Cold-stored whole blood platelet function is preserved in injured children with hemorrhagic shock

Review of Low Titer Group O Whole Blood (LTOWB) Transfusion in Initial Resuscitation of Pediatric Trauma Patients: Assessing Potential Benefits

BACKGROUND

Hemorrhagic shock secondary to trauma is a leading cause of pediatric mortality in the United States. Timely intervention is crucial to prevent many of these deaths. Children and adults exhibit distinct responses to trauma due to varying blood volume ratios and injury patterns. Pediatric patients with hypotension face a heightened risk of shock, demanding a more assertive resuscitation.

METHODS

This study is a review of the literature on LTOWB transfusion in pediatric trauma. We conducted electronic database searches until December 2022, using keywords related to LTOWB and pediatric trauma resuscitation. Randomized/non-randomized, retrospective/prospective studies were considered, assessing serological safety, adverse reactions, clinical outcomes, and cost-effectiveness.

RESULTS

Six articles were ultimately reviewed. No adverse reactions related to hemolysis biomarkers were observed. Clinical outcomes exhibited no significant differences in mortality, hospital, or ventilator days between LTOWB and component therapy (CT). However, LTOWB transfusion resulted in faster resolution of base deficit, lower INR, and reduced requirement for additive plasma and platelet transfusions. In military and massive transfusion cases, LTOWB was associated with decreased mortality and lower transfusion volumes. One article suggested potential economic advantages.

CONCLUSIONS

LTOWB transfusion appears to be a promising option for pediatric trauma resuscitation, offering benefits in rapid administration and component balance. While some studies indicate potential advantages in clinical outcomes and cost-effectiveness, the current evidence is limited and requires further investigation. Future research should focus on large-scale studies to validate these findings, especially concerning economic benefits, and develop standardized protocols for LTOWB use in pediatric settings.

LEVELS OF EVIDENCE

Treatment Study, LEVEL III.

Use of low titer O whole blood in infants and young children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Low titer group O whole blood (LTOWB) is commonly used for severe bleeding in trauma patients. LTOWB may also benefit young children requiring cardiac surgery with cardiopulmonary bypass (CPB) at risk of severe bleeding.

STUDY DESIGN AND METHODS

In this retrospective study, children <2 years old who underwent cardiac surgery with CPB were included. Comparisons were performed between those receiving component therapy (CT) versus those receiving LTOWB plus CT (LTOWB+CT). Outcomes included drainage tube (DT) output and total transfusion volumes. Optimization-based weighting was used for adjusted analyses between groups.

RESULTS

There were 117 patients transfused with only CT and 127 patients transfused with LTOWB+CT. In the LTOWB+CT group, 66 were Group non-O and 61 were Group O. Total transfusion volumes given from the start of the operation until the first 24 h in the cardiac intensive care unit was a median (IQR) 41 (10, 93) mL/kg in the CT group and 48 (28, 77) mL/kg in the LTOWB+CT group, (p = .28). Median (IQR) DT output was 22 (15-32) in CT versus 22 (16-28) in LTOWB+CT groups, (p = .27). There were no differences in death, renal failure and a composite of death and renal failure between the two groups, but there were statistically fewer re-explorations for bleeding in the LTOWB+CT group (p < .001).

CONCLUSIONS

The use of LTOWB appears to be safe in <2 years old undergoing cardiac surgery and may reduce re-explorations for severe bleeding. Large trials are needed to determine the efficacy and safety of LTOWB in this population with severe bleeding.

Whole blood to total transfusion volume ratio in injured children: A national database analysis

BACKGROUND

Whole blood (WB) resuscitation is increasingly common in adult trauma centers and some pediatric trauma centers, as studies have noted its safety and potential superiority to component therapy (CT). Previous analyses have evaluated WB as a binary variable (any versus none), and little is known regarding the "dose response" of WB in relation to total transfusion volume (TTV) (WB/TTV ratio).

METHODS

Injured children younger than 18 years who received any blood transfusion within 4 hours of hospital arrival across 456 US trauma centers were included from the American College of Surgeons Trauma Quality Improvement Program database. The primary outcome was 24-hour mortality, and the secondary outcome was 4-hour mortality. Multivariate analysis was used to evaluate associations between WB administration and mortality and WB/TTV ratio and mortality.

