Prescreened Whole O Blood Group Walking Blood Bank Capabilities for Nontraditional Maritime Medical Receiving Platforms: A Case Series

BACKGROUND

Tactical Combat Casualty Care (TCCC) guidelines recognize low-titer group O whole blood (LTOWB) as the resuscitative fluid of choice for combat wounded. Utilization of prescreened LTOWB in a walking blood bank (WBB) format has been well described by the Ranger O low-titer blood (ROLO) and the United States Marine Corps Valkyrie programs, but it has not been applied to the maritime setting.

METHODS

We describe three WBB experiences of an expeditionary resuscitative surgical system (ERSS) team, attached to three nontraditional maritime medical receiving platforms, over 6 months.

RESULTS

Significant variations were identified in the number of screened eligible donors, the number of LTOWB donors, and the timely arrival at WBB activation sites between the platforms. Overall, 95% and 84% of the screened eligible group O blood donors on the Arleigh Burke Class Destroyer (DDG) and Nimitz Class Aircraft Carrier (CVN), respectively, were determined to be LTOWB. However, only 37% of the eligible screened group O blood donors aboard the Harper's Ferry Class Dock Landing Ship (LSD) were found to be LTOWB. Of the eligible donors, 66% did not complete screening, with 52% citing a correctable reason for nonparticipation.

CONCLUSION

LTOWB attained through WBBs may be the only practical resuscitative fluid on maritime platforms without inherent blood product storage capabilities to perform remote damage control resuscitation. Future efforts should focus on optimizing WBBs through capability development, education, and training efforts.

Innovative blood transfusion strategies to address global blood deserts: a consensus statement from the Blood Delivery via Emerging Strategies for Emergency Remote Transfusion (Blood DESERT) Coalition

In rural settings worldwide, many people live in effective blood deserts without access to any blood transfusion. The traditional system of blood banking is logistically complex and expensive for many resource-restricted settings and demands innovative and multidisciplinary solutions. 17 international experts in medicine, industry, and policy participated in an exploratory process with a 2-day hybrid seminar centred on three promising innovative strategies for blood transfusions in blood deserts: civilian walking blood banks, intraoperative autotransfusion, and drone-based blood delivery. Participant working groups conducted literature reviews and interviews to develop three white papers focused on the current state and knowledge gaps of each innovation. Seminar discussion focused on defining blood deserts and developing innovation-specific implementation agendas with key research and policy priorities for future work. Moving forward, advocates should prioritise the identification of blood deserts and address the context-specific challenges for these innovations to alleviate the ongoing crisis in blood deserts.

Prolyl hydroxylase domain inhibitor is an effective pre-hospital pharmaceutical intervention for trauma and hemorrhagic shock

Pre-hospital potentially preventable trauma related deaths are mainly due to hypoperfusion-induced tissue hypoxia leading to irreversible organ dysfunction at or near the point of injury or during transportation prior to receiving definitive therapy. The prolyl hydroxylase domain (PHD) is an oxygen sensor that regulates tissue adaptation to hypoxia by stabilizing hypoxia inducible factor (HIF). The benefit of PHD inhibitors (PHDi) in the treatment of anemia and lactatemia arises from HIF stabilization, which stimulates endogenous production of erythropoietin and activates lactate recycling through gluconeogenesis. The results of this study provide insight into the therapeutic roles of MK-8617, a pan-inhibitor of PHD-1, 2, and 3, in the mitigation of lactatemia in anesthetized rats with polytrauma and hemorrhagic shock. Additionally, in an anesthetized rat model of lethal decompensated hemorrhagic shock, acute administration of MK-8617 significantly improves one-hour survival and maintains survival at least until 4 h following limited resuscitation with whole blood (20% EBV) at one hour after hemorrhage. This study suggests that pharmaceutical interventions to inhibit prolyl hydroxylase activity can be used as a potential pre-hospital countermeasure for trauma and hemorrhage at or near the point of injury.

Intravenous Autologous Bone Marrow-derived Mesenchymal Stromal Cells Delay Acute Respiratory Distress Syndrome in Swine

Rationale: Early post injury mitigation strategies in ARDS are in short supply. Treatments with allogeneic stromal cells are administered after ARDS develops, require specialized expertise and equipment, and to date have shown limited benefit. Objectives: Assess the efficacy of immediate post injury intravenous administration of autologous or allogeneic bone marrow-derived mesenchymal stromal cells (MSCs) for the treatment of acute respiratory distress syndrome (ARDS) due to smoke inhalation and burns. Methods: Yorkshire swine (n = 32, 44.3 ± 0.5 kg) underwent intravenous anesthesia, placement of lines, severe smoke inhalation, and 40% total body surface area flame burns, followed by 72 hours of around-the-clock ICU care. Mechanical ventilation, fluids, pressors, bronchoscopic cast removal, daily lung computed tomography scans, and arterial blood assays were performed. After injury and 24 and 48 hours later, animals were randomized to receive autologous concentrated bone marrow aspirate (n = 10; 3 × 106 white blood cells and a mean of 56.6 × 106 platelets per dose), allogeneic MSCs (n = 10; 6.1 × 106 MSCs per dose) harvested from healthy donor swine, or no treatment in injured control animals (n = 12). Measurements and Main Results: The intravenous administration of MSCs after injury and at 24 and 48 hours delayed the onset of ARDS in swine treated with autologous MSCs (48 ± 10 h) versus control animals (14 ± 2 h) (P = 0.004), reduced ARDS severity at 24 (P < 0.001) and 48 (P = 0.003) hours, and demonstrated visibly diminished consolidation on computed tomography (not significant). Mortality at 72 hours was 1 in 10 (10%) in the autologous group, 5 in 10 (50%) in the allogeneic group, and 6 in 12 (50%) in injured control animals (not significant). Both autologous and allogeneic MSCs suppressed systemic concentrations of TNF-α (tumor necrosis factor-α). Conclusions: The intravenous administration of three doses of freshly processed autologous bone marrow-derived MSCs delays ARDS development and reduces its severity in swine. Bedside retrieval and administration of autologous MSCs in swine is feasible and may be a viable injury mitigation strategy for ARDS.

Factor XI Inhibition With Heparin Reduces Clot Formation in Simulated Pediatric Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) supplies circulatory support and gas exchange to critically ill patients. Despite the use of systemic anticoagulation, blood exposure to ECMO surfaces causes thromboembolism complications. Inhibition of biomaterial surface-mediated activation of coagulation factor XI (FXI) may prevent device-associated thrombosis. Blood was collected from healthy volunteers (n = 13) following the U.S. Army Institute of Surgical Research standard operating procedure for testing in an ex vivo ECMO circuit. A roller-pump circuit circulated either 0.5 U/ml of unfractionated heparin alone or in combination with the anti-FXI immunoglobulin G (IgG) (AB023) for 6 hours or until clot formation caused device failure. Coagulation factor activity, platelet counts, time to thrombin generation, peak thrombin, and endogenous thrombin potential were quantified. AB023 in addition to heparin sustained circuit patency in all tested circuits (5/5) after 6 hours, while 60% of circuits treated with heparin alone occluded (3/8), log-rank p < 0.03. AB023 significantly prolonged the time to clot formation as compared to heparin alone (15.5 vs . 3.3 minutes; p < 0.01) at the 3-hour time point. AB023 plus heparin significantly reduced peak thrombin compared to heparin alone (123 vs . 217 nM; p < 0.01). Inhibition of contact pathway activation of FXI may be an effective adjunct to anticoagulation in extracorporeal life support.

