Meta-analysis of plasma to red blood cell ratios and mortality in massive blood transfusions for trauma

Is there a need for fresh frozen plasma and platelet transfusion in trauma patients receiving submassive transfusion?

Background

Blood transfusions have become a vital intervention in trauma care. There are limited data on the safety and effectiveness of submassive transfusion (SMT), that is defined as receiving less than 10 units packed red blood cells (PRBCs) in the first 24 hours. This study aimed to evaluate the efficacy and safety of fresh frozen plasma (FFP) and platelet transfusions in patients undergoing SMT.

Methods

This is a retrospective cohort, reviewing the Trauma Quality Improvement Program database spanning 3 years (2016 to 2018). Adult patients aged 18 years and older who had received at least 1 unit of PRBC within 24 hours were included in the study. We used a multivariate regression model to analyze the cut-off units of combined resuscitation (CR) (which included PRBCs along with at least one unit of FFP and/or platelets) that leads to survival improvement. Patients were then stratified into two groups: those who received PRBC alone and those who received CR. Propensity score matching was performed in a 1:1 ratio.

Results

The study included 85 234 patients. Based on the multivariate regression model, transfusion of more than 3 units of PRBC with at least 1 unit of FFP and/or platelets demonstrated improved mortality compared with PRBC alone. Among 66 319 patients requiring SMT and >3 units of PRBCs, 25 978 received PRBC alone, and 40 341 received CR. After propensity matching, 4215 patients were included in each group. Patients administered CR had a lower rate of complications (15% vs 26%), acute respiratory distress syndrome (3% vs 5%) and acute kidney injury (8% vs 11%). Rates of sepsis and venous thromboembolism were similar between the two groups. Multivariate regression analysis indicated that patients receiving 4 to 7 units of PRBC alone had significantly higher ORs for mortality than those receiving CR.

Conclusion

Trauma patients requiring more than 3 units of PRBCs who received CR with FFP and platelets experienced improved survival and reduced complications.

Level of evidence

Level III retrospective study.

Air Medical Blood Transfusion as a Trigger of Massive Transfusion Protocol

Air medical services can improve access to blood products at the point of injury. Studies have shown that early activation of mass transfusion protocols (MTPs) can improve the survival of trauma patients by up to 25%. There are several scoring systems to guide early activation, but the use of a single criterion has been elusive. Our study sought to determine if air medical administration of blood products was a risk factor for massive transfusion activation and utilization of prehospital vital signs for calculation of the shock index. In our retrospective study, we evaluated adult trauma patients transfused by helicopter emergency medical services (HEMS) and as a control all patients in our institution receiving the MTP. Our study found HEMS blood transfusion was not a reliable trigger for MTP, although the sample size may have limited our findings. We found that HEMS care resulted in an overall reduction in the volume of transfusion and an improvement in hemodynamic parameters upon trauma center arrival. HEMS transfusion and a higher rate of tranexamic acid administration may have contributed to these findings. Of note, the assessment of blood consumption score and shock index were nonspecific in the study populations.

Association of Trauma Molecular Endotypes With Differential Response to Transfusion Resuscitation Strategies

Importance

It is not clear which severely injured patients with hemorrhagic shock may benefit most from a 1:1:1 vs 1:1:2 (plasma:platelets:red blood cells) resuscitation strategy. Identification of trauma molecular endotypes may reveal subgroups of patients with differential treatment response to various resuscitation strategies.

Objective

To derive trauma endotypes (TEs) from molecular data and determine whether these endotypes are associated with mortality and differential treatment response to 1:1:1 vs 1:1:2 resuscitation strategies.

Design, Setting, and Participants

This was a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized clinical trial. The study cohort included individuals with severe injury from 12 North American trauma centers. The cohort was taken from the participants in the PROPPR trial who had complete plasma biomarker data available. Study data were analyzed on August 2, 2021, to October 25, 2022.

Exposures

TEs identified by K-means clustering of plasma biomarkers collected at hospital arrival.

Main Outcomes and Measures

An association between TEs and 30-day mortality was tested using multivariable relative risk (RR) regression adjusting for age, sex, trauma center, mechanism of injury, and injury severity score (ISS). Differential treatment response to transfusion strategy was assessed using an RR regression model for 30-day mortality by incorporating an interaction term for the product of endotype and treatment group adjusting for age, sex, trauma center, mechanism of injury, and ISS.

Results

A total of 478 participants (median [IQR] age, 34.5 [25-51] years; 384 male [80%]) of the 680 participants in the PROPPR trial were included in this study analysis. A 2-class model that had optimal performance in K-means clustering was found. TE-1 (n = 270) was characterized by higher plasma concentrations of inflammatory biomarkers (eg, interleukin 8 and tumor necrosis factor α) and significantly higher 30-day mortality compared with TE-2 (n = 208). There was a significant interaction between treatment arm and TE for 30-day mortality. Mortality in TE-1 was 28.6% with 1:1:2 treatment vs 32.6% with 1:1:1 treatment, whereas mortality in TE-2 was 24.5% with 1:1:2 treatment vs 7.3% with 1:1:1 treatment (P for interaction = .001).

Conclusions and Relevance

Results of this secondary analysis suggest that endotypes derived from plasma biomarkers in trauma patients at hospital arrival were associated with a differential response to 1:1:1 vs 1:1:2 resuscitation strategies in trauma patients with severe injury. These findings support the concept of molecular heterogeneity in critically ill trauma populations and have implications for tailoring therapy for patients at high risk for adverse outcomes.

Association between perioperative plasma transfusion and in-hospital mortality in patients undergoing surgeries without massive transfusion: A nationwide retrospective cohort study

Background

An aggressive plasma transfusion is associated with a decreased mortality in traumatic patients requiring massive transfusion (MT). However, it is controversial whether non-traumatic or non-massively transfused patients can benefit from high doses of plasma.

Methods

We performed a nationwide retrospective cohort study using data from Hospital Quality Monitoring System, which collected anonymized inpatient medical records from 31 provinces in mainland China. We included the patients who had at least one record of surgical procedure and received red blood cell transfusion on the day of surgery from 2016 to 2018. We excluded those receiving MT or diagnosed with coagulopathy at admission. The exposure variable was the total volume of fresh frozen plasma (FFP) transfused, and the primary outcome was in-hospital mortality. The relationship between them was assessed using multivariable logistic regression model adjusting 15 potential confounders.