RESULTS

Of 4,323 pediatric patients included in final analysis, 88% (3,786) received CT only, and 12% (537) received WB with or without CT. Compared with the CT group, WB recipients were more likely to be in shock, according to pediatric age-adjusted shock index (71% vs. 60%) and had higher median (interquartile range) Injury Severity Score (26 [17-35] vs. 25 [16-24], p = 0.007). Any WB transfusion was associated with 42% decreased odds of mortality at 4 hours (adjusted odds ratio [aOR], 0.58 [95% confidence interval, 0.35-0.97]; p = 0.038) and 54% decreased odds of mortality at 24 hours (aOR, 0.46 [0.33-0.66]; p < 0.001). Each 10% increase in WB/TTV ratio was associated with a 9% decrease in 24-hour mortality (aOR, 0.91 [0.85-0.97]; p = 0.006). Subgroup analyses for age younger than 14 years and receipt of massive transfusion (>40 mL/kg) also showed statistically significant survival benefit for 24-hour mortality.

CONCLUSION

In this retrospective American College of Surgeons Trauma Quality Improvement Program analysis, use of WB was independently associated with reduced 24-hour mortality in children; further, higher proportions of WB used over the total resuscitation (WB/TTV ratio) were associated with a stepwise increase in survival.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Low Titer Group O Whole Blood In Injured Children Requiring Massive Transfusion

OBJECTIVE

The aim of this study was to assess the survival impact of low-titer group O whole blood (LTOWB) in injured pediatric patients who require massive transfusion.

SUMMARY BACKGROUND DATA

Limited data are available regarding the effectiveness of LTOWB in pediatric trauma.

METHODS

A prospective observational study of children requiring massive transfusion after injury at UPMC Children's Hospital of Pittsburgh, an urban academic pediatric Level 1 trauma center. Injured children ages 1 to 17 years who received a total of >40 mL/kg of LTOWB and/or conventional components over the 24 hours after admission were included. Patient characteristics, blood product utilization and clinical outcomes were analyzed using Kaplan-Meier survival curves, log rank tests and Cox proportional hazards regression analyses. The primary outcome was 28-day survival.

RESULTS

Of patients analyzed, 27 of 80 (33%) received LTOWB as part of their hemostatic resuscitation. The LTOWB group was comparable to the component therapy group on baseline demographic and physiologic parameters except older age, higher body weight, and lower red blood cell and plasma transfusion volumes. After adjusting for age, total blood product volume transfused in 24 hours, admission base deficit, international normalized ratio (INR), and injury severity score (ISS), children who received LTOWB as part of their resuscitation had significantly improved survival at both 72 hours and 28 days post-trauma [adjusted odds ratio (AOR) 0.23, P = 0.009 and AOR 0.41, P = 0.02, respectively]; 6-hour survival was not statistically significant (AOR = 0.51, P = 0.30). Survivors at 28 days in the LTOWB group had reduced hospital LOS, ICU LOS, and ventilator days compared to the CT group.

CONCLUSION

Administration of LTOWB during the hemostatic resuscitation of injured children requiring massive transfusion was independently associated with improved 72-hour and 28-day survival.

Whole Blood Resuscitation is Safe in Pediatric Trauma Patients: A Multicenter Study

INTRODUCTION

Whole blood (WB) resuscitation has been associated with a mortality benefit in trauma patients. Several small series report the safe use of WB in the pediatric trauma population. We performed a subgroup analysis of the pediatric patients from a large prospective multicenter trial comparing patients receiving WB or blood component therapy (BCT) during trauma resuscitation. We hypothesized that WB resuscitation would be safe compared to BCT resuscitation in pediatric trauma patients.

METHODS

This study included pediatric trauma patients (0-17 y), from ten level-I trauma centers, who received any blood transfusion during initial resuscitation. Patients were included in the WB group if they received at least one unit of WB during their resuscitation, and the BCT group was composed of patients receiving traditional blood product resuscitation. The primary outcome was in-hospital mortality with secondary outcomes being complications. Multivariate logistic regression was performed to assess for mortality and complications in those treated with WB vs BCT.

RESULTS

Ninety patients, with both penetrating and blunt mechanisms of injury (MOI), were enrolled in the study (WB: 62 (69%), BCT: 28 (21%)). Whole blood patients were more likely to be male. There were no differences in age, MOI, shock index, or injury severity score between groups. On logistic regression, there was no difference in complications. Mortality was not different between the groups (P = .983).

CONCLUSION

Our data suggest WB resuscitation is safe when compared to BCT resuscitation in the care of critically injured pediatric trauma patients.