A novel, quantitative clot retraction assay to evaluate platelet function

Blood platelets are crucial to prevent excessive bleeding following injury to blood vessels. Platelets are crucial for the formation of clots and for clot strength. Platelet activation involves aggregation, attachment to fibrin and clot retraction. Most assays that address platelet function measure platelet aggregation, not clot retraction. Here, we describe a 96-well-based clot retraction assay that requires a relatively short runtime and small sample volume. The assay involves continuous optical density monitoring of platelet-rich plasma that is activated with thrombin. The data can be analyzed using time-series analytical tools to generate quantitative information about different phases of clot formation and clot retraction. The assay demonstrated good repeatability and reproducibility and was robust to different calcium concentrations. Impairment of platelet bioenergetics, actin polymerization, fibrin interaction, and signaling significantly affected clot retraction and was detected and showed good agreement with light transmission aggregometry, suggesting that clot retraction is predictive of platelet function. Using this microplate clot retraction assay, we showed a significant difference in platelets stored in autologous plasma compared with platelet additive solution after 7 days of room temperature storage.

Genetically engineered transfusable platelets using mRNA lipid nanoparticles

Platelet transfusions are essential for managing bleeding and hemostatic dysfunction and could be expanded as a cell therapy due to the multifunctional role of platelets in various diseases. Creating these cell therapies will require modifying transfusable donor platelets to express therapeutic proteins. However, there are currently no appropriate methods for genetically modifying platelets collected from blood donors. Here, we describe an approach using platelet-optimized lipid nanoparticles containing mRNA (mRNA-LNP) to enable exogenous protein expression in human and rat platelets. Within the library of mRNA-LNP tested, exogenous protein expression did not require nor correlate with platelet activation. Transfected platelets retained hemostatic function and accumulated in regions of vascular damage after transfusion into rats with hemorrhagic shock. We expect this technology will expand the therapeutic potential of platelets.

Assessment of ethynylestradiol-3-sulfate on coagulation, metabolism, and survival in pigs with traumatic hemorrhage

BACKGROUND

The beneficial effects of estrogens on survival from hemorrhage have been suggested in some preclinical models. This study investigated the effects of ethynylestradiol-3-sulfate (EE-3-S) on coagulation, metabolism and survival in pigs following traumatic hemorrhage.

METHODS

Twenty-six pigs were randomized into: normal saline group (NS, n = 10), EE-3-S group (EE-3, n = 11) groups, and no resuscitation group (NR, n = 5). Femur fracture was performed in each pig's left leg, followed by hemorrhage of 55% of estimated blood volume and a 10-minute shock period. Afterward, pigs were resuscitated with a small volume of either NS alone (4 mL/kg) or EE-3-S with NS (1 mL/kg at concentration of 1 mg/mL, plus NS solution of 3 mL/kg). Pigs in NR group were not resuscitated with any fluid. All pigs were then monitored for 6 hours or until death, with hemodynamics and survival times recorded. Blood samples were taken during the study for measurements of oxygen metabolism (oxygen delivery, extraction, and consumption) and coagulation function (using Rotem with Extem reagents).

RESULTS

All baseline measurements were similar among the three groups. In the NS group, femur fracture and hemorrhage immediately reduced mean arterial pressure (MAP, 74 ± 3 mm Hg to 44 ± 4 mm Hg) and increased heart rate (97 ± 5 bpm to 218 ± 14 bpm, both p < 0.05). Similar changes in MAP and heart rate were observed in the EE-3 and NR groups. There were no differences observed in changes of Rotem ® measurements or oxygen metabolism among the groups during the study. At 6 hours, four pigs in NS, four pigs in EE-3-S, and two pigs in the NR group survived to the end of the study. The mean survival times were similar among the NS (212 ± 43 minutes), EE-3 (212 ± 39 minutes), and NR (223 ± 63 minutes) groups ( p = 0.9845).

CONCLUSION

Following severe traumatic hemorrhage, hypotensive resuscitation with EE-3-S did not impact coagulation, metabolism, or survival in pigs.

Short-term assays for mesenchymal stromal cell immunosuppression of T-lymphocytes

Introduction

Trauma patients are susceptible to coagulopathy and dysfunctional immune responses. Mesenchymal stromal cells (MSCs) are at the forefront of the cellular therapy revolution with profound immunomodulatory, regenerative, and therapeutic potential. Routine assays to assess immunomodulation activity examine MSC effects on proliferation of peripheral blood mononuclear cells (PBMCs) and take 3-7 days. Assays that could be done in a shorter period of time would be beneficial to allow more rapid comparison of different MSC donors. The studies presented here focused on assays for MSC suppression of mitogen-stimulated PBMC activation in time frames of 24 h or less.

Methods

Three potential assays were examined-assays of apoptosis focusing on caspase activation, assays of phosphatidyl serine externalization (PS+) on PBMCs, and measurement of tumor necrosis factor alpha (TNFα) levels using rapid ELISA methods. All assays used the same initial experimental conditions: cryopreserved PBMCs from 8 to 10 pooled donors, co-culture with and without MSCs in 96-well plates, and PBMC stimulation with mitogen for 2-72 h.

Results

Suppression of caspase activity in activated PBMCs by incubation with MSCs was not robust and was only significant at times after 24 h. Monitoring PS+ of live CD3+ or live CD4+/CD3+ mitogen-activated PBMCs was dose dependent, reproducible, robust, and evident at the earliest time point taken, 2 h, although no increase in the percentage of PS+ cells was seen with time. The ability of MSC in co-culture to suppress PBMC PS+ externalization compared favorably to two concomitant assays for MSC co-culture suppression of PBMC proliferation, at 72 h by ATP assay, or at 96 h by fluorescently labeled protein signal dilution. TNFα release by mitogen-activated PBMCs was dose dependent, reproducible, robust, and evident at the earliest time point taken, with accumulating signal over time. However, suppression levels with MSC co-culture was reliably seen only after 24 h.

Discussion

Takeaways from these studies are as follows: (1) while early measures of PBMC activation is evident at 2-6 h, immunosuppression was only reliably detected at 24 h; (2) PS externalization at 24 h is a surrogate assay for MSC immunomodulation; and (3) rapid ELISA assay detection of TNFα release by PBMCs is a robust and sensitive assay for MSC immunomodulation at 24 h.

APPRAISE-HRI: AN ARTIFICIAL INTELLIGENCE ALGORITHM FOR TRIAGE OF HEMORRHAGE CASUALTIES

ABSTRACT

Background: Hemorrhage remains the leading cause of death on the battlefield. This study aims to assess the ability of an artificial intelligence triage algorithm to automatically analyze vital-sign data and stratify hemorrhage risk in trauma patients. Methods: Here, we developed the APPRAISE-Hemorrhage Risk Index (HRI) algorithm, which uses three routinely measured vital signs (heart rate and diastolic and systolic blood pressures) to identify trauma patients at greatest risk of hemorrhage. The algorithm preprocesses the vital signs to discard unreliable data, analyzes reliable data using an artificial intelligence-based linear regression model, and stratifies hemorrhage risk into low (HRI:I), average (HRI:II), and high (HRI:III). Results: To train and test the algorithm, we used 540 h of continuous vital-sign data collected from 1,659 trauma patients in prehospital and hospital (i.e., emergency department) settings. We defined hemorrhage cases (n = 198) as those patients who received ≥1 unit of packed red blood cells within 24 h of hospital admission and had documented hemorrhagic injuries. The APPRAISE-HRI stratification yielded a hemorrhage likelihood ratio (95% confidence interval) of 0.28 (0.13-0.43) for HRI:I, 1.00 (0.85-1.15) for HRI:II, and 5.75 (3.57-7.93) for HRI:III, suggesting that patients categorized in the low-risk (high-risk) category were at least 3-fold less (more) likely to have hemorrhage than those in the average trauma population. We obtained similar results in a cross-validation analysis. Conclusions: The APPRAISE-HRI algorithm provides a new capability to evaluate routine vital signs and alert medics to specific casualties who have the highest risk of hemorrhage, to optimize decision-making for triage, treatment, and evacuation.

