Emergency whole-blood use in the field: a simplified protocol for collection and transfusion

Which is the best storage temperature to preserve the haemostatic quality of non-leukoreduced whole blood units collected under a military emergency protocol - Cold or room temperature?

OBJECTIVES

Emergency collection may be the only way to access blood when an urgent need arises, such as in a military setting. However, it is important to preserve any excess whole blood donations for future transfusion needs. Cold or room temperature (RT) storage has been reported in the literature. This raises the question of which storage temperature best preserves haemostatic properties of whole blood (WB). Our study investigated this question for storage times up to 48 h.

METHODS

This comparison study used 30 bags of WB collected from eligible military personnel. WB bags were randomly stored at either 22 °C or 4 °C. Samples from each bag were taken immediately after blood collection and analysed again after 48 h storage. Analyses included: metabolic and haematological parameters, coagulation factors, thrombin generation potential and platelet function (platelet activity, clotting capacity and aggregometry).

RESULTS

The overall quality of both storage conditions at 48 h was adequate according to metabolic parameters. Aggregometry was significantly affected in both groups. Clot stiffness was better preserved in WB stored at RT, however coagulation time was extended compared to storage at 4 °C. The platelet count was reduced in 4 °C. The thrombin generation potential was maintained irrespective of storage conditions.

CONCLUSION

The storage at RT offers encouraging in vitro results to promote its use to recover haemostatic functions. As both conservation temperature is acceptable, this will offer greater flexibility to access blood in a resource-limited environment. The choice of either temperature should depend on the frequency of patient admissions.

Quality of whole blood stored in room temperature for up to 5 days

BACKGROUND

Non-refrigerated whole blood can be used for bleeding emergencies when cold-stored whole blood is unavailable. Storage time in room temperature is usually limited to 24 h although there is little evidence supporting this practice. We studied the quality of whole blood stored in room temperature for 5 days to investigate the effects of prolonged storage time.

STUDY DESIGN AND METHODS

Non-leukoreduced whole blood in CPDA-1 from 10 group O or A RhD positive male donors was stored in +22°C for 120 h. Samples were taken daily to assess blood cultures, blood count and metabolic parameters. Platelet function and blood coagulation were evaluated with multiple electrode aggregometry, viscoelastic tests (sonorheometry and rotational thromboelastometry), thrombin generation assay and measurements of individual clotting factors.

RESULTS

Blood cell counts remained stable during storage. Metabolic changes were similar to those previously reported in cold-stored blood products. Most coagulation factor levels, including FVIII, decreased during storage but remained within physiological range. Thrombin generation remained mostly intact during storage. In viscoelastic tests, clotting times prolonged, but clot strength remained stable. Platelet function in multiple electrode aggregometry impaired along with storage. No bacterial growth was detected in any sample.

CONCLUSION

Whole blood stored in room temperature for 5 days seems bacteriologically safe and retains most of its metabolic and hemostatic function. These results suggest that whole blood stored in room temperature may be usable for longer than the currently recommended 24 h.

Drawing and storing blood using a 3D printed bottle cap and a disinfected 500 mL drinking bottle: A proof-of-concept study

BACKGROUND

Today, with wars raging in Ukraine and the Middle East, the demand for blood is high. Despite this, few companies produce the necessary equipment to draw, store, and transfuse whole blood. This study evaluated the safety and performance of a 3D printed bottle cap in conjunction with a water bottle and some available consumables to draw and store fresh whole blood.

STUDY DESIGN AND METHODS

Bags of saline, and freshly donated whole blood, was transferred to the water bottle through a 3D printed bottle cap and stored for 72 h. An identical setup, transferring saline to a Terumo blood collection bag was used as control. Performance and safety were evaluated by calculating infusion rate and observing for backflow, respectively. The blood was also tested for hemolysis and bacterial growth at four sampling points.

RESULTS

The cap-and-bottle setup was faster than control in terms of flow rate when transferring saline (1.53 vs. 1.81 mL/s, p < .001), and non-inferior to saline control when transfusing blood (1.53 vs. 1.49 mL/s, p = .641). We did not observe any risks of causing the donor iatrogenic harm, and there was no evidence of increased hemolysis. However, there were traces of bacterial contamination in three of six bottles.

CONCLUSION

This study indicates that drawing blood is both feasible and safe, utilizing a 3D printed cap and bottle setup. Flow rate was faster than control, and mechanical properties of the blood were not affected. We were unable to determine the source of bacterial contamination in the blood.

Training of medical students in the use of emergency whole blood collection and transfusion in the framework of a civilian walking blood

INTRODUCTION

In this report, we describe a training program in emergency whole blood collection and transfusion for medical students at the University of Bergen. The overall aim of the program is to improve the availability of early balanced blood transfusion for the treatment of patients with life-threatening bleeding in rural health care services.

STUDY DESIGN AND METHODS

The voluntary training program provides the knowledge needed to practice emergency whole blood transfusions and understand the system for emergency whole blood collection in the framework of a civilian walking blood bank (WBB). It includes theoretical and practical sessions. In-person teaching and web-based learning resources are provided. An anonymous survey of the students attending the training course in the autumn of 2022 and spring 2023 was performed.

RESULTS

128 of 178 students participated in the practical training. 88 of 128 (69%) responded to the survey. 82 (93%) performed blood typing, 71 (81%) performed donor interviews, 61 (69%) partially performed whole blood collection (up to blood in bag) and 27 (30%) participated in complete whole blood collection and performed autologous reinfusion. No complications occurred during training. The students reported that the training course increased their understanding of how to ensure access to emergency blood transfusion by the use of a WBB.

DISCUSSION

Structured theoretical and practical training in emergency whole blood collection and emergency transfusion is feasible and of interest to medical students. A multidisciplinary approach to student training in emergency whole blood collection and transfusion should be considered.

Is Low-Titer Group O Whole Blood Truly a Universal Blood Product?

BACKGROUND

Whole blood was historically transfused as a type-specific product. Given recent advocacy for low-titer group O whole blood (LTOWB) as a universal blood product, we examined outcomes after LTOWB transfusion stratified by recipient blood groups.