Resuscitative practices and the use of low-titer group O whole blood in pediatric trauma

ABSTRACT

Increasing rates of penetrating trauma in the United States makes rapid identification of hemorrhagic shock, coagulopathy, and early initiation of balanced resuscitation in injured children of critical importance. Hemorrhagic shock begins early after injury and can be challenging to identify in children, as hypotension is a late sign that a child is on the verge of circulatory collapse and should be aggressively resuscitated. Recent data support shifting away from crystalloid and toward early resuscitation with blood products because of worse coagulopathy and clinical outcomes in injured patients resuscitated with crystalloid. Multicenter studies have found improved survival in injured children who receive balanced resuscitation with higher fresh frozen plasma: red blood cell ratios. Whole blood is an efficient way to achieve balanced resuscitation in critically injured children with limited intravenous access and decreased exposure to multiple donors. Administration of cold-stored, low-titer O-negative whole blood (LTOWB) appears to be safe in adults and children and may be associated with improved survival in children with life-threatening hemorrhage. Many pediatric centers use RhD-negative LTOWB for all female children because of the risk of hemolytic disease of the fetus and newborn (0-6%); however. there is a scarcity of LTOWB compared with the demand. Low risks of hemolytic disease of the fetus and newborn affecting a future pregnancy must be weighed against high mortality rates in delayed blood product administration in children in hemorrhagic shock. Survey studies involving key stakeholder's opinions on pediatric blood transfusion practices are underway. Existing pediatric-specific literature on trauma resuscitation is often limited and underpowered; multicenter prospective studies are urgently needed to define optimal resuscitation products and practices in injured children in an era of increasing penetrating trauma.

The hemostatic profile of cold-stored whole blood from non-greyhound and greyhound dogs over 42 days

Objectives

To compare the hemostatic characteristics of cold-stored whole blood (CSWB) from non-greyhound dogs (NGD) and greyhound dogs (GD) over 42 days of storage, notably, platelet closure time (PCT) (NGD only), manual platelet count (PLT) (GD only), ellagic acid (INTEM) and tissue factor activated (EXTEM) rotational thromboelastometry, prothrombin (PT) and activated partial thromboplastin time (aPTT), fibrinogen concentration (FIB), and the activities of factors (F) FII, FV, FVII, FVIII, FIX, FX, FXIII antigen (FXIII:Ag), and von Willebrand factor antigen (vWF:Ag).

Design

Whole blood from 10 NGD and 10 GD, was refrigerated in CPD blood bags at 4°C for 42 days. Blood was analyzed before refrigeration (day 0) and at day 1 (d1), 3, 5, 7, 10, 14, 17, 21, 24, 28, 31, 35, 38, and 42. Multivariate linear mixed effects models were created to evaluate coagulation parameters over time and compare NGD and GD. Data are summarized as estimated marginal means with 95% confidence intervals. Significance was set at P < 0.05.

Results

The PCT for all NGD CSWB was above the device limit by d7. The PLT for GD CSWB did not change during storage. The mean alpha-angle for INTEM and EXTEM decreased to <50% of baseline at d38 and d31 for NGD, and d31 and d17 for GD CSWB. The mean maximum clot firmness (MCF) for INTEM and EXTEM reduced to <50% of baseline at d42 and d28 for both GD and NGD. PT and aPTT for NGD and GD increased over time. For NGD CSWB, the mean FVIII and vWF:Ag activities decreased to <50% of baseline at d7 and d28, respectively, and FIB reached 0.982 g/dL by d24. For GD CSWB, FVIII, FXIII:Ag and FV activities decreased to <50% of baseline by d3, d38, and d38, respectively, and FIB was 0.982 g/dL at baseline. Alpha-angle and MCF for both INTEM and EXTEM, and activities for FII, FV, FIX, FXIII:Ag were significantly lower, and vWF:Ag was significantly higher overall in GD CSWB compared with NGD. A significant difference in the pattern of change over time was detected between NGD and GD in EXTEM alpha-angle, INTEM and EXTEM MCF, FII, and FVIII activities.

Conclusions

The in vitro viscoelastic parameters of GD and NGD CSWB declines over 42 days, but numerous hemostatic parameters (INTEM and EXTEM alpha-angle and MCF, activity of FII, FV, FV, FVII, FIX, FX, FXIII:Ag, vWF:Ag, and FIB) remain within 50% of baseline for more than 14 days. CSWB from GD compared to NGD has reduced hemostatic activity overall, but a similar pattern of decline for most parameters over time.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Neonatal subgaleal hemorrhage: twenty years of trends in incidence, associations, and outcomes

BACKGROUND

In 2011, we reported 38 neonates with subgaleal hemorrhage (SH), relating an increasing incidence. It is unclear whether the incidence in our hospitals continued to rise and which risk factors and outcomes are associated with this condition.

DESIGN

We retrospectively analyzed every recognized case of SH in our hospitals from the end of our previous report (2010) to the present (2022). We redescribed the incidence, scored severity, tabulated blood products transfused, and recorded outcomes.

RESULTS

Across 141 months, 191 neonates were diagnosed with SH; 30 after vacuum or forceps. The incidence (one/1815 births) was higher than in our 2011 report (one/7124 births). Also, severe SH (requiring transfusion) was more common (one/10,033 births vs. one/20,950 births previously). Four died (all with severe SH) and 12 had neurodevelopmental impairment.