Refrigerated human mesenchymal stromal cells as an alternative to cryostorage for use in clinical investigation

BACKGROUND

Mesenchymal stromal cells (MSCs) and other therapeutic cells show efficacy for cardiac damage, neurological disease, chronic lung disease, pediatric graft versus host disease, and several inflammatory conditions. Based on their anti-inflammatory and immune-modulatory activities, responsiveness, and secretion of beneficial factors, cellular therapeutics may provide benefits in acute and chronic traumatic injury. However, the use of live cells presents logistical challenges, especially for military trauma. MSCs are generally shipped and stored frozen but require sterile handling before infusion. This requires skilled personnel and equipment not readily available in a forward medical treatment facility or even a small community hospital.

METHODS

Commercial human bone marrow- and adipose-derived MSCs from multiple donors were cultured under standard conditions, harvested and stored at 4°C in solution for up to 21 days. Cell viability, ATP content, apoptosis, proliferation capability, immunomodulation activity, and responsiveness were assessed after different amounts of time.

RESULTS

Human MSCs can be stored at 4°C in MSC culture medium for 14 days while maintaining a reasonable level of viability and function. Both viability and function are reduced when MSCs are stored in crystalloid solutions.

CONCLUSIONS

This approach makes it feasible to prepare cellular therapeutic agents in a laboratory or commercial facility and ship them under refrigerated conditions. Once they reach their destination, they can be stored at 4°C under conditions similar to blood products. Cells prepared and stored this way could also be used directly with minimal handling, making them more practical for both civilian and military trauma.

Screening for Zika Virus in U.S. Armed Services Blood Program Donors: An Opportunity to Compare Emerging Infectious Disease Risk between the General U.S. Population and Military Donors

BACKGROUND

The U.S. Department of Defense (DoD) collects blood from volunteer DoD donors in U.S. Food and Drug Administration (FDA)-regulated centers, and from emergency donor panels in overseas operations. Emerging infectious diseases could reduce DoD access to blood products. In August 2016, FDA determined that Zika virus was transfusion-transmitted and advised that donated blood should be screened for Zika utilizing one of two investigational new drug (IND) applications. The Armed Services Blood Program (ASBP) tested blood using its own protocol concurrently with the IND study sponsored by Roche Molecular Systems, Inc., titled "A Prospective Study to Evaluate the Specificity of the cobas Zika test for use on the cobas 6800/8800 System for Screening of Blood Donations for the Presence of Zika virus RNA."

STUDY DESIGN AND METHODS

This prospective clinical trial (September 2016 to August 2017) evaluated the specificity of the cobas Zika 6800/8800 System. Consenting volunteers were screened for Zika by participating reference labs. Participants with positive screens were offered a follow-up study using alternative PCR and serology assays.

RESULTS

92,618 DoD donors enrolled; four tested positive on screening (0.0043%; CI 0.001176896%, 0.01105894%). Three enrolled in follow-up testing and none were positive. These results were comparable to all U.S. donors: 3,858,114 enrolled (excluding Puerto Rico) with 459 positive screens (0.0119%; CI 0.01083582%, 0.01303962%).

CONCLUSION

The study demonstrated the effectiveness of the cobas Zika test. DoD donors, who are included in emergency donor panels during military operations, were at no higher risk for Zika than the overall U.S. donor population. This article is protected by copyright. All rights reserved.

Hyperbaric treatment of platelets is comparable to cold storage alone over 14 days

BACKGROUND

Platelets stored at room temperature (22-24°C) for transfusion purposes have a shelf life of 5-7 days or 72h when stored refrigerated (1-6°C). The limited shelf life of platelet products severely compromises platelet inventory. We hypothesized that cold storage of platelets in 100% plasma using xenon gas under high pressure would extend shelf life to 14 days.

STUDY DESIGN AND METHODS

Double apheresis platelet units were collected and split equally between two bags. One unit was placed in a hyperbaric chamber, pressurized to 4 bar with a xenon/oxygen gas mixture, and placed in a refrigerator for 14 days (Xe). The remaining unit was aliquoted into mini-bags (10 mL) for storage at room temperature (RTP) or in cold (CSP). Samples were assayed on days 5 (RTP) or 14 (Xe and CSP) for count, metabolism, clot strength, platelet aggregation, and activation markers.

RESULTS

Platelet count in Xe samples was lower than that of RTP but significantly higher than CSP. Despite similar levels of glucose and lactate, the pH of Xe samples was significantly lower than CSP. Glycoprotein expression was better preserved by Xe storage compared to CSP, but no differences in activation were observed. Thromboelastography and aggregometry results were comparable between all groups.

DISCUSSION

Cold storage of platelets in plasma with hyperbaric xenon provides no significant improvement in platelet function over cold storage alone. Use of a hyperbaric chamber and slow off-gassing of Xe-stored units complicate platelet storage and delivery logistics. This article is protected by copyright. All rights reserved.

Comparison of Platelet Quality and Function Across Apheresis Collection Platforms

BACKGROUND

Platelet concentrates (PLT) can be manufactured using a combination of apheresis collection devices and suspension media (plasma or platelet additive solution (PAS)). It is unclear how platelet quality and hemostatic function differ across the current in-use manufacturing methods in the United States. The objective of this study was therefore to compare baseline function of PLT collected using different apheresis collection platforms and storage media.

STUDY DESIGN AND METHODS

PLT were collected at two sites with identical protocols(N=5 per site, N=10 total per group) on the MCS®+ 9000 (Haemonetics; "MCS"), the Trima Accel® 7 (Terumo; "Trima"), and the Amicus Cell Separator (Fresenius Kabi, "Amicus"). MCS PLT were collected into plasma while Trima and Amicus PLT were collected into plasma or PAS (Trima into Isoplate and Amicus into InterSol; yielding groups "TP", "TI" and "AP", "AI", respectively). PLT units were sampled 1 hour after collection and assayed to compare cellular counts, biochemistry, and hemostatic function.

RESULTS

Differences in biochemistry were most evident between plasma and PAS groups, as anticipated. MCS and TP had the highest clot strength as assessed by viscoelastometry. AI had the lowest thrombin generation capacity. Both TP and TI had the highest responses on platelet aggregometry. AI had the greatest number of microparticles.

DISCUSSION

Platelet quality and function differs among collection platforms at baseline. MCS and Trima platelets overall appear to trend towards higher hemostatic function. Future investigations will assess how these differences change throughout storage, and if these in vitro measures are clinically relevant. This article is protected by copyright. All rights reserved.

A prospective assessment of the time required to obtain one unit of fresh whole blood by civilian phlebotomists and Army laboratory technicians (68 K)

BACKGROUND

Resuscitation with blood products improves survival after major hemorrhage. Blood product administration at or near the point-of-injury (POI) amplifies this benefit. Size, weight, and cold-chain management challenges all limit the amount of blood medics can carry. Warm fresh whole blood (WFWB) transfusions from a pre-screened donor within the unit represent an alternative source of blood at the POI. We measured the time required for civilian and Army technicians performing phlebotomy frequently to obtain one unit of blood to serve as a goal metric for combat medics being trained in this skill.

METHODS

We gathered demographic and experience data along with proportion of first intravenous cannulation attempt success, time to blood flow initiated, and time to unit draw complete.