STUDY DESIGN

Adult trauma patients receiving prehospital or in-hospital transfusion of LTOWB (November 2017 to July 2020) at a single trauma center were prospectively evaluated. The patients were divided into blood type groups (O, A, B, and AB). Major complications and survival to 30 days were compared. Univariate analyses among blood groups were followed by purposeful regression modeling, reflecting 6 variables of significance: male sex, White race, injury severity, arrival lactate, arrival systolic blood pressure, and emergency department blood products.

RESULTS

Of 1,075 patients receiving any LTOWB, 539 (50.1%) were Group O, 340 (31.6%) were Group A, 150 (14.0%) were Group B, and 46 (4.3%) were Group AB. There were no statistically significant differences in demographics, injury severity, hemolysis panels, prehospital vitals, or resuscitation parameters (all p > 0.05). However, arrival systolic pressure was lower (91 vs 102, p = 0.034) and lactate was worse (5.5 vs 4.1, p = 0.048) in Group B patients compared to other groups. While survival and most major complications did not differ across recipient groups, acute kidney injury (AKI) initially appeared higher for Group B. Stepwise regression did not show a difference in AKI rates. This analysis was repeated in patients receiving only component products. Group B again showed no significantly increased risk of AKI (13%) compared to other groups (O 7%, A 7%, AB 5%; p = 0.091).

CONCLUSIONS

LTOWB appears to be a safe product for universal use across all blood groups. Group B recipients arrived with worse physiologic values associated with hemorrhagic shock whether receiving LTOWB or standard component products.

The Norwegian blood preparedness project: A whole blood program including civilian walking blood banks for early treatment of patients with life-threatening bleeding in municipal health care services, ambulance services, and rural hospitals

Background

Civilian and military guidelines recommend early balanced transfusion to patients with life‐threatening bleeding to improve survival. To provide the best care to patients with hemorrhagic shock in regions with reduced access to evacuation, blood preparedness must be ensured also on a municipal health care level. The primary aim of the Norwegian Blood Preparedness project is to enable rural hospitals, prehospital ambulance services, and municipal health care services to start early balanced blood transfusions for patients with life‐threatening bleeding regardless of etiology.

Study Design and Methods

The project is designed based on three principles: (1) Early balanced transfusion should be provided for patients with life‐threatening bleeding, (2) Management of an emergency requires a planned and rehearsed day‐to‐day system for blood preparedness, and (3) A decentralized system is needed to ensure local self‐sufficiency in an emergency. We developed a system for education and training in blood‐based resuscitation with a focus on the municipal health care service.

Results

In this publication, we describe the implementation of emergency whole blood collections from a preplanned civilian walking blood bank in the municipal health care service. This includes donor selection, whole blood collection, emergency transfusion and quality assessment of practice.

Conclusion

We conclude that implementation of a Whole Blood based emergency transfusion program is feasible on all health care levels and that a preplanned civilian walking blood bank should be considered in locations were prolonged transport‐times may reduce access to blood transfusion for patients with life threatening bleeding.

The regional whole blood program in San Antonio, TX: A 3-year update on prehospital and in-hospital transfusion practices for traumatic and non-traumatic hemorrhage

Low titer type O Rh-D + whole blood (LTO + WB) has become a first-line resuscitation medium for hemorrhagic shock in many centers around the World. Showing early effectiveness on the battlefield, LTO + WB is used in both the pre-hospital and in-hospital settings for traumatic and non-traumatic hemorrhage resuscitation. Starting in 2018, the San Antonio Whole Blood Collaborative has worked to provide LTO + WB across Southwest Texas, initially in the form of remote damage control resuscitation followed by in-hospital trauma resuscitation. This program has since expanded to include pediatric trauma resuscitation, obstetric hemorrhage, females of childbearing potential, and non-traumatic hemorrhage. The objective of this manuscript is to provide a three-year update on the successes and expansion of this system and outline resuscitation challenges in special populations.

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.

Impact of Incorporating Whole Blood into Hemorrhagic Shock Resuscitation: Analysis of 1,377 Consecutive Trauma Patients Receiving Emergency-Release Uncrossmatched Blood Products

BACKGROUND

Use of whole blood (WB) for trauma resuscitation has seen a resurgence. The purpose of this study was to investigate survival benefit of WB across a diverse population of bleeding trauma patients.

STUDY DESIGN

A prospective observational cohort study of injured patients receiving emergency-release blood products was performed. All adult trauma patients resuscitated between November 2017 and September 2020 were included. The WB group included patients receiving any group O WB units. The component (COMP) group received no WB units, instead relying on fractionated blood (red blood cells, plasma, and platelets). Univariate and multivariate analyses were performed. Given large observed differences in our regression model, post hoc adjustments with inverse probability of treatment were conducted and a propensity score created. Propensity scoring and Poisson regression supported these findings.

RESULTS

Of 1,377 patients receiving emergency release blood products, 840 received WB and 537 remained in the COMP arm. WB patients had higher Injury Severity Score (ISS; 27 vs 20), lower field blood pressure (103 vs 114), and higher arrival lactate (4.2 vs 3.5; all p < 0.05). Postarrival transfusions and complications were similar between groups, except for sepsis, which was lower in the WB arm (25 vs 30%, p = 0.041). Although univariate analysis noted similar survival between WB and COMP (75 vs 76%), logistic regression found WB was independently associated with a 4-fold increased survival (odds ratio [OR] 4.10, p < 0.001). WB patients also had a 60% reduction in overall transfusions (OR 0.38, 95% CI 0.21-0.70). This impact on survival remained regardless of location of transfusion, ISS, or presence of head injury.

CONCLUSION

In patients experiencing hemorrhagic shock, WB transfusion is associated with both improved survival and decreased overall blood utilization.

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.

Trends in Prehospital Blood, Crystalloid, and Colloid Administration in Accordance With Changes in Tactical Combat Casualty Care Guidelines

INTRODUCTION

Hemorrhage is the leading threat to the survival of battlefield casualties. This study aims to investigate the types of fluids and blood products administered in prehospital trauma encounters to discover the effectiveness of Tactical Combat Casualty Care (TCCC) recommendations.

