Clinical outcomes among low-titer group O whole blood recipients compared to recipients of conventional components in civilian trauma resuscitation

The Efficacy of Low-Titer Group O Whole Blood Compared With Component Therapy in Civilian Trauma Patients: A Meta-Analysis

OBJECTIVES

To assess if transfusion with low-titer group O whole blood (LTOWB) is associated with improved early and/or late survival compared with component blood product therapy (CT) in bleeding trauma patients.

DATA SOURCES

A systematic search of PubMed, CINAHL, and Web of Science was performed from their inception through December 1, 2023. Key terms included injury, hemorrhage, bleeding, blood transfusion, and whole blood.

STUDY SELECTION

All studies comparing outcomes in injured civilian adults and children who received LTOWB versus CT were included.

DATA EXTRACTION

Data including author, publication year, sample size, total blood volumes, and clinical outcomes were extracted from each article and reported following the Meta-analysis Of Observational Studies in Epidemiology guidelines. Main outcomes were 24-hour (early) and combined 28-day, 30-day, and in-hospital (late) mortality rates between recipients of LTOWB versus CT, which were pooled using random-effects models.

DATA SYNTHESIS

Of 1297 studies reviewed, 24 were appropriate for analysis. Total subjects numbered 58,717 of whom 5,164 received LTOWB. Eleven studies included adults-only, seven included both adults and adolescents, and six only included children. The median (interquartile range) age for patients who received LTOWB and CT was 35 years (24-39) and 35.5 years (23-39), respectively. Overall, 14 studies reported early mortality and 22 studies reported late mortality. LTOWB was associated with improved 24-hour survival (risk ratios [RRs] [95% CI] = 1.07 [1.03-1.12]) and late (RR [95% CI] = 1.05 [1.01-1.09]) survival compared with component therapy. There was no evidence of small study bias and all studies were graded as a moderate level of bias.

CONCLUSIONS

These data suggest hemostatic resuscitation with LTOWB compared with CT improves early and late survival outcomes in bleeding civilian trauma patients. The majority of subjects were injured adults; multicenter randomized controlled studies in injured adults and children are underway to confirm these findings.

Prehospital Blood Transfusion in Helicopter Emergency Medical Services: An Italian Survey

OBJECTIVE

Hemorrhage remains the most common cause of preventable death after trauma. Prehospital blood product (PHBP) administration may improve outcomes. No data are available about PHBP use in Italian helicopter emergency medical services (HEMS). The primary aim of this survey was to establish the degree of PHBP used throughout Italy. The secondary aims were to evaluate the main indications for their use, the opinions about PHBPs, and users' experience.

METHODS

The study group performed a telephone/e-mail survey of all 56 Italian HEMS bases. The questions concerned whether PHBPs were used in their HEMS bases, the frequency of transfusions, the PHBP used, and the perceived benefits.

RESULTS

Four of 56 HEMS bases use PHBPs. Overall, 7% have prehospital access to packed red cells and only 1 to fresh plasma. In addition to blood product administration, 4 of 4 use tranexamic acid, and 3 of 4 also use fibrinogen. Seventy-five percent use PHBPs once a month and 25% once a week. The users' experience was that PHBPs are beneficial and lifesaving.

CONCLUSION

Only 4 of 56 HEMS in Italy use PHBPs. There is an absolute consensus among providers on the benefit of PHBPs despite the lack of evidence on PHBP use.

Optimal dose of cryoprecipitate in massive transfusion following trauma

BACKGROUND

While cryoprecipitate (Cryo) is commonly included in massive transfusion protocols for hemorrhagic shock, the optimal dose of Cryo transfusion remains unknown. We evaluated the optimal red blood cell (RBC) to RBC to Cryo ratio during resuscitation in massively transfused trauma patients.

METHODS

Adult patients in the American College of Surgeon Trauma Quality Improvement Program (2013-2019) receiving massive transfusion (≥4 U of RBCs, ≥1 U of fresh frozen plasma, and ≥1 U of platelets within 4 hours) were included. A unit of Cryo was defined as a pooled unit of 100 mL. The RBC:Cryo ratio was calculated for blood products transfused within 4 hours of presentation. The association between RBC:Cryo and 24-hour mortality was analyzed with multivariable logistic regression adjusting for the volume of RBC, plasma and platelet transfusions, global and regional injury severity, and other relevant variables.

RESULTS

The study cohort included 12,916 patients. Among those who received Cryo (n = 5,511 [42.7%]), the median RBC and Cryo transfusion volume within 4 hours was 11 U (interquartile range, 7-19 U) and 2 U (interquartile range, 1-3 U), respectively. Compared with no Cryo administration, only RBC:Cryo ratios ≤8:1 were associated with a significant survival benefit, while lower doses of Cryo (RBC:Cryo >8:1) were not associated with decreased 24-hour mortality. Compared with the maximum dose of Cryo administration (RBC:Cryo, 1:1-2:1), there was no difference in 24-hour mortality up to RBC:Cryo of 7:1 to 8:1, whereas lower doses of Cryo (RBC:Cryo, >8:1) were associated with significantly increased 24-hour mortality.

CONCLUSION

One pooled unit of Cryo (100 mL) per 7 to 8 U of RBCs could be the optimal dose of Cryo in trauma resuscitation that provides a significant survival benefit while avoiding unnecessary blood product transfusions.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level IV.

Doing more with less: low-titer group O whole blood resulted in less total transfusions and an independent association with survival in adults with severe traumatic hemorrhage

BACKGROUND

Low-titer group O whole blood (LTOWB) or component therapy (CT) may be used to resuscitate hemorrhaging trauma patients. LTOWB may have clinical and logistical benefits and may improve survival.

OBJECTIVES

We hypothesized LTOWB would improve 24-hour survival in hemorrhaging patients and would be safe and equally efficacious in non-group O compared with group O patients.

METHODS

Adult trauma patients with massive transfusion protocol activations were enrolled in this observational study. The primary outcome was 24-hour mortality. Secondary outcomes included 72-hour total blood product use. A Cox regression determined the independent associations with 24-hour mortality.

RESULTS

In total, 348 patients were included (CT, n = 180; LTOWB, n = 168). Demographics were similar between cohorts. Unadjusted 24-hour mortality was reduced in LTOWB vs CT: 8% vs 19% (P = .003), but 6-hour and 28-day mortality were similar. In an adjusted analysis with multivariable Cox regression, LTOWB was independently associated with reduced 24-hour mortality (hazard ratio, 0.21; 95% CI, 0.07-0.67; P = .004). LTOWB patients received significantly less 72-hour total blood products (80.9 [41.6-139.3] mL/kg vs 48.9 [25.9-106.9] mL/kg; P < .001). In stratified 24-hour survival analyses, LTOWB was associated with improved survival for patients in shock or with coagulopathy. LTOWB use in non-group O patients was not associated with increased mortality, organ injury, or adverse events.

CONCLUSION

In this hypothesis-generating study, LTOWB use was independently associated with improved 24-hour survival, predominantly in patients with shock or coagulopathy. LTOWB also resulted in a 40% reduction in blood product use which equates to a median 2.4 L reduction in transfused products.