Results

A total of 69319 patients were included, and 808 died among them. A 100-ml increase in FFP transfusion volume was associated with a higher in-hospital mortality (odds ratio 1.05, 95% confidence interval 1.04-1.06, p < 0.001) after controlling for the confounders. FFP transfusion volume was also associated with superficial surgical site infection, nosocomial infection, prolonged length of hospital stay, ventilation time, and acute respiratory distress syndrome. The significant association between FFP transfusion volume and in-hospital mortality was extended to the subgroups of cardiac surgery, vascular surgery, and thoracic or abdominal surgery.

Conclusions

A higher volume of perioperative FFP transfusion was associated with an increased in-hospital mortality and inferior postoperative outcomes in surgical patients without MT.

Clinical decision support for severe trauma patients: Machine learning based definition of a bundle of care for hemorrhagic shock and traumatic brain injury

BACKGROUND

Deviation from guidelines is frequent in emergency situations, and this may lead to increased mortality. Probably because of time constraints, 55% is the greatest reported guidelines compliance rate in severe trauma patients. This study aimed to identify among all available recommendations a reasonable bundle of items that should be followed to optimize the outcome of hemorrhagic shocks (HSs) and severe traumatic brain injuries (TBIs).

METHODS

We first estimated the compliance with French and European guidelines using the data from the French TraumaBase registry. Then, we used a machine learning procedure to reduce the number of recommendations into a minimal set of items to be followed to minimize 7-day mortality. We evaluated the bundles using an external validation cohort.

RESULTS

This study included 5,924 trauma patients (1,414 HS and 4,955 TBI) between 2011 and August 2019 and studied compliance to 36 recommendation items. Overall compliance rate to recommendation items was 71.6% and 66.9% for HS and TBI, respectively. In HS, compliance was significantly associated with 7-day decreased mortality in univariate analysis but not in multivariate analysis (risk ratio [RR], 0.91; 95% confidence interval [CI], 0.90-1.17; p = 0.06). In TBI, compliance was significantly associated with decreased mortality in univariate and multivariate analysis (RR, 0.85; 95% CI, 0.75-0.92; p = 0.01). For HS, the bundle included 13 recommendation items. In the validation cohort, when this bundle was applied, patients were found to have a lower 7-day mortality rate (RR, 0.46; 95% CI, 0.27-0.63; p = 0.01). In TBI, the bundle included seven items. In the validation cohort, when this bundle was applied, patients had a lower 7-day mortality rate (RR, 0.55; 95% CI, 0.34-0.71; p = 0.02).

DISCUSSION

Using a machine-learning procedure, we were able to identify a subset of recommendations that minimizes 7-day mortality following traumatic HS and TBI. These two bundles remain to be evaluated in a prospective manner.

LEVEL OF EVIDENCE

Care Management, level II.

Pre-hospital transfusion of post-traumatic hemorrhage: Medical and regulatory aspects

Data of good methodological quality have recently become available to support prehospital use of transfusion in the severe trauma setting. Consistent with recent guidelines for the implementation of damage control resuscitation in the hospital in this setting and in the wake of numerous cohort study data from wartime medicine, they are now guided by recent guidelines for the use of freeze-dried plasma. The main difficulties to overcome in order to implement a practice are of a regulatory and logistic nature.

Viscoelastic monitoring in trauma resuscitation

BACKGROUND

Traumatic injury results in both physical and physiologic insult. Successful care of the trauma patient depends upon timely correction of both physical and biochemical injury. Trauma-induced coagulopathy is a derangement of hemostasis and thrombosis that develops rapidly and can be fatal if not corrected. Viscoelastic monitoring (VEM) assays have been developed to provide rapid, accurate, and relatively comprehensive depictions of an individual's coagulation profile. VEM are increasingly being integrated into trauma resuscitation guidelines to provide dynamic and individualized guidance to correct coagulopathy.

STUDY DESIGN AND METHODS

We performed a narrative review of the search terms viscoelastic, thromboelastography, thromboelastometry, TEG, ROTEM, trauma, injury, resuscitation, and coagulopathy using PubMed. Particular focus was directed to articles describing algorithms for management of traumatic coagulopathy based on VEM assay parameters.

RESULTS

Our search identified 16 papers with VEM-guided resuscitation strategies in adult patients based on TEG, 12 such protocols in adults based on ROTEM, 1 protocol for children based on TEG, and 2 protocols for children based on ROTEM.

CONCLUSIONS

This review presents evidence to support VEM use to detect traumatic coagulopathy, discusses the role of VEM in trauma resuscitation, provides a summary of proposed treatment algorithms, and discusses pending questions in the field.

Re-introducing whole blood for transfusion: considerations for blood providers

Whole blood is the original blood preparation but disappeared from the blood bank inventories in the 1980s following the advent of component therapy. In the early 2000s, both military and civilian practice called for changes in the transfusion support for massive haemorrhage. The 'clear fluid' policy was abandoned and replaced by early balanced transfusion of platelets, plasma and red cells. Whole blood is an attractive alternative to multi-component therapy, which offers reduced hemodilution, lower donor exposure and simplified logistics. However, the potential for wider re-introduction of whole blood requires re-evaluation of haemolysins, storage conditions and shelf-life, the need for leucocyte depletion/ pathogen reduction and inventory management for blood providers. This review addresses these questions and calls for research to define the optimal whole blood product and the indications for its use.

Plasma Transfusion Practice in Adult Surgical Patients: Systematic Review of the Literature

Background

Plasma transfusions are most commonly used therapeutically for bleeding or prophylactically in non-bleeding patients prior to invasive procedures or surgery. Although plasma transfusions generally seem to decline, plasma usage for indications that lack evidence of efficacy prevail.

Summary

There is wide international, interinstitutional, and interindividual variance regarding the compliance with guidelines based on published references, supported by appropriate testing. There is furthermore a profound lack of evidence from randomized controlled trials comparing the effect of plasma transfusion with that of other therapeutic interventions for most indications, including massive bleeding. The expected benefit of a plasma transfusion needs to be balanced carefully against the associated risk of adverse events. In light of the heterogeneous nature of bleeding conditions and their rapid evolvement over time, fibrinogen and factor concentrate therapy, directed at specific phases of coagulation identified by alternative laboratory assays, may offer advantages over conventional blood product ratio-driven resuscitation. However, their outcome benefit has not been demonstrated in well-powered prospective trials. This systematic review will detail the current evidence base for plasma transfusion in adult surgical patients.