MATERIALS AND METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry with a focus on prehospital fluid and blood administration in conjunction with changes in the TCCC guidelines. We collected demographic information on each patient. We categorized receipt of each fluid type and blood product as a binary variable for each casualty and evaluated trends over 2007-2020 both unadjusted and controlling for injury severity and mechanism of injury.

RESULTS

Our original dataset comprised 25,897 adult casualties from January 1, 2007 through March 17, 2020. Most (97.3%) of the casualties were male with a median age of 25. Most (95.5%) survived to hospital discharge, and 12.2% of the dataset received fluids of any kind. Medical personnel used crystalloids in 7.4% of encounters, packed red blood cells in 2.0%, and whole blood in 0.5% with very few receiving platelets or freeze-dried plasma. In the adjusted model, we noted significant year-to-year increases in intravenous fluid administration from 2014 to 2015 and 2018 to 2019, with significant decreases noted in 2008-2009, 2010-2012, and 2015-2016. We noted no significant increases in Hextend used, but we did note significant decreases in 2010-2012. For any blood product, we noted significant increases from 2016 to 2017, with decreases noted in 2009-2013, 2015-2016, and 2017-2018. Overall, we noted a general spike in all uses in 2011-2012 that rapidly dropped off 2012-2013. Crystalloids consistently outpaced the use of blood products. We noted a small upward trend in all blood products from 2017 to 2019.

CONCLUSIONS

Changes in TCCC guidelines did not immediately translate into changes in prehospital fluid administration practices. Crystalloid fluids continue to dominate as the most commonly administered fluid even after the 2014 TCCC guidelines changed to use of blood products over crystalloids. There should be future studies to investigate the reasons for delay in guideline implementation and efforts to improve adherence.

Ranger O Low Titer (ROLO): Whole Blood Transfusion for Forward Deployed Units

First-time use of Ranger O Low Titer (ROLO) blood and implementation of a forward-walking blood bank using predetermined donors proved essential in the survival of a 33-year-old active duty soldier following a complex blast injury during combat operations. The patient sustained significant bone, soft tissue, and vascular damage and continued to deteriorate despite resuscitation with cold-stored whole blood (WB). Only after utilizing the ROLO battle drill and transfusing with fresh WB was the patient able to be stabilized and evacuated. In this case report, we discuss how ROLO walking blood bank takes the next step in aiding resuscitation, providing smaller, forward-deployed units with blood resupply without the administrative burden of storage, particularly in resource-scarce environments. We provide an overview of WB and contrast its use to that of component therapy. In conjunction with the Golden Hour, ROLO can be incorporated as the standard damage control resuscitation to reduce the risks of noncompressible hemorrhage. By taking precautionary steps in the pre-deployment setting, ROLO offers an invaluable alternative to conventional resuscitation.

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.

Pathogen reduction of whole blood: Supplementing fibrinogen partly corrects clot formation in a massive transfusion model

BACKGROUND

The use of whole blood (WB) to treat trauma patients is becoming more common. Similar to the treatment of individual components, pathogen inactivation (PI) technologies are available to treat WB. The impact of PI on WB function is not well understood. This study investigated the impact of PI of WB with riboflavin/ultraviolet (UV) light on its hemostatic function by modeling transfusion scenarios for trauma patients and assessing transfusion efficacy by rotational thromboelastometry (ROTEM). As fibrinogen is affected by PI of WB, the effect of fibrinogen supplementation commonly used in trauma patients was also analyzed in this model.

STUDY DESIGN AND METHODS

Trauma transfusion scenarios were simulated by mixing untreated WB or WB treated with the Mirasol PI technology (riboflavin/UV) in different ratios with hemodiluted blood, and the thromboelasticity was monitored by ROTEM. The impact of supplementation with the fibrinogen concentrate RiaSTAP was investigated in this model.

RESULTS

Pathogen-inactivated WB (PI-WB) showed decreased activity in the hemostatic profile compared to the untreated control. Hemodiluted blood at a hematocrit (hct) of 20%, which was reconstituted with PI-WB or untreated WB, exhibited increased alpha values, maximum clot firmness, and clot formation time. Simulating transfusion scenarios by blood replacement with PI-WB resulted in a significant difference in ROTEM parameters between reconstituted PI-treated and -untreated WB (p ≥ .05). The effect of PI treatment waned when PI-WB was enriched with fibrinogen.

CONCLUSION

ROTEM investigations suggest that PI treatment has a negative impact on WB clot formation unless fibrinogen supplementation is used.

Whole Blood Administration: Comparison of In Vitro Platelet Function of Pressure Bag, Pressure Bag With Fluid Warming Device, and Rapid Infuser Methods

BACKGROUND

Use of low-titer group O whole blood for emergent transfusion of patients with unknown blood type became AABB approved in January 2018. Since that time, there is increasing use of whole blood in massive transfusion protocols. Whole blood stored at refrigerator temperature (2-4 °C) contains functional platelets that some research proposes may provide better clot dynamics than standard platelets, which are stored at room temperature (20-24 °C). Conventional teaching does not promote infusion of platelet products with pressure or warming, due to concerns of activation and subsequent inactivity of the infused platelets. Although a few reports found no significant changes in platelet function with warming or pressure during infusion of conventional room-temperature-stored platelets, there is limited data to support use of warming or pressure for infusion of whole blood products containing cold-stored platelets.

METHODS

This study design is to evaluate and compare three commonly used methods of administering blood products in a massive transfusion setting for their potential effects on platelets contained within whole blood units (pressure bag alone, pressure bag with fluid warming line, and rapid infuser).

RESULTS

Platelet function of 10 units tested pre- and post-infusion by thromboelastography (TEG) and platelet aggregation studies found no significant difference in platelet activity pre- and post-infusion with any of the three methods evaluated.

CONCLUSIONS

This study supports the use of rapid infuser or pressure bag devices (with or without warming) as acceptable for infusion of whole blood products. Infusion of whole blood with warming is preferable to prevent potential transfusion-associated hypothermia.