Incompatible plasma transfusion is not associated with increased mortality in civilian trauma patients

BACKGROUND

The introduction of low titer group O whole blood (LTOWB) that contains potentially ABO-incompatible plasma and the increasing use of group A plasma, due to shortages of AB plasma, in trauma patients whose ABO group is unknown could put the recipients of incompatible plasma at risk of increased morbidity and mortality. This study evaluated civilian trauma patient outcomes following receipt of incompatible plasma.

METHODS

One trauma center's patient contributions to three multicenter studies of different trauma resuscitation strategies was analyzed; these patients were separated into two groups based on receipt of only compatible plasma versus receipt of any quantity of incompatible plasma. Multivariate analysis was performed to determine if receipt of incompatible plasma was associated with 24-hour or 30-day mortality.

RESULTS

There were 347 patients eligible for this secondary analysis with 167 recipients of only compatible plasma and 180 recipients of incompatible plasma. The two groups were well matched demographically and on both prehospital and hospital arrival vital signs. The median (IQR) volume of incompatible plasma received by these patients was 684 ml (342, 1229). There was not a significant difference between the groups in 24-hour and 30-day mortality, nor in in-hospital or intensive care unit lengths of stay. In the Cox proportional-hazards regression model for both 24-hour and 30-day survival, receipt of incompatible plasma was not independently predictive of either mortality endpoint.

CONCLUSION

Receipt of incompatible plasma was not independently associated with increased mortality in trauma patients. Prospective studies are needed to confirm these findings.

What is the Role of Whole Blood Transfusions on Trauma Patients?

Whole blood use in trauma has historically been limited to military use, but in recent years, there has been increasing data for use in civilian trauma. Emerging clinical data demonstrate an associated survival benefit, while some authors have also identified decreased use of an overall number of blood products and decreased complications. Use of whole blood is gradually moving toward becoming the standard of care in the hemorrhaging trauma patient.

Whole blood transfusion in the treatment of acute hemorrhage, a systematic review and meta-analysis

BACKGROUND

Whole blood (WB) transfusion received renewed interest after recent armed conflicts. The effectiveness as compared with blood component transfusion (BCT) is, however, still topic of debate. Therefore, this study investigated the effect of WB ± BCT as compared with BCT transfusion on survival in trauma patients with acute hemorrhage.

METHODS

Studies published up to January 16, 2023, including patients with traumatic hemorrhage comparing WB ± BCT and BCT were included in meta-analysis. Subanalyses were performed on the effectiveness of WB in the treatment of civilian or military trauma patients, patients with massive hemorrhage and on platelet (PLT)/red blood cell (RBC), plasma/RBC and WB/RBC ratios. Methodological quality of studies was interpreted using the Cochrane risk of bias tool. The study protocol was registered in PROSPERO under number CRD42022296900.

RESULTS

Random effect pooled odds ratio (OR) for 24 hours mortality in civilian and military patients treated with WB as compared with BCT was 0.72 (95% confidence interval [CI], 0.53-0.97). In subanalysis of studies conducted in civilian setting (n = 20), early (4 hours, 6 hours, and emergency department) and 24 hours mortality was lower in WB groups compared with BCT groups (OR, 0.65; 95% CI, 0.44-0.96 and OR, 0.71; 95% CI, 0.52-0.98). No difference in late mortality (28 days, 30 days, in-hospital) was found. In military settings (n = 7), there was no difference in early, 24 hours, or late mortality between groups. The WB groups received significant higher PLT/RBC ( p = 0.030) during early treatment and significant higher PLT/RBC and plasma/RBC ratios during 24 hours of treatment ( p = 0.031 and p = 0.007). The overall risk of bias in the majority of studies was judged as serious due to serious risk on confounding and selection bias, and unclear information regarding cointerventions.

CONCLUSION

Civilian trauma patients with acute traumatic hemorrhage treated with WB ± BCT as compared to BCT had lower odds on early and 24-hour mortality. In addition, WB transfusion resulted in higher PLT/RBC and plasma/RBC ratios.

LEVEL OF EVIDENCE

Systematic Review and Meta-Analysis; Level III.

Emergency transfusion with whole blood versus packed red blood cells: A study of 1400 patients

BACKGROUND

Low-titer group O whole blood (LTOWB) is increasingly used for emergency transfusion. We studied whether initial release of LTOWB compared with packed red blood cells (pRBCs) reduced overall blood requirements for patients needing emergency transfusion. Secondary outcomes examined included survival and non-lethal adverse clinical outcomes.

STUDY DESIGN AND METHODS

A retrospective, single-center, before-versus-after study compared patients transfused with emergency-release, uncrossmatched pRBC followed by component therapy (2016-2019) versus patients transfused with emergency-release, uncrossmatched LTOWB followed by component therapy (2019-2022).

RESULTS

Outcomes were available for 602 patients in the pRBC group versus 749 in the whole blood group. The two groups were similar for age, sex, race, estimated blood volume, ABO blood groups, and underlying diagnosis. Use of LTOWB was associated with increased blood product use at 24 h (4.0 (2.0-12.0) in pRBC group versus 6.5 (4.2-12.7) in LTOWB group, p < .0001) and at 7 days (5.5 (3.0-13.0) in pRBC group versus 7.3 (4.3-14.3) in LTOWB group, p < .0001). Initial use of LTOWB was not associated with improved 24 h or 30 day survival nor lower incidence of non-lethal adverse clinical outcomes compared with pRBC.

DISCUSSION

Our study showed a statistically significant increase in total blood use and blood acquisition costs for patients receiving initial emergency transfusion with LTOWB compared with pRBC. The initial use of LTOWB offered no advantage over component therapy for 30 day survival or selected non-lethal adverse outcomes.

In vitro comparison of CPD whole blood with conventional blood components

INTRODUCTION

Resuscitation of severely injured trauma patients is commonly performed using red blood cells in additive solution supplemented with plasma and platelet concentrates. There is an increasing interest in the use of low anti-A titer Group O whole blood (LTOWB) in the early management of the resuscitation. It is unclear whether clinical outcome is improved using this approach.

METHODS

Expired units of CPD-LTOWB were studied on Day 22 and expired units of thawed plasma on Day 6 and Day 7. LTOWB was assessed for hemoglobin content, clotting factor levels and platelet numbers and function using thromboelastography (TEG) and impedance aggregation. Assays of fibrinogen and FV, FVIII, FVII and FX were performed on the expired plasma. The LTOWB hemoglobin was compared to red cells in additive solution (AS-RBCs) and the clotting factor levels to those of expired thawed plasma. Platelet function was compared to fresh whole blood samples from healthy subjects.

RESULTS

LTOWB contained slightly more hemoglobin than the AS-RBCs (Medians, 66 v 59 G), and the plasma content of fibrinogen was similar. Other clotting factors were reduced by approximately 15% except for FVIII which was 30% less. Both TEG and impedance aggregometry showed evidence of residual platelet function despite the prolonged period of refrigerator storage.

CONCLUSION

LTOWB contains higher hemoglobin and adequate clotting factors, and residual platelet function is demonstrated indicating that this product would be expected to be at least equivalent to a single unit of each of the conventional components commonly used in trauma resuscitation.

Achieving optimal massive transfusion ratios: The trauma white board, whole blood, and liquid plasma. Real world low-tech solutions for a high stakes issue

BACKGROUND

It is well established that achieving optimal ratios of packed red blood cells (PRBC) to fresh frozen plasma (FFP) to platelet ratios during massive transfusion leads to improved outcomes but is difficult to accomplish.