CONCLUSION

Recognized cases of SH are increasing in our system without a clear explanation. Adverse outcomes are rare but continue to occur.

Platelet-Inspired Intravenous Nanomedicine for Injury-Targeted Direct Delivery of Thrombin to Augment Hemostasis in Coagulopathies

Severe hemorrhage associated with trauma, surgery, and congenital or drug-induced coagulopathies can be life-threatening and requires rapid hemostatic management via topical, intracavitary, or intravenous routes. For injuries that are not easily accessible externally, intravenous hemostatic approaches are needed. The clinical gold standard for this is transfusion of blood products, but due to donor dependence, specialized storage requirements, high risk of contamination, and short shelf life, blood product use faces significant challenges. Consequently, recent research efforts are being focused on designing biosynthetic intravenous hemostats, using intravenous nanoparticles and polymer systems. Here we report on the design and evaluation of thrombin-loaded injury-site-targeted lipid nanoparticles (t-TLNPs) that can specifically localize at an injury site via platelet-mimetic anchorage to the von Willebrand factor (vWF) and collagen and directly release thrombin via diffusion and phospholipase-triggered particle destabilization, which can locally augment fibrin generation from fibrinogen for hemostatic action. We evaluated t-TLNPs in vitro in human blood and plasma, where hemostatic defects were created by platelet depletion and anticoagulation. Spectrophotometric studies of fibrin generation, rotational thromboelastometry (ROTEM)-based studies of clot viscoelasticity, and BioFlux-based real-time imaging of fibrin generation under simulated vascular flow conditions confirmed that t-TLNPs can restore fibrin in hemostatic dysfunction settings. Finally, the in vivo feasibility of t-TLNPs was tested by prophylactic administration in a tail-clip model and emergency administration in a liver-laceration model in mice with induced hemostatic defects. Treatment with t-TLNPs was able to significantly reduce bleeding in both models. Our studies demonstrate an intravenous nanomedicine approach for injury-site-targeted direct delivery of thrombin to augment hemostasis.

Bioinspired artificial platelets: past, present and future

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

What Laboratory Tests and Physiologic Triggers Should Guide the Decision to Administer a Platelet or Plasma Transfusion in Critically Ill Children and What Product Attributes Are Optimal to Guide Specific Product Selection? From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present consensus statements and supporting literature for plasma and platelet product variables and related laboratory testing for transfusions in general critically ill children from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill pediatric patients at risk of bleeding and receiving plasma and/or platelet transfusions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of 10 experts developed evidence-based and, when evidence was insufficient, expert-based statements for laboratory testing and blood product attributes for platelet and plasma transfusions. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative - Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed five expert consensus statements and two recommendations in answer to two questions: what laboratory tests and physiologic triggers should guide the decision to administer a platelet or plasma transfusion in critically ill children; and what product attributes are optimal to guide specific product selection?

CONCLUSIONS

The Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding program provides some guidance and expert consensus for the laboratory and blood product attributes used for decision-making for plasma and platelet transfusions in critically ill pediatric patients.

Whole Blood Transfusion: Past, Present, and Future

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

Cold-stored whole blood and platelet counts in severe acute injury: A comparison of four retrospective cohorts

BACKGROUND

Low-titer group O whole blood (LTOWB) is attractive for acute trauma care as it delivers concentrated and balanced hemostatic resuscitation in single large bags. Whether cold-stored LTOWB can sustain platelet counts is unclear.

STUDY DESIGN AND METHODS

Four cohorts of trauma patients-three historic, one retrospective-were identified by their urgency of blood use. Admission and all subsequent platelet counts over the first 24 h of care were compared with t-tests. The cohorts were as follows: 1292 patients at Maryland Shock Trauma as described by Stansbury and colleagues in 2013; 35 patients enrolled locally in the 1:1:2 arm of the pragmatic randomized optimal plasma and platelet ratios (PROPPR) trial; 34 patients enrolled locally in the 1:1:1 arm of PROPPR; and 59 patients receiving more than 3 units of LTOWB enroute to or at our Level 1 trauma center, 2019-2020.

RESULTS

Mean age of LTOWB units transfused was 9 ± 5 days and mean dose was 5 ± 2 units. All four cohorts were profoundly injured (mean Injury Severity Score ≥ 31), with mean first platelet counts 204-228 K/μ and subsequent counts approximately 100 k/μl lower. Through the first 24 h of care, mean platelet counts decreased least, 79 and 83 10³ /μl, in the 1:1:1 PROPPR and LTOWB cohorts. Mean platelet counts in patients transfused with LTOWB remained stable after the third hour of care.

DISCUSSION

LTOWB transfusion was associated with lesser mean decrease in platelet counts during the first 24 h after injury, similar to those observed among patients receiving components 1:1:1 component in the PROPPR study.