Obstacles to an Effective Low-Titer O Walking Blood Bank: A Deployed Unit's Experience

INTRODUCTION

We present the experience of our U.S. Navy Role 2's deployment to the U.S. Central Command area of responsibility in support of Operation Inherent Resolve and serving a multinational, joint-service military base. We detail our efforts to establish a low-titer O (LTO) walking blood bank (WBB) in an effort to prepare for potential combat casualties.

MATERIALS AND METHODS

We decided on an LTO WBB based on our available resources and a review of the literature. We collected blood samples from volunteer O-type donors throughout deployment. We conducted some titers locally and sent all samples to the ASBP in San Antonio for confirmatory testing. We conducted internal training on the WBB to improve our efficiency. We conducted monthly base-wide drills and blood drives to increase our donor pool and improve coordination between the multiple units on base.

RESULTS

We were able to collect samples from 108 military members during our deployment. Because of cold chain and shipping issues, by the time we departed theater, we had confirmation of 31 LTO donors from the Armed Services Blood Program. Thanks to local titers and units arriving to theater with titers complete; we were able to maintain an LTO donor pool close to our intended target of 50 available donors through most of our deployment.

CONCLUSIONS

A WBB based on LTO blood is possible in theater. In order to maximize donor pools, it is imperative that units deploying to forward areas complete titer and transfusion transmissible disease testing before arrival in theater.

Practical limitations of emergency donor panels as a risk mitigation in small-scale short-term training team operations

Haemostatic resuscitation with blood products has become the expected standard of care for trauma casualties. As UK Defence increases its deployment of small-scale, short-term training teams (STTTs) in Defence Engagement and influence operations, ever greater reliance is being placed on emergency donor panels (EDP) as a source of whole blood. This paper outlines the practical limitations of using EDPs as a risk mitigation in conventional STTTs which must be considered prior to every deployment.

Cold-stored whole blood in a Norwegian emergency helicopter service: an observational study on storage conditions and product quality

BACKGROUND

Increasing numbers of emergency medical service agencies and hospitals are developing the capability to administer blood products to patients with hemorrhagic shock. Cold-stored whole blood (WB) is the only single product available to prehospital providers who aim to deliver a balanced resuscitation strategy. However, there are no data on the safety and in vitro characteristics of prehospital stored WB. This study aimed to describe the effects on in vitro quality of storing WB at remote helicopter bases in thermal insulating containers.

STUDY DESIGN AND METHODS

We conducted a two-armed single-center study. Twenty units (test) were stored in airtight thermal insulating containers, and 20 units (controls) were stored according to routine procedures in the Haukeland University Hospital Blood Bank. Storage conditions were continuously monitored during emergency medical services missions and throughout remote and blood bank storage. Hematologic and metabolic variables, viscoelastic properties, and platelet (PLT) aggregation were measured on Days 1, 8, 14, and 21.

RESULTS

Storage conditions complied with the EU guidelines throughout remote and in-hospital storage for 21 days. There were no significant differences in PLT aggregation, viscoelastic properties, and hematology variables between the two groups. Minor significantly lower pH, glucose, and base excess and higher lactate were observed after storage in airtight containers.

CONCLUSION

Forward cold storage of WB is safe and complies with EU standards. No difference is observed in hemostatic properties. Minor differences in metabolic variables may be related to the anaerobic conditions within the thermal box.

The History of Fluid Resuscitation for Bleeding

Damage control resuscitation (DCR) is a bundle of care first described by Holcomb et al. that is aimed at reducing death from hemorrhage for patients with severe traumatic bleeding. DCR principles include compressible hemorrhage control; hypotensive resuscitation; rapid surgical control of bleeding; avoidance of the overuse of crystalloids and colloids, prevention or correction of acidosis, hypothermia, and hypocalcaemia; and hemostatic resuscitation (blood-based resuscitation). Remote damage control resuscitation (RDCR) is defined as the prehospital application of DCR concepts. The term RDCR was first published by Gerhardt and has been disseminated by the (Trauma Hemostasis and Oxygenation Research), or THOR Network. The history of DCR and RDCR starts well before the inception of the terms. The concepts behind the principles of DCR and RDCR stretch far back into the past. This chapter provides an outline of this history, but it is limited to the fluid resuscitation aspect of DCR/RDCR.

Fresh Low Titer O Whole Blood Transfusion in the Austere Medical Environment

Massive hemorrhage is an immediate threat to life. The military developed the Tactical Combat Casualty Care guidelines to address the management of acute trauma, including administration of blood products. The guidelines have been expanded to include low titer O whole blood, which is in limited use by the military. This proposal describes how the transfusion of fresh whole blood might be applied to the remote civilian environment. In doing so, this life-saving intervention may be brought to the austere medical environment, allowing critically hemorrhaging patients to survive to reach definitive medical care.

Effects of platelet-sparing leukocyte reduction and agitation methods on in vitro measures of hemostatic function in cold-stored whole blood

BACKGROUND

Agitation of platelet units stored at room temperature is performed routinely to maintain platelet function, and leukoreduction of blood products is the standard of care in many countries to reduce immune consequences of transfusion. The effect of agitation and leukoreduction on whole blood stored at 4°C requires investigation, as reductions in hemostatic capacity of whole blood may reduce its efficacy in treating trauma-induced coagulopathy and platelet dysfunction. We hypothesize that agitation of whole blood will not affect hemostatic function and that leukoreduction will reduce hemostatic function of whole blood.

METHODS

In this in vitro randomized controlled study, 21 units of leukoreduced and 20 nonleukoreduced whole blood units were each randomly assigned into four agitation groups. Hemostatic parameters were measured using viscoelastic assays (rotational thromboelastometry-Extrinsic Screening Test (ROTEM-EXTEM) and thromboelastography (TEG) platelet mapping), impedance aggregometry (agonists-adenosine phosphate, arachidonic acid, thrombin receptor activating peptide, and collagen), and a thrombin generation assay from these whole blood units before and after filtration and on 0, 5, 10, and 15 days of storage at 4°C.

RESULTS

Leukoreduction compared to nonleukoreduction reduced platelet concentration on Day 0. Viscoelastic measures and thrombin generation parameters revealed significant reduction in hemostatic function between the leukoreduced units and the nonleukoreduced units at a few time points. Leukoreduced units consistently demonstrated reduced platelet aggregation compared to the nonleukoreduced units. Agitation methods did not significantly affect any of the hemostatic parameters examined.