METHODS

Between September 2018 and May 2019 our level 2 trauma center implemented 3 new processes to optimize transfusion ratios during massive transfusion protocol (MTP). Two units of low titer group O whole blood (LTOWB) were added as the first step to our MTP. Second, a dry erase board whiteboard was attached to each fluid warmer for real time recording of transfusions. Last, liquid plasma was incorporated into our MTP. We performed a retrospective review evaluating PRBC:FFP ratios for patients who had the massive transfusion protocol initiated and received 4 or more units of blood.

RESULTS

A total of 50 patients had the massive transfusion protocol initiated and received 4 or more units of PRBCs and/or LTOWB within 4 h of arrival. There were 21 patients evaluated prior to protocol changes and 29 patients after the changes. In the study group mean age, sex, pulse, systolic blood pressure (SBP), and injury severity scale (ISS) on admission were not different. In the pre-protocol (preP) group 90% of patients were blunt trauma and in the post-protocol group (postP) 72% were blunt trauma, p = 0. 22. For the preP group the mean units of PRBCs was 7.6 units and FFP 4.7 units. PostP the mean units of PRBCs was 11.4 units and FFP 10.0 units. PRBC/FFP ratios were 1.7 preP and 1.2 postP, p = 0.0072.

CONCLUSION

The institution of whole blood, use of the trauma white board, and the addition of liquid plasma to our transfusion services have allowed us to approach a 1:1 transfusion ratio during the course of our massive transfusions.

Use of Cold-Stored Whole Blood is Associated with Improved Mortality in Hemostatic Resuscitation of Major Bleeding: A Multicenter Study

OBJECTIVE

The aim of this study was to identify a mortality benefit with the use of whole blood as part of the resuscitation of bleeding trauma patients.

SUMMARY BACKGROUND DATA

Blood component therapy (BCT) is the current standard for resuscitating trauma patients, with whole blood (WB) emerging as the blood product of choice. We hypothesized that the use of WB versus BCT alone would result in decreased mortality.

METHODS

We performed a 14-center, prospective-observational study of trauma patients who received WB versus BCT during their resuscitation. We applied a generalized linear mixed-effects model with a random effect and controlled for age, sex, mechanism of injury (MOI), and injury severity score (ISS). All patients who received blood as part of their initial resuscitation were included. Primary outcome was mortality and secondary outcomes included AKI, DVT/PE, pulmonary complications, and bleeding complications.

RESULTS

A total of 1,623 (WB: 1,180(74%), BCT: 443(27%)) patients who sustained penetrating (53%) or blunt (47%) injury were included. Patients who received WB had a higher shock index (0.98 vs. 0.83), more comorbidities, and more blunt MOI (all P<0.05). After controlling for center, age, sex, MOI, and ISS, we found no differences in the rates of AKI, DVT/PE or pulmonary complications. WB patients were 9% less likely to experience bleeding complications and were 48% less likely to die than BCT patients (P<0.0001).

CONCLUSIONS

Compared with BCT, the use of WB was associated with a 48% reduction in mortality in trauma patients. Our study supports the use of WB use in the resuscitation of trauma patients.

Remote Damage Control Resuscitation: A Case Report of Hemorrhagic Shock Secondary to Multiple Gunshot Wounds

Hypovolemic shock is the leading cause of preventable death on the battlefield. Remote damage control resuscitation has evolved dramatically in the past decade by introducing novel treatments and approaches to bleeding in the prehospital setting. This report presents a case of a casualty who sustained multiple gunshot wounds to the chest and gluteal regions and suffered from hemorrhagic shock with an Injury Severity Score of 34. The casualty was treated at the point of injury and during evacuation according to the IDF's remote damage control resuscitation algorithm utilizing the range of blood products available in the IDF. Prompt identification of the mechanism of injury, clinical and tactical decision-making, and immediate advanced medical care through several prehospital medical evacuation platforms culminated in this casualty's survival. This case emphasizes the importance of medical advancements in prehospital field care and guideline-directed treatment to improve casualty survival.

Implementation of a low-titer stored whole blood transfusion program for civilian trauma patients: Early experience and logistical challenges

INTRODUCTION

Cold-stored low titer group O whole blood (LTOWB) is increasingly utilized in the initial resuscitation of exsanguinating trauma patients. We report on our early experience with LTOWB, focusing on logistics, implementation challenges, and outcomes.

METHODS

In February, 2019, LTOWB was incorporated into the massive transfusion protocol (MTP) activated for trauma patients in the emergency department (ED.) Up to 4 units of LTOWB were included in the MTP cooler, depending on availability, and were transfused prior to transfusion of any other blood products from the MTP cooler. Demographics, injury characteristics, and outcomes were obtained, and the logistics of LTOWB availability were reviewed.

RESULTS

Over a 12-month period, MTP was activated for 74 trauma patients. Of those, 38 (51%) MTP included at least one unit of LTOWB, with 19/38 (50%) including 4 LTOWB units. A total of 177 units of LTOWB were purchased during the study period, and of those, 74 (42%) expired before use. Patients who received LTOWB had a similar mortality compared to those who received component therapy (39% vs. 47%; Odds Ratio [95% CI]: 0.7 [0.3, 2.0]; p = 0.72,) however, they were able to achieve a significantly higher plasma:pRBC ratio during the duration of MTP activation (mean [SD] 0.8 [0.2] vs. 0.4 [0.4]; mean difference [95% CI]: 0.4 [0.2, 0.5]; p < 0.01.) CONCLUSIONS: Our early experience with LTOWB transfusion demonstrates feasibility, but also highlights challenges with inventory management. These findings triggered changes to our protocol aiming at minimizing wastage. The use of LTOWB may yield a higher plasma:pRBC ratio early during the resuscitation period. Further investigation is required to explore whether this may yield a survival advantage.

LEVEL OF EVIDENCE

III (Therapeutic/Care Management).

Prehospital low titer group O whole blood is feasible and safe: Results of a prospective randomized pilot trial

INTRODUCTION

Low titer group O whole blood (LTOWB) resuscitation is increasingly common in both military and civilian settings. Data regarding the safety and efficacy of prehospital LTOWB remain limited.

METHODS

We performed a single-center, prospective, cluster randomized, prehospital through in-hospital whole blood pilot trial for injured air medical patients. We compared standard prehospital air medical care including red cell transfusion and crystalloids followed by in-hospital component transfusion to prehospital and in-hospital LTOWB resuscitation. Prehospital vital signs were used as inclusion criteria (systolic blood pressure ≤90 mm Hg and heart rate ≥108 beats per minute or systolic blood pressure ≤70 mm Hg for patients at risk of hemorrhage). Primary outcome was feasibility. Secondary outcomes included 28-day and 24-hour mortality, multiple organ failure, nosocomial infection, 24-hour transfusion requirements, and arrival coagulation parameters.