RESULTS

We prospectively enrolled 12 civilian phlebotomy technicians and 10 Army laboratory technicians performing whole blood collections on 50 and 68 donors respectively. The mean time from setup to needle insertion was 3.7 min for civilians versus 4.2 min for Army technicians. The mean time from blood flowing to the bag being full was 10.7 min versus 8.4 min for civilians versus Army technicians respectively. The mean bag weights were 514 g versus 522 g. First-pass intravenous cannulation success was 96% versus 98% respectively.

CONCLUSIONS

We found a high first intravenous cannulation attempt success among both the civilian and Army technicians. Medians times were <5 min to obtain venipuncture and <11 min to obtain one unit. These findings provide time-based benchmarks for potential use during transfusion training among military medics.

Hemostatic in vitro Properties of Novel Plasma Supernatants Produced from Late-Storage Low-Titer Type O Whole Blood

BACKGROUND

The use of low-titer group O whole blood is increasing. To reduce wastage, unused units can be converted to packed red blood cells. Supernatant is currently discarded post-conversion; however, it could be a valuable transfusable product. The aim of this study was to evaluate supernatant prepared from late-storage low-titer group O whole blood being converted to red blood cells, hypothesizing it will have higher hemostatic activity compared to fresh never-frozen liquid plasma.

METHODS

Low-titer group O whole blood supernatant (n=12) prepared on storage day 15 was tested on day 15, 21, and 26 and liquid plasma (n=12) on 3, 15, 21, and 26. Same day assays included cell counts, rotational thromboelastometry, and thrombin generation. Centrifuged plasma from units was banked for microparticle characterization, conventional coagulation, clot structure, hemoglobin, and additional thrombin generation assays.

RESULTS

Low-titer group O whole blood supernatant contained more residual platelets and microparticles compared to liquid plasma. At day 15, low-titer group O whole blood supernatant elicited a faster intrinsic clotting time compared to liquid plasma (257 +/- 41 vs. 299 +/- 36 seconds, p=0.044), and increased clot firmness (49 +/- 9 vs. 28 +/- 5 mm, p<0.0001). Low-titer group O whole blood supernatant showed more significant thrombin generation compared to liquid plasma (day 15 endogenous thrombin potential 1071 +/- 315 vs. 285 +/- 221 nM*min, p<0.0001). Flow cytometry demonstrated low-titer group O whole blood supernatant contained significantly more phosphatidylserine and CD41+ microparticles. However, thrombin generation in isolated plasma suggested residual platelets in low-titer group O whole blood supernatant were a greater contributor over microparticles. Additionally, low-titer group O whole blood supernatant and liquid plasma showed no difference in clot structure, despite higher CD61+ microparticle presence.

CONCLUSIONS

Plasma supernatant produced from late-storage low-titer group O whole blood shows comparable, if not enhanced, in vitro hemostatic efficacy to liquid plasma.

A prospective assessment of the medic autologous blood transfusion skills for field transfusion preparation

BACKGROUND

Data demonstrate the benefit of blood product administration near point-of-injury (POI). Fresh whole blood transfusion from a pre-screened donor provides a source of blood at the POI when resources are constrained. We captured transfusion skills data for medics performing autologous blood transfusion training.

METHODS

We conducted a prospective, observational study of medics with varying levels of experience. Inexperienced medics were those with minimal or no reported experience learning the autologous transfusion procedures, versus reported experience among special operations medics. When available, medics were debriefed after the procedure for qualitative feedback. We followed them for up to 7 days for adverse events.

RESULTS

The median number of attempts for inexperienced and experienced medics was 1 versus 1 (interquartile range 1-1 for both, p = .260). The inexperienced medics had a slower median time to needle venipuncture access for the donation of 7.3 versus 1.5 min, needle removal after clamping time of 0.3 versus 0.2 min, time to bag preparation of 1.9 versus 1.0 min, time to IV access for reinfusion of 6.0 versus 3.0 min, time to transfusion completion of 17.3 versus 11.0 min, and time to IV removal of 0.9 versus 0.3 min (all p < .05). We noted one administrative safety event in which an allogeneic transfusion occurred. No major adverse events occurred. Qualitative data saturated around the need for quarterly training.

CONCLUSIONS

Inexperienced medics have longer procedure times when training autologous whole blood transfusion skills. This data will help establish training measures of performance for skills optimization when learning this procedure.

Approach to Handling Atypical Field Blood Transfusion Scenarios

Special Operations Forces (SOF) medical personnel have been at the forefront of administering blood products in the austere field medicine environment. These far-forward medical providers regularly treat patients and deliver blood transfusions in some of the world's most extreme environments with minimal resources. A multitude of questions have been raised on this topic based on the unique experiences of senior providers in this field. In this paper, we analyze the available literature and present the recommendations of several experts in transfusion medicine for managing atypical field transfusion scenarios.

Analysis of the U.S. Military Trauma System in Accordance With Doctrinal Levels of Warfare

INTRODUCTION

In recent conflicts, the Joint Theater Trauma System (JTTS) led the systematic approach to improve battlefield trauma care, substantially contributing to the unprecedented survival of combat casualties. The Joint Trauma System (JTS) was codified in 2016 to preserve the lessons learned and functions of the JTTS, including the Department of Defense Trauma Registry. Concurrently, Combatant Commands (CCMD) were directed to establish CCMD Trauma Systems (CTS) "modeled after the JTTS" and to maintain a baseline of core functions intended to rapidly scale as needed. The complex nature of both CCMDs and the military trauma system has challenged the full implementation of the CTS. Analyzing the historical experiences of the JTTS, JTS, and CTS within a military doctrinal framework might enable the further success of the military trauma system.

METHODS

The strategic, operational, and tactical levels of warfare, in accordance with Joint Publication 1-0, Doctrine of the Armed Forces of the United States, and Joint Publication 3-0, Joint Operations, established the analytic framework for this study. The literature regarding the JTTS, CTS, and JTS was reviewed for relevant information concerning organizational structure and functions of trauma system performance improvement (PI) capabilities. A comprehensive analysis was performed using a thematic approach to evaluating descriptive data contained within the collected data set. Deployed trauma system PI tasks, functions, and responsibilities were identified, defined, and correlated according to the respective levels of warfare.

RESULTS

The comprehensive analysis revealed both discrete and overlapping tasks, functions, and responsibilities of the trauma system PI capabilities at each of the three levels of warfare. Strategic-level actions were categorized according to 12 distinct themes: reduce mortality; strategic reporting; centralized trauma registry; strategic communications; centralized organization; direct support to CCMDs; Department of Defense policy and doctrine; strategic-level PI; clinical practice guidelines; training and readiness standards; force structure, standardization, and interoperability; and research and development. Operational-level actions were categorized according to seven distinct themes: theater trauma system policies and requirements; theater trauma system leadership; stakeholder coordination; theater communication; theater standards for readiness and skill sustainment; trauma system planning; and medical logistics support. Tactical-level actions were categorized according to seven distinct themes: trauma system personnel; PI; documentation enforcement and patient care data collection; tactical planning recommendations for employing medical assets; research support; communication and reporting; and training and skills sustainment.

CONCLUSION

The deployed U.S. military trauma system requires a robust PI capability to optimize combat casualty care. Policy updates, a joint military trauma system doctrine, and force design updates are necessary for deployed military trauma system PI capabilities to function optimally across all levels of warfare.