CONCLUSIONS

Leukoreduction of whole blood with a platelet-sparing filter caused a moderate but significant reduction in some measures of whole blood hemostatic function most evident early in storage. The benefits of leukoreduction should be weighed against the potential reduced hemostatic function of leukoreduced units. Agitation of whole blood is not required to maintain hemostatic function.

LEVEL OF EVIDENCE

In vitro randomized controlled trial, level 1.

Transfusion strategies for major haemorrhage in trauma

Trauma is a leading cause of death worldwide in persons under 44 years of age, and uncontrolled haemorrhage is the most common preventable cause of death in this patient group. The transfusion management of trauma haemorrhage is unrecognisable from 20 years ago. Changes in clinical practice have been driven primarily by an increased understanding of the pathophysiology of trauma-induced coagulopathy (TIC), which is associated with poor clinical outcomes, including a 3- to 4-fold increased risk of death. Targeting this coagulopathy alongside changes to surgical and anaesthetic practices (an overarching strategy known as damage control surgery/damage control resuscitation) has led to a significant reduction in mortality rates over the last two decades. This narrative review will discuss the transfusion practices that are currently used for trauma haemorrhage and the evidence that supports these practices.

Blood transfusion management in the severely bleeding military patient

PURPOSE OF REVIEW

Hemorrhage remains the primary cause of preventable death on the battlefield and in civilian trauma. Hemorrhage control is multifactorial and starts with point-of-injury care. Surgical hemorrhage control and time from injury to surgery is paramount; however, interventions in the prehospital environment and perioperative period affect outcomes. The purpose of this review is to understand concepts and strategies for successful management of the bleeding military patient. Understanding the life-threatening nature of coagulopathy of trauma and implementing strategies aimed at full spectrum hemorrhage management from point of injury to postoperative care will result in improved outcomes in patients with life-threatening bleeding.

RECENT FINDINGS

Timely and appropriate therapies impact survival. Blood product resuscitation for life-threatening hemorrhage should either be with whole blood or a component therapy strategy that recapitulates the functionality of whole blood. The US military has transfused over 10 000 units of whole blood since the beginning of the wars in Iraq and Afghanistan. The well recognized therapeutic benefits of whole blood have pushed this therapy far forward into prehospital care in both US and international military forces. Multiple hemostatic adjuncts are available that are likely beneficial to the bleeding military patient; and other products and techniques are under active investigation.

SUMMARY

Lessons learned in the treatment of combat casualties will likely continue to have positive impact and influence and the management of hemorrhage in the civilian trauma setting.

Whole Blood Transfusion

Whole blood is the preferred product for resuscitation of severe traumatic hemorrhage. It contains all the elements of blood that are necessary for oxygen delivery and hemostasis, in nearly physiologic ratios and concentrations. Group O whole blood that contains low titers of anti-A and anti-B antibodies (low titer group O whole blood) can be safely transfused as a universal blood product to patients of unknown blood group, facilitating rapid treatment of exsanguinating patients. Whole blood can be stored under refrigeration for up to 35 days, during which it retains acceptable hemostatic function, though supplementation with specific blood components, coagulation factors or other adjuncts may be necessary in some patients. Fresh whole blood can be collected from pre-screened donors in a walking blood bank to provide effective resuscitation when fully tested stored whole blood or blood components are unavailable and the need for transfusion is urgent. Available clinical data suggest that whole blood is at least equivalent if not superior to component therapy in the resuscitation of life-threatening hemorrhage. Low titer group O whole blood can be considered the standard of care in resuscitation of major hemorrhage.

Prehospital Blood Product Administration Opportunities in Ground Transport ALS EMS – A Descriptive Study

Introduction

Hemorrhage remains the major cause of preventable death after trauma. Recent data suggest that earlier blood product administration may improve outcomes. The purpose of this study was to determine whether opportunities exist for blood product transfusion by ground Emergency Medical Services (EMS).

Methods

This was a single EMS agency retrospective study of ground and helicopter responses from January 1, 2011 through December 31, 2015 for adult trauma patients transported from the scene of injury who met predetermined hemodynamic (HD) parameters for potential transfusion (heart rate [HR]≥120 and/or systolic blood pressure [SBP]≤90).

Results

A total of 7,900 scene trauma ground transports occurred during the study period. Of 420 patients meeting HD criteria for transfusion, 53 (12.6%) had a significant mechanism of injury (MOI). Outcome data were available for 51 patients; 17 received blood products during their emergency department (ED) resuscitation. The percentage of patients receiving blood products based upon HD criteria ranged from 1.0% (HR) to 5.9% (SBP) to 38.1% (HR+SBP). In all, 74 Helicopter EMS (HEMS) transports met HD criteria for blood transfusion, of which, 28 patients received prehospital blood transfusion. Statistically significant total patient care time differences were noted for both the HR and the SBP cohorts, with HEMS having longer time intervals; no statistically significant difference in mean total patient care time was noted in the HR+SBP cohort.

Conclusions

In this study population, HD parameters alone did not predict need for ED blood product administration. Despite longer transport times, only one-third of HEMS patients meeting HD criteria for blood administration received prehospital transfusion. While one-third of ground Advanced Life Support (ALS) transport patients manifesting HD compromise received blood products in the ED, this represented 0.2% of total trauma transports over the study period. Given complex logistical issues involved in prehospital blood product administration, opportunities for ground administration appear limited within the described system.

MixFM, ZielinskiMD, MyersLA, BernsKS, LukeA, StubbsJR, ZietlowSP, JenkinsDH, SztajnkrycerMD. Prehospital blood product administration opportunities in ground transport ALS EMS – a descriptive study. Prehosp Disaster Med. 2018;33(3):230–236.

Limited Resuscitation With Fresh or Stored Whole Blood Corrects Cardiovascular and Metabolic Function in a Rat Model of Polytrauma and Hemorrhage

INTRODUCTION

We have recently shown that human whole blood stored at 4°C maintains hemostatic and platelet function. In this study, we compared restoration of hemodynamic, metabolic and hemostatic function after limited resuscitation with rat fresh whole blood, rat stored whole blood, or Lactated Ringers in traumatized rats.