Critical Care Society of Southern Africa adult patient blood management guidelines: 2019 Round-table meeting, CCSSA Congress, Durban, 2018

The CCSSA PBM Guidelines have been developed to improve patient blood management in critically ill patients in southern Africa. These consensus recommendations are based on a rigorous process by experts in the field of critical care who are also practicing in South Africa (SA). The process comprised a Delphi process, a round-table meeting (at the CCSSA National Congress, Durban, 2018), and a review of the best available evidence and international guidelines. The guidelines focus on the broader principles of patient blood management and incorporate transfusion medicine (transfusion guidelines), management of anaemia, optimisation of coagulopathy, and administrative and ethical considerations. There are a mix of low-middle and high-income healthcare structures within southern Africa. Blood products are, however, provided by the same not-for-profit non-governmental organisations to both private and public sectors. There are several challenges related to patient blood management in SA due most notably to a high incidence of anaemia, a frequent shortage of blood products, a small donor population, and a healthcare system under financial strain. The rational and equitable use of blood products is important to ensure best care for as many critically ill patients as possible. The summary of the recommendations provides key practice points for the day-to-day management of critically ill patients. A more detailed description of the evidence used to make these recommendations follows in the full clinical guidelines section.

French lyophilized plasma versus normal saline for post-traumatic coagulopathy prevention and correction: PREHO-PLYO protocol for a multicenter randomized controlled clinical trial

BACKGROUND

Post-trauma bleeding induces an acute deficiency in clotting factors, which promotes bleeding and hemorrhagic shock. However, early plasma administration may reduce the severity of trauma-induced coagulopathy (TIC). Unlike fresh frozen plasma, which requires specific hospital logistics, French lyophilized plasma (FLYP) is storable at room temperature and compatible with all blood types, supporting its use in prehospital emergency care. We aim to test the hypothesis that by attenuating TIC, FLYP administered by prehospital emergency physicians would benefit the severely injured civilian patient at risk for hemorrhagic shock.

METHODS/DESIGN

This multicenter randomized clinical trial will include adults severely injured and at risk for hemorrhagic shock, with a systolic blood pressure < 70 mmHg or a Shock Index > 1.1. Two parallel groups of 70 patients will receive either FLYP or normal saline in addition to usual treatment. The primary endpoint is the International Normalized Ratio (INR) at hospital admission. Secondary endpoints are transfusion requirement, length of stay in the intensive care unit, survival rate at day 30, usability and safety related to FLYP use, and other biological coagulation parameters.

CONCLUSION

With this trial, we aim to confirm the efficacy of FLYP in TIC and its safety in civilian prehospital care. The study results will contribute to optimizing guidelines for treating hemorrhagic shock in civilian settings.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02736812. Registered on 13 April 2016. The trial protocol has been approved by the French ethics committee (CPP 3342) and the French Agency for the Safety of Medicines and Health Products (IDRCB 2015-A00866-43).

Intraoperative Resuscitation by Specialized Trauma Nurse Clinicians Improves Adherence to Massive Transfusion Protocol

A massive transfusion protocol (MTP) was implemented at a Level I trauma center in 2007 for patients with massive blood loss. A goal ratio of plasma to pheresed platelets to packed red blood cells (PRBCs) of 1:1:1 was established. From 2007 to 2014, trauma nurse clinicians (TNCs) administered the MTP during initial resuscitation and anesthesia personnel administered the MTP intraoperatively. In 2015, TNCs began administering the MTP intraoperatively. This study evaluates intraoperative blood product ratios and crystalloid volume administered by anesthesia personnel or TNCs. A retrospective review of trauma registry patients requiring MTP from 2007 to 2017 was performed. Patient data were stratified according to MTP administration by either anesthesia personnel (2007–2015) or TNCs (2015–2017). Ninety-seven patients were included with 54 anesthesia patients and 44 TNC patients. Patients undergoing resuscitation by MTP administered by TNCs received less median crystalloid (3000 mL vs 1500 mL, P < 0.001). The ratio of plasma:PRBC (0.75 vs 0.93, P = 0.027) and platelets:PRBC (0.75 vs 1.04, P = 0.003) was found to be significantly closer to 1:1 for TNC patients. MTP intraoperative blood product administration by TNCs reduced the amount of infused crystalloid and improved adherence to MTP in achieving a 1:1:1 ratio of blood products.

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.

Does the evidence support the importance of high transfusion ratios of plasma and platelets to red blood cells in improving outcomes in severely injured patients: a systematic review and meta-analyses

BACKGROUND

Deaths by exsanguination in trauma are preventable with hemorrhage control and resuscitation with allogeneic blood products (ABPs). The ideal transfusion ratio is unknown. We compared efficacy and safety of high transfusion ratios of FFP:RBC and PLT:RBC with low ratios in trauma.

STUDY DESIGN AND METHODS

Medline, Embase, Cochrane, and Controlled Clinical Trials Register were searched. Observational and randomized data were included. Risk of bias was assessed using validated tools. Primary outcome was 24-h and 30-day mortality. Secondary outcomes were exposure to ABPs and improvement of coagulopathy. Meta-analysis was conducted using a random-effects model. Strength and evidence quality were graded using GRADE profile RESULTS: 55 studies were included (2 randomized and 53 observational), with low and moderate risk of bias, respectively, and overall low evidence quality. The two RCTs showed no mortality difference (odds ratio [OR], 1.35; 95% confidence interval [CI], 0.40-4.59). Observational studies reported lower mortality in high FFP:RBCs ratio (OR, 0.38 [95% CI, 0.22-0.68] for 1:1 vs. <1:1; OR, 0.42 [95% CI, 0.22-0.81] for 1:1.5 vs. <1:1.5; and OR, 0.47 [95% CI, 0.31-0.71] for 1:2 vs. <1:2, respectively). Meta-analyses in observational studies showed no difference in exposure to ABPs. No data on coagulopathy for meta-analysis was identified.