RESULTS

Between November 2018 and October 2020, 86 injured patients were cluster randomized by helicopter base. The trial has halted early at 77% enrollment. Overall, 28-day mortality for the cohort was 26%. Injured patients randomized to prehospital LTOWB (n = 40) relative to standard care (n = 46) were similar in demographics and injury characteristics. Intent-to-treat Kaplan-Meier survival analysis demonstrated no statistical mortality benefit at 28 days (25.0% vs. 26.1%, p = 0.85). Patients randomized to prehospital LTOWB relative to standard care had lower red cell transfusion requirements at 24 hours (p < 0.01) and a lower incidence of abnormal thromboelastographic measurements. No transfusion reactions during the prehospital or in-hospital phase of care were documented.

CONCLUSION

Prehospital through in-hospital LTOWB resuscitation is safe and may be associated with hemostatic benefits. A large-scale clinical trial is feasible with protocol adjustment and would allow the effects of prehospital LTOWB on survival and other pertinent clinical outcomes to be appropriately characterized.

LEVEL OF EVIDENCE

Therapeutic/Care Management, Level II.

The Role of Whole Blood Transfusions in Civilian Trauma: A Review of Literature in Military and Civilian Trauma

Resuscitation techniques for the management of adult trauma patients have evolved over the 20th century. Whole blood transfusions were previously used as the standard of care, whereas blood component therapy is the current method employed across most trauma centers across the United States. Prior to the transition, no studies were conducted to show improved efficacy of hemostatic potential in trauma patients. Recent conflicts in Iraq and Afghanistan have challenged the dogma that whole blood transfusions are not the standard of care and have shown potential as the superior transfusion product for adult trauma patients. The purpose of this review is to provide a comprehensive review and elucidate if whole blood transfusions have a role in civilian trauma patients based upon recent military medical literature and civilian pilot studies using whole blood transfusions.

After 9,000 Laparotomies for Blunt Trauma, Resuscitation Is Becoming More Balanced and Time to Intervention Shorter: Evidence in Action

INTRODUCTION

Several advancements in hemorrhage control have been advocated for in the past decade, including balanced transfusions and earlier times to intervention. The aim of this study is to examine the effect of these advancements on outcomes of blunt trauma patients undergoing emergency laparotomy.

METHODS

This is a 5-year (2013-2017) analysis of the Trauma Quality Improvement Program. Adult (age ≥ 18 years) blunt trauma patients with early (≤4 hours) PRBC and FFP transfusions and an emergency (≤4 hours) laparotomy for hemorrhage control were identified. Time-trend analysis of 24-hour mortality, PRBC/FFP ratio, and time to laparotomy was performed over the study period. The association between mortality and PRBC/FFP ratio, patient demographics, injury characteristics, transfusion volumes, and ACS verification level was examined by hierarchical regression analysis adjusting for inter-year variability.

RESULTS

A total of 9,773 blunt trauma patients with emergency laparotomy were identified. Mean age was 44 ± 18 years, 67.5% were male, and median ISS was 34 [24-43]. Mean SBP at presentation was 73 ± 28 mm Hg, and median transfusion requirements were PRBC 9 [5-17] and FFP 6 [3-12]. During the 5-year analysis, time to laparotomy decreased from 1.87 hours to 1.37 hours (p < 0.001), PRBC/FFP ratio at 4 hours decreased from 1.93 to 1.71 (p < 0.001), and 24-hour mortality decreased from 23.0% to 19.3% (p = 0.014). (Figure) On multivariate analysis, decreased PRBC/FFP ratio was independently associated with decreased 24-hour mortality (OR 0.88; p < 0.001) and in-hospital mortality (OR 0.89; p < 0.001).

CONCLUSION

Resuscitation is becoming more balanced and time to emergency laparotomy shorter in blunt trauma patients, with a significant improvement in mortality. Future efforts should be directed towards incorporating transfusion practices and timely surgical interventions as markers of trauma center quality.

LEVEL OF EVIDENCE

Level III.

Whole blood at the tip of the spear: A retrospective cohort analysis of warm fresh whole blood resuscitation versus component therapy in severely injured combat casualties

BACKGROUND

Death from uncontrolled hemorrhage occurs rapidly, particularly among combat casualties. The US military has used warm fresh whole blood during combat operations owing to clinical and operational exigencies, but published outcomes data are limited. We compared early mortality between casualties who received warm fresh whole blood versus no warm fresh whole blood.

METHODS

Casualties injured in Afghanistan from 2008 to 2014 who received ≥2 red blood cell containing units were reviewed using records from the Joint Trauma System Role 2 Database. The primary outcome was 6-hour mortality. Patients who received red blood cells solely from component therapy were categorized as the non-warm fresh whole blood group. Non- warm fresh whole blood patients were frequency-matched to warm fresh whole blood patients on identical strata by injury type, patient affiliation, tourniquet use, prehospital transfusion, and average hourly unit red blood cell transfusion rates, creating clinically unique strata. Multilevel mixed effects logistic regression adjusted for the matching, immortal time bias, and other covariates.

RESULTS

The 1,105 study patients (221 warm fresh whole blood, 884 non-warm fresh whole blood) were classified into 29 unique clinical strata. The adjusted odds ratio of 6-hour mortality was 0.27 (95% confidence interval 0.13-0.58) for the warm fresh whole blood versus non-warm fresh whole blood group. The reduction in mortality increased in magnitude (odds ratio = 0.15, P = .024) among the subgroup of 422 patients with complete data allowing adjustment for seven additional covariates. There was a dose-dependent effect of warm fresh whole blood, with patients receiving higher warm fresh whole blood dose (>33% of red blood cell-containing units) having significantly lower mortality versus the non-warm fresh whole blood group.

CONCLUSION

Warm fresh whole blood resuscitation was associated with a significant reduction in 6-hour mortality versus non-warm fresh whole blood in combat casualties, with a dose-dependent effect. These findings support warm fresh whole blood use for hemorrhage control as well as expanded study in military and civilian trauma settings.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

Effect of Massive Transfusion Protocol on Coagulation Function in Elderly Patients with Multiple Injuries

Objective

To evaluate the effect of massive transfusion protocol on coagulation function in elderly patients with multiple injuries.

Methods

In this retrospective cohort study, clinical data were collected from a total of 94 elderly patients with multiple injuries, including 44 cases who received routine transfusion protocol (control group) and 50 cases who concurrently received massive transfusion protocol in our hospital (research group). The changes in platelet parameters, coagulation function, and organ dysfunction scores at admission and 24 h after transfusion were compared between the two groups. The 24-hour plasma and red blood cell transfusion volume, length of stay, complications, and mortality of the two groups were analyzed statistically.

Results

Twenty-four hours after blood transfusion, the hematocrit, platelets, and hemoglobin in the research group were higher than those in the control group, while the activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, and scores of Marshall scoring system and Sequential Organ Failure Assessment were lower than those in the control group (P < 0.01). The 24-hour plasma transfusion volume was higher, and the length of intensive care unit (ICU) stay and total length of stay were lower in the research group compared with the control group (P < 0.01). No significant difference was found in the mortality rate between the research group and the control group (10.00% vs. 13.64%, P > 0.05). The incidence of complications in the research group was lower than that in the control group (12.00% vs. 31.82%, P < 0.05).

Conclusion

Massive transfusion protocol for elderly patients with multiple injuries can improve their coagulation function and platelet parameters, alleviate organ dysfunction, shorten length of ICU stay, and decrease the incidence of complications, which is conducive to improving the prognosis of patients.