A pilot study of stored low titer group O whole blood + component therapy versus component therapy only for civilian trauma patients

BACKGROUND

This pilot assessed transfusion requirements during resuscitation with whole blood followed by standard component therapy (CT) versus CT alone, during a change in practice at a large urban Level I trauma center.

METHODS

This was a single-center prospective cohort pilot study. Male trauma patients received up to 4 units of cold-stored low anti-A, anti-B group O whole blood (LTOWB) as initial resuscitation followed by CT as needed (LTOWB + CT). A control group consisting of women and men who presented when LTOWB was unavailable, received CT only (CT group). Exclusion criteria included antiplatelet or anticoagulant medication and death within 24 hours. The primary outcome was total transfusion volume at 24 hours. Secondary outcomes were mortality, morbidity, and intensive care unit- and hospital-free days.

RESULTS

Thirty-eight patients received LTOWB, with a median of 2.0 (interquartile range [IQR] 1.0-3.0) units of LTOWB transfused. Thirty-two patients received CT only. At 24 hours after presentation, the LTOWB +CT group had received a median of 2,138 mL (IQR, 1,275-3,325 mL) of all blood products. The median for the CT group was 4,225 mL (IQR, 1,900-5,425 mL; p = 0.06) in unadjusted analysis. When adjusted for Injury Severity Score, sex, and positive Focused Assessment with Sonography for Trauma, LTOWB +CT group patients received 3307 mL of blood products, and CT group patients received 3,260 mL in the first 24 hours (p = 0.95). The adjusted median ratio of plasma to red cells transfused was higher in the LTOWB + CT group (0.85 vs. 0.63 at 24 hours after admission; p = 0.043. Adjusted mortality was 4.4% in the LTOWB + CT group, and 11.7% in the CT group (p = 0.19), with similar complications, intensive care unit-, and hospital-free days in both groups.

CONCLUSION

Beginning resuscitation with LTOWB results in equivalent outcomes compared with resuscitation with CT only.

LEVEL OF EVIDENCE

Therapeutic (Prospective study with 1 negative criterion, limited control of confounding factors), level III.

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

BACKGROUND

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

STUDY DESIGN AND METHODS

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

RESULTS

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

DISCUSSION

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

Survey to inform trial of low-titer group O whole-blood compared to conventional blood components for children with severe traumatic bleeding

BACKGROUND

Low-titer group O whole-blood (LTOWB) is being used for children with life-threatening traumatic bleeding. A survey was conducted to determine current LTOWB utilization and interest in participation in a randomized control trial (RCT) of LTOWB versus standard blood component transfusion in this population.

STUDY DESIGN AND METHODS

Transfusion medicine (TM) directors and pediatric trauma directors at 36 US children's hospitals were surveyed by e-mail in June 2020. Hospitals were selected by participation in the Massive Transfusion Epidemiology and Outcomes in Children Study or being among the largest 30 children's hospitals by bed capacity per the Becker Hospital Review.

RESULTS

The response rate was 83.3% (30/36) from TM directors and 88.9% (32/36) from trauma directors. The median of massive transfusion protocol activations for traumatic bleeding was reported as 12 (IQR 5.8-20) per year by TM directors. LTOWB was used by 18.8% (6/32) of trauma directors. Survey responses indicate that 86.7% (26/30) of TM directors and 90.6% (29/32) of trauma directors either moderately or strongly agree that a LTOWB RCT is important to perform. About 83.3% (25/30) of TM directors and 93.8% (30/32) of trauma directors were willing to participate in the proposed trial. About 80% (24/30) of TM directors and 71.9% (23/32) of trauma directors would transfuse RhD+ LTOWB to male children, but fewer would transfuse Rh + LTOWB to females [20% (6/30) TM directors and 37.5% (12/32) of trauma directors].

CONCLUSIONS

A majority of respondents supported an RCT comparing LTOWB to component therapy in children with severe traumatic bleeding.

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.

Platelet aggregation in whole blood is not impaired by a platelet-sparing leukoreduction filter and instead depends upon the presence of leukocytes

BACKGROUND

Recent studies characterizing in vitro hemostatic properties of whole blood (WB) leukoreduced (LR) with a platelet-sparing filter have described subtle, if any, changes to viscoelastic clotting; however, reductions in platelet (PLT) content and impedance aggregometry (IA) responses have been noted. The effects of filtration of WB (i.e., filter-contact effects, reduction in platelet and leukocyte count) have not been rigorously investigated as to their individual impacts on platelet IA responses.

STUDY DESIGN AND METHODS

WB units from healthy donors were collected and characterized to assess the effects of platelet-sparing leukoreduction (LR) upon the in vitro hemostatic measures of platelet IA and thromboelastometry. Further characterization of platelet IA responses was carried out in WB samples to delineate the effects of platelet count and leukocyte presence/absence upon the response.