CONCLUSIONS

Meta-analyses in observational studies suggest survival benefit and no difference in exposure to ABPs. No survival benefit in RCTs was identified. These conflicting results should be interpreted with caution. Studies are mostly observational, with relatively small sample sizes, nonrandom treatment allocation, and high potential for confounding. Further research is warranted.

The value of institutional protocols and focused cardiac ultrasound during a case of ultramassive transfusion

A 53-year-old female was admitted to the emergency department with an exsanguinating bleed from the rectum which was of unclear origin. In what could be considered an ultramassive transfusion, 60 units packed red blood cells, 23 units fresh frozen plasma, 20 units platelets, 6 units cryoprecipitate, 30 L of crystalloids, 2 L of colloids, and 4 g of tranexamic acid were transfused over the course of 7 h. An arterio-enteric fistula was diagnosed and treated by an interventional radiologist. The patient recovered rapidly thereafter without any major neurologic, pulmonary, cardiac, or hematologic complications.

Evaluation of massive transfusion protocol practices by type of trauma at a level I trauma center

PURPOSE

To evaluate massive transfusion protocol practices by trauma type at a level I trauma center.

METHODS

A retrospective analysis was performed on a sample of 76 trauma patients with MTP activation between March 2010 and January 2015 at a regional trauma center. Patient demographics, transfusion practices, and clinical outcomes were compared by type of trauma sustained.

RESULTS

Penetrating trauma patients who required MTP activation were significantly younger, had lower injury severity score (ISS), higher probability of survival (POS), decreased mortality, and higher Glasgow Coma scale (GCS) compared to blunt trauma patients. Overall, the mortality rate was 38.16%. The most common injury sustained among blunt trauma patients was head injury (36.21%), whereas the majority of the penetrating trauma patients sustained abdominal injuries (55.56%). Although the admission coagulation parameters and timing of coagulopathy were not significantly different between the two groups of patients, a significantly higher proportion of penetrating trauma patients received high plasma content therapy relative to blunt trauma patients (p < 0.01).

CONCLUSION

Despite the use of the same MTP for all injured patients requiring massive transfusion, significant differences existed between blunt trauma patients and penetrating trauma patients. These differences in transfusion characteristics and outcomes following MTP activation underscore the complexity of implementing MTPs and warrant vigilant transfusion practices to improve outcomes in trauma patients.

Implementation and evaluation of a major haemorrhage protocol in the Emergency Department Resuscitation Area in the University-affiliated Hospital of Brest (France)

Haemorrhagic shock is a rare occurrence in emergency medicine but it can be associated with significant mortality. The purpose of this study was to evaluate the impact of a major haemorrhage protocol on patient management in Emergency Department Resuscitation Area.

METHODS

A single-centre study was conducted to compare two periods, before and after institution of a massive haemorrhage protocol including the use of massive transfusion orders and the availability of packed red blood cell concentrates prior to patient's admission. Two groups of patients (in both trauma and non-trauma settings) were defined: "before protocol" and "after protocol". The primary outcome was the median transfusion time for a unit of red blood cell concentrate.

RESULTS

Forty patients were included: 22 for the "pre-protocol" group and 18 for the "post-protocol" group. The two groups were balanced with baseline characteristics. This study showed a significantly reduced median transfusion time for a unit of red blood cell concentrate from 20min pre-protocol to 9min post-protocol. The time between patient's admission and transfusion of the first red blood cell concentrate was reduced but non-significantly from 71min to 36min.

CONCLUSION

The major haemorrhage protocol optimised patient management by reducing the median transfusion time for red blood cell concentrates.

Blood products and procoagulants in traumatic bleeding: use and evidence

PURPOSE OF REVIEW

Death from uncontrolled haemorrhage is one of the leading causes of trauma-related mortality and is potentially preventable. Advances in understanding the mechanisms of trauma-induced coagulopathy (TIC) have focused attention on the role of blood products and procoagulants in mitigating the sequelae of TIC and how these therapies can be improved.

RECENT FINDINGS

A host of preclinical and clinical studies have evaluated blood product availability and efficacy in trauma. Recently published randomized controlled trials have investigated the ratio of platelet:plasma:red cell transfusion and the role of early cryoprecipitate in trauma. Demand for readily available plasma has led to changes particularly in the use of thawed group A plasma. Furthermore, ex-vivo and early clinical work has demonstrated variations in the haemostatic activity of different plasma, platelet and whole blood products. A number of multicentre trials are in progress aiming to answer key questions regarding tranexamic acid, procoagulant factor and fibrinogen concentrates and their effect on trauma outcomes.

SUMMARY

There are promising results from ex-vivo studies in manufacturing and storage of blood products to optimize haemostatic activity and availability, particularly with alternative plasma and platelet products and whole blood. There is an urgent need for these products needs to be tested prospectively.

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

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

Damage Control Resuscitation

Damage control surgery is a combination of temporizing surgical interventions to arrest hemorrhage and control infectious source, with goal directed resuscitation to restore normal physiology. The convention of damage control surgery largely arose following the discovery of the lethal triad of hypothermia, acidosis, and coagulopathy, with the goal of Damage Control Surgery (DCS) is to avoid the initiation of this "bloody vicious cycle" or to reverse its progression. While hypothermia and acidosis are generally corrected with resuscitation, coagulopathy remains a challenging aspect of DCS, and is exacerbated by excessive crystalloid administration. This chapter focuses on resuscitative principles in the four settings of trauma care: the prehospital setting, emergency department, operating room, and intensive care unit including historical perspectives, resuscitative methods, controversies, and future directions. Each setting provides unique challenges with specific goals of care.

Prehospital Blood Product Resuscitation for Trauma: A Systematic Review

Introduction:

Administration of high ratios of plasma to packed red blood cells is a routine practice for in-hospital trauma resuscitation. Military and civilian emergency teams are increasingly carrying prehospital blood products (PHBP) for trauma resuscitation. This study systematically reviewed the clinical literature to determine the extent to which the available evidence supports this practice.

Methods:

Bibliographic databases and other sources were searched to July 2015 using keywords and index terms related to the intervention, setting, and condition. Standard systematic review methodology aimed at minimizing bias was used for study selection, data extraction, and quality assessment (protocol registration PROSPERO: CRD42014013794). Synthesis was mainly narrative with random effects model meta-analysis limited to mortality outcomes.