Clinical Assessment of Low Calcium In traUMa (CALCIUM)

Major trauma frequently occurs in the deployed, combat setting and is especially applicable in the recent conflicts with explosives dominating the combat wounded. In future near-peer conflicts, we will likely face even more profound weapons including mortars and artillery. As such, the number of severely wounded will likely increase. Hypocalcemia frequently occurs after blood transfusions, secondary to the preservatives in the blood products; however, recent data suggests major trauma in and of itself is a risk factor for hypocalcemia. Calcium is a major ion involved in heart contractility; thus, hypocalcemia can lead to poor contractility. Smaller studies have linked hypocalcemia to worse outcomes, but it remains unclear what causes hypocalcemia and if intervening could potentially save lives. The objective of this study is to determine the incidence of hypocalcemia on hospital arrival and the association with survival. We are seeking to address the following scientific questions, (1) Is hypocalcemia present following traumatic injury prior to transfusion during resuscitation? (2) Does hypocalcemia influence the amount of blood products transfused? (3) To what extent is hypocalcemia further exacerbated by transfusion? (4) What is the relationship between hypocalcemia following traumatic injury and mortality? We will conduct a multicenter, prospective, observational study. We will gather ionized calcium levels at 0, 3, 6, 12, 18, and 24 hours as part of scheduled calcium measurements. This will ensure we have accurate data to assess the early and late effects of hypocalcemia throughout the course of resuscitation and hemorrhage control. These data will be captured by a trained study team at every site. Our findings will inform clinical practice guidelines and optimize the care delivered in the combat and civilian trauma setting. We are seeking 391 patients with complete data to meet our a priori inclusion criteria. Our study will have major immediate short-term findings including risk prediction modeling to assess who is at risk for hypocalcemia, data assessing interventions associated with the incidence of hypocalcemia, and outcome data including mortality and its link to early hypocalcemia.

Clinical Assessment of Low Calcium In traUMa (CALCIUM)

Major trauma frequently occurs in the deployed, combat setting and is especially applicable in the recent conflicts with explosives dominating the combat wounded. In future near-peer conflicts, we will likely face even more profound weapons including mortars and artillery. As such, the number of severely wounded will likely increase. Hypocalcemia frequently occurs after blood transfusions, secondary to the preservatives in the blood products; however, recent data suggests major trauma in and of itself is a risk factor for hypocalcemia. Calcium is a major ion involved in heart contractility; thus, hypocalcemia can lead to poor contractility. Smaller studies have linked hypocalcemia to worse outcomes, but it remains unclear what causes hypocalcemia and if intervening could potentially save lives. The objective of this study is to determine the incidence of hypocalcemia on hospital arrival and the association with survival. We are seeking to address the following scientific questions, (1) Is hypocalcemia present following traumatic injury prior to transfusion during resuscitation? (2) Does hypocalcemia influence the amount of blood products transfused? (3) To what extent is hypocalcemia further exacerbated by transfusion? (4) What is the relationship between hypocalcemia following traumatic injury and mortality? We will conduct a multicenter, prospective, observational study. We will gather ionized calcium levels at 0, 3, 6, 12, 18, and 24 hours as part of scheduled calcium measurements. This will ensure we have accurate data to assess the early and late effects of hypocalcemia throughout the course of resuscitation and hemorrhage control. These data will be captured by a trained study team at every site. Our findings will inform clinical practice guidelines and optimize the care delivered in the combat and civilian trauma setting. We are seeking 391 patients with complete data to meet our a priori inclusion criteria. Our study will have major immediate short-term findings including risk prediction modeling to assess who is at risk for hypocalcemia, data assessing interventions associated with the incidence of hypocalcemia, and outcome data including mortality and its link to early hypocalcemia.

Perfluorocarbons cause thrombocytopenia, changes in RBC morphology and death in a baboon model of systemic inflammation

A perfluorocarbon (PFC) investigated for treatment of traumatic brain injury (TBI) delivers oxygen to support brain function, but causes transient thrombocytopenia. TBI can cause acute inflammation with resulting thrombocytopenia; an interaction between the PFC effects and TBI inflammation might exacerbate thrombocytopenia. Therefore, PFC effects on platelet (PLT) function and hemostasis in a lipopolysaccharide (LPS) model of inflammation in the baboon were studied. Animals were randomized to receive saline ±LPS, and ± one of two doses of PFC. PLT count, transmission electron microscopy, and microparticle populations were quantified at baseline (BL) and at 2, 24, 48, 72, and 96 hours; hemostatic parameters for aggregometry and for blood clotting were measured at baseline (BL) and days 3 and 4. Injection of vehicle and LPS caused thrombocytopenia within hours; PFCs caused delayed thrombocytopenia beginning 48 hours post-infusion. LPS+PFC produced a more prolonged PLT decline and decreased clot strength. LPS+PFC increased ADP-stimulated aggregation, but PFC alone did not. Microparticle abundance was greatest in the LPS+PFC groups. LPS+PFC caused diffuse microvascular hemorrhage and death in 2 of 5 baboons in the low dose LPS-PFC group and 2 of 2 in the high dose LPS-PFC group. Necropsy and histology suggested death was caused by shock associated with hemorrhage in multiple organs. Abnormal morphology of platelets and red blood cells were notable for PFC inclusions. In summary, PFC infusion caused clinically significant thrombocytopenia and exacerbated LPS-induced platelet activation. The interaction between these effects resulted in decreased hemostatic capacity, diffuse bleeding, shock and death.

Traumatized triad of complementopathy, endotheliopathy, and coagulopathy ˗ Impact on clinical outcomes in severe polytrauma patients

Complementopathy, endotheliopathy, and coagulopathy following a traumatic injury are key pathophysiological mechanisms potentially associated with multiple-organ failure (MOF) and mortality. However, the heterogeneity in the responses of complementopathy, endotheliopathy, and coagulopathy to trauma, the nature and extent of their interplay, and their relationship to clinical outcomes remain unclear. Fifty-four poly-trauma patients were enrolled and divided into three subgroups based on their ISS. Biomarkers in blood plasma reflecting complement activation, endothelial damage, and coagulopathy were measured starting from admission to the emergency department and at 3, 6, 12, 24, and 120 hours after admission. Comparative analyses showed that severely injured patients (ISS>24) were associated with longer days on mechanical ventilation, in the intensive care unit and hospital stays, and a higher incidence of hyperglycemia, bacteremia, respiratory failure and pneumonia compared to mildly (ISS<16) or moderately (ISS=16-24) injured patients. In this trauma cohort, complement was activated early, primarily through the alternative complement pathway. As measured in blood plasma, severely injured patients had significantly higher levels of complement activation products (C3a, C5a, C5b-9, and Bb), endothelial damage markers (syndecan-1, sTM, sVEGFr1, and hcDNA), and fibrinolytic markers (D-dimer and LY30) compared to less severely injured patients. Severely injured patients also had significantly lower thrombin generation (ETP and peak) and lower levels of coagulation factors (I, V, VIII, IX, protein C) than less severely injured patients. Complement activation correlated with endothelial damage and hypocoagulopathy. Logistic regression analyses revealed that Bb >1.57 μg/ml, syndecan-1 >66.6 ng/ml or D-dimer >6 mg/L at admission were associated with a higher risk of MOF/mortality. After adjusting for ISS, each increase of the triadic score defined above (Bb>1.57 µg/ml/Syndecan-1>66.6 ng/ml/D-dimer>6.0mg/L) was associated with a 6-fold higher in the odds ratio of MOF/death [OR: 6.83 (1.04-44.96, P=0.046], and a 4-fold greater in the odds of infectious complications [OR: 4.12 (1.04-16.36), P=0.044]. These findings provide preliminary evidence of two human injury response endotypes (traumatized triad and non-traumatized triad) that align with clinical trajectory, suggesting a potential endotype defined by a high triadic score. Patients with this endotype may be considered for timely intervention to create a pro-survival/organ-protective phenotype and improve clinical outcomes.