Bioinspired artificial platelets: past, present and future

Platelets are anucleate blood cells produced from megakaryocytes predominantly in the bone marrow and released into blood circulation at a healthy count of 150,000-400,00 per μL and circulation lifespan of 7-9 days. Platelets are the first responders at the site of vascular injury and bleeding, and participate in clot formation via injury site-specific primary mechanisms of adhesion, activation and aggregation to form a platelet plug, as well as secondary mechanisms of augmenting coagulation via thrombin amplification and fibrin generation. Platelets also secrete various granule contents that enhance these mechanisms for clot growth and stability. The resultant clot seals the injury site to stanch bleeding, a process termed as hemostasis. Due to this critical role, a reduction in platelet count or dysregulation in platelet function is associated with bleeding risks and hemorrhagic complications. These scenarios are often treated by prophylactic or emergency transfusion of platelets. However, platelet transfusions face significant challenges due to limited donor availability, difficult portability and storage, high bacterial contamination risks, and very short shelf life (~5-7 days). These are currently being addressed by a robust volume of research involving reduced temperature storage and pathogen reduction processes on donor platelets to improve shelf-life and reduce contamination, as well as bioreactor-based approaches to generate donor-independent platelets from stem cells in vitro. In parallel, a complementary research field has emerged that involves the design of artificial platelets utilizing biosynthetic particle constructs that functionally emulate various hemostatic mechanisms of platelets. Here, we provide a comprehensive review of the history and the current state-of-the-art artificial platelet approaches, along with discussing the translational opportunities and challenges.

Prehospital Whole Blood Transfusion Programs in Norway

BACKGROUND

Prehospital management of severe hemorrhage has evolved significantly in Norwegian medical emergency services in the last 10 years. Treatment algorithms for severe bleeding were previously focused on restoration of the blood volume by administration of crystalloids and colloids, but now the national trauma system guidelines recommend early balanced transfusion therapy according to remote damage control resuscitation principles.

MATERIALS AND METHODS

This survey describes the implementation, utilization, and experience of the use of low titer group O whole blood (LTOWB) and blood components in air ambulance services in Norway. Medical directors from all air ambulance bases in Norway as well as the blood banks that support LTOWB were invited to participate.

RESULTS

Medical directors from all 13 helicopter emergency medical services (HEMS) bases, the 7 search and rescue (SAR) helicopter bases, and the 4 blood banks that support HEMS with LTOWB responded to the survey. All HEMS and SAR helicopter services carry LTOWB or blood components. Four of 20 (20%) HEMS bases have implemented LTOWB. A majority of services (18/20, 90%) have a preference for LTOWB, primarily because LTOWB enables early balanced transfusion and has logistical benefits in time-critical emergencies and during prolonged evacuations.

CONCLUSION

HEMS services and blood banks report favorable experiences in the implementation and utilization of LTOWB. Prehospital balanced blood transfusion using whole blood is feasible in Norway.

Whole Blood Versus Conventional Blood Component Massive Transfusion Protocol Therapy in Civilian Trauma Patients

BACKGROUND

Military data demonstrating an improved survival rate with whole blood (WB) have led to a shift toward the use of WB in civilian trauma. The purpose of this study is to compare a low-titer group O WB (LTOWB) massive transfusion protocol (MTP) to conventional blood component therapy (BCT) MTP in civilian trauma patients.

METHODS

Trauma patients 15 years or older who had MTP activations from February 2019 to December 2020 were included. Patients with a LTOWB MTP activation were compared to BCT MTP patients from a historic cohort.

RESULTS

299 patients were identified, 169 received LTOWB and 130 received BCT. There were no differences in age, gender, or injury type. The Injury Severity Score was higher in the BCT group (27 vs 25, P = .006). The LTOWB group had a longer transport time (33 min vs 26 min, P < .001) and a lower arrival temperature (35.8 vs 36.1, P < .001). Other hemodynamic parameters were similar between the groups. The LTOWB group had a lower in-hospital mortality rate compared to the BCT group (19.5% vs 30.0%, P = .035). There were no differences in total transfusion volumes at 4 hours and 24 hours. No differences were seen in transfusion reactions or hospital complications. Multivariable logistic regression identified ISS, age, and 24-hour transfusion volume as predictors of mortality.

DISCUSSION

Resuscitating severely injured trauma patient with LTOWB is safe and may be associated with an improved survival.

Is the whole greater than the sum of its parts? The implementation and outcomes of a whole blood program in Ecuador

BACKGROUND

Hemorrhagic shock is a major cause of mortality in low-income and middle-income countries (LMICs). Many institutions in LMICs lack the resources to adequately prescribe balanced resuscitation. This study aims to describe the implementation of a whole blood (WB) program in Latin America and to discuss the outcomes of the patients who received WB.

METHODS

We conducted a retrospective review of patients resuscitated with WB from 2013 to 2019. Five units of O+ WB were made available on a consistent basis for patients presenting in hemorrhagic shock. Variables collected included gender, age, service treating the patient, units of WB administered, units of components administered, admission vital signs, admission hemoglobin, shock index, Revised Trauma Score in trauma patients, intraoperative crystalloid (lactated Ringer's or normal saline) and colloid (5% human albumin) administration, symptoms of transfusion reaction, length of stay, and in-hospital mortality.

RESULTS

The sample includes a total of 101 patients, 57 of which were trauma and acute care surgery patients and 44 of which were obstetrics and gynecology patients. No patients developed symptoms consistent with a transfusion reaction. The average shock index was 1.16 (±0.55). On average, patients received 1.66 (±0.80) units of WB. Overall mortality was 13.86% (14 of 101) in the first 24 hours and 5.94% (6 of 101) after 24 hours.

DISCUSSION

Implementing a WB protocol is achievable in LMICs. WB allows for more efficient delivery of hemostatic resuscitation and is ideal for resource-restrained settings. To our knowledge, this is the first description of a WB program implemented in a civilian hospital in Latin America.

LEVEL OF EVIDENCE

Level IV.

Hemostatic Resuscitation in Children

Trauma is a major source of morbidity and mortality for children worldwide; life-threatening hemorrhage is a primary cause of preventable death. Essential interventions in children with life-threatening hemorrhage include hemostatic resuscitation and mechanical control of bleeding. Herein we review pediatric hemostatic resuscitation, a strategy that addresses both hemorrhagic shock and the coagulopathic complications described in patients with major hemorrhage. Some components of hemostatic resuscitation may include: early and aggressive resuscitation with blood products, minimizing crystalloid and hemodilution, antifibrinolytic adjuncts such as tranexamic acid, and the novel use of low-titer group O whole-blood (LTOWB) transfusion in injured children. The following selection of important publications address the current state of hemostatic resuscitation strategies in pediatric trauma patients as well as the remaining knowledge gaps and areas for further research.

Whole Blood Transfusion: Past, Present, and Future

Transfusion of whole blood largely was replaced by component therapy in the 1970s and 1980s. The recent military operations in Iraq and Afghanistan returned whole blood to military trauma care. Eventually, whole blood use was incorporated into some civilian trauma care. It has been utilized in several other civilian populations as well. Trials to compare whole blood to component therapy are ongoing.