METHODS

Rat whole blood was stored for 10 days at 4°C for evaluation of hemostatic function. Polytrauma was performed on isoflurane-anesthetized Sprague-Dawley rats (350-450 g) by damage to the intestines, liver, right leg skeletal muscle, and right femur fracture, followed by 40% hemorrhage. At 1 h, rats were resuscitated (20%) with either fresh whole blood (FWB), stored whole blood, 4°C for 7 days (SWB), Lactated Ringers (LR), or nothing. Blood samples were taken before and 2 h after trauma and hemorrhage to evaluate metabolic and hemostatic function.

RESULTS

Whole blood stored for 10 days showed a significant prolongation in prothrombin time (PT) and activated partial thromboplastin time (aPTT), and fall in fibrinogen concentration, but no change in Maximum Clot Firmness or speed of clot formation. Platelet function was maintained until day 7 in storage, than fell significantly. Polytrauma and hemorrhage in rats led to a fall in arterial pressure, plasma bicarbonate, fibrinogen, and platelet function, and a rise in plasma lactate, PT, aPTT, and creatinine. Resuscitation with either FWB or 7 day SWB, but not LR, returned arterial pressure, plasma lactate and plasma bicarbonate to levels similar to control, but had no effect on the fall in fibrinogen or platelet function, or the rise in PT, aPTT, or creatinine.

CONCLUSION

Hemostatic and platelet function of rat whole blood stored at 4°C is preserved for at least 7 days in vitro. Low volume resuscitation with SWB or FWB, but not LR, restores hemodynamic and metabolic function, but not the coagulopathy after severe trauma and hemorrhage.

What If I Don't Have Blood? Hextend is Superior to 3% Saline in an Experimental Model of Far Forward Resuscitation After Hemorrhage

INTRODUCTION

Hypertonic crystalloid solutions, colloids, and fresh whole blood (FWB) have all been proposed for prehospital resuscitation after hemorrhage. However, there are no direct comparisons of the efficacy of these different fluids. We compared Hextend, 3% hypertonic saline (HS), and FWB in a porcine model of hemorrhagic shock.

MATERIALS AND METHODS

Female swine (n = 5/group) underwent splenectomy and pressure-controlled hemorrhage followed by resuscitation with Hextend, 3% HS, or FWB. They were maintained at a target mean arterial pressure (MAP) for 4 h, holding or infusing fluid as necessary. Sham animals for comparison underwent splenectomy alone.

RESULTS

The mean volume required to maintain target MAP was significantly higher for 3% HS (1,016 ± 386 mL) than for Hextend (346 ± 299 mL, P < 0.05). After 4 h of resuscitation, the MAP in the 3% HS group (44 ± 3 mmHg) was significantly lower than shams (56 ± 7 mmHg, P < 0.05). Three percent HS recipients had a significantly worse metabolic acidosis and anemia than shams or FWB recipients, as well as significant increases in serum sodium and chloride. Serum interleukin-6 was significantly elevated in 3% HS and FWB recipients relative to Hextend recipients (105.3 ± 58.6 and 97.2 ± 21 vs. 38.6 ± 27.1 pcg/mL, P < 0.05).

CONCLUSIONS

HS performed inferiorly to Hextend as a volume expanding resuscitative fluid after hemorrhage. On the basis of our data, we would recommend the use of Hextend over 3% saline in far forward resuscitation after hemorrhage.

Remote Damage Control Resuscitation in Austere Environments

Hemorrhage is the leading cause of preventable military and civilian trauma death. Damage control resuscitation with concomitant mechanical hemorrhage control has become the preferred in-hospital treatment of hemorrhagic shock. In particular, plasma-based resuscitation with decreased volumes of crystalloids and artificial colloids as part of damage control resuscitation has improved outcomes in the military and civilian sectors. However, translation of these principles and techniques to the prehospital, remote, and austere environments, known as remote damage control resuscitation, is challenging given the resource limitations in these settings. Rapid administration of tranexamic acid and reconstituted freeze-dried (lyophilized) plasma as early as the point of injury are feasible and likely beneficial, but comparative studies in the literature are lacking. Whole blood is likely the best fluid therapy for traumatic hemorrhagic shock, but logistical hurdles need to be addressed. Rapid control of external hemorrhage with hemostatic dressings and extremity tourniquets are proven therapies, but control of noncompressible hemorrhage (ie, torso hemorrhage) remains a significant challenge.

Fluid Resuscitation in Tactical Combat Casualty Care: Yesterday and Today

The prevailing wisdom for the prehospital fluid resuscitation of trauma victims in hemorrhagic shock in 1992 was to administer 2 L of crystalloid solution as rapidly as possible. A review of the fluid resuscitation literature found that this recommendation was not well supported by the evidence at the time. Prehospital fluid resuscitation strategies were reevaluated in the 1993-1996 Tactical Combat Casualty Care (TCCC) research program. This article reviews the advances in prehospital fluid resuscitation as recommended by the original TCCC Guidelines and modified over the following 2 decades. These advances include hypotensive resuscitation, use of prehospital whole blood or blood components when feasible, and use of Hextend or selected crystalloids when logistical considerations make blood or blood component use not feasible.

Evaluation of a lateral flow-based technology card for blood typing using a simplified protocol in a model of extreme blood sampling conditions

BACKGROUND

Life-threatening situations requiring blood transfusion under extreme conditions or in remote and austere locations, such as the battlefield or in traffic accidents, would benefit from reliable blood typing practices that are easily understood by a nonscientist or nonlaboratory technician and provide quick results.

STUDY DESIGN AND METHODS

A simplified protocol was developed for the lateral flow-based device MDmulticard ABO-D-Rh subgroups-K. Its performance was compared to a reference method (PK7300, Beckman Coulter) in native blood samples from donors. The method was tested on blood samples stressed in vitro as a model of hemorrhage cases (through hemodilution using physiologic serum) and dehydration (through hemoconcentration by removing an aliquot of plasma after centrifugation), respectively.