Indices of complement activation and coagulation changes in trauma patients

Objectives

Early complementopathy and coagulopathy are shown often after trauma. However, the prevalence of any interplay between complement cascade (ComC) and coagulation cascade (CoaC) after trauma remains unclear. This study intended to explore whether complement-coagulation crosstalk exists, which may provide a reliable guide to clinical implications in trauma patients.

Methods

This single-center cohort study of trauma patients enrolled 100 patients along with 20 healthy volunteers. Blood samples from patients were collected at admission, 45, 90, 135 minutes, and 18 hours after admission. Demographic characteristics were recorded, blood levels of ComC and CoaC factors, and inflammatory cytokines were measured by ELISA, clot-based assays, or luminex multiplex assay, and partial thromboplastin (PT) and partial thromboplastin time (PTT) were assessed using a Behring blood coagulation system.

Results

Compared with the healthy controls, plasma levels of complement factors (C5b-9 and Bb) and 11 tested inflammatory cytokines increased in moderately and severely injured patients as early as 45 minutes after admission and sustained higher levels up to 18 hours after admission. C5b-9 correlated positively to patients’ hospital stay. In parallel, the consumption of coagulation factors I, II, X, and XIII was shown throughout the first 18 hours after admission in moderately and severely injured patients, whereas PT, PTT, D-dimer, factor VII, and factor VIII values significantly increased from the admission to 135 minutes in moderately and severely injured patients. Along with an inverse correlation between plasma Bb, factors I and II, a positive correlation between C5b-9, Bb, D-dimer, PT, and PTT was evident.

Conclusions

This study demonstrates trauma-induced early activation of plasma cascades including ComC, CoaC, and fibrinolytic cascade, and their correlation between plasma cascades in severe trauma patients. Our study suggests that the simultaneous modulation of plasma cascades might benefit clinical outcomes for trauma patients.

Level of evidence

Prospective study, level III.

Hypothermia in the Combat Trauma Population

BACKGROUND

The MARCH (Massive hemorrhage, Airway, Respirations, Circulation, and Hypothermia/Head injuries) algorithm taught to military medics includes interventions to prevent hypothermia. As possible sequelae from major trauma, hypothermia is associated with coagulopathy and lower survival. This paper sought to define hypothermia within our combat trauma population using an outcomes-based method, and determine clinical variables associated with hypothermia.

METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry focused on casualties who received prehospital care. A receiver operating curve was constructed and Youden's index was used to define hypothermia within the predetermined population based on mortality risk. A multivariable regression model was used to identify associations.

RESULTS

There were 23,243 encounters that met the inclusion criteria for this study with patients having received prehospital care and documentation of at least one emergency department temperature. An optimal threshold of 36.2° C was found to predict mortality; 3,159 casualties had temperatures below this threshold (14%). Survival to discharge was lower among casualties with hypothermia (91% versus 98%). Hypothermic casualties were less likely to undergo blanket application (38% versus 40%). However, they had higher proportions with Hypothermia Prevention and Management Kit application (11% versus 7%) and radiant warming (2% versus 1%). On multivariable regression modeling, none of the hypothermia interventions were associated with a decreased likelihood of hypothermia. Non-hypothermia interventions associated with hypothermia included prehospital intubation (OR 1.57, 95% CI 1.45-1.69) and blood product administration.

CONCLUSIONS

Hypothermia, including a single recorded low temperature in the patient care record, was associated with worse outcomes in this combat trauma population. Prehospital intubation was most strongly associated with developing hypothermia. Prehospital warming interventions were not associated with a reduction in hypothermia risk. Our dataset suggests that current methods for prehospital warming are inadequate.

The risk of thromboembolic events with early intravenous 2- and 4-g bolus dosing of tranexamic acid compared to placebo in patients with severe traumatic bleeding: A secondary analysis of a randomized, double-blind, placebo-controlled, single-center trial

BACKGROUND

Screening for the risk of thromboembolism (TE) due to tranexamic acid (TXA) in patients with severe traumatic injury has not been performed in randomized clinical trials. Our objective was to determine if TXA dose was independently-associated with thromboembolism.

STUDY DESIGN AND METHODS

This is a secondary analysis of a single-center, double-blinded, randomized controlled trial comparing placebo to a 2-g or 4-g intravenous TXA bolus dose in trauma patients with severe injury. We used multivariable discrete-time Cox regression models to identify associations with risk for thromboembolic events within 30 days post-enrollment. Event curves were created using discrete-time Cox regression.

RESULTS

There were 50 patients in the placebo group, 49 in the 2-g, and 50 in the 4-g TXA group. In adjusted analyses for thromboembolism, a 2-g dose of TXA had an hazard ratio (HR, 95% confidence interval [CI]) of 3.20 (1.12-9.11) (p = .029), and a 4-g dose of TXA had an HR (95% CI) of 5.33 (1.94-14.63) (p = .001). Event curves demonstrated a higher probability of thromboembolism for both doses of TXA compared to placebo. Other parameters independently associated with thromboembolism include time from injury to TXA administration, body mass index, and total blood products transfused.

DISCUSSION

In patients with severe traumatic injury, there was a dose-dependent increase in the risk of at least one thromboembolic event with TXA. TXA should not be withheld, but thromboembolism screening should be considered for patients receiving a dose of at least 2-g TXA intravenously for traumatic hemorrhage.

The U.S. Armed Services Blood Program support to U.S. Central Command 2014-2021: Transformation of combat trauma resuscitation through blood product innovation and expansion of blood availability far forward

BACKGROUND

The United States Armed Services Blood Program (ASBP) faced complex blood supply challenges during two decades of military operations in the U.S. Central Command (CENTCOM) and through an adaptive, responsive, and agile system, gained valuable insights on blood product usage in combat casualty care.

STUDY DESIGN AND METHODS

A retrospective review of blood product introduction and utilization trends was compiled from ASBP data collected during CENTCOM operations from 2014 through 2021.

RESULTS

During the study period, several blood products were introduced to the CENTCOM area of operations including Low Titer O Whole Blood (LTOWB), Cold-Stored Platelets (CSP), Liquid Plasma (LP), and French Freeze Dried Plasma (FDP) manufactured from U.S. sourced donor plasma, all while expanding Walking Blood Bank capabilities. There was a gradual substitution of component therapy for whole blood; blood utilization peaked in 2017. Transfusion of Fresh Whole Blood (FWB) from Walking Blood Banks decreased as fully pre-tested LTOWB was supplied by the ASBP. LTOWB was initially supplied in citrate-phosphate-dextrose (CPD) anticoagulant (21-day shelf life) but was largely replaced with LTOWB in citrate-phosphate-dextrose-adenine (CPDA-1) anticoagulant (35-day shelf life) by 2019. Implementation of prehospital transfusion and expansion of surgical and resuscitation teams led to an increase in the number of sites receiving blood.

DISCUSSION

ASBP introduced new products to its inventory in order to meet changing blood product demands driven by changes in the Joint Trauma System Clinical Practice Guidelines and operational demands. These products were adopted into clinical practice with a resultant evolution in transfusion strategies.

Resuscitation of an exsanguinated obstetrics patient with HBOC-201: A case report

BACKGROUND

Hemorrhagic shock is a clinically challenging disease process with high mortality. When conventional blood products are unable to be administered, oxygen-carrying blood alternatives are sometimes utilized. The international experience with this scenario is limited. We aim to add to this body of literature.

STUDY DESIGN AND METHODS

This is a case report of the administration of bovine hemoglobin-based oxygen-carrying red blood cell (RBC) substitute HBOC-201 (HemoPure®) to a patient with post-partum bleeding and hemorrhagic shock because the patient declined RBC transfusion. HBOC-201 was administered with consent under a one-time Emergency Investigational New Drug (eIND) approval from the Food and Drug Administration with appropriate notification of the Institutional Review Board.

RESULTS

The patient was successfully resuscitated with HBOC-201 from hemorrhagic shock. She was weaned off of vasopressor support and extubated with the recovery of her baseline mental status within 4 h. However, approximately 36 h after this, the patient developed multi-organ system dysfunction, volume overload, right heart failure and ultimately expired early on post-partum day 4.

DISCUSSION

Resuscitation from hemorrhagic shock with HBOC-201 as an RBC alternative is feasible, but significant challenges remain with the management of sequelae resulting from prolonged low-flow, ischemic states as well as the significant colloid pressure and volume overload experienced after massive transfusion with an acellular colloid oxygen carrier.

U.S. cities will not meet blood product resuscitation standards during major mass casualty incidents: Results of a THOR-AABB working party prospective analysis

BACKGROUND

Mass casualty incidents (MCIs) create an immediate surge in blood product demand. We hypothesize local inventories in major U.S. cities would not meet this demand.

STUDY DESIGN AND METHODS

A simulated blast in a large crowd estimated casualty numbers. Ideal resuscitation was defined as equal amounts of red blood cells (RBCs), plasma, platelets, and cryoprecipitate. Inventory was prospectively collected from six major U.S. cities at six time points between January and July 2019. City-wide blood inventories were classified as READY (>1 U/injured survivor), DEFICIENT (<10 U/severely injured survivor), or RISK (between READY and DEFICIENT), before and after resupply from local distribution centers (DC), and features of DEFICIENT cities were identified.

RESULTS

The simulated blast resulted in 2218 injured survivors including 95 with severe injuries. Balanced resuscitation would require between 950 and 2218 units each RBC, plasma, platelets and cryoprecipitate. Inventories in 88 hospitals/health systems and 10 DCs were assessed. Of 36 city-wide surveys, RISK inventories included RBCs (n = 16; 44%), plasma (n = 24; 67%), platelets (n = 6; 17%), and cryoprecipitate (n = 22; 61%) while DEFICIENT inventories included platelets (n = 30; 83%) and cryoprecipitate (n = 12; 33%). Resupply shifted most RBC and plasma inventories to READY, but some platelet and cryoprecipitate inventories remained at RISK (n = 24; 67% and n = 12; 33%, respectively) or even DEFICIENT (n = 11; 31% and n = 6; 17%, respectively). Cities with DEFICIENT inventories were smaller (p <.001) with fewer blood products per trauma bed (p <.001).

DISCUSSION

In this simulated blast event, blood product demand exceeded local supply in some major U.S. cities. Options for closing this gap should be explored to optimize resuscitation during MCIs.

Regional blood acidification inhibits coagulation during extracorporeal carbon dioxide removal (ECCO2 R)

BACKGROUND

Consumption of platelets and coagulation factors during extracorporeal carbon dioxide removal (ECCO₂ R) increases bleeding complications and associated mortality. Regional infusion of lactic acid enhances ECCO₂ R by shifting the chemical equilibrium from bicarbonate to carbon dioxide. Our goal was to test if regional blood acidification during ECCO₂ R inhibits platelet function and coagulation.

METHODS

An ECCO₂ R system containing a hemofilter circulated blood at 0.25 L/min in 8 healthy ewes (Ovis aries) for 36 hours. Three of the sheep received ECCO₂ R with no recirculation compared to 5 sheep that received ECCO₂ R plus 12 hours of regional blood acidification via the hemofilter, placed upstream from the oxygenator, into which 4.4 M lactic acid was infused. Blood gases, platelet count and function, thromboelastography, coagulation-factor activity, and von Willebrand factor activity (vWF:Ag) were measured at baseline, at start of lactic acid infusion, and after 36 hours of extracorporeal circulation.

RESULTS

Twelve hours of regional acid infusion significantly inhibited platelet aggregation response to adenosine diphosphate; vWF; and platelet expression of P-selectin compared to control. It also significantly reduced consumption of fibrinogen and of coagulation factors V, VII, IX, compared to control.

CONCLUSIONS

Regional acidification reduces platelet activation and vitamin-K-dependent coagulation-factor consumption during ECCO₂ R. This is the first report of a simple method that may enhance effective anticoagulation for ECCO₂ R.

Suppression of fibrin(ogen)-driven pathologies in disease models through controlled knockdown by lipid nanoparticle delivery of siRNA

Fibrinogen plays a pathologic role in multiple diseases. It contributes to thrombosis and modifies inflammatory and immune responses, supported by studies in mice expressing fibrinogen variants with altered function or with a germline fibrinogen deficiency. However, therapeutic strategies to safely and effectively tailor plasma fibrinogen concentration are lacking. Here, we developed a strategy to tune fibrinogen expression by administering lipid nanoparticle (LNP)-encapsulated small interfering RNA (siRNA) targeting the fibrinogen α chain (siFga). Three distinct LNP-siFga reagents reduced both hepatic Fga messenger RNA and fibrinogen levels in platelets and plasma, with plasma levels decreased to 42%, 16%, and 4% of normal within 1 week of administration. Using the most potent siFga, circulating fibrinogen was controllably decreased to 32%, 14%, and 5% of baseline with 0.5, 1.0, and 2.0 mg/kg doses, respectively. Whole blood from mice treated with siFga formed clots with significantly decreased clot strength ex vivo, but siFga treatment did not compromise hemostasis following saphenous vein puncture or tail transection. In an endotoxemia model, siFga suppressed the acute phase response and decreased plasma fibrinogen, D-dimer, and proinflammatory cytokine levels. In a sterile peritonitis model, siFga restored normal macrophage migration in plasminogen-deficient mice. Finally, treatment of mice with siFga decreased the metastatic potential of tumor cells in a manner comparable to that observed in fibrinogen-deficient mice. The results indicate that siFga causes robust and controllable depletion of fibrinogen and provides the proof-of-concept that this strategy can modulate the pleiotropic effects of fibrinogen in relevant disease models.

Intravenous administration of mesenchymal stromal cells leads to a dose-dependent coagulopathy and is unable to attenuate acute traumatic coagulopathy in rats

BACKGROUND

Mesenchymal stromal cells (MSCs) express surface tissue factor (TF), which may affect hemostasis and detract from therapeutic outcomes of MSCs if administered intravenously. In this study, we determine a safe dose of MSCs for intravenous (IV) administration and further demonstrate the impact of IV-MSC on acute traumatic coagulopathy (ATC) in rats.

METHODS

Tissue factor expression of rat bone marrow-derived mesenchymal stromal cell (BMSC) or adipose-derived mesenchymal stromal cell (AMSC) was detected by immunohistochemistry and enzyme-linked immunosorbent assay. The coagulation properties were measured in MSC-treated rat whole blood, and blood samples were collected from rats after IV administration of MSCs. Acute traumatic coagulopathy rats underwent polytrauma and 40% hemorrhage, followed by IV administration of 5 or 10 million/kg BMSCs (BMSC-5, BMSC-10), or vehicle at 1 hour after trauma.

RESULTS

Rat MSCs expressed TF, and incubation of rat BMSCs or AMSCs with whole blood in vitro led to a significantly shortened clotting time. However, a dose-dependent prolongation of prothrombin time with reduction in platelet counts and fibrinogen was found in healthy rat treated with IV-MSCs. Bone marrow-derived mesenchymal stromal cells at 5 million/kg or less led to minimal effect on hemostasis. Mesenchymal stromal cells were not found in circulation but in the lungs after IV administration regardless of the dosage. Acute traumatic coagulopathy with prolonged prothrombin time was not significantly affected by 5 or 10 million/kg BMSCs. Intravenous administration of 10 million/kg BMSCs led to significantly lower fibrinogen and platelet counts, while significantly higher levels of lactate, wet/dry weight ratio, and leukocyte infiltration in the lung were present compared with BMSC-5 or vehicle. No differences were seen in immune or inflammatory profiles with BMSC treatment in ATC rats, at least in the acute timeframe.

CONCLUSION

Intravenous administration of MSCs leads to a risk of coagulopathy associated with a dose-dependent reduction in platelet counts and fibrinogen and is incapable of restoring hemostasis of rats with ATC after polytrauma and hemorrhagic shock.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Joint Trauma System Clinical Practice Guideline (JTS CPG): Prehospital Blood Transfusion. 30 October 2020

This Clinical Practice Guideline (CPG) provides a brief summary of the scientific literature for prehospital blood use, with an emphasis on the en route care environment. Updates include the importance of calcium administration to counteract the deleterious effects of hypocalcemia, minimal to no use of crystalloid, and stresses the importance of involved and educated en route care medical directors alongside at a competent prehospital and en route care providers (see Table 1). With the paradigm shift to use FDA-approved cold stored low titer group O whole blood (CS-LTOWB) along with the operational need for continued use of walking blood banks (WBB) and point of injury (POI) transfusion, there must be focused, deliberate training incorporating the different whole blood options. Appropriate supervision of autologous blood transfusion training is important for execution of this task in support of deployed combat operations as well as other operations in which traumatic injuries will occur. Command emphasis on the importance of this effort as well as appropriate logistical support are essential elements of a prehospital blood program as part of a prehospital/en route combat casualty care system.

Fluid Resuscitation in Tactical Combat Casualty Care; TCCC Guidelines Change 21-01. 4 November 2021

Hemorrhagic shock in combat trauma remains the greatest life threat to casualties with potentially survivable injuries. Advances in external hemorrhage control and the increasing use of damage control resuscitation have demonstrated significant success in decreasing mortality in combat casualties. Presently, an expanding body of literature suggests that fluid resuscitation strategies for casualties in hemorrhagic shock that include the prehospital use of cold-stored or fresh whole blood when available, or blood components when whole blood is not available, are superior to crystalloid and colloid fluids. On the basis of this recent evidence, the Committee on Tactical Combat Casualty Care (TCCC) has conducted a review of fluid resuscitation for the combat casualty who is in hemorrhagic shock and made the following new recommendations: (1) cold stored low-titer group O whole blood (CS-LTOWB) has been designated as the preferred resuscitation fluid, with fresh LTOWB identified as the first alternate if CS-LTOWB is not available; (2) crystalloids and Hextend are no longer recommended as fluid resuscitation options in hemorrhagic shock; (3) target systolic blood pressure (SBP) resuscitation goals have been redefined for casualties with and without traumatic brain injury (TBI) coexisting with their hemorrhagic shock; and (4) empiric prehospital calcium administration is now recommended whenever blood product resuscitation is required.

Whole blood resuscitation restores intestinal perfusion and influences gut microbiome diversity

OBJECTIVE

Gut dysbiosis, an imbalance in the gut microbiome, occurs after trauma, which may be ameliorated with transfusion. We hypothesized that gut hypoperfusion following trauma causes dysbiosis and that whole blood (WB) resuscitation mitigates these effects.

METHODS

Anesthetized rats underwent sham (S; laparotomy only, n = 6); multiple injuries (T; laparotomy, liver and skeletal muscle crush injuries, and femur fracture, n = 5); multiple injuries and 40% hemorrhage (H; n = 7); and multiple injuries, hemorrhage, and WB resuscitation (R; n = 7), which was given as 20% estimated blood volume from donor rats 1 hour posttrauma. Baseline cecal mesenteric tissue oxygen (O2) concentration was measured following laparotomy and at 1 hour and 2 hours posttrauma. Fecal samples were collected preinjury and at euthanasia (2 hours). 16S rRNA sequencing was performed on purified DNA, and diversity and phylogeny were analyzed with QIIME (Knight Lab, La Jolla, CA; Caporaso Lab, Flagstaff, AZ) using the Greengenes 16S rRNA database (operational taxonomic units; 97% similarity). α and β diversities were estimated using observed species metrics. Permutational analysis of variance was performed for overall significance.

RESULTS

In H rats, an average decline of 36% ± 3.6% was seen in the mesenteric O2 concentration at 1 hour without improvement by 2 hours postinjury, which was reversed following resuscitation at 2 hours postinjury (4.1% ± 3.1% difference from baseline). There was no change in tissue O2 concentration in the S or T rats. β Diversity differed among groups for all measured indices except Bray-Curtis, with the spatial median of the S and R rats more similar compared with S and H rats (p < 0.05). While there was no difference in α diversity found among the groups, indices were significantly correlated with mesenteric O2 concentration. Members of the family Enterobacteriaceae were significantly enriched in only 2 hours.

CONCLUSION

Mesenteric perfusion after trauma and hemorrhage is restored with WB resuscitation, which influences β diversity of the gut microbiome. Whole blood resuscitation may also mitigate the effects of hemorrhage on intestinal dysbiosis, thereby influencing outcomes.

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

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

Intraoperative blood transfusions in burn patients

BACKGROUND

Donated blood is a valuable and limited resource. Excision of burn wounds often leads to significant blood loss requiring transfusion. Accurately estimating blood loss is difficult, so examining the amount of blood products given intraoperatively is a clinically relevant way to measure utilization of this valuable resource. In this study, we examined the factors that influenced the amount of blood given intraoperatively during burn wound excisions.

STUDY DESIGN AND METHODS

A retrospective analysis of patients admitted to a single burn center over 5 years who underwent excision of their burn wounds and received intraoperative blood products was performed. Patient and burn characteristics as well as pertinent surgical data and laboratory values on the day of surgery and postoperatively were gathered. A linear regression analysis examined factors influencing the number of units of products given and a predictive model was generated.

RESULTS

A total of 563 operations performed on 166 patients were included. The amount of burn excised was the most influential variable on the amount of blood products given. Hemoglobin level, international normalized ratio, and platelet count on the day of surgery were associated with transfusion of different blood products. A predictive model was generated to aid in preoperative ordering of blood products.

CONCLUSION

The amount of burn excised and common hematology and coagulation lab values were associated with the amount of different blood products administered during burn surgery. The predictive model generated needs to be validated prospectively to aid in preoperative planning for burn excisions.

Cold-stored platelets have better preserved contractile function in comparison with room temperature-stored platelets over 21 days

Although it is well established that transfusion of platelets in cases of severe bleeding reduces mortality, the availability of platelets is hampered by harsh restrictions on shelf life due to elevated risks of microbial contamination and functional losses with room temperature-stored platelets (RTP) kept at 22°C. In contrast, many recent studies have shown that 4°C cold-stored platelets (CSP) are able to overcome these shortcomings leading to the recent Food and Drug Administration licensure for 14-day stored CSP when conventional platelets are unavailable. This work expands the evidence supporting superiority of CSP function by assaying the less explored platelet-mediated clot retraction of RTP and CSP in either autologous plasma (AP) or platelet additive solution (PAS) for up to 21 days. The results demonstrate that CSP have better preservation of contractile function, exhibiting retraction for up to 21 days in both AP and PAS and forming highly ordered fibrin scaffolds similar to those of fresh platelets. In contrast, RTP stored in AP showed impaired contractile function by Day 5 with no retraction after 10 days, whereas PAS-stored RTP retained contractile function for up to 21 days. Collectively, these findings support extended storage of CSP and suggest that storage in PAS can mitigate functional losses in RTP.