Impact of hypocalcemia on mortality in pediatric trauma patients who require transfusion

INTRODUCTION

Admission hypocalcemia has been associated with poor outcomes in injured adults. The impact of hypocalcemia on mortality has not been widely studied in pediatric trauma.

METHODS

A pediatric trauma center database was queried retrospectively (2013-2022) for children age < 18 years who received blood transfusion within 24 hours of injury and had ionized calcium (iCal) level on admission. Children who received massive transfusion (>40 mL/kg) prior to hospital arrival or calcium prior to laboratory testing were excluded. Hypocalcemia was defined by the laboratory lower limit (iCal <1.00). Main outcomes were in-hospital mortality and 24-hour blood product requirements. Logistic regression analysis was performed to adjust for injury severity score (ISS), admission shock index, Glasgow Coma Score (GCS) and weight-adjusted total transfusion volume.

RESULTS

In total, 331 children with median (IQR) age of 7 years (2-13) and median (IQR) ISS 25 (14-33) were included, 32 (10%) of whom were hypocalcemic on arrival to the hospital. The hypocalcemic cohort had higher ISS (median (IQR) 30(24-36) vs 22(13-30)) and lower admission GCS (median (IQR) 3 (3-12) vs 8 (3-15)). Age, sex, race, and mechanism were not significantly different between groups. On univariate analysis, hypocalcemia was associated with increased in-hospital (56% vs 18%; p < 0.001) and 24-hour (28% vs 5%; p < 0.001) mortality. Children who were hypocalcemic received a median (IQR) of 22 mL/kg (7-38) more in total weight-adjusted 24-hour blood product transfusion following admission compared to the normocalcemic cohort (p = 0.005). After adjusting for ISS, shock index, GCS, and total transfusion volume, hypocalcemia remained independently associated with increased 24-hour (Odds Ratio(OR) 95% Confidence Interval(CI) = 4.93(1.77-13.77); p = 0.002) and in-hospital mortality (OR 95% CI =3.41(1.22-9.51); p = 0.019).

CONCLUSION

Hypocalcemia is independently associated with mortality and receipt of greater weight-adjusted volumes of blood product transfusion after injury in children. The benefit of timely calcium administration in pediatric trauma needs further exploration.

LEVEL OF EVIDENCE

III; prognostic/epidemiological.

Receipt of RhD-positive whole blood for life-threatening bleeding in female children: A survey in alloimmunized mothers regarding minimum acceptable survival benefit relative to risk of maternal alloimmunization to anti-D

BACKGROUND

Low-titer group O whole blood (LTOWB) for treatment of hemorrhagic shock sometimes necessitates transfusion of RhD-positive units due to short supply of RhD-negative LTOWB. Practitioners must choose between using RhD-positive LTOWB when RhD-negative is unavailable against the risk to a female of childbearing potential of becoming RhD-alloimmunized, risking hemolytic disease of the fetus and newborn (HDFN) in future children, or using component therapy with RhD-negative red cells. This survey asked females with a history of red blood cell (RBC) alloimmunization about their risk tolerance of RhD alloimmunization compared to the potential for improved survival following transfusion of RhD-positive blood for an injured RhD negative female child.

STUDY DESIGN AND METHODS

A survey was administered to RBC alloimmunized mothers. Respondents were eligible if they were living in the United States with at least one red cell antibody known to cause HDFN and if they had at least one RBC alloimmunized pregnancy.

RESULTS

Responses from 107 RBC alloimmmunized females were analyzed. There were 32/107 (30%) with a history of severe HDFN; 12/107 (11%) had a history of fetal or neonatal loss due to HDFN. The median (interquartile range) absolute improvement in survival at which the respondents would accept RhD-positive transfusions for a female child was 4% (1%-14%). This was not different between females with and without a history of severe or fatal HDFN (p = .08 and 0.38, respectively).

CONCLUSION

Alloimmunized mothers would accept the risk of D-alloimmunization in a RhD-negative female child for improved survival in cases of life-threatening bleeding.

Cold-stored platelet hemostatic capacity is maintained for three weeks of storage and associated with taurine metabolism

BACKGROUND

Platelet (PLT) product transfusion is a life-saving therapy for actively bleeding patients. There is an urgent need to maintain PLT function and extend shelf life to improve outcomes in these patients. Cold-stored PLT (CS-PLT) maintain hemostatic potential better than room temperature-stored PLT (RT-PLT). However, whether function in long-term CS-PLT is maintained under physiological flow regimes and/or determined by cold-induced metabolic changes is unknown.

OBJECTIVES

This study aimed to (i) compare the function of RT-PLT and CS-PLT under physiological flow conditions, (ii) determine whether CS-PLT maintain function after 3 weeks of storage, and (iii) identify metabolic pathways associated with the CS-PLT lesion.

METHODS

We performed phenotypic and functional assessments of RT- and CS-PLT (22 °C and 4 °C storage, respectively; N = 10 unique donors) at storage days 0, 5, and/or 21 via metabolomics, flow cytometry, aggregation, thrombin generation, viscoelastic testing, and a microfluidic assay to measure primary hemostatic function.