RESULTS

A total of 146 tests were performed on 52 samples; 126 in the hemodilution group (42 for each native, diluted 1/2, and diluted 1/4 samples) and 20 in the hemoconcentration group (10 for each native and 10% concentrated samples). Hematocrit in the tested samples ranged from 9.8% to 57.6% while hemoglobin levels ranged from 3.2 to 20.1 g/dL. The phenotype profile detected with the MDmulticard using the simplified protocol resulted in 22 A, seven B, 20 O, and three AB, of which nine were D- and five were Kell positive. No discrepancies were found with respect to the results obtained with the reference method.

CONCLUSION

The simplified protocol for MDmulticard use could be considered a reliable method for blood typing in extreme environment or emergency situations, worsened by red blood cell dilution or concentration.

Logistical Concerns for Prehospital Blood Product Use by Air Medical Services

Over the past few decades, reports have described favorable results from transfusion of blood products in helicopter EMS (HEMS). Nevertheless, the initiation of a HEMS transfusion program requires consideration of many factors, some unique to each clinical site. This paper describes our experience developing a HEMS transfusion program in an urban non-hospital based HEMS program with a history of long transport times. When considering blood use away from the hospital, major consideration must be given to safe storage and monitoring of blood products both on the ground and while in flight. PRBCs have been shown to generally be resilient to helicopter transit and have a prolonged storage duration. Transfusion of other blood products, such as plasma, involves additional challenges but has been achieved by some HEMS sites. Flight protocols should be developed addressing when and how many blood products should be transported, potentially considering patient factors, scene factors, and the regional availability of blood products during interfacility transport. Quality assurance and documentation protocols must also be developed for blood product use in flight. In our center's experience, we have so far transfused a limited number of patients with generally good results. Patient outcomes are described as below.

Deployed skills training for whole blood collection by a special operations expeditionary surgical team

BACKGROUND

Noncompressible hemorrhage is the leading cause of potentially preventable battlefield death. Combining casualty retrieval from the battlefield and damage control resuscitation (DCR) within the "golden hour" increases survival. However, transfusion requirements may exceed the current blood component stocks held by forward surgical teams. Warm fresh whole blood (WFWB) is an alternative. We report WFWB transfusion training developed by and delivered to a US Golden Hour Offset Surgical Treatment Team and the resulting improvement in confidence with WFWB transfusion.

METHODS

A bespoke instructional package was derived from existing operational clinical guidelines. All Golden Hour Offset Surgical Treatment Team personnel completed initial training, reinforced through ongoing casualty simulations. A record of blood types and donor eligibility was established to facilitate rapid identification of potential WFWB donors. Self-reported confidence in seven aspects of the WFWB transfusion process was assessed before and after training using a five-point Likert scale. Personnel were analyzed by groups consisting of those whose operational role includes WFWB transfusion ("transfusers"), clinical personnel without such responsibilities ("nontransfusers") and nonclinical personnel (other). Comparisons within and between groups were made using appropriate nonparametric tests.

RESULTS

Data were collected from 39 (89%) of 44 training participants: 24 (62%) transfusers, 12 (31%) nontransfusing clinicians, and 3 (8%) other personnel. Transfusers and nontransfusers reported increased comfort with all practical elements of WFWB transfusion. The confidence of other personnel also increased, but (likely due to small numbers) was not statistically significant.

CONCLUSION

WFWB transfusion is an integral part of modern deployed military remote DCR. Our in-theater training program rapidly and reproducibly enhanced the comfort in WFWB transfusion in providers from a range of backgrounds and skill-mixes. This model has the potential to improve both safety and effectiveness of WFWB remote DCR in the far-forward deployed setting.

LEVEL OF EVIDENCE

Therapeutic/care management study, level IV.

Volumetric control of whole blood collection in austere environments

INTRODUCTION

Fresh whole blood transfusions are a powerful tool in prehospital care; however, the lack of equipment such as a scale in field situations frequently leads to collections being under- or overfilled, leading to complications for both patient and physician. This study describes two methods for simple, rapid control of collection bag volume: (1) a length of material to constrict the bag, and (2) folding/clamping the bag.

METHOD

Whole blood collection bags were allowed to fill with saline via gravity. Paracord, zip-tie, beaded cable tie, or tourniquet was placed around the bag at circumferences of 6 to 8.75 inches. A hemostat was used to clamp folds of 1 to 1.5 inches. Several units were drawn during training exercises of the 75th Ranger Regiment with volume controlled by three methods: vision/touch estimation, constriction by paracord, and clamping with hemostat.

RESULTS

Method validation in the Terumo 450-mL bag indicated that paracord, zip-tie, and beaded cable tie lengths of 6.5 inches or clamping 1.25 inches with a hemostat provided accurate filling. The volume variance was significantly lower when using the beaded cable tie. Saline filling time was approximately 2 minutes. With the Fenwal 450-mL bag, the beaded cable tie gave best results; even if incorrectly placed by one/two beads, the volume was still within limits. In training exercises, the use of the cord/clamp greatly reduced the variability; more bags were within limits.

CONCLUSIONS

Both constricting and clamping allow for speed and consistency in blood collection. The use of common cord is appealing, but knot tying induces inevitable variability; a zip/cable tie is easier. Clamping was quicker but susceptible to high variance and bag rupturing. With proper methodological training, appropriate volumes can be obtained in any environment with minimal tools.

LEVEL OF EVIDENCE

Therapeutic/care management study, level IV.