RESULTS

WB filtration reduced the platelet count and IA responses but had no impact on viscoelastic clotting measures in fresh WB. Experiments revealed that IA responses have a linear correlation with platelet count in both apheresis platelets and WB and that passage of platelets through the WB-LR filter has no impact upon the strength of this response. Further experiments in LR WB showed that addition of autologous leukocytes back to the platelets fully restored the platelet aggregation response to pre-filtration levels.

CONCLUSION

WB filtration results in platelet count reduction and leukocyte removal; however, platelet IA is not degraded by passage through the filter. Apparent declines in platelet IA responses can be fully attributed to the reduction in platelet count and the removal of leukocytes.

An analysis of outcomes for pediatric trauma warm fresh whole blood recipients in Iraq and Afghanistan

BACKGROUND

Whole blood therapy-which contains the ideal balance of components, and particularly fresh whole blood-has been shown to be beneficial in adult trauma. It remains unclear whether there is potential benefit in the pediatric population.

STUDY DESIGN AND METHODS

This is a secondary analysis of previously published data analyzing pediatric casualties undergoing massive transfusion in the Department of Defense Trauma Registry. Pediatric patients with traumatic injury who were transfused at least one blood product were included in the analysis. We compared children who received component therapy exclusively to those who received any amount of warm fresh whole blood.

RESULTS

Of the 3439 pediatric casualties within our dataset, 1244 were transfused at least one blood product within the first 24 h. There were 848 patients without severe head injury. Within this cohort, 23 children received warm fresh whole blood overall, 20 of whom did not have severe head injury. In an adjusted analysis, the odds ratio (95% confidence interval [CI]) for survival for warm fresh whole blood recipients was 2.86 (0.40-20.45). After removing children with severe brain injury, there was an independent association with improved survival for warm fresh whole blood recipients with an odds ratio (95% CI) of 58.63 (2.70-1272.67).

DISCUSSION

Our data suggest that warm fresh whole blood may be associated with improved survival in children without severe head injury. Larger prospective studies are needed to assess the efficacy and safety of whole blood in children with severe traumatic bleeding.

A whole blood based resuscitation strategy in civilian medical services: Experience from a Norwegian hospital in the period 2017-2020

BACKGROUND

Civilian and military guidelines recommend early balanced transfusion to patients with life-threatening bleeding. Low titer group O whole blood was introduced as the primary blood product for resuscitation of massive hemorrhage at Haukeland University Hospital, Bergen, Norway, in December 2017. In this report, we describe the whole blood program and present results from the first years of routine use.

STUDY DESIGN AND METHODS

Patients who received whole blood from December 2017 to April 2020 were included in our quality registry for massive transfusions. Post-transfusion blood samples were collected to analyze isohemagglutinin (anti-A/-B) and hemolysis markers. Administration of other blood products, transfusion reactions, and patient survival (days 1 and 30) were recorded. User experiences were surveyed for both clinical and laboratory staff.

RESULTS

Two hundred and five patients (64% male and 36% female) received 836 units in 226 transfusion episodes. Patients received a mean of 3.7 units (range 1-35) in each transfusion episode. The main indications for transfusion were trauma (26%), gastrointestinal (22%), cardiothoracic/vascular (18%), surgical (18%), obstetric (11%), and medical (5%) bleeding. There was no difference in survival between patients with blood type O when compared with non-group O. Haptoglobin level was lower in the transfusion episodes for non-O group patients, however no clinical hemolysis was reported. No patients had conclusive transfusion-associated adverse events. Both clinical and laboratory staff preferred whole blood to component therapy for massive transfusion.

DISCUSSION

The experience from Haukeland University Hospital indicates that whole blood is feasible, safe, and effective for in-hospital treatment of bleeding.

Adverse events after low titer group O whole blood versus component product transfusion in pediatric trauma patients: A propensity-matched cohort study

BACKGROUND

Low titer group O whole blood (LTOWB) is used as the initial resuscitative fluid in an increasing number of pediatric trauma and massive bleeding transfusion protocols. There is little data on adverse events following its transfusion in pediatric trauma patients.

STUDY DESIGN AND METHODS

Blood bank records were queried for pediatric recipients of at least one unit of red blood cells (RBCs) (component group) or LTOWB (LTOWB group) within 24 h of admission between May 2013 and August 2020. Subjects with early death (<72 h) were excluded. Propensity-score matching of LTOWB and component groups was performed. Adverse events were recorded, including transfusion reaction, thromboembolism, acute kidney injury, sepsis, and organ failure based on PELOD-2 score, along with hospital and ICU length of stay (LOS) and ventilator days.