RESULTS

Day 21 4 °C PLT formed an occlusive thrombus under arterial shear at a similar rate to day 5 22 °C PLT. Day 21 4 °C PLTs had enhanced thrombin generation capacity compared with day 0 PLT and maintained functionality comparable to day RT-PLT across all assays performed. Key metrics from microfluidic assessment, flow cytometry, thrombin generation, and aggregation were associated with 4 °C storage, and metabolites involved in taurine and purine metabolism significantly correlated with these metrics. Taurine supplementation of PLT during storage improved hemostatic function under flow.

CONCLUSION

CS-PLT stored for 3 weeks maintain hemostatic activity, and storage-induced phenotype and function are associated with taurine and purine metabolism.

Increased platelet to red blood cell transfusion ratio associated with acute kidney injury in children with life-threatening bleeding

INTRODUCTION

Transfusion may increase the risk of organ failure through immunomodulatory effects. The primary objective of this study was to assess for patient or transfusion-related factors that are independently associated with the risk of acute kidney injury (AKI) and acute respiratory distress syndrome (ARDS) in a cohort of children with life-threatening bleeding from all etiologies.

METHODS

In a secondary analysis of the prospective observational massive transfusion in children (MATIC) study, multivariable logistic regression was performed in an adjusted analysis to determine if blood product ratios or deficits were independently associated with AKI or ARDS in children with life-threatening bleeding.

RESULTS

There were 449 children included with a median (interquartile range, IQR) age of 7.3 years (1.7-14.7). Within 5 days of the life-threatening bleeding event, AKI occurred in 18.5% and ARDS occurred in 20.3% of the subjects. Every 10% increase in the platelet to red blood cell transfusion ratio is independently associated with a 12.7% increase in the odds of AKI (adjusted odds ratio 1.127; 95% confidence interval 1.025-1.239; p-value .013). Subjects with operative or medical etiologies were independently associated with an increased risk of AKI compared to those with traumatic injury. No transfusion-related variables were independently associated with the risk of developing ARDS.

CONCLUSION

The use of increased platelet to red blood cell transfusion ratios in children with life-threatening bleeding of any etiology may increase the risk of AKI but not ARDS. Prospective trials are needed to determine if increased platelet use in this cohort increases the risk of AKI to examine possible mechanisms.

Patient sex and outcomes in children with life-threatening hemorrhage

BACKGROUND

Recent data suggest female sex imparts a survival benefit after trauma in adults. The independent associations between patient sex and age with outcomes have not been examined in children with life-threatening hemorrhage (LTH) from all etiologies.

STUDY DESIGN AND METHODS

In a secondary analysis of a multicenter prospective observational study of children with LTH, Massive Transfusion in Children (MATIC), we analyzed if patient sex and age were associated with differences in severity of illness, therapies, and outcomes. Primary outcomes were 24 hour mortality and weight-adjusted transfusion volume during LTH. Kruskal-Wallis, chi-square testing, and multivariable linear regression were used for adjusted analyses.

RESULTS

Of 449 children, 45% were females and 55% were males. Females were more commonly younger, white, and with less trauma as the etiology of LTH compared to males. Markers of clinical severity were similar between groups, except injury severity score (ISS) was higher in females in the trauma subgroup. In terms of resuscitative practices, females received greater weight-adjusted total transfusion volumes compared to males (76 (40-150) mL/kg vs. 53 (24-100) mL/kg), as well as increased red blood cells (RBCs), plasma, and platelets compared to males. After adjustment for confounders, female sex and age 0-11 years were independently associated with increased transfusion volume during LTH. There were no differences in mortality or adverse outcomes according to patient sex.

CONCLUSION

Patient sex and age may impact factors associated with LTH and therapies received. Studies in developmental hemostasis are needed to determine the optimal transfusion strategy for LTH according to patient sex and age.

Survey of policies at US hospitals on the selection of RhD type of low-titer O whole blood for use in trauma resuscitation

BACKGROUND

Low-titer group O whole blood (LTOWB) use is increasing due to data suggesting improved outcomes and safety. One barrier to use is low availability of RhD-negative LTOWB. This survey examined US hospital policies regarding the selection of RhD type of blood products in bleeding emergencies.

STUDY DESIGN AND METHODS

A web-based survey of blood bank directors was conducted to determine their hospital's RhD-type selection policies for blood issued for massive bleeding.

RESULTS

There was a 61% response rate (101/157) and of those responses, 95 were complete. Respondents indicated that 40% (38/95) use only red blood cells (RBCs) and 60% (57/95) use LTOWB. For hospitals that issue LTOWB (N = 57), 67% are supplied only with RhD-positive, 2% only with RhD-negative, and 32% with both RhD-positive and RhD-negative LTOWB. At sites using LTOWB, RhD-negative LTOWB is used exclusively or preferentially more commonly in adult females of childbearing potential (FCP) (46%) and pediatric FCP (55%) than in men (4%) and boys (24%). RhD-positive LTOWB is used exclusively or preferentially more commonly in men (94%) and boys (54%) than in adult FCP (40%) or pediatric FCP (21%). At sites using LTOWB, it is not permitted for adult FCPs at 12%, pediatric FCP at 21.4%, and boys at 17.1%.

CONCLUSION

Hospitals prefer issuing RhD-negