Role of Transfusion Volume and Transfusion Rate as Markers of Futility During Ultramassive Blood Transfusion in Trauma

TiME OUT: Time-specific machine-learning evaluation to optimize ultramassive transfusion

BACKGROUND

Ultramassive transfusion (UMT) is a resource-demanding intervention for trauma patients in hemorrhagic shock, and associated mortality rates remains high. Current research has been unable to identify a transfusion ceiling or point where UMT transitions from lifesaving to futility. Furthermore, little consideration has been given to how time-specific patient data points impact decisions with ongoing high-volume resuscitation. Therefore, this study sought to use time-specific machine learning modeling to predict mortality and identify parameters associated with survivability in trauma patients undergoing UMT.

METHODS

A retrospective review was conducted at a Level I trauma (2018-2021) and included trauma patients meeting criteria for UMT, defined as ≥20 red blood cell products within 24 hours of admission. Cross-sectional data were obtained from the blood bank and trauma registries, and time-specific data were obtained from the electronic medical record. Time-specific decision-tree models predicating mortality were generated and evaluated using area under the curve.

RESULTS

In the 180 patients included, mortality rate was 40.5% at 48 hours and 52.2% overall. The deceased received significantly more blood products with a median of 71.5 total units compared with 55.5 in the survivors ( p < 0.001) and significantly greater rates of packed red blood cells and fresh frozen plasma at each time interval. Time-specific decision-tree models predicted mortality with an accuracy as high as 81%. In the early time intervals, hemodynamic stability, undergoing an emergency department thoracotomy, and injury severity were most predictive of survival, while, in the later intervals, markers of adequate resuscitation such as arterial pH and lactate level became more prominent.

CONCLUSION

This study supports that the decision of "when to stop" in UMT resuscitation is not based exclusively on the number of units transfused but rather the complex integration of patient and time-specific data. Machine learning is an effective tool to investigate this concept, and further research is needed to refine and validate these time-specific decision-tree models.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Defining Ultra-Massive Transfusion through a Systematic Review

Background

Despite the widespread use of ultra-massive transfusion (UMT) as an intervention for trauma patients in hemorrhagic shock, no standard definition exists. We performed a systematic review to determine a consensus definition for UMT.

Methods

A search was performed from 1979-2022. The authors screened studies defining UMT and associated outcomes as defined by our prespecified PICO questions. The PRISMA guidelines were used.

Results

1662 articles met criteria for eligibility assessment, 17 for full-text review and eight for data extraction. Only two studies demonstrated a consensus definition of UMT, which used ≥20 units of red blood cell product within 24hrs. Parameters associated with increased mortality included lower blood pressure, lower pulse and lower Glasgow Coma Score at the time of presentation and a higher injury severity score and undergoing a resuscitative thoracotomy.

Conclusions

The absence of a consensus definition for UMT raises challenges from clinical, research and ethical perspectives. Based on our findings, the authors advocate for the feasibility of standardizing the definition of UMT as ≥20 units of red blood cell product within 24hrs.

Achieving balanced transfusion early in critically bleeding trauma patients: an observational study exploring the effect of attending trauma surgical presence during resuscitation

Background

After 15 years of damage control resuscitation (DCR), studies still report high mortality rates for critically bleeding trauma patients. Adherence to massive hemorrhage protocols (MHPs) based on a 1:1:1 ratio of plasma, platelets, and red blood cells (RBCs) as part of DCR has been shown to improve outcomes. We wanted to assess MHP use in the early (6 hours from admission), critical phase of DCR and its impact on mortality. We hypothesized that the presence of an attending trauma surgeon during all MHP activations from 2013 would contribute to improving institutional resuscitation strategies and patient outcomes.

Methods

We conducted a retrospective analysis of all trauma patients receiving ≥10 RBCs within 6 hours of admission and included in the institutional trauma registry between 2009 and 2019. The cohort was divided in period 1 (P1): January 2009-August 2013, and period 2 (P2): September 2013-December 2019 for comparison of outcomes.

Results

A total of 141 patients were included, 81 in P1 and 60 in P2. Baseline characteristics were similar between the groups for Injury Severity Score, lactate, Glasgow Coma Scale, and base deficit. Patients in P2 received more plasma (16 units vs. 12 units; p<0.01), resulting in a more balanced plasma:RBC ratio (1.00 vs. 0.74; p<0.01), and platelets:RBC ratio (1.11 vs. 0.92; p<0.01). All-cause mortality rates decreased from P1 to P2, at 6 hours (22% to 8%; p=0.03), at 24 hours (36% vs 13%; p<0.01), and at 30 days (48% vs 30%, p=0.03), respectively. A stepwise logistic regression model predicted an OR of 0.27 (95% CI 0.08 to 0.93) for dying when admitted in P2.

Conclusions

Achieving balanced transfusion rates at 6 hours, facilitated by the presence of an attending trauma surgeon at all MHP activations, coincided with a reduction in all-cause mortality and hemorrhage-related deaths in massively transfused trauma patients at 6 hours, 24 hours, and 30 days.

Level of evidence

IV.

Finding the bleeding edge: 24-hour mortality by unit of blood product transfused in combat casualties from 2002-2020

BACKGROUND

Transfusion studies in civilian trauma patients have tried to identify a general futility threshold. We hypothesized that in combat settings there is no general threshold where blood product transfusion becomes unbeneficial to survival in hemorrhaging patients. We sought to assess the relationship between the number of units of blood products transfused and 24-hour mortality in combat casualties.

METHODS

A retrospective analysis of the Department of Defense Trauma Registry supplemented with data from the Armed Forces Medical Examiner. Combat casualties who received at least one unit of blood product at US military medical treatment facilities (MTFs) in combat settings (2002-2020) were included. The main intervention was the total units of any blood product transfused, which was measured from the point of injury until 24 hours after admission from the first deployed MTF. The primary outcome was discharge status (alive, dead) at 24 hours from time of injury.

RESULTS

Of 11,746 patients included, the median age was 24 years, and most patients were male (94.2%) with penetrating injury (84.7%). The median injury severity score was 17 and 783 (6.7%) patients died by 24 hours. Median units of blood products transfused was 8. Most blood products transfused were red blood cells (50.2%), followed by plasma (41.1%), platelets (5.5%), and whole blood (3.2%). Among the 10 patients who received the most units of blood product (164 units to 290 units), 7 survived to 24 hours. The maximum amount of total blood products transfused to a patient who survived was 276 units. Of the 58 patients who received over 100 units of blood product, 20.7% died by 24 hours.

CONCLUSION

While civilian trauma studies suggest the possibility of futility with ultra-massive transfusion, we report that the majority (79.3%) of combat casualties who received transfusions greater than 100 units survived to 24 hours. These results do not support a threshold for futility of blood product transfusion. Further analysis as to predictors for mortality will help in situations of blood product and resource constraints.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Predictors of Mortality in Trauma patients Receiving massive Transfusion Protocol

INTRODUCTION

Massive transfusion protocol (MTP) is often defined as the transfusion of ≥10 units of packed red blood cells (PRBCs) in 24 hours. The purpose of this study is to determine which factors most significantly contribute to mortality in patients receiving MTP after trauma.

METHODS

An initial database search followed by retrospective chart review was performed on patients treated at four trauma centers in Southern California. Data were collected on all patients who received MTP, defined as at least 10 units PRBCs within the first 24 hours of admission, between January 2015 and December 2019. Patients with isolated head injuries were excluded. Univariate and multivariate analyses were used to determine which factors most significantly influenced mortality.

RESULTS

Of 1278 patients who met our inclusion criteria in the database, 596 (46.6%) survived and 682 (53.4%) died. On univariate analysis initial vitals and labs, except for initial hemoglobin and initial platelet count were significant predictors of mortality. A multivariate regression model showed the strongest predictors of mortality were pRBC transfusions at 4 hours (OR 1.073, CI 1.020-1.128, P = .006) and 24 hours (OR 1.045, CI 1.003-1.088, P = .036), and FFP transfusion at 24 hours (OR 1.049, CI 1.016-1.084, P = .003).

CONCLUSION

Our data indicates that several factors may contribute to mortality in patients receiving MTP. In particular age, mechanism, initial GCS, and PRBC transfusions at 4 and 24 hours provided the strongest correlation. Further multicenter trials are indicated to provide further guidance in deciding when to discontinue massive transfusion.

Narrative Review: Is There a Transfusion Cutoff Value After Which Nonsurvivability Is Inevitable in Trauma Patients Receiving Ultramassive Transfusion?

The institution of massive transfusion protocols (MTPs) has improved the timely delivery of large quantities of blood products and improves patient outcomes. In recent years, the cost of blood products has increased, compounded by significant blood product shortages. There is practical need for identification of a transfusion volume in trauma patients that is associated with increased mortality, or a threshold after which additional transfusion is futile and associated with nonsurvivability. This transfusion threshold is often described in the setting of an ultramassive transfusion (UMT). There are few studies defining what constitutes amount or outcomes associated with such large volume transfusion. The purpose of this narrative review is to provide an analysis of existing literature examining the effects of UMT on outcomes including survival in adult trauma patients and to determine whether there is a threshold transfusion limit after which mortality is inevitable. Fourteen studies were included in this review. The data examining the utility of UMT in trauma are of poor quality, and with the variability inherent in trauma patients, and the surgeons caring for them, no universally accepted cutoff for transfusion exists. Not surprisingly, there is a trend toward increasing mortality with increasing transfusions. The decision to continue transfusing is multifactorial and must be individualized, taking into consideration patient characteristics, institution factors, blood bank supply, and most importantly, constant reevaluation of the need for ongoing transfusion rather than blind continuous transfusion until the heart stops.

Ultramassive Transfusion for Trauma in the Age of Hemostatic Resuscitation: A Retrospective Single-Center Cohort From a Large US Level-1 Trauma Center, 2011-2021

BACKGROUND

Uncontrolled bleeding is a leading cause of death in trauma. In the last 40 years, ultramassive transfusion (UMT; ≥20 units of red blood cells [RBCs]/24 hours) for trauma has been associated with 50% to 80% mortality; the question remains as to whether the increasing number of units transfused in urgent resuscitation is a marker of futility. We asked whether the frequency and outcomes of UMT have changed in the era of hemostatic resuscitation.

METHODS

We performed a retrospective cohort study of all UMTs in the first 24 hours of care over an 11-year period at a major US level-1 adult and pediatric trauma center. UMT patients were identified, and a dataset was built by linking blood bank and trauma registry data, then reviewing individual electronic health records. Success in achieving hemostatic proportions of blood products was estimated as (units of plasma + apheresis-platelets-in-plasma + cryoprecipitate-pools + whole blood]/[all units given] ≥0.5. Demographics, injury type (blunt or penetrating), severity (Injury Severity Score [ISS]), severity pattern (Abbreviated Injury Scale score for head [AIS-Head] ≥4), admitting laboratory, transfusion, selected emergency department interventions, and discharge status were assessed using χ2 tests of categorical association, the Student t-test of means, and multivariable logistic regression. P <.05 was considered significant.

RESULTS

Among 66,734 trauma admissions from April 6, 2011 to December 31, 2021, we identified 6288 (9.4%) who received any blood products in the first 24 hours, 159 of whom received UMT (0.23%; 154 aged 18-90 + 5 aged 9-17), 81% in hemostatic proportions. Overall mortality was 65% (n = 103); mean ISS = 40; median time to death, 6.1 hours. In univariate analyses, death was not associated with age, sex, or more RBC units transfused beyond 20 but was associated with blunt injury, increasing injury severity, severe head injury, and failure to receive hemostatic blood product ratios. Mortality was also associated with decreased pH and evidence of coagulopathy at admission, especially hypofibrinogenemia. Multivariable logistic regression showed severe head injury, admission hypofibrinogenemia and not receiving a hemostatic resuscitation proportion of blood products as independently associated with death.

CONCLUSIONS

One in 420 acute trauma patients at our center received UMT, a historically low rate. A third of these patients lived, and UMT was not itself a marker of futility. Early identification of coagulopathy was possible, and failure to give blood components in hemostatic ratios was associated with excess mortality.

Biochemical disturbance in damage control resuscitation: mechanisms, management and prognostic utility

PURPOSE OF REVIEW

With advances in resuscitative techniques, trauma patients are surviving increasingly severe injuries and physiological insult. Timely recognition of futility remains important in terms of patient dignity and resource preservation yet is increasingly challenging in the face of these advances. The understanding of biochemical derangement from pathophysiological processes of trauma and iatrogenic effects of resuscitation has expanded recently.

RECENT FINDINGS

Acidosis and hypocalcaemia have been recognized as important contributors to mortality among trauma patients. Although less well recognized and studied, critical injury and high blood product volume resuscitation render patients vulnerable to life-threatening hyperkalaemia. The methods of correcting disruptions to acid-base and electrolyte homeostasis during damage control resuscitation have changed little recently and often rely on evidence from undifferentiated populations. Biochemical disturbances have value as ancillary predictors of futility in trauma resuscitation.

SUMMARY

These findings will contribute to a greater understanding among anaesthesiologists of the causative mechanisms and effects of biochemical derangement after severe injury and aid them in the delivery of well tolerated and effective damage control resuscitation. Gaps in the evidence base are highlighted to encourage future work.

Predicting Futility in Severely Injured Patients: Using Arrival Lab Values and Physiology to Support Evidence-Based Resource Stewardship

BACKGROUND

The recent pandemic exposed a largely unrecognized threat to medical resources, including daily available blood products. Some of the most severely injured patients who arrive in extremis consume tremendous resources yet succumb shortly after arrival. We sought to identify cut points available early in the patient's resuscitation that predicted 100% mortality.

STUDY DESIGN

Cut points were developed from a previously collected data set of all level 1 trauma patients admitted January 2010 to December 2016. Objective values available on or shortly after arrival were evaluated. Once generated, we then validated these variables against (1) a prospective data set November 2017 to October 2021 of severely injured patients and (2) a multicenter, randomized trial of hemorrhagic shock patients. Analyses were conducted using STATA 17.0 (College Station, TX), generating positive predictive value (PPV), negative predictive value, sensitivity, and specificity.

RESULTS

The development data set consisted of 9,509 patients (17% mortality), with 2,137 (24%) and 680 (24%) in the two validation data sets. Several combinations of arrival vitals and labs had 100% PPV. Patients undergoing CPR in the field or on arrival (with subsequent return of spontaneous circulation) required lower fibrinolysis LY-30 (30%) than those with systolic blood pressures of ≤50 (30 to 50%), ≤70 (80 to 90%), and ≤90 mmHg (90%). Using a combination of these validated variables, the Suspension of Transfusions and Other Procedures (STOP) criteria were developed, with each element predicting 100% mortality, allowing physicians to cease further resuscitative efforts.

CONCLUSIONS

The use of evidence-based STOP criteria provides cut points of futility to help guide early decisions for discontinuing aggressive treatment of severely injured patients arriving in extremis.