RESULTS

Thirty-six LTOWB recipients were matched to 36 conventional component recipients. Subjects were 52% male, with blunt injury mechanism (82%), median (IQR) injury severity score = 27 (21-35), and 26% in-hospital mortality. The groups were well matched in terms of demographics and injury characteristics. There were no clinically or statistically significant differences in adverse outcomes including reported transfusion reaction, organ failure, acute kidney injury, sepsis/bacteremia, and venous thromboembolism. Hospital LOS, ventilator days, mortality, and functional disability at discharge were also not significantly different. The LTOWB group had significantly shorter ICU LOS compared to the component group.

CONCLUSION

LTOWB transfusion did not increase the risk of adverse events in children. However, larger studies are required to confirm these results.

The Use of Whole Blood Transfusion During Non-Traumatic Resuscitation

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Expired But Not Yet Dead: Examining the Red Blood Cell Storage Lesion in Extended-Storage Whole Blood

ABSTRACT

Whole blood is a powerful resuscitation strategy for trauma patients but has a shorter shelf life than other blood products. The red blood cell storage lesion in whole blood has not previously been investigated beyond the standard storage period. In the present study, we hypothesized that erythrocytes in stored whole blood exhibit similar aspects of the red blood cell storage lesion and that transfusion of extended storage whole blood would not result in a more severe inflammatory response after hemorrhage in a murine model. To test this hypothesis, we stored low-titer, O-positive, whole blood units, and packed red blood cells (pRBCs) for up to 42 days, then determined aspects of the red blood cell storage lesion. Compared with standard storage pRBCs, whole blood demonstrated decreased microvesicle and free hemoglobin at 21 days of storage and no differences in osmotic fragility. At 42 days of storage, rotational thromboelastometry demonstrated that clotting time was decreased, alpha angle was increased, and clot formation time and maximum clot firmness similar in whole blood as compared with pRBCs with the addition of fresh frozen plasma. In a murine model, extended storage whole blood demonstrated decreased microvesicle formation, phosphatidylserine, and cell-free hemoglobin. After hemorrhage and resuscitation, TNF-a, IL-6, and IL-10 were decreased in mice resuscitated with whole blood. Red blood cell survival was similar at 24 h after transfusion. Taken together, these data suggest that red blood cells within whole blood stored for an extended period of time demonstrate similar or reduced accumulation of the red blood cell storage lesion as compared with pRBCs. Further examination of extended-storage whole blood is warranted.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Therapeutic study, level V.

Novel Blood Component Therapies in the Pediatric Setting

There have been recent advances in safer blood component preparation and use of adjuvant blood derivatives, which have limited safety and efficacy data on use in children. This article reviews the literature on use of whole blood, solvent/detergent-treated plasma, pathogen-reduced platelets, and fibrinogen concentrate in pediatric patients. Many countries have adopted pathogen-reduced blood product technology, and hospitals in the United States are slowly adopting these products. The pediatric transfusion medicine community needs to appraise the evidence for their use and continue to advocate the inclusion of children in the most robust randomized clinical trials for novel blood components.

Massive Transfusion in Pediatric Patients

Massive transfusion in pediatric patients is infrequent but associated with much higher mortality than in adults. Blood transfusion and hematology has conceptualized ideas such as blood failure and the interplay of the blood-endothelium interface to understand coagulopathy in the context of hemorrhagic shock. Researchers are still searching for an appropriate definition of what constitutes a pediatric massive transfusion. There is no universally accepted protocol for massive transfusion and how to address the many complications that can arise. Pharmacologic adjuncts to resuscitation may prove beneficial in reducing coagulopathy during pediatric massive transfusion, but high-quality evidence has not yet emerged.

Whole Blood is Superior to Component Transfusion for Injured Children: A Propensity Matched Analysis

OBJECTIVE

To compare a propensity-matched cohort of injured children receiving conventional blood component transfusion to injured children receiving low-titer group O negative whole blood.

SUMMARY OF BACKGROUND DATA

Transfusion of whole blood in pediatric trauma patients is feasible and safe. Effectiveness has not been evaluated.

METHODS

Injured children ≥1 years old can receive up to 40 mL/kg of cold-stored, uncrossmatched whole blood during initial hemostatic resuscitation. Whole blood recipients (2016-2019) were compared to a propensity-matched cohort who received at least 1 uncrossmatched red blood cell unit in the trauma bay (2013-2016). Cohorts were matched for age, hypotension, traumatic brain injury, injury mechanism, and need for emergent surgery. Outcomes included time to resolution of base deficit, product volumes transfused, and INR after resuscitation.

RESULTS

Twenty-eight children who received whole blood were matched to 28 children who received components. The whole blood group had faster time to resolution of base deficit [median (IQR) 2 (1-2.5) hours vs 6 (2-24) hours, respectively; P < 0.001]. The post-transfusion INR was decreased in whole blood vs component cohort [median (IQR) 1.4 (1.3-1.5) vs 1.6 (1.4-2.2); P = 0.01]. Lower plasma volumes [median (IQR) = 5 (0-15) mL/kg vs 11 (5-35) mL/kg; P = 0.04] and lower platelet volumes [median (IQR) = 0 (0-2) vs 3 (0-8); P = 0.03] were administered to the whole blood group versus component group. Other clinical variables (in-hospital death, hospital length of stay, intensive care unit length of stay, and ventilator days) did not differ between groups.

CONCLUSIONS

Compared to component transfusion, whole blood transfusion results in faster resolution of shock, lower post-transfusion INR, and decreased component product transfusion. Larger cohorts are required to support these findings.

Transition from room temperature to cold-stored platelets for the preservation of blood inventories during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic has placed great strain on blood resources. In an effort to extend platelet (PLT) shelf life and minimize waste, our institution transitioned room temperature to cold-stored PLTs for administration to bleeding patients.

STUDY DESIGN AND METHODS

We describe the administrative and technical processes involved in transitioning room temperature PLTs to cold storage in April 2020. Additionally, we describe the clinical utilization of cold-stored PLTs in the first month of this practice change, with a focus on changes in PLT counts after transfusion, hemostasis, and safety outcomes.

RESULTS

A total of 61 cold-stored PLT units were transfused to 40 bleeding patients, with a median (interquartile range [IQR]) of 1 (1-2) units per patient. The median age was 68 (59-73) years; 58% male. Median pretransfusion and posttransfusion PLTs counts were 88 (67-109) and 115 (93-145). A total of 95% of transfusions were administered in the operating room: 57% cardiac surgery, 20% vascular surgery, 8% general surgery, and 5% solid organ transplantation. Hemostasis was deemed to be adequate in all cases after transfusion. There were no transfusion reactions. One patient (3%) experienced a fever and infection within 5 days of transfusion, which was unrelated to transfusion. Median (IQR) hospital length of stay was 8.5 (6-17) days. Two patients (5%) died in the hospital of complications not related to transfusion.

CONCLUSION

Cold-stored PLT utilization was associated with adequate hemostasis and no overt signal for patient harm. Conversion from room temperature to cold-stored PLTs may be one method of reducing waste in times of scarce blood inventories.

Massive Transfusion Protocols for Pediatric Patients: Current Perspectives

In adults, the use of balanced resuscitation and study of massive transfusion protocols have led to improved outcomes for patients and continues to be refined. In children, massive transfusion protocols require further development and study to assess efficacy. Standardization is needed as transfusions and activation of protocols still rely on physician discretion in most pediatric settings. Further research is required to define the pediatric trauma population that will benefit, when to activate these protocols and how to use adjuncts such as tranexamic acid or factor VII in resuscitation. In addition, future implementation of technology such as hemoglobin-based oxygen carriers to increase survival should be studied further in this subset of patients.

Pooling, room temperature, and extended storage time increase the release of adult-specific biologic response modifiers in platelet concentrates: a hidden transfusion risk for neonates?

BACKGROUND

Adult donor platelets (PLTs) are frequently transfused to prevent or stop bleeding in neonates with thrombocytopenia. There is evidence for PLT transfusion-related morbidity and mortality, leading to the hypothesis on immunomodulatory effects of transfusing adult PLTs into neonates. Candidate factors are biologic response modifiers (BRMs) that are expressed at higher rates in adult than in neonatal PLTs. This study investigated whether storage conditions or preparation methods impact on the release of those differentially expressed BRMs.

STUDY DESIGN AND METHODS

Pooled PLT concentrates (PCs) and apheresis PCs (APCs) were stored under agitation for up to 7 days at room temperature (RT) or at 2 to 8°C. The BRMs CCL5/RANTES, TGFβ1, TSP1, and DKK1 were measured in PCs' supernatant, lysate, and corresponding plasma. PLT function was assessed by light transmission aggregometry.

RESULTS

Concerning the preparation method, higher concentrations of DKK1 were found in pooled PCs compared to APCs. In supernatants, the concentrations of CCL5, TGFβ1, TSP1, and DKK1 significantly increased, both over standard (≤4 days) and over extended storage times (7 days). Each of the four BRMs showed an up to twofold increase in concentration after storage at RT compared to cold storage (CS). There was no difference in the aggregation capacity.

CONCLUSION

This analysis shows that the release of adult-specific BRMs during storage is lowest in short- and CS APCs. Our study points to strategies for reducing the exposure of sick neonates to BRMs that can be specifically associated to PLT transfusion-related morbidity.