Results:

No prospective comparative or randomized studies were identified. Sixteen case series and 11 comparative studies were included in the review. Seven studies included mixed populations of trauma and non-trauma patients. Twenty-five of 27 studies provided only very low quality evidence. No association between PHBP and survival was found (OR for mortality: 1.29, 95% CI: 0.84–1.96, P = 0.24). A single study showed improved survival in the first 24 h. No consistent physiological or biochemical benefit was identified, nor was there evidence of reduced in-hospital transfusion requirements. Transfusion reactions were rare, suggesting the short-term safety of PHBP administration.

Conclusions:

While PHBP resuscitation appears logical, the clinical literature is limited, provides only poor quality evidence, and does not demonstrate improved outcomes. No conclusions as to efficacy can be drawn. The results of randomized controlled trials are awaited.

RePHILL: protocol for a randomised controlled trial of pre-hospital blood product resuscitation for trauma

OBJECTIVES

To describe the 'Resuscitation with Pre-HospItaL bLood products' trial (RePHILL) - a multi-centre randomised controlled trial of pre-hospital blood product (PHBP) administration vs standard care for traumatic haemorrhage.

BACKGROUND

PHBP are increasingly used for pre-hospital trauma resuscitation despite a lack of robust evidence demonstrating superiority over crystalloids. Provision of PHBP carries additional logistical and regulatory implications, and requires a sustainable supply of universal blood components.

METHODS

RePHILL is a multi-centre, two-arm, parallel group, open-label, phase III randomised controlled trial currently underway in the UK. Patients attended by a pre-hospital emergency medical team, with traumatic injury and hypotension (systolic blood pressure <90 mmHg or absent radial pulse) believed to be due to traumatic haemorrhage are eligible. Exclusion criteria include age <16 years, blood product receipt on scene prior to randomisation, Advanced Medical Directive forbidding blood product administration, pregnancy, isolated head injury and prisoners. A total of 490 patients will be recruited in a 1 : 1 ratio to receive either the intervention (up to two units of red blood cells and two units of lyophilised plasma) or the control (up to four boluses of 250 mL 0.9% saline). The primary outcome measure is a composite of failure to achieve lactate clearance of ≥20%/h over the first 2 hours after randomisation and all-cause mortality between recruitment and discharge from the primary receiving facility to non-acute care. Secondary outcomes include pre-hospital time, coagulation indices, in-hospital transfusion requirements and morbidity.

RESULTS

Pilot study recruitment began in December 2016. Approval to proceed to the main trial was received in June 2017. Recruitment is expected to continue until 2020.

CONCLUSIONS

RePHILL will provide high-quality evidence regarding the efficacy and safety of PHBP resuscitation for trauma.

Prehospital Blood Transfusions in Non-Trauma Patients

INTRODUCTION

Despite advances in trauma care, hemorrhage continues to be the leading cause of preventable mortality in trauma. The evidence to support its use in non-trauma patients is limited. We aim to report our experience with prehospital blood product transfusion. We hypothesize that it is safe, appropriately utilized, and that our protocol, which was designed for trauma patients, is adaptable to fit the needs of non-trauma patients.

METHODS

Patients transfused with blood products, packed red blood cells (pRBCs) or plasma, in the prehospital environment between 2002 and 2014 were included. Trauma patients were compared to non-trauma patients using descriptive statistics.

RESULTS

A total of 857 patients (n = 549 trauma and n = 308 non-trauma) were transfused with pRBCs (76 %, n = 654, mean 1.6 ± 1.1 units en route), plasma (53 %, n = 455, mean 1.7 ± 0.7 unit), or both (29 %, n = 252) during ground (12 %) or air (84 %) critical care transport. Mean age was 60.8 ± 21.6 years with 60.1 % (n = 515) males. Subsequently, in-hospital blood transfusions were performed in 80 % of patients, operations in 44 %, and endoscopy in 31 %. Five percent (n = 41) of patients did not require any of these interventions. Thirty-day mortality rate was 18 %, and one patient (<0.01 %) had a transfusion reaction. The majority of patients were non-trauma (n = 549, 64 %). Of the non-trauma patients, 219 (40 %) were surgical, 193 (35 %) gastrointestinal bleeds, and 137 (25 %) medical.

CONCLUSION

Both non-trauma and trauma patients require blood products for life threatening hemorrhage and the majority required further interventions. Further research on the benefits of transfusion among non-trauma patients is warranted.

Prehospital plasma resuscitation associated with improved neurologic outcomes after traumatic brain injury

BACKGROUND

Trauma-related hypotension and coagulopathy worsen secondary brain injury in patients with traumatic brain injuries (TBIs). Early damage control resuscitation with blood products may mitigate hypotension and coagulopathy. Preliminary data suggest resuscitation with plasma in large animals improves neurologic function after TBI; however, data in humans are lacking.

METHODS

We retrospectively identified all patients with multiple injuries age >15 years with head injuries undergoing prehospital resuscitation with blood products at a single Level I trauma center from January 2002 to December 2013. Inclusion criteria were prehospital resuscitation with either packed red blood cells (pRBCs) or thawed plasma as sole colloid resuscitation. Patients who died in hospital and those using anticoagulants were excluded. Primary outcomes were Glasgow Outcomes Score Extended (GOSE) and Disability Rating Score (DRS) at dismissal and during follow-up.

RESULTS

Of 76 patients meeting inclusion criteria, 53% (n = 40) received prehospital pRBCs and 47% (n = 36) received thawed plasma. Age, gender, injury severity or TBI severity, arrival laboratory values, and number of prehospital units were similar (all p > 0.05). Patients who received thawed plasma had an improved neurologic outcome compared to those receiving pRBCs (median GOSE 7 [7-8] vs. 5.5 [3-7], p < 0.001). Additionally, patients who received thawed plasma had improved functionality compared to pRBCs (median DRS 2 [1-3.5] vs. 9 [3-13], p < 0.001). Calculated GOSE and DRS scores during follow-up, median 6 [5-7] months, demonstrated increased function in those resuscitated with thawed plasma compared to pRBCs by both median GOSE (8 [7-8] vs. 6 [6-7], p < 0.001) and DRS (0 [0-1] vs. 4 [2-8], p < 0.001).