The Pathophysiology and Management of Hemorrhagic Shock in the Polytrauma Patient

The recognition and management of life-threatening hemorrhage in the polytrauma patient poses several challenges to prehospital rescue personnel and hospital providers. First, identification of acute blood loss and the magnitude of lost volume after torso injury may not be readily apparent in the field. Because of the expression of highly effective physiological mechanisms that compensate for a sudden decrease in circulatory volume, a polytrauma patient with a significant blood loss may appear normal during examination by first responders. Consequently, for every polytrauma victim with a significant mechanism of injury we assume substantial blood loss has occurred and life-threatening hemorrhage is progressing until we can prove the contrary. Second, a decision to begin damage control resuscitation (DCR), a costly, highly complex, and potentially dangerous intervention must often be reached with little time and without sufficient clinical information about the intended recipient. Whether to begin DCR in the prehospital phase remains controversial. Furthermore, DCR executed imperfectly has the potential to worsen serious derangements including acidosis, coagulopathy, and profound homeostatic imbalances that DCR is designed to correct. Additionally, transfusion of large amounts of homologous blood during DCR potentially disrupts immune and inflammatory systems, which may induce severe systemic autoinflammatory disease in the aftermath of DCR. Third, controversy remains over the composition of components that are transfused during DCR. For practical reasons, unmatched liquid plasma or freeze-dried plasma is transfused now more commonly than ABO-matched fresh frozen plasma. Low-titer type O whole blood may prove safer than red cell components, although maintaining an inventory of whole blood for possible massive transfusion during DCR creates significant challenges for blood banks. Lastly, as the primary principle of management of life-threatening hemorrhage is surgical or angiographic control of bleeding, DCR must not eclipse these definitive interventions.

Choice of Whole Blood versus Lactated Ringer's Resuscitation Modifies the Relationship between Blood Pressure Target and Functional Outcome after Traumatic Brain Injury plus Hemorrhagic Shock in Mice

Civilian traumatic brain injury (TBI) guidelines recommend resuscitation of patients with hypotensive TBI with crystalloids. Increasing evidence, however, suggests that whole blood (WB) resuscitation may improve physiological and survival outcomes at lower resuscitation volumes, and potentially at a lower mean arterial blood pressure (MAP), than crystalloid after TBI and hemorrhagic shock (HS). The objective of this study was to assess whether WB resuscitation with two different MAP targets improved behavioral and histological outcomes compared with lactated Ringer's (LR) in a mouse model of TBI+HS. Anesthetized mice (n = 40) underwent controlled cortical impact (CCI) followed by HS (MAP = 25-27 mm Hg; 25 min) and were randomized to five groups for a 90 min resuscitation: LR with MAP target of 70 mm Hg (LR70), LR60, WB70, WB60, and monitored sham. Mice received a 20 mL/kg bolus of LR or autologous WB followed by LR boluses (10 mL/kg) every 5 min for MAP below target. Shed blood was reinfused after 90 min. Morris Water Maze testing was performed on days 14-20 post-injury. Mice were euthanized (21 d) to assess contusion and total brain volumes. Latency to find the hidden platform was greater versus sham for LR60 (p < 0.002) and WB70 (p < 0.007) but not LR70 or WB60. The WB resuscitation did not reduce contusion volume or brain tissue loss. The WB targeting a MAP of 60 mm Hg did not compromise function versus a 70 mm Hg target after CCI+HS, but further reduced fluid requirements (p < 0.03). Using LR, higher achieved MAP was associated with better behavioral performance (rho = -0.67, p = 0.028). Use of WB may allow lower MAP targets without compromising functional outcome, which could facilitate pre-hospital TBI resuscitation.

Novel resuscitation strategies in patients with a pelvic fracture

Patients with a pelvic ring injury and hemodynamic instability can be challenging to manage with high rates of morbidity and mortality rates. Protocol-based resuscitation strategies are critical to successfully manage these potentially severely injured patients in a well-coordinated manner. While some aspects of treatment may vary slightly from institution to institution, it is critical to identify pelvic injuries and their associated injuries expediently. The first step at the scene of injury or in the trauma resuscitation bay should be the immediate application of a circumferential pelvic sheet or binder, initiation of physiologically optimal fluid resuscitation in the form 1:1:1 (pRBC:FFP:platelets) or whole blood, and to consider TXA as a safe adjunct to treat coagulopathy. Providers should have a very low threshold for emergent operative intervention in the form of pelvic external fixation and/or pelvic packing. This occurs in addition to simultaneous interventions addressing the other possible sources of bleeding in patients demonstrating signs of hemorrhagic shock and failure to respond to early resuscitation and external pelvic tamponade. Finally, while arterial injury is only present in a small percentage of patients with a pelvic ring injury, percutaneous vascular intervention with selective angiography and REBOA have been shown to be efficacious for patients with clinical indicators of arterial injury or who remain hemodynamically unstable despite external pelvic tamponade and packing to address venous bleeding. They should be performed when as early as possible for patients in true extremis limit further hemorrhage and allow resuscitation efforts to continue.

Whole Blood for Resuscitation of Traumatic Hemorrhagic Shock in Adults

Injured patients with traumatic hemorrhagic shock often require resuscitation with transfusion of red blood cells, plasma, and platelets. Resuscitation with whole blood (WB) has been used in military settings, and its use is increasingly common in civilian practice. We provide an overview of the benefits and challenges, guidelines, and unanswered questions related to the use of WB in the treatment of civilian trauma-related hemorrhage. Implications for advanced practice nurses and nursing staff are also discussed.

The rebirth of the cool: a narrative review of the clinical outcomes of cold stored low titer group O whole blood recipients compared to conventional component recipients in trauma

There has been renewed interest in the use of low titer group O whole blood (LTOWB) for the resuscitation of civilian casualties. LTOWB offers several advantages over conventional components such as providing balanced resuscitation in one bag that contains less additive/preservative solution than an equivalent volume of conventional components, is easier and faster to transfuse than multiple components, avoids blood product ratio confusion, contains cold stored platelets, and reduces donor exposures. The resurgence in its use in the resuscitation of civilian trauma patients has led to the publication of an increasing number of studies on its use, primarily amongst adult recipients but also in pediatric patients. These studies have indicated that hemolysis does not occur amongst adult and pediatric non-group O recipients of a modest quantity of LTOWB. The published studies to date on mortality have shown conflicting results with some demonstrating a reduction following LTOWB transfusion while most others have not shown a reduction; there have not been any studies to date that have found significantly increased overall mortality amongst LTOWB recipients. Similarly, when other clinical outcomes, such as venous thromboembolism, sepsis, hospital or intensive care unit lengths of stay are evaluated, LTOWB recipients have not demonstrated worse outcomes compared to conventional component recipients. While definitive proof of the trends in these morbidity and mortality outcomes awaits confirmation in randomized controlled trials, the evidence to date indicates the safety of transfusing LTOWB to injured civilians.

Safety profile of low-titer group O whole blood in pediatric patients with massive hemorrhage

BACKGROUND

Low-titer Group O Whole Blood (LTOWB) is used with increasing frequency in adult and pediatric trauma and massive bleeding transfusion protocols. There is a risk of acute hemolytic reactions in non-group O recipients due to the passive transfusion of anti-A and anti-B in the LTOWB. This study investigated the hemolysis risk among pediatric recipients of LTOWB.