Whole blood for hemostatic resuscitation of major bleeding

Recent combat experience reignited interest in transfusing whole blood (WB) for patients with life-threatening bleeding. US Army data indicate that WB transfusion is associated with improved or comparable survival compared to resuscitation with blood components. These data complement randomized controlled trials that indicate that platelet (PLT)-containing blood products stored at 4°C have superior hemostatic function, based on reduced bleeding and improved functional measures of hemostasis, compared to PLT-containing blood products at 22°C. WB is rarely available in civilian hospitals and as a result is rarely transfused for patients with hemorrhagic shock. Recent developments suggest that impediments to WB availability can be overcome, specifically the misconceptions that WB must be ABO specific, that WB cannot be leukoreduced and maintain PLTs, and finally that cold storage causes loss of PLT function. Data indicate that the use of low anti-A and anti-B titer group O WB is safe as a universal donor, WB can be leukoreduced with PLT-sparing filters, and WB stored at 4°C retains PLT function during 15 days of storage. The understanding that these perceived barriers are not insurmountable will improve the availability of WB and facilitate its use. In addition, there are logistic and economic advantages of WB-based resuscitation compared to component therapy for hemorrhagic shock. The use of low-titer group O WB stored for up to 15 days at 4°C merits further study to compare its efficacy and safety with current resuscitation approaches for all patients with life-threatening bleeding.

"Blood failure" time to view blood as an organ: how oxygen debt contributes to blood failure and its implications for remote damage control resuscitation

Hemorrhagic shock is both a local and systemic disorder. In the context of systemic effects, blood loss may lead to levels of reduced oxygen delivery (DO2 ) sufficient to cause tissue ischemia. Similar to other physiologic debts such as sleep, it is not possible to incur a significant oxygen debt and suffer no consequences for lack of timely repayment. While the linkage between oxygen debt and traditional organ failure (renal, hepatic, lung, and circulation) has been long recognized, we should consider failure in two additional linked and very dynamic organ systems, the endothelium and blood. These systems are very sensitive to oxygen debt and at risk for failing, having further implications on all other organ systems. The degree of damage to the endothelium is largely modulated by the degree of oxygen debt. Thus hypoperfusion is believed to begin a cascade of events leading to acute traumatic coagulopathy (ATC). This combination of oxygen debt driven endothelial damage and ATC might be considered collectively as "blood failure" due to the highly connected networks between these drivers. This article presents the implications of oxygen debt for remote damage control resuscitation strategies, such as permissive hypotension and hemostatic resuscitation. We review the impact of whole blood resuscitation and red blood cell efficacy in mitigation of oxygen debt. At last, this article recognizes the need for simple and durable, lightweight equipment that can detect the adequacy of tissue DO2 and thus patient needs for resuscitative care. Point-of-care lactate measuring may be a predictive tool for identifying high-risk trauma patients and occult shock because it provides information beyond that of vital signs and mechanism of injury as it may help predict the level of oxygen debt accumulation and need for resuscitation. Serial measurements may also be valuable as a tool in guiding resuscitative efforts.

Whole blood transfusion closest to the point-of-injury during French remote military operations

To improve the survival of combat casualties, interest in the earliest resort to whole blood (WB) transfusion on the battlefield has been emphasized. Providing volume, coagulation factors, plasma, and oxygenation capacity, WB appears actually as an ideal product severe trauma management. Whole blood can be collected in advance and stored for subsequent use, or can be drawn directly on the battlefield, once a soldier is wounded, from an uninjured companion and immediately transfused.Such concepts require a great control of risks at each step, especially regarding ABO mismatches, and transfusion-transmitted diseases. We present here the "warm and fresh" WB field transfusion program implemented among the French armed forces. We focus on the followed strategies to make it applicable on the battlefield, even during special operations and remote settings, and safe for recipients as well as for donors.

Tactical damage control resuscitation in austere military environments

BACKGROUND

Despite the early uses of tourniquets and haemostatic dressings, blood loss still accounts for the vast majority of preventable deaths on the battlefield. Over the last few years, progress has been made in the management of such injuries, especially with the use of damage control resuscitation concepts. The early application of these procedures, on the field, may constitute the best opportunity to improve survival from combat injury during remote operations.

DATA SOURCES

Currently available literature relating to trauma-induced coagulopathy treatment and far-forward transfusion was identified by searches of electronic databases. The level of evidence and methodology of the research were reviewed for each article. The appropriateness for field utilisation of each medication was then discussed to take into account the characteristics of remote military operations.

CONCLUSIONS

In tactical situations, in association with haemostatic procedures (tourniquet, suture, etc), tranexamic acid should be the first medication used according to the current guidelines. The use of fibrinogen concentrate should also be considered for patients in haemorrhagic shock, especially if point-of-care (POC) testing of haemostasis or shock severity is available. If POC evaluation is not available, it seems reasonable to still administer this treatment after clinical assessment, particularly if the evacuation is delayed. In this situation, lyophilised plasma may also be given as a resuscitation fluid while respecting permissive hypotension. Whole blood transfusion in the field deserves special attention. In addition to the aforementioned treatments, if the field care is prolonged, whole blood transfusion must be considered if it does not delay the evacuation.

The effect of stationary versus rocked storage of whole blood on red blood cell damage and platelet function

BACKGROUND

Increasingly, cold-stored whole blood (WB) is being considered for the resuscitation of civilian trauma patients. It is unclear whether the WB should be agitated to enhance the function of the platelets (PLTs) or whether agitation will cause RBC damage.

STUDY DESIGN AND METHODS

WB units were collected by standard procedures using a PLT-sparing inline leukoreduction filter and stored between 1 and 6°C. On Storage Day 3 each unit was divided into 4 subunits that were stored under one of the following conditions for 21 days: unrocked, manually rocked once daily, continuously rocked end over end, or continuously rocked horizontally. From Day 3 to Day 10, hemolysis and the mechanical fragility index (MFI) for RBC injury were measured daily and again on Days 15 and 21 (n = 9-16 units tested each time). On Days 4 and 10, rapid thromboelastogram (rTEG) measurements were performed (n = 8-10 units tested each time).

RESULTS

Hemolysis and MFI increased significantly between Day 3 and Day 21 (p < 0.0001) for all RBC rocking conditions, as well as the unrocked units. Only the manually and horizontally rocked units demonstrated higher hemolysis (on Day 21) and MFI (starting on Day 10) compared to the unrocked units. Only the α-angle and maximum amplitude in the end-over-end rocked units increased significantly between Day 4 and Day 10. There were no significant differences between the rocked and unrocked units on Day 10 for any rTEG variable.

CONCLUSIONS

Rocking does not appear to enhance in vitro PLT activity in cold-stored WB and can lead to increased hemolysis.