CONCLUSION

In critically injured trauma patients with TBI, early resuscitation with thawed plasma is associated with improved neurologic and functional outcomes at discharge and during follow-up compared to pRBCs alone. These preliminary data support the further investigation and use of plasma in the resuscitation of critically injured TBI patients.

LEVEL OF EVIDENCE

Therapeutic, level V.

Prehospital Transfusion for Gastrointestinal Bleeding

OBJECTIVE

Gastrointestinal (GI) bleeding is a common medical emergency with significant morbidity and mortality. Many patients are coagulopathic, which may perpetuate bleeding. Remote damage control resuscitation, including early correction of coagulopathy and anemia, may benefit exsanguinating patients with GI bleeding.

METHODS

We conducted a retrospective review of patients with acute GI bleeding who received packed red blood cells (pRBC) and/or plasma during transportation to our institution between 2010 and 2014. A comparison group of patients who were not transfused en route was selected, and demographics, outcomes, and response to resuscitation were compared.

RESULTS

A total of 112 patients with GI bleeding received pRBC (82%, n = 92 pRBC, mean 1.7 ± 0.9 units), plasma (62%, n = 69, mean 1.7 ± 0.8 units) or both (44%, n = 49) en-route. The comparison group comprised 49 patients transported by helicopter who were not transfused en-route. Demographics, crystalloid resuscitation, transfusion prior to transfer, rate of intervention, ICU days, length of stay, and mortality were similar between groups. Patients transfused en route had a significant increase in hemoglobin from 8.3 ± 2.2 to 8.9 ± 2.1 (P = .03) and decrease in INR from 2.0 ± 1.0 to 1.6 ± 1.4 (P = .01), whereas those not transfused en route experienced stable hemoglobin (8.7 ± 2.8 to 9.4 ± 2.5; P = .21) and INR values (1.9 ± 1.0 to 1.6 ± 1.4; P = .32). Both groups had a significant improvement in hemodynamic parameters with resuscitation.

CONCLUSION

Prehospital damage control resuscitation with pRBC and/or plasma resulted in the improvement of hemodynamic instability, coagulopathy and anemia in patients with acute GI bleeding. Almost all patients required additional inpatient interventions and/or transfusions, suggesting that pre-hospital transfusion is being utilized for appropriately selected patients.

Massive transfusion: An update for the anesthesiologist

Exsanguination from trauma, gastrointestinal bleeding, and obstetric hemorrhage remains a major source of mortality across the planet. Continued research into resuscitation strategies and evolving technology and blood product storage has allowed for patient to undergo very large volume transfusions, even to the point of replacing a patient’s blood volume several times over. As massive transfusions have become more common, more studies have been performed delineating the exact patient population that would benefit, start- and stop-points of transfusions, complications and avoidance of the same. We discuss these points and provide information and strategies for massive transfusion.

[Efficacy of high versus low plasma: red blood cell ratio resuscitation in patients with severe trauma requiring massive blood transfusion: a meta-analysis]

OBJECTIVE

To evaluate the efficacy of high (≥1:2) and low (<1:2) plasma: red blood cell (RBC) ratio resuscitation in patients with severe trauma requiring massive blood transfusion.

METHODS

The databases including the Cochrane Library, Pubmed, Web of Science, and EMBASE were systemically searched for relevant studies published between January, 2009 and April, 2016. The selection of studies, assessment of methodological quality and data extraction were performed by two researchers independently according to the inclusion and exclusion criteria. The main endpoint was 24-h mortality, 30-day mortality and 24-h survival rate.

RESULTS

Five observational studies reporting outcomes of 1024 patients were included in this meta-analysis. Four studies documented civilian cases and one study had a military setting. No significant differences were found in the Injury Severity Score (ISS) between patient groups receiving high and low plasma: RBC ratio resuscitation. Compared with the low-ratio group, the patients with high-ratio resuscitation showed a significant reduction in the 24-h mortality rate (OR=0.35, 95%CI [0.25, 0.48], P<0.000 01) and the 30-day mortality rate (OR=0.55, 95%CI [0.41, 0.75], P=0.0001). An increased survival rate was observed in patients receiving high plasma: RBC ratio resuscitation within the initial 24 h following the trauma (HR=2.34, 95%CI [1.46, 3.73], P=0.00001).

CONCLUSION

Raising the plasma: RBC ratio to 0.5 or higher may decrease the mortality rate of the patients with severe trauma who need massive blood transfusion.

Recurrent event frailty models reduced time-varying and other biases in evaluating transfusion protocols for traumatic hemorrhage

OBJECTIVE

Transfusion research seeks to improve survival for severely injured and hemorrhaging patients using optimal plasma and platelet ratios over red blood cells (RBCs). However, most published studies comparing different ratios are plagued with serious bias and ignore time-varying effects. We applied joint recurrent event frailty models to increase validity and clinical utility.

STUDY DESIGN AND SETTING

Using the PRospective Observational Multicenter Major Trauma Transfusion study data, our joint random-effects models estimated the association of (1) clinical covariates with transfusion rate intensities and (2) varying plasma:RBC and platelet:RBC ratios with survival over the 24 hours after hospital admission. Along with survival time, baseline patient vital signs, laboratory values, and longitudinal data on types and volumes of transfusions were included.

RESULTS

Baseline systolic blood pressure, heart rate, pH, and hemoglobin were significantly associated with RBC transfusion rates. Increased transfusion rates (per hour) of plasma (P = 0.05), platelets (P < 0.001), or RBCs were associated with increased 24-hour mortality. Higher ratios of plasma:RBC (P = 0.107) and platelet:RBC (P < 0.001) were associated with reduced mortality in a time-varying pattern (P < 0.001).

CONCLUSIONS

The proposed joint analysis of transfusion rates and ratios offers a more valid statistical approach to evaluate survival effects in the presence of informative censoring by early death.

The impact of increased plasma ratios in massively transfused trauma patients: a prospective analysis

PURPOSE

Transfusion ratios approaching 1:1 FFP:PRBC for trauma resuscitation have become the de facto standard of care. The aim of this study was to prospectively evaluate the effect of increasing ratios of FFP:PRBC transfusion on survival for massively transfused civilian trauma patients as well as determine if time to reach the target ratio had any effect on outcomes.