STUDY DESIGN AND METHODS

Blood bank records were queried for pediatric recipients of LTOWB between June 2016 and August 2020 and merged with clinical data. The primary outcome was laboratory evidence of hemolysis as manifested by changes in lactate dehydrogenase (LDH), haptoglobin, total bilirubin, reticulocyte count, potassium, and creatinine. Per protocol, these values were collected on hospital days 0-2 for recipients of LTOWB. Transfusion reactions were reported to the hospital's blood bank.

RESULTS

Forty-seven children received LTOWB transfusion between 2016 and 2020; 21 were group O and 26 were non-group O. The groups were comparable in terms of the total volume of transfused blood products, demographics, and clinical outcomes. The most common indication for LTOWB transfusion was hemorrhagic shock due to trauma. There were no clinically or statistically significant differences in baseline, post-transfusion day 1, or post-transfusion day 2 hemolysis markers between the group O and non-group O LTOWB recipients. There were no adverse events or transfusion reactions reported.

DISCUSSION

Use of up to 40 ml/kg of LTOWB appears to be serologically safe for children in hemorrhagic shock.

Coagulation function of never frozen liquid plasma stored for 40 days

BACKGROUND

Never frozen liquid plasma (LP) has limited shelf life versus fresh frozen plasma (FFP) or plasma frozen within 24 h (PF24). Previous studies showed decreasing factor activities after Day (D)14 in thawed FFP but no differences between LP and FFP until D10. This study examined LP function through D40.

STUDY DESIGN AND METHODS

FFP and PF24 were stored at -20°C until assaying. LP was assayed on D5 then stored (4°C) for testing through D40. A clinical coagulation analyzer measured Factor (F)V, FVIII, fibrinogen, prothrombin time (PT), and activated partial thromboplastin time (aPTT). Thromboelastography (TEG) and thrombogram measured functional coagulation. Ristocetin cofactor assay quantified von Willebrand factor (vWF) activity. Residual platelets were counted.

RESULTS

FV/FVIII showed diminished activity over time in LP, while PT and aPTT both increased over time. LP vWF declined significantly by D7. Fibrinogen remained high through D40. Thrombin lagtime was delayed in LP but consistent to D40, while peak thrombin was significantly lower in LP but did not significantly decline over time. TEG R-time and angle remained constant. LP and PF24 (with residual platelets) had initially higher TEG maximum amplitudes (MA), but by D14 LP was similar to FFP.

CONCLUSION

Despite significant declines in some factors in D40 LP, fibrinogen concentration and TEG MA were stable suggesting stored LP provides fibrinogen similarly to frozen plasmas even at D40. LP is easier to store and prepare for prehospital transfusion, important benefits when the alternative is crystalloid.

The Use of Whole Blood Transfusion During Non-Traumatic Resuscitation

BACKGROUND

Evidence from military populations showed that resuscitation using whole blood (WB), as opposed to component therapies, may provide additional survival benefits to traumatically injured patients. However, there is a paucity of data available for the use of WB in uninjured patients requiring transfusion. We sought to describe the use of WB in non-trauma patients at Brooke Army Medical Center (BAMC).

MATERIALS AND METHODS

Between January and December 2019, the BAMC ClinComp electronic medical record system was reviewed for all patients admitted to the hospital who received at least one unit of WB during this time period. Patients were sorted based on their primary admission diagnosis. Patients with a primary trauma-based admission were excluded.

RESULTS

One hundred patients were identified who received at least one unit of WB with a primary non-trauma admission diagnosis. Patients, on average, received 1,064 mL (750-2,458 mL) of WB but received higher volumes of component therapy. Obstetric/gynecologic (OBGYN) indications represented the largest percentage of non-trauma patients who received WB (23%), followed by hematologic/oncologic indications (16%).

CONCLUSION

In this retrospective study, WB was most commonly used for OBGYN-associated bleeding. As WB becomes more widespread across the USA for use in traumatically injured patients, it is likely that WB will be more commonly used for non-trauma patients. More outcome data are required to safely expand the indications for WB use beyond trauma.

Practical Considerations for a Military Whole Blood Program

INTRODUCTION

Prehospital care in the combat environment has always been of great importance to the U.S. military, and trauma resuscitation has remained a cornerstone. More evidence continues to demonstrate the advantages of intervention with early transfusion of blood products at the point of injury. The military has recognized these benefits; as such, the Department of Defense Joint Trauma System and the Committee on Tactical Combat Casualty Care have developed new advanced resuscitation guidelines, which now encourage the use of whole blood (WB) in the prehospital setting.

MATERIALS AND METHODS

This general review of peer-reviewed journal articles was performed through an extensive electronic search from the databases of PubMed Central (MEDLINE) and the Cochrane Library.

RESULTS

Based on this literature search, the current evidence suggests that transfusion with WB is safe and efficacious. Additionally, soldier function is preserved after donating fresh WB in the field. Currently, the collection and implementation of WB is accomplished through several different protocol-driven techniques.

CONCLUSION

WB has become the favored transfusion product as it provides all of the components of blood in a convenient package that is easy to store and transport. Specifically, group O WB containing low titers of anti-A and -B antibodies has become the transfusion product of choice, offering the ability to universally fluid resuscitate patients despite not knowing their blood group. This new ability to obtain low titer group O WB has transformed the approach to the management of hemorrhagic shock in the prehospital combat environment.

Injured recipients of low-titer group O whole blood have similar clinical outcomes compared to recipients of conventional component therapy: A single-center, retrospective study

INTRODUCTION

Low-titer group O whole blood (LTOWB) is being increasingly transfused to injured patients. This study evaluated a range of clinical outcomes to determine if receipt of LTOWB predisposed recipients to worse outcomes compared to recipients of conventional component therapy (CCT).

METHODS

A retrospective analysis of trauma patients who received at least 3 units of LTOWB (LTOWB group) versus those that received at least 3 units of RBCs, 1 unit of plasma and 1 unit of platelets but no LTOWB (CCT group) during the first 24 h of their admission was performed. Causal treatment effects were explored using propensity score matching (PSM) and coarsened exact matching (CEM). Important clinical outcomes were evaluated.

RESULTS

There were 165 CCT and 155 LTOWB recipients eligible for matching. PSM and CEM reduced covariate imbalances between the CCT and LTOWB groups, with the exception that males remained over-represented in the LTOWB group due to the hospital's former resuscitation policy of not administering RhD-positive LTOWB to females <50. In both of the matched analyses, the LTOWB group received a median of 4 LTOWB units. There were no significant differences in 6-, 24-h mortality or 30-day mortality between groups, nor were there differences in the frequency of other clinical outcomes such as acute kidney injury, sepsis, venous/arterial thromboembolism; delta MODS was lower for the LTOWB recipients in the exact match group.

CONCLUSION

In both matched analyses, administration of a median of four LTOWB units did not result in a different frequency of major clinical outcomes including mortality.

Conservation of Rh negative Low Titer O Whole Blood (LTOWB) and the need for a national conversation to define its use in trauma transfusion protocols

Low‐titer group O whole blood (LTOWB) use is growing steadily in the United States. Although the percentage of O negative LTOWB use by Red Cross hospitals has remained steady at ~23% over the last 2 years, this elevated use rate is twice that of O negative RBC components. Given the more restricted group O donor pool, this level of use will make it difficult to expand the use of this product. Evaluation of hospital practices regarding females of childbearing potential show significant variability with some hospitals transfusing O positive, with others choosing to restrict this population to O negative LTOWB or only O negative RBC component therapy. To ensure access of LTOWB to all patients who may benefit and to maintain sufficient supplies, we recommend developing standardized practice recommendations for its use.

Effectiveness and safety of whole blood compared to balanced blood components in resuscitation of hemorrhaging trauma patients - A systematic review

INTRODUCTION

Hemorrhage is a leading cause of death among trauma patients, and is the most common cause of preventable death after trauma. Since the advent of blood component fractioning, most patients receive blood components rather than whole blood (WB). WB contains all of the individual blood components and has the advantages of simplifying resuscitation logistics, providing physiological ratios of components, reducing preservative volumes and allowing transfusion of younger red blood cells (RBC). Successful experience with fresh whole blood (FWB) by the US military is well documented. In the civilian setting, transfusion of cold-stored low titer type O whole blood (LTOWB) was shown to be safe. Reports of WB are limited by small numbers and low transfusion volumes.

STUDY DESIGN

We conducted a systematic review of the available published studies, comparing efficacy and safety of resuscitation with WB to resuscitation with blood components, in hemorrhaging trauma patients, using MEDLINE, EMBASE and ISI Web of Science. The main outcomes of interest were 24 hour and 30-day survival, blood product utilization and adverse events. Two reviewers independently abstracted the studies and assessed for bias. Sub-group analyses were pre-planned on the FWB and LTOWB groups separately.

RESULTS

Out of 126 references identified through our search strategy, five studies met the inclusion criteria. Only one study of FWB showed a significant benefit on 24 hour and 30-day survival. Other studies of both FWB and LTOWB showed no statistically significant difference in survival. There is an apparent benefit in blood product utilization with the use of WB across most studies. There were no reports of transfusion related reactions, however there was an increase in the organ failure rates in the FWB groups.

CONCLUSIONS

WB was not associated with a significant survival benefit or reduced blood product utilization. Nonetheless, it seems that the use of LTOWB is safe and might carry a significant logistic benefit. The quality of the existing data is poor and further high quality studies are required.

The risk to future pregnancies of transfusing Rh(D)-negative females of childbearing potential with Rh(D)-positive red blood cells during trauma resuscitation is dependent on their age at transfusion

BACKGROUND

A risk assessment model for predicting the risk of haemolytic disease of the fetus and newborn (HDFN) in future pregnancies following the transfusion of Rh(D)-positive red blood cell (RBC)-containing products to females of childbearing potential (FCP) was developed, accounting for the age that the FCP is transfused in various countries.

METHODS

The HDFN risk prediction model included the following inputs: risk of FCP death in trauma, Rh(D) alloimmunization rate following Rh(D)-positive RBC transfusion, expected number of live births following resuscitation, probability of carrying an Rh(D)-positive fetus, the probability of HDFN in an Rh(D)-positive fetus carried by an alloimmunized mother. The model was implemented in Microsoft R Open, and one million FCPs of each age between 18 and 49 years old were simulated. Published data from eight countries, including the United States, were utilized to generate country-specific HDFN risk estimates.

RESULTS

The risk predictions showed similar characteristics for each country in that the overall risk of having a pregnancy affected by HDFN was higher if the FCP was younger when she received her Rh(D)-positive transfusion than if she was older. In the United States, the overall risk of HDFN if the FCP was transfused at age 18 was 3·4% (mild: 1·20%, moderate: 0·45%; severe: 1·15%; IUFD: 0·57%); the risk was approximately 0% if the FCP was 43 years or older at the time of transfusion.

CONCLUSION

This model can be used to predict HDFN outcomes when establishing transfusion policies as it relates to the administration of Rh(D)-positive products for massively bleeding FCPs.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.

The use of whole blood in traumatic bleeding: a systematic review

Hemostatic resuscitation is currently considered a standard of care for the management of life-threatening hemorrhage, but in some critical settings the access to high quantities of blood components is problematic. Whole blood (WB) transfusion has been proposed as an alternative modality for hemostatic resuscitation of traumatic major bleeding. To assess the efficacy and safety of WB in trauma-associated massive bleeding, we performed a systematic review of the literature. We selected studies comparing WB transfusions to transfusion of blood components (COMP) in massive trauma bleeding; both randomized clinical trial (RCT) and observational studies were considered. The outcomes were mortality (30-day/in-hospital and 24-h mortality) and adverse events/transfusion reactions. The effect sizes were crude odds ratio (OR), adjusted OR and hazard ratio (HR). The methodological quality of studies was assessed using the Cochrane Risk of Bias tool for RCTs, and the ROBIN-1 tool for observational studies. The overall quality of the available evidence was assessed with the GRADE system. One RCT (2 reports) and 6 cohort studies were included (3642 adult patients; 675 receiving WB, 2967 receiving COMP). Three studies were conducted in military setting, and 4 in civilian setting. In the overall analysis, 30-day/in-hospital and 24-h mortality did not differ significantly between groups (very low quality of the evidence due to high risk of bias, imprecision and inconsistency). After adjustment for baseline covariates in three cohort studies, the OR for mortality was significantly lower in WB recipients compared to COMP (OR 0.22; 95% CIs 0.10/0.45) (moderate grade of evidence). Adverse events and transfusion reactions were overlooked and not consistently reported. The available evidence does not allow to draw definite conclusions on the short-term and long-term efficacy and safety of WB transfusion compared to COMP transfusion. Further well designed research is needed.

Low titer group O whole blood resuscitation: Military experience from the point of injury

INTRODUCTION

In the far forward combat environment, the use of whole blood is recommended for the treatment of hemorrhagic shock after injury. In 2016, US military special operations teams began receiving low titer group O whole blood (LTOWB) for use at the point of injury (POI). This is a case series of the initial 15 patients who received LTOWB on the battlefield.

METHODS

Patients were identified in the Department of Defense Trauma Registry, and charts were abstracted for age, sex, nationality, mechanism of injury, injuries and physiologic criteria that triggered the transfusion, treatments at the POI, blood products received at the POI and the damage-control procedures done by the first surgical team, next level of care, initial interventions by the second surgical team, Injury Severity Score, and 30-day survival. Descriptive statistics were used to characterize the clinical data when appropriate.

RESULTS

Of the 15 casualties, the mean age was 28, 50% were US military, and 63% were gunshot wounds. Thirteen patients survived to discharge, one died of wounds after arrival at the initial resuscitative surgical care, and two died prehospital. The mean Injury Severity Score was 21.31 (SD, 18.93). Eleven (68%) of the causalities received additional blood products during evacuation/role 2 and/or role 3. Vital signs were available for 10 patients from the prehospital setting and 9 patients upon arrival at the first surgical capable facility. The mean systolic blood pressure was 80.5 prehospital and 117 mm Hg (p = 0.0002) at the first surgical facility. The mean heart rate was 105 beats per minute prehospital and 87.4 beats per minute (p = 0.075) at the first surgical facility. The mean hospital stay was 24 days.

CONCLUSION

The use of cold-stored LTOWB at POI is feasible during combat operations. Further data are needed to validate and inform best practice for POI transfusion.

LEVEL OF EVIDENCE

Therapeutic study, level V.