation (21.41‰-7.48‰) among women who underwent MBT showed decreasing trends (p for trend <0.001).

CONCLUSION

To minimise the incidence of obstetric MBT, more attention should be paid to education on the importance of the antenatal visit, evidence-based transfusion practice and females who are multiparous and have an advanced age, amniotic fluid embolism, uterine atony, severe anaemia and placenta previa.

High Interleukin-6 Plasma Concentration upon Admission Is Predictive of Massive Transfusion in Severely Injured Patients

Severe bleeding remains a prominent cause of early in-hospital mortality in major trauma patients. Thus, prompt prediction of patients at risk of massive transfusion (MT) is crucial. We investigated the ability of the inflammatory marker interleukin (IL)-6 to forecast MT in severely injured trauma patients. IL-6 plasma levels were measured upon admission. Receiver operating characteristic curves (ROCs) were calculated, and sensitivity and specificity were determined. In this retrospective study, a total of 468 predominantly male (77.8%) patients, with a median injury severity score (ISS) of 25 (17–34), were included. The Youden index for the prediction of MT within 6 and 24 h was 351 pg/mL. Patients were dichotomized into two groups: (i) low-IL-6 < 350 pg/mL and (ii) high-IL-6 ≥ 350 pg/mL. IL-6 ≥ 350 pg/mL was associated with a lower prothrombin time index, a higher activated partial thromboplastin time, and a lower fibrinogen concentration compared with IL-6 < 350 pg/mL (p <0.0001 for all). Thromboelastometric parameters were significantly different between groups (p <0.03 in all). More patients in the high-IL-6 group received MT (p <0.0001). The ROCs revealed an area under the curve of 0.76 vs. 0.82 for the high-IL-6 group for receiving MT in the first 6 and 24 h. IL-6 ≥ 350 pg/mL predicted MT within 6 and 24 h with a sensitivity of 45% and 58%, respectively, and a specificity of 89%. IL-6 ≥ 350 pg/mL appears to be a reasonable early predictor for coagulopathy and MT within the first 6 and 24 h intervals. Large-scale prospective studies are warranted to confirm these findings.

Massive transfusion experience, current practice and decision support: A survey of Australian and New Zealand anaesthetists

Massive transfusions guided by massive transfusion protocols are commonly used to manage critical bleeding, when the patient is at significant risk of morbidity and mortality, and multiple timely decisions must be made by clinicians. Clinical decision support systems are increasingly used to provide patient-specific recommendations by comparing patient information to a knowledge base, and have been shown to improve patient outcomes. To investigate current massive transfusion practice and the experiences and attitudes of anaesthetists towards massive transfusion and clinical decision support systems, we anonymously surveyed 1000 anaesthetists and anaesthesia trainees across Australia and New Zealand. A total of 228 surveys (23.6%) were successfully completed and 227 were analysed for a 23.3% response rate. Most respondents were involved in massive transfusions infrequently (88.1% managed five or fewer massive transfusion protocols per year) and worked at hospitals which have massive transfusion protocols (89.4%). Massive transfusion management was predominantly limited by timely access to point-of-care coagulation assessment and by competition with other tasks, with trainees reporting more significant limitations compared to specialists. The majority of respondents reported that they were likely, or very likely, both to use (73.1%) and to trust (85%) a clinical decision support system for massive transfusions, with no significant difference between anaesthesia trainees and specialists (P = 0.375 and P = 0.73, respectively). While the response rate to our survey was poor, there was still a wide range of massive transfusion experience among respondents, with multiple subjective factors identified limiting massive transfusion practice. We identified several potential design features and barriers to implementation to assist with the future development of a clinical decision support system for massive transfusion, and overall wide support for a clinical decision support system for massive transfusion among respondents.

MATRA-A: A study on massive transfusion

BACKGROUND

We use massive transfusion in various clinical conditions and it is associated with high mortality. Although some massive transfusion protocols improve patient outcomes, the clinical circumstances requiring it are not well defined.

METHODS

MATRA-A is a multicenter retrospective study. Six University and Training Research Hospitals in Ankara participated in the study. We collected clinical data on patients (>18 years) who received massive transfusions (≥10 units/24 h) from 2017 through 2019.

RESULTS

Overall, 167 (0·27% of transfused patients) received a massive transfusion of 2586 units of red blood cells (1·5% of total RBCs transfused). The median interquartile range values for RBCs, fresh frozen plasma (FFP) and platelets were 13 (11-176), 16 (9-33) and 4 (0-11), respectively. Surgical patients received 90% of massive transfusions. The most common clinical indications for massive transfusion were cardiovascular diseases (42·6%), trauma (20·3%) and malignancies (11%). FFP: RBC: Platelets ratio was 1·9:1:0·5. The overall and trauma-related mortality rates were 57·4% and 61·8%, respectively. The hospital mortality rates of trauma patients that received high vs. low ratio (FFP: RBCs > 1:1·5 vs. ≤1:1·5) transfusions were 47·6% and 86·6% and the difference was statistically significant (P = 0·03).

CONCLUSION

Cardiovascular diseases and trauma occasion are the most common causes of massive transfusion. It is infrequent in clinical settings and is associated with high mortality rates. Additionally, in massively transfused trauma patients, a high FFP:RBCs ratio seems to be associated with increased survival. Focused prospective studies are required to define the areas that need improvement on a national scale.

Fibrin monomers and association with significant hemorrhage or mortality in severely injured trauma patients

BACKGROUND

Post-traumatic hemorrhage is still the leading cause of potentially preventable death in patients with severe trauma. Traumatic-induced coagulopathy has been described as a risk factor for significant hemorrhage and mortality in this population. Fibrin monomers (FMs) are a direct marker of thrombin action, and thus reflect coagulation activation. This study sought to determine the association of FMs levels at admission with significant hemorrhage and 28-day mortality after a severe trauma.

METHODS

We conducted a retrospective, observational study including all severe trauma patients admitted in a level-1 trauma center between January 2012 and December 2017. Patients with severe traumatic brain injury or previous anticoagulant / antiaggregant therapies were excluded. FMs measurements and standard coagulation test were taken at admission. Significant hemorrhage was defined as a hemorrhage requiring the transfusion of ≥ 4 Red Blood Cells units during the first 6 h. Multivariable analysis was applied to identify predictors of significant hemorrhage and a simple logistic regression analysis was applied to identify an association between FMs and 28-day mortality.

RESULTS

Overall, 299 patients were included. A total of 47 (16%) experienced a significant hemorrhage. The ROC curve demonstrated that FMs had a poor accuracy to predict the occurrence of significant hemorrhage with an AUC of 0.65 (0.57-0.74). The best threshold at 92.45 µg/ml had excellent sensitivity (87%) and negative predictive value (95%), but was not independently associated with significant hemorrhage (OR = 1.5; 95%CI (0.5-4.2)). The 28-day mortality rate was 5%. In simple logistic regression analysis, FMs values ≥109.5 µg/ml were significantly associated with 28-day mortality (unadjusted OR = 13.2; 95%CI (1.7-102)).

CONCLUSIONS

FMs levels at admission are not associated with the occurrence of a significant hemorrhage in patients with severe trauma. However, the excellent sensitivity and NPV of FMs could help to identify patients with a low risk of severe bleeding during hospital care. In addition, FMs levels ≥109.5 µg/ml might be predictive of 28-day mortality.

A Delphi study to establish consensus on a definition of major bleeding in adult trauma

BACKGROUND

The majority of potentially preventable deaths in trauma are due to uncontrolled hemorrhage and occur early after injury. How major bleeding is defined is integral to early identification and treatment of this group of high-risk patients. However, there is no consensus on a definition of major bleeding in trauma. The aim of this Delphi study was to develop a consensus definition for research, with transfusion used as a surrogate marker of bleeding.

STUDY DESIGN AND METHODS

Trauma experts from three international groups were invited to take part in an online Delphi survey. Over the course of four rounds, the group developed a number of definitions of major bleeding and reached consensus on a new definition.

RESULTS

Forty-four trauma experts agreed to become members of the Delphi panel, and 30 of 44 (68%) completed all four rounds. The panel agreed to exclude the historical massive transfusion definition (≥10 units of red blood cells within 24 hours). Consensus was reached on a new definition for use in clinical research: 4 or more units of any blood component within 2 hours of injury.

CONCLUSION

This Delphi process has yielded a pragmatic transfusion-based definition of major bleeding. The consensus definition differs from historical definitions: a shorter time frame to reflect the acuity of bleeding, and multiple blood components in keeping with a balanced approach to resuscitation. The definition developed may be best suited to mature trauma systems (reflecting the demographics of the expert panel), and could be used to guide registry data recording and to characterize patients at risk of major bleeding.

How well does your massive transfusion protocol perform? A scoping review of quality indicators

BACKGROUND

Management of patients with major haemorrhage often requires urgent administration of multiple blood products, commonly termed a massive transfusion (MT). Clinical practice in these scenarios is supported in part by evidence-based MT guidelines, which typically recommend use of an MT protocol (MTP). MTPs aim to provide practical and specific interpretation of MT guidelines for local institutional use, outlining tasks and pre-configuration of blood product packs to be transfused to provide efficient and evidence-based transfusion management. Institutions can support this aim by the measurement of MTP performance and patient outcomes through collection of quality indicators (QI). Many international guidelines now recommend the routine collection of a range of QIs relating to MT/MTP; however, there is significant variation in procedures and no benchmarks or minimal evidence to guide practice.

MATERIALS AND METHODS

We conducted a scoping review to document and evaluate reported QIs for MTP. We conducted a search of CENTRAL, MEDLINE and EMBASE for published studies from inception until May 14, 2020, that reported at least one MTP QI and use of an MTP or equivalent protocol. Included studies were evaluated using a QI classification system based on current MT QI guidelines and the Donabedian QI framework.

RESULTS

We identified 107 eligible studies. Trauma patients were the most commonly evaluated group, and total blood products transfused and in-hospital mortality were the most commonly reported QIs. Reflecting the lack of international consensus and benchmarks, we found significant variability in the reporting of QIs, which often did not reflect guideline recommendations.

DISCUSSION

Our review highlights the importance of establishing international consensus on prioritised QIs with quantifiable targets that are important to the process of MT.

Emergency department resuscitative thoracotomy at an adult major trauma centre: Outcomes following a training programme with standardised indications

OBJECTIVE

The objective of this study was to report the procedural incidence and patient outcomes after the 2009 introduction of an institutional resuscitative thoracotomy (RT) programme. Emergency physicians, general surgeons and emergency nursing trauma team members were trained to perform RT on thoracic trauma patients with an unresponsive systolic blood pressure (SBP) <70 mmHg within 30 min of arrival, prior to cardiothoracic team back-up.

METHODS

A retrospective cohort study was conducted on patients who underwent RT from 2009 to 2017. The primary outcome measures were the incidence of the procedure and patients' survival to hospital discharge. Variables associated with survival were assessed using univariable logistic regression analyses.

RESULTS

There were 12 399 major trauma patients, including 7657 with major thoracic trauma and 315 presenting with SBP <70 mmHg. There were 32 RTs performed (incidence of 0.4%; 95% confidence interval [CI] 0.3-0.6) among patients with major thoracic trauma and 10.2% (99% CI 7.3-13.4) among patients with major thoracic trauma and SBP <70 mmHg. There were eight (25%; 95% CI 13.2-42.1) survivors to hospital discharge and no late mortality (mean follow-up 2.8 years). Survival was significantly associated with the procedure performed within 30 min of arrival (odds ratio 0.09; 95% CI 0.01-0.67) while mortality was associated with the procedure being performed in the setting of traumatic cardiac arrest (odds ratio 18.3; 95% CI 2.4-140.4).

CONCLUSIONS

A formal training and credentialing programme was associated with a low incidence of the procedure, yet achieved a survival rate of 25%, which is comparable to other reported literature.

Clinical characteristics of women captured by extending the definition of severe postpartum haemorrhage with 'refractoriness to treatment': a cohort study

Background

The absence of a uniform and clinically relevant definition of severe postpartum haemorrhage hampers comparative studies and optimization of clinical management. The concept of persistent postpartum haemorrhage, based on refractoriness to initial first-line treatment, was proposed as an alternative to common definitions that are either based on estimations of blood loss or transfused units of packed red blood cells (RBC). We compared characteristics and outcomes of women with severe postpartum haemorrhage captured by these three types of definitions.

Methods

In this large retrospective cohort study in 61 hospitals in the Netherlands we included 1391 consecutive women with postpartum haemorrhage who received either ≥4 units of RBC or a multicomponent transfusion. Clinical characteristics and outcomes of women with severe postpartum haemorrhage defined as persistent postpartum haemorrhage were compared to definitions based on estimated blood loss or transfused units of RBC within 24 h following birth. Adverse maternal outcome was a composite of maternal mortality, hysterectomy, arterial embolisation and intensive care unit admission.

Results

One thousand two hundred sixty out of 1391 women (90.6%) with postpartum haemorrhage fulfilled the definition of persistent postpartum haemorrhage. The majority, 820/1260 (65.1%), fulfilled this definition within 1 h following birth, compared to 819/1391 (58.7%) applying the definition of ≥1 L blood loss and 37/845 (4.4%) applying the definition of ≥4 units of RBC. The definition persistent postpartum haemorrhage captured 430/471 adverse maternal outcomes (91.3%), compared to 471/471 (100%) for ≥1 L blood loss and 383/471 (81.3%) for ≥4 units of RBC. Persistent postpartum haemorrhage did not capture all adverse outcomes because of missing data on timing of initial, first-line treatment.

Conclusion

The definition persistent postpartum haemorrhage identified women with severe postpartum haemorrhage at an early stage of haemorrhage, unlike definitions based on blood transfusion. It also captured a large majority of adverse maternal outcomes, almost as large as the definition of ≥1 L blood loss, which is commonly applied as a definition of postpartum haemorrhage rather than severe haemorrhage.

Clinical coding data algorithm to categorize type of gastrointestinal bleeding as a primary reason for massive transfusion: results from the Australian and New Zealand Massive Transfusion Registry

BACKGROUND

Management of major gastrointestinal bleeding (GIB) may require massive transfusion (MT), but limited data are available. Upper and lower GIB have different aetiologies, prognosis, bleeding patterns and outcomes. Better understanding of current transfusion management and outcomes in these patients is important. We sought to define and validate an algorithm based on clinical coding data to distinguish critical upper and lower GIB using data from the Australian and New Zealand Massive Transfusion Registry (ANZ-MTR).

STUDY DESIGN AND METHODS

Australian and New Zealand Massive Transfusion Registry hospital-source data on adult patients receiving a MT (defined as ≥5 red cell units within 4 h) for any bleeding context were used. An algorithm allocating ICD-10-AM codes into 'probable' or 'possible' causes of GIB was developed and applied to the ANZ-MTR. Source medical records of 69 randomly selected cases were independently reviewed to validate the algorithm.

RESULTS

Of 5482 MT cases available from 25 hospitals, 716 (13%) were identified as GIB with 538/716 (75%) categorized 'probable' and 178/716 'possible' GIB. Upper and lower GIB causes of MT were identified for 455/538 (85%) and 76/538 (14%) 'probable' cases, respectively; 7/538 (1·3%) cases had both upper and lower GIB. Allocation by the algorithm into a 'probable' GIB category had a 95·7% (CI: 90-100%) positive predictive value when validated against source medical records.

CONCLUSION

An algorithm based on ICD-10-AM codes can be used to accurately categorize patients with luminal GIB as the primary reason for MT, enabling further study of this critically unwell and resource-intensive cohort of patients.

Application of a recursive partitioning decision tree algorithm for the prediction of massive transfusion in civilian trauma: the MTPitt prediction tool

BACKGROUND

A supervised machine learning algorithm was used to generate decision trees for the prediction of massive transfusion at a Level 1 trauma center.

METHODS

Trauma patients who received at least one unit of RBCs and/or low-titer group O whole blood between January 1, 2015, and December 31, 2017, were included. Massive transfusion was defined as the transfusion of 10 or more units of RBCs and/or low-titer group O whole blood in the first 24 hours of admission. A recursive partitioning algorithm was used to generate two decision trees for prediction of massive transfusion using a training data set (n = 550): the first, MTPitt, was based on demographic and clinical parameters, and the second, MTPitt+Labs, also included laboratory data. Decision tree performance was compared with the Assessment of Blood Consumption score and the Trauma Associated Severe Hemorrhage score.

RESULTS

The incidence of massive transfusion in the validation data set (n = 199) was 7.5%. The MTPitt decision tree had a higher balanced accuracy (81.4%) and sensitivity (86.7%) compared to an Assessment of Blood Consumption Score of 2 or higher (77.9% and 66.7%, respectively) and a Trauma Associated Severe Hemorrhage score of 9 or higher (75.0% and 73.3%, respectively), although the 95% confidence intervals overlapped. Addition of laboratory data to the MTPitt decision tree (MTPitt+Labs) resulted in a higher specificity and balanced accuracy compared to MTPitt without an increase in sensitivity.

CONCLUSIONS

The MTPitt decisions trees are highly sensitive tools for identifying patients who received a massive transfusion and do not require computational resources to be implemented in the trauma setting.

Massive transfusion triggers in severe trauma: Scoping review

OBJECTIVE

to identify the predictive variables or the massive transfusion triggers in severely traumatized patients through the existing scales.

METHOD

a review of the literature was carried out using the Scoping Review method across the electronic databases CINAHL, MEDLINE, LILACS, the Cochrane and IBECS libraries, and the Google Scholar search tool.

RESULTS

in total, 578 articles were identified in the search and the 36 articles published in the last ten years were included, of which 29 were original articles and 7 review articles. From the analysis, scales for massive transfusion and their predictive triggers were examined.

CONCLUSION

the absence of universal criteria regarding the massive transfusion triggers in traumatized patients has led to the development of different scales, and the studies on their validation are considered relevant for the studies about when to initiate this strategy.

How useful are hemoglobin concentration and its variations to predict significant hemorrhage in the early phase of trauma? A multicentric cohort study

Background

The diagnostic value of hemoglobin (Hb) for detecting a significant hemorrhage (SH) in the early phase of trauma remains controversial. The present study aimed to assess the abilities of Hb measurements taken at different times throughout trauma management to identify patients with SH.

Methods

All consecutive adult trauma patients directly admitted to six French level-1 trauma centers with at least one prehospital Hb measurement were analyzed. The abilities of the following variables to identify SH (≥ 4 units of red blood cells in the first 6 h and/or death related to uncontrolled bleeding within 24 h) were determined and compared to that of shock index (SI): Hb as measured with a point-of-care (POC) device by the prehospital team on scene (POC-Hb_prehosp) and upon patient’s admission to the hospital (POC-Hb_hosp), the difference between POC-Hb_hosp and POC-Hb_prehosp (DeltaPOC-Hb) and Hb as measured by the hospital laboratory on admission (Hb-Lab_hosp).

Results

A total of 6402 patients were included, 755 with SH and 5647 controls (CL). POC-Hb_prehosp significantly predicted SH with an area under ROC curve (AUC) of 0.72 and best cutoff values of 12 g/dl for women and 13 g/dl for men. POC-Hb_prehosp < 12 g/dl had 90% specificity to predict of SH. POC-Hb_hosp and Hb-Lab_hosp (AUCs of 0.92 and 0.89, respectively) predicted SH better than SI (AUC = 0.77, p < 0.001); best cutoff values of POC-Hb_hosp were 10 g/dl for women and 12 g/dl for men. DeltaPOC-Hb also predicted SH with an AUC of 0.77, a best cutoff value of − 2 g/dl irrespective of the gender. For a same prehospital fluid volume infused, DeltaPOC-Hb was significantly larger in patients with significant hemorrhage than in controls.

Conclusions

Challenging the classical idea that early Hb measurement is not meaningful in predicting SH, POC-Hb_prehosp was able, albeit modestly, to predict significant hemorrhage. POC-Hb_hosp had a greater ability to predict SH when compared to shock index. For a given prehospital fluid volume infused, the magnitude of the Hb drop was significantly higher in patients with significant hemorrhage than in controls.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0420-8) contains supplementary material, which is available to authorized users.

Massive transfusions for critical bleeding: is everything old new again?

Massive transfusion or major haemorrhage protocols have been widely adopted in the treatment of critically bleeding patients. Following evidence that higher ratios of transfused plasma and platelets to red blood cells may offer survival benefits in military trauma patients, these ratios are now commonly incorporated into massive transfusion protocols. They more closely resemble the effects of whole blood transfusion, which in the second half of last century was largely replaced by individual blood component transfusion based on laboratory-guided indicators. However, high-quality evidence to guide transfusion support for critically bleeding patients across the range of bleeding contexts is lacking, including for both trauma and non-trauma patients. More data on major haemorrhage support and clinical outcomes are needed to inform guidelines and practice.

Fractures of the femur and blood transfusions

BACKGROUND

Blood loss estimation after trauma (i.e. physical injury) and early identification of potential sources of bleeding are important for planning of investigation and management of trauma. Long bone fractures have been reported to be associated with substantial volumes of blood loss requiring blood transfusion. The aim of this study was to assess rates and amounts of blood transfusion in the setting of isolated extra capsular femur fractures and to determine variables associated with the need for transfusion within the first 48 h of admission.

METHODS

A retrospective cohort study was conducted of patients in The Alfred Trauma Registry with isolated extra capsular femur fractures over a 7-year period. We compared patients with a femoral shaft fracture (FSF) to patients with either distal femur or proximal femur fractures (i.e. extremity fracture). We collected data potentially associated with blood transfusion within 48 h as well as operation details and patient outcomes.

RESULTS

There were 293 patients included, of which 121 had FSF and 172 extremity fracture. 105 (36%) patients received a blood transfusion during their admission. Admission haemoglobin (AOR 0.92; 95%CI 0.89-0.94, p < 0.01) was the only independently associated variable with blood transfusion within the first 48 h of hospital admission.

CONCLUSION

Volume of blood transfused to patients with extra-capsular femoral fractures was low and usually in the post-operative period. FSF, compared to femoral extremity fractures, were not more likely to receive blood transfusion within the first 48 h of admission, and did not receive a higher volume of blood overall. In the setting of major trauma with haemorrhagic shock, alternate sources of bleeding should be sought.

Massive Transfusion in Cardiac Surgery: The Impact of Blood Component Ratios on Clinical Outcomes and Survival

BACKGROUND

Cardiac surgery is the most common setting for massive transfusion in medically advanced countries. Studies of massive transfusion after injury suggest that the ratios of administered plasma and platelets (PLT) to red blood cells (RBCs) affect mortality. Data from the Red Cell Storage Duration Study (RECESS), a large randomized trial of the effect of RBC storage duration in patients undergoing complex cardiac surgery, were analyzed retrospectively to investigate the association between blood component ratios used in massively transfused patients and subsequent clinical outcomes.

METHODS

Massive transfusion was defined as those who had ≥6 RBC units or ≥8 total blood components. For plasma, high ratio was defined as ≥1 plasma unit:1 RBC unit. For PLT transfusion, high ratio was defined as ≥0.2 PLT doses:1 RBC unit; PLT dose was defined as 1 apheresis PLT or 5 whole blood PLT equivalents. The clinical outcomes analyzed were mortality and the change in the Multiple Organ Dysfunction Score (ΔMODS) comparing the preoperative score with the highest composite score through the earliest of death, discharge, or day 7. Outcomes were compared between patients transfused with high and low ratios. Linear and Cox regression were used to explore relationships between predictors and continuous outcomes and time to event outcomes.

RESULTS

A total of 324 subjects met the definition of massive transfusion. In those receiving high plasma:RBC ratio, the mean (SE) 7- and 28-day ΔMODS was 1.24 (0.45) and 1.26 (0.56) points lower, (P = .007 and P = .024), respectively, than in patients receiving lower ratios. In patients receiving high PLT:RBC ratio, the mean (SE) 7- and 28-day ΔMODS were 1.55 (0.53) and 1.49 (0.65) points lower (P = .004 and P = .022), respectively. Subjects who received low-ratio plasma:RBC transfusion had excess 7-day mortality compared with those who received high ratio (7.2% vs 1.7%, respectively, P = .0318), which remained significant at 28 days (P = .035). The ratio of PLT:RBCs was not associated with differences in mortality.

CONCLUSIONS

This analysis found that in complex cardiac surgery patients who received massive transfusion, there was an association between the composition of blood products used and clinical outcomes. Specifically, there was less organ dysfunction in those who received high-ratio transfusions (plasma:RBCs and PLT:RBCs), and lower mortality in those who received high-ratio plasma:RBC transfusions.

Cryoprecipitate administration after trauma

OBJECTIVES

Haemorrhage remains among the most preventable causes of trauma death. Massive transfusion protocols, as part of 'haemostatic resuscitation', have been implemented in most trauma centres. Relative to the attention to the ideal ratio of red blood cells to fresh frozen plasma and platelets, cryoprecipitate treatment has been infrequently discussed. We aimed to outline the use of cryoprecipitate during trauma resuscitation and analyse outcomes in patients who received cryoprecipitate after hypofibrinogenaemia detection.

METHODS

A retrospective review of registry data on all major trauma patients (Injury Severity Score>15) presenting to a level I trauma centre over a 4-year period (2008-2011) was conducted. We selected all patients who had received cryoprecipitate and then analysed patients who had received cryoprecipitate following the detection of hypofibrinogenaemia (<1.0 g/l). Mortality at hospital discharge among hypofibrinogenaemic patients who had received cryoprecipitate was compared with that among patients who had not received cryoprecipitate.

RESULTS

Of 3996 trauma patients, 3571 had fibrinogen levels recorded. Most patients (n=3517, 98.5%) had initial fibrinogen counts of 1.0 g/l or higher, and cryoprecipitate was administered to a small proportion of these patients (n=126, 3.6%). Of the 54 patients with hypofibrinogenaemia on arrival, one patient died immediately and was excluded from further analysis. Of the 53 patients, 30 received cryoprecipitate and 28/53 died (53%). There was no difference in mortality between those who had received and those who had not received cryoprecipitate (14/30 vs. 14/23, P=0.31).

CONCLUSION

Administration of cryoprecipitate was uncommon during trauma resuscitation, even among patients with hypofibrinogenaemia on presentation. This study provides no evidence towards improved outcomes from administration of cryoprecipitate.

Fibrinogen concentration and use of fibrinogen supplementation with cryoprecipitate in patients with critical bleeding receiving massive transfusion: a bi-national cohort study

We aimed to compare hypofibrinogenaemia prevalence in major bleeding patients across all clinical contexts, fibrinogen supplementation practice, and explore the relationship between fibrinogen concentrations and mortality. This cohort study included all adult patients from 20 hospitals across Australia and New Zealand who received massive transfusion between April 2011 and October 2015. Of 3566 patients, 2829 (79%) had fibrinogen concentration recorded, with a median first and lowest concentration of 2·0 g/l (interquartile range [IQR] 1·5-2·7) and 1·8 g/l (IQR 1·3-2·4), respectively. Liver transplant (1·7 g/l, IQR 1·2-2·1), trauma (1·8, IQR 1·3-2·5) and vascular surgery (1·9 g/l, IQR 1·4-2·5) had lower concentrations. Total median fibrinogen dose administered from all products was 7·3 g (IQR 3·3-13·0). Overall, 1732 (61%) received cryoprecipitate and 9 (<1%) fibrinogen concentrate. Time to cryoprecipitate issue in those with initial fibrinogen concentration <1 g/l was 2·5 h (IQR 1·2-4·3 h). After adjustment, initial fibrinogen concentration had a U-shaped association with in-hospital mortality [adjusted odds ratios: fibrinogen <1 g/l, 2·31 (95% confidence interval (CI) 1·48-3·60); 1-1·9 g/l, 1·29 (95% CI 0·99-1·67) and >4 g/l, 2·03 (95% CI 1·35-3·04), 2-4 g/l reference category]. The findings indicate areas for practice improvement including timely administration of cryoprecipitate, which is the most common source of concentrated fibrinogen in Australia and New Zealand.

Utilizing Group-based Trajectory Modeling to Understand Patterns of Hemorrhage and Resuscitation

OBJECTIVE

The purpose of this study was to describe variations in blood-based resuscitation in an injured cohort. We hypothesize that distinct transfusion trajectories are present.

BACKGROUND

Retrospective studies of hemorrhage utilize the concept of massive transfusion, where a set volume of blood is required. Patterns of hemorrhage vary and massive transfusion does little to describe these differences.

METHODS

Patients were prospectively included from June 2012 to 2013. Time of transfusion for each packed red blood cell (PRBC) transfused was recorded, in minutes, for all patients. Additional measures included demographic and injury data, admission laboratory values, and vital signs and outcomes including mortality, tempo of transfusion, and operative requirements. Group-based trajectory modeling was utilized to describe transfusion trajectories throughout the cohort.

RESULTS

Three hundred sixteen patients met the inclusion criteria. Among them, 72% were men and median age was 35 years (interquartile range [IQR] 24-50), median injury severity score was 13 (IQR 9-22), median 24-hour transfusion volume was 4 units of PRBCs (IQR 2-8), and mortality was 14%. Six transfusion trajectories were identified. Among the patients, 35% received negligible transfusions (group 1). Groups 2 and 3 received greater than 15 units PRBCs-the former as early resuscitation, whereas the latter intermittently throughout the day. Groups 4 and 5 had similar small resuscitations with distinct demographic differences. Group 6 suffered blunt injuries and required rapid resuscitation.

CONCLUSIONS

Traditional definitions of massive transfusion are broad and imprecise. In cohorts of severely injured patients, there are distinct, identifiable transfusion trajectories. Identification of subgroups is important in understanding clinical course and to anticipate resuscitative and therapeutic needs.

Age of blood and survival after massive transfusion

BACKGROUND

Massive transfusion is the clinical scenario where the presumed adverse effects of stored blood are expected to be more evident because the whole patient's blood volume is replaced by stored blood.

OBJECTIVE

To analyse the association between age of transfused red blood cells (RBC) and survival in massively transfused patients.

METHODS

In this retrospective study, clinical and transfusion data of all consecutive patients massively transfused between 2008 and 2014 in a large, tertiary-care hospital were electronically extracted from the Transfusion Service database and the patients' electronic medical records. Prognostic factors for in-hospital mortality were investigated by multivariate logistic regression.

RESULTS

A total of 689 consecutive patients were analysed (median age: 61 years; 65% males) and 272 died in-hospital. Projected mortality at 2, 30, and 90 days was 21%, 35% and 45%, respectively. The odds ratio (OR) for in-hospital mortality among patients who survived after the 2nd day increased with patient age (OR: 1.037, 95% CI: 1.021-1.054; per year P<0.001), with the number of RBC unit transfused in the first 48hours (OR: 1.060; 95% CI: 1.038-1.020 per unit; P<0.001), and the percentage of such RBC stored for more than 28 days (1.010, 95% CI: 1.005-1.018 per percent point; P=0.01).

CONCLUSION

Mortality after massive transfusion was associated with a higher proportion of old RBCs transfused in the first 48hours. Other factors associated with poor prognosis were older patient's age and larger volumes of transfused RBCs.

Viscoelastic Tissue Plasminogen Activator Challenge Predicts Massive Transfusion in 15 Minutes

BACKGROUND

Coagulopathy is associated with massive transfusion in trauma, yet most clinical scores to predict this end point do not incorporate coagulation assays. Previous work has identified that shock increases circulating tissue plasminogen activator (tPA). When tPA levels saturate endogenous inhibitors, systemic hyperfibrinolysis can occur. Therefore, the addition of tPA to a patient's blood sample could stratify a patients underlying degree of shock and early coagulation changes to predict progression to massive transfusion. We hypothesized that a modified thrombelastography (TEG) assay with exogenous tPA would unmask patients' impending risk for massive transfusion.

STUDY DESIGN

Trauma activations were analyzed using rapid TEG and a modified TEG assay with a low and high dose of tPA. Clinical scores (shock index, assessment of blood consumption, and trauma-associated severe hemorrhage) were compared with TEG measurements to predict the need for massive transfusion using areas under the receiver operating characteristic curves.

RESULTS

Three hundred and twenty-four patients were analyzed, 17% required massive transfusion. Massive transfusion patients had a median shock index of 1.2, assessment of blood consumption score of 1, and trauma-associated severe hemorrhage score of 12. Rapid TEG and tPA TEG parameters were significantly different in all massive transfusion patients compared with non-massive transfusion patients (all p < 0.02). The low-dose tPA lysis at 30 minutes had the largest the area under the receiver operating characteristic curve (0.86; 95% CI 0.79 to 0.93) for prediction of massive transfusion, similar to international normalized ratio of prothrombin time of 0.86 (95% CI 0.81 to 0.91), followed by trauma-associated severe hemorrhage score (0.83; 95% CI 0.77 to 0.89). Combing trauma-associated severe hemorrhage and tPA-TEG variables results in a positive prediction of massive transfusion in 49% of patients with a 98% negative predictive value.

CONCLUSIONS

The tPA-TEG identifies trauma patients who require massive transfusion efficiently in a single assay that can be completed in a shorter time than other scoring systems, which has improved performance when combined with international normalized ratio. This new method is consistent with our understanding of the molecular events responsible for trauma-induced coagulopathy.

Evaluation of clinical coding data to determine causes of critical bleeding in patients receiving massive transfusion: a bi-national, multicentre, cross-sectional study

OBJECTIVES

To evaluate the use of routinely collected data to determine the cause(s) of critical bleeding in patients who receive massive transfusion (MT).

BACKGROUND

Routinely collected data are increasingly being used to describe and evaluate transfusion practice.

MATERIALS/METHODS

Chart reviews were undertaken on 10 randomly selected MT patients at 48 hospitals across Australia and New Zealand to determine the cause(s) of critical bleeding. Diagnosis-related group (DRG) and International Classification of Diseases (ICD) codes were extracted separately and used to assign each patient a cause of critical bleeding. These were compared against chart review using percentage agreement and kappa statistics.

RESULTS

A total of 427 MT patients were included with complete ICD and DRG data for 427 (100%) and 396 (93%), respectively. Good overall agreement was found between chart review and ICD codes (78·3%; κ = 0·74, 95% CI 0·70-0·79) and only fair overall agreement with DRG (51%; κ = 0·45, 95% CI 0·40-0·50). Both ICD and DRG were sensitive and accurate for classifying obstetric haemorrhage patients (98% sensitivity and κ > 0·94). However, compared with the ICD algorithm, DRGs were less sensitive and accurate in classifying bleeding as a result of gastrointestinal haemorrhage (74% vs 8%; κ = 0·75 vs 0·1), trauma (92% vs 62%; κ = 0·78 vs 0·67), cardiac (80% vs 57%; κ = 0·79 vs 0·60) and vascular surgery (64% vs 56%; κ = 0·69 vs 0·65).

CONCLUSION

Algorithms using ICD codes can determine the cause of critical bleeding in patients requiring MT with good to excellent agreement with clinical history. DRG are less suitable to determine critical bleeding causes.

Improving outcomes for hospital patients with critical bleeding requiring massive transfusion: the Australian and New Zealand Massive Transfusion Registry study methodology

Background

The Australian and New Zealand (ANZ) Massive Transfusion (MT) Registry (MTR) has been established to improve the quality of care of patients with critical bleeding (CB) requiring MT (≥ 5 units red blood cells (RBC) over 4 h). The MTR is providing data to: (1) improve the evidence base for transfusion practice by systematically collecting data on transfusion practice and clinical outcomes; (2) monitor variations in practice and provide an opportunity for benchmarking, and feedback on practice/blood product use; (3) inform blood supply planning, inventory management and development of future clinical trials; and (4) measure and enhance translation of evidence into policy and patient blood management guidelines. The MTR commenced in 2011. At each participating site, all eligible patients aged ≥18 years with CB from any clinical context receiving MT are included using a waived consent model. Patient information and clinical coding, transfusion history, and laboratory test results are extracted for each patient’s hospital admission at the episode level.

Results

Thirty-two hospitals have enrolled and 3566 MT patients have been identified across Australia and New Zealand between 2011 and 2015. The majority of CB contexts are surgical, followed by trauma and gastrointestinal haemorrhage. Validation studies have verified that the definition of MT used in the registry correctly identifies 94 % of CB events, and that the median time of transfusion for the majority of fresh products is the ‘product event issue time’ from the hospital blood bank plus 20 min. Data linkage between the MTR and mortality databases in Australia and New Zealand will allow comparisons of risk-adjusted mortality estimates across different bleeding contexts, and between countries. Data extracts will be examined to determine if there are differences in patient outcomes according to transfusion practice. The ratios of blood components (e.g. FFP:RBC) used in different types of critical bleeding will also be investigated.

Conclusions

The MTR is generating data with the potential to have an impact on management and policy decision-making in CB and MT and provide benchmarking and monitoring tools for immediate application.

Prediction of critical haemorrhage following trauma: A narrative review

Introduction: Traumatic haemorrhagic shock can be difficult to diagnose. Models for predicting critical bleeding and massive transfusion have been developed to aid clinicians. The aim of this review is to outline the various available models and report on their performance and validation. Methods: A review of the English and non-English literature in Medline, PubMed and Google Scholar was conducted from 1990 to September 2015. We combined several terms for i) haemorrhage AND ii) prediction, in the setting of iii) trauma. We included models that had at least two data points. We extracted information about the models, their developments, performance and validation. Results: There were 36 different models identified that diagnose critical bleeding, which included a total of 36 unique variables. All models were developed retrospectively. The models performed with variable predictive abilities–the most superior with an area under the receiver operating characteristics curve of 0.985, but included detailed findings on imaging and was based on a small cohort. The most commonly included variable was systolic blood pressure, featuring in all but five models. Pattern or mechanism of injury were used by 16 models. Pathology results were used by 15 models, of which nine included base deficit and eight models included haemoglobin. Imaging was utilised in eight models. Thirteen models were known to be validated, with only one being prospectively validated. Conclusions: Several models for predicting critical bleeding exist, however none were deemed accurate enough to dictate treatment. Potential areas of improvement identified include measures of variability in vital signs and point of care imaging and pathology testing.

Antithrombotic therapy in blunt cerebrovascular injury—Do we need more information?

Introduction

Blunt cerebrovascular injury is an infrequent, but potentially devastating cause of morbidity following blunt trauma. Most recommendations regarding treatment of blunt cerebrovascular injury advocate the use of antithrombotic medications, based on biased evidence. We aim to describe the experience with blunt cerebrovascular injury at a major trauma center and to validate the benefits of antithrombotic treatment in blunt cerebrovascular injury.

Methods

A retrospective cohort study of all adult (>16 years) patients diagnosed with blunt cerebrovascular injury at a major trauma center over a 6-year period. Outcomes were assessed and analyzed to determine neurological sequelae related specifically to blunt cerebrovascular injury.

Results

Blunt cerebrovascular injury had an incidence of 0.57% in our patient population and 97 patients were initially included for analysis. In subsequent analysis, 39 patients (40.2%) were deemed nonassessable and were excluded, leaving 44 treated and 14 untreated patients. There were no differences between the groups in neurological change or outcome. Three treated patients suffered hemorrhagic complications.

Conclusions

While there is an association between treatment of blunt cerebrovascular injury with antithrombotics and improved outcomes, selection bias influences these results. Accounting for this bias, the association is no longer demonstrable and treatment does not appear to alter the outcome.

Massive transfusion prediction with inclusion of the pre-hospital Shock Index

BACKGROUND

Detecting occult bleeding can be challenging and may delay resuscitation. The Shock Index (SI) defined as heart rate divided by systolic blood pressure has attracted attention. Prediction models using combinations of pre-hospital SI (phSI) and the trauma centre SI (tcSI) values may be effective in identifying patients requiring massive blood transfusions (MT).

AIM

To explore whether combinations of the phSI and the tcSI augment MT prediction.

METHODS

The scores were retrospectively developed using all major trauma patients that presented to The Alfred Hospital between 2006 and 2012. The first PH and TC observations were used. To avoid exclusion of the 'sickest' patients, the SI was imputed to 2 where SBP was missing, but HR was present. We developed 4 models. (i) 'Dichotomised', defined as positive when both phSI and tcSI were ≥1. (ii) 'Formulaic', defined by logistic regression analysis. (iii) 'Combination', defined pragmatically based on the logistic regression. (iv) 'Trending', defined as: tcSI minus phSI.

RESULTS

There were 6990 major trauma patients and 360 (5.2%) received MT. There were 1371 cases with either phSI or tcSI missing and were thus excluded from the analysis. The 'Dichotomised' had higher positive predictive value than the tcSI with a further 5 per 100 patients identified. The 'Formulaic' model, defined as: log Odds (MT)=2.16×tcSI+0.89×phSI-5.42, and the 'Combination' model, defined as: phSI×0.5+tcSI, performed equally (AUROC 0.83 versus 0.83, χ(2)=0.86, p=0.35). The 'Formulaic' performed marginally, but statistically significantly, more accurate than the tcSI alone (AUROC 0.83 versus 0.82, χ(2)=6.89, p<0.01). An 'Upward Trending' SI was observed in 1758 patients, revealing a 4.6-fold univariate association with MT (OR 4.55; 95%CI 2.64-7.83), and an AUROC of 0.79 (95%CI 0.74-0.83). The 'Downward Trending' SI was protective against MT (OR 0.44; 95%CI 0.34-0.57).

CONCLUSION

The initial pre-hospital SI is associated with MT. However, this relationship did not clinically augment MT decision when combined with the in-hospital SI. The simplicity of the SI makes it a favourable option to explore further. Computer-assisted technology in data capturing, analysis and prognostication presents avenues for further research.

"After-hours" staffing of trauma centres and outcomes among patients presenting with acute traumatic coagulopathy

OBJECTIVE

To examine the effect of the "after-hours" (18:00-07:00) model of trauma care on a high-risk subgroup - patients presenting with acute traumatic coagulopathy (ATC).

DESIGN, PARTICIPANTS AND SETTING

Retrospective analysis of data from the Alfred Trauma Registry for patients with ATC presenting between 1 January 2006 and 31 December 2011.

MAIN OUTCOME MEASURE

Mortality at hospital discharge, adjusted for potential confounders, describing the association between after-hours presentation and mortality.

RESULTS

There were 398 patients with ATC identified during the study period, of whom 197 (49.5%) presented after hours. Mortality among patients presenting after hours was 43.1%, significantly higher than among those presenting in hours (33.1%; P = 0.04). Following adjustment for possible confounding variables of age, presenting Glasgow Coma Scale score, urgent surgery or angiography and initial base deficit, after-hours presentation was significantly associated with higher mortality at hospital discharge (adjusted odds ratio, 1.77; 95% CI, 1.10-2.87).

CONCLUSION

The after-hours model of care was associated with worse outcomes among some of the most critically ill trauma patients. Standardising patient reception at major trauma centres to ensure a consistent level of care across all hours of the day may improve outcomes among patients who have had a severe injury.

Indications for blood transfusion following trauma - a pilot study

Background: Indications for blood transfusion during trauma resuscitation remain poorly understood. This study aimed to objectively determine the range of factors that lead to initiation of blood transfusion during trauma resuscitation. Design and method: This was a prospective, observational pilot study. A questionnaire was distributed to all clinicians following any transfusion of packed red blood cells during trauma resuscitation. The questionnaire focused on the clinicians’ opinion regarding the indication for red cell transfusion. Results: Complete data on 37 individual episodes of transfusion initiation in the Emergency Department were collected. The most commonly used pre-hospital factors that influenced initiation of transfusion was a pre-hospital systolic blood pressure (SBP) of < 100 mm Hg (65%), pre-hospital tachycardia (38%) or estimated blood loss of >1 L (30%) by paramedics. On arrival to hospital, the activation of a massive transfusion protocol was the commonest indication for transfusion, followed by a positive FAST examination (43%), low systolic blood pressure (35%), tachycardia (32%) or pallor (35%). Blood tests to guide initiation of transfusion were less commonly used with 9 (24%) patients transfused for a low haemoglobin level and 6 (16%) patients transfused for coagulopathy. Conclusions: A combination of objective pre- and in-hospital vital signs, together with subjective indicators such as pallor and estimation of blood loss guided initiation of transfusion following injury.