METHODS

This is a prospective, observational study of all trauma patients requiring a massive transfusion (≥10 PRBC in ≤24 h) at a level 1 trauma center over a 2.5-year period. The ratio of FFP:PRBC was tracked hourly up to 24 h post-initiation of massive transfusion. A logistic regression model was utilized to identify the ideal ratio associated with mortality prediction. A stepwise logistic regression was performed to identify independent predictors of mortality.

RESULTS

The study population was predominantly male (89 %) with a mean age of 34.8 ± 16. On admission, 22 % had a systolic blood pressure ≤90 mmHg, 47 % had a heart rate ≥120, and 25 % had a GCS ≤8. The overall mortality was 33 %. The ratio of FFP:PRBC ≥ 1:1.5 was the second most important independent predictor of mortality for this population (R (2) = 0.59). Survivors had a higher FFP:PRBC ratio at all times during the first 24 h of resuscitation.

CONCLUSIONS

Achieving a ratio of FFP:PRBC ≥ 1:1.5 after the initial 24 h of resuscitation significantly improves survival in massively transfused trauma patients compared to patients that achieved a ratio <1:1.5.

Prehospital use of plasma in traumatic hemorrhage (The PUPTH Trial): study protocol for a randomised controlled trial

Background

Severe traumatic injury and haemorrhagic shock are frequently associated with disruptions of coagulation function (such as trauma-induced coagulopathy TIC) and activation of inflammatory cascades. These pathologies may be exacerbated by current standard of care resuscitation protocols. Observational studies suggest early administration of plasma to severely-injured haemorrhaging patients may correct TIC, minimise inflammation, and improve survival. The proposed randomised clinical trial will evaluate the clinical effectiveness of pre-hospital plasma administration compared with standard- of-care crystalloid resuscitation in severely-injured patients with major traumatic haemorrhage.

Methods/design

This is a prospective, randomized, open-label, non-blinded trial to determine the effect of pre-hospital administration of thawed plasma (TP) on mortality, morbidity, transfusion requirements, coagulation, and inflammatory response in severely-injured bleeding trauma patients. Two hundred and ten eligible adult trauma patients will be randomised to receive either two units of plasma, to be administered in-field, vs standard of care normal saline (NS). Main analyses will compare subjects allocated to TP to those allocated to NS, on an intention-to-treat basis. Primary outcome measure is all-cause 30-day mortality. Secondary outcome measures include coagulation and lipidomic/pro-inflammatory marker responses, volume of resuscitation fluids (crystalloid, colloid) and blood products administered, and major hospital outcomes (e.g. incidence of MSOF, length of ICU stay, length of hospital stay).

Discussion

This study is part of a US Department of Defense (DoD)-funded multi-institutional investigation, conducted independently of, but in parallel with, the University of Pittsburgh and University of Denver. Demonstration of significant reductions in mortality and coagulopathic/inflammatory-related morbidities as a result of pre-hospital plasma administration would be of considerable clinical importance for the management of haemorrhagic shock in both civilian and military populations.

Trial registration

ClinicalTrials.gov: NCT02303964 on 28 November 2014

Estimating the ratio of multivariate recurrent event rates with application to a blood transfusion study

In comparative effectiveness studies of multicomponent, sequential interventions like blood product transfusion (plasma, platelets, red blood cells) for trauma and critical care patients, the timing and dynamics of treatment relative to the fragility of a patient's condition is often overlooked and underappreciated. While many hospitals have established massive transfusion protocols to ensure that physiologically optimal combinations of blood products are rapidly available, the period of time required to achieve a specified massive transfusion standard (e.g. a 1:1 or 1:2 ratio of plasma or platelets:red blood cells) has been ignored. To account for the time-varying characteristics of transfusions, we use semiparametric rate models for multivariate recurrent events to estimate blood product ratios. We use latent variables to account for multiple sources of informative censoring (early surgical or endovascular hemorrhage control procedures or death). The major advantage is that the distributions of latent variables and the dependence structure between the multivariate recurrent events and informative censoring need not be specified. Thus, our approach is robust to complex model assumptions. We establish asymptotic properties and evaluate finite sample performance through simulations, and apply the method to data from the PRospective Observational Multicenter Major Trauma Transfusion study.

Collider bias in trauma comparative effectiveness research: the stratification blues for systematic reviews

BACKGROUND

Collider bias, or stratifying data by a covariate consequence rather than cause (confounder) of treatment and outcome, plagues randomised and observational trauma research. Of the seven trials of prehospital hypertonic saline in dextran (HSD) that have been evaluated in systematic reviews, none found an overall between-group difference in survival, but four reported significant subgroup effects. We hypothesised that an avoidable type of collider bias often introduced inadvertently into trauma comparative effectiveness research could explain the incongruous findings.

METHODS

The two most recent HSD trials, a single-site pilot and a multi-site pivotal study, provided data for a secondary analysis to more closely examine the potential for collider bias. The two trials had followed the a priori statistical analysis plan to subgroup patients by a post-randomisation covariate and well-established surrogate for bleeding severity, massive transfusion (MT), ≥ 10 unit of red blood cells within 24h of admission. Despite favourable HSD effects in the MT subgroup, opposite effects in the non-transfused subgroup halted the pivotal trial early. In addition to analyzing the data from the two trials, we constructed causal diagrams and performed a meta-analysis of the results from all seven trials to assess the extent to which collider bias could explain null overall effects with subgroup heterogeneity.

RESULTS

As in previous trials, HSD induced significantly greater increases in systolic blood pressure (SBP) from prehospital to admission than control crystalloid (p=0.003). Proportionately more HSD than control decedents accrued in the non-transfused subgroup, but with paradoxically longer survival. Despite different study populations and a span of over 20 years across the seven trials, the reported mortality effects were consistently null, summary RR=0.99 (p=0.864, homogeneity p=0.709).

CONCLUSIONS

HSD delayed blood transfusion by modifying standard triggers like SBP with no detectable effect on survival. The reported heterogeneous HSD effects in subgroups can be explained by collider bias that trauma researchers can avoid by improved covariate selection and data capture strategies.

Impact of infusion rates of fresh frozen plasma and platelets during the first 180 minutes of resuscitation

BACKGROUND

Whether high-ratio resuscitation (HRR) provides patients with survival advantage remains controversial. We hypothesized a direct correlation between HRR infusion rates in the first 180 minutes of resuscitation and survival.

STUDY DESIGN

This was a retrospective analysis of massively transfused trauma patients surviving more than 30 minutes and undergoing surgery at a level 1 trauma center. Mean infusion rates (MIR) of packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets (Plt) were calculated for length of intervention (emergency department [ED] time + operating room [OR] time). Patients were categorized as HRR (FFP:PRBC > 0.7, and/or Plts: PRBC > 0.7) vs low-ratio resuscitation (LRR). Student's t-tests and chi-square tests were used to compare survivors with nonsurvivors. Cox proportional hazards regression models and Kaplan-Meier curves were generated to evaluate the association between MIR for FFP:PRBC and Plt:PRBC and 180-minute survival.

RESULTS

There were 151 patients who met criteria: 121 (80.1%) patients survived 180 minutes (MIR:PRBC 71.9 mL/min, FFP 92.0 mL/min, Plt 3.5 mL/min) vs 30 (19.9%) who did not survive (MIR:PRBC 47.3 mL/min, FFP 33.7 mL/min, Plt 1.1 mL/min), p = 0.43, p < 0.0001 and p < 0.011, respectively. A Cox regression model evaluated PRBC rate, FFP rate, and Plt rate (mL/min) as mortality predictors within 180 minutes to assess if they significantly affected survival (hazard ratios 1.01 [p = 0.054], 0.97 [p < 0.0001], and 0.75 [p = 0.01], respectively). Another model used stepwise Cox regression including PRBC rate, FFP rate, and Plt rate (hazard ratios 1.00 [p = 0.85], 0.97 [p < 0.0001], and 0.88 [p = 0.24], respectively), as well as possible confounding variables.

CONCLUSIONS

This is the first study to examine effects of MIRs on survival. Further studies on the effects of narrow time-interval analysis for blood product resuscitation are warranted.

Acute coagulopathy of trauma: Mechanism, monitoring, management

Coagulopathy is a well-known consequence of trauma and is the most common cause of mortality in the young. However, its cause and management is still controversial. A new concept in the understanding of coagulopathy in trauma is the occurrence of Acute coagulopathy of trauma (ACoT). ACoT is associated with hypo perfusion and tissue trauma as seen in massive injury. The incidence of coagulopathy increases with injury scores and is associated with higher number of ventilator days, higher morbidity and mortality. The process of coagulation is better described by the cell based model with a central role for platelets rather than the older plasma based model. This shift in our understanding supports the theory that ACoT results from the endothelial release of thrombomodulin and activated protein C in the presence of hypoperfusion. This in turn leads on to a hyperfibrinolytic and hypocoagulable state. Viscoelastic hemostatic assays are replacing the older tests like prothrombin time in the assessment of coagulopathy. These tests are accurate, determine the need for transfusion and can be performed at the point of care. Damage control resuscitation includes newer concepts like permissive hypotension, increased use of plasma as a part of massive transfusion protocols and damage control surgery.

Management of hemorrhage in trauma

Hemorrhage remains one of the leading causes of trauma-related deaths. Uncontrolled diffuse microvascular bleeding in the course of initial care is common, potentially resulting in exsanguination. Early and aggressive hemostatic intervention increases survival and reduces the incidence of massive transfusion. Thus, timely diagnosis of the underlying coagulation disorders is mandatory. It has been shown that standard coagulation tests do not sufficiently characterize trauma-induced coagulopathy (TIC). This has led to increasing interest in alternatives, such as the viscoelastic test, to diagnose TIC and to provide the basis for a goal-directed hemostatic therapy. The concept of damage control resuscitation (DCR) has been introduced widely in trauma patients with severe bleeding. This strategy addresses important confounders of the coagulation process such as hemodilution, hypothermia, and acidosis; DCR is based on a damage control surgical approach, permissive hypotension, and improvement of hemostatic competence. Many studies have shown benefit in mortality when using high ratios of fresh frozen plasma (FFP) to red blood cells (RBC) as early treatment. However, there is increased awareness that coagulation factor concentrate could be beneficial in the treatment of trauma-induced coagulopathy.

Primary hemostatic capacity of whole blood: a comprehensive analysis of pathogen reduction and refrigeration effects over time

BACKGROUND

Whole blood (WB) has been used in combat since World War I as it is readily available and replaces every element of shed blood. Component therapy has become standard; however, recent military successes with WB resuscitation have revived the debate regarding wider WB use. Characterization of optimal WB storage is needed. We hypothesized that refrigeration preserves WB function and that a pathogen reduction technology (PRT) based on riboflavin and ultraviolet light has no deleterious effect over 21 days of storage.

STUDY DESIGN AND METHODS

WB units were stored for 21 days either at 4°C or 22°C. Half of each temperature group underwent PRT, yielding four final treatment groups (n = 8 each): CON 4 (WB at 4°C); CON 22 (WB at 22°C); PRT 4 (PRT WB at 4°C); and PRT 22 (PRT WB at 22°C). Testing was at baseline, Days 1-7, 10, 14, and 21. Assays included coagulation factors; platelet activation, aggregation, and adhesion; and thromboelastography (TEG).

RESULTS

Prothrombin time (PT) and partial thromboplastin time increased over time; refrigeration attenuated the effects on PT (p ≤ 0.009). Aggregation decreased over time (p ≤ 0.001); losses were attenuated by refrigeration (p ≤ 0.001). Refrigeration preserved TEG parameters (p ≤ 0.001) and PRT 4 samples remained within normal limits throughout the study. Refrigeration in combination with PRT inhibited fibrinolysis (p ≤ 0.001) and microparticle formation (p ≤ 0.031). Cold storage increased shear-induced platelet aggregation and ristocetin-induced platelet agglutination (p ≥ 0.032), as well as GPIb-expressing platelets (p ≤ 0.009).

CONCLUSION

The in vitro hemostatic function of WB is largely unaffected by PRT treatment and better preserved by cold storage over 21 days. Refrigerated PRT WB may be suitable for trauma resuscitation. Clinical studies are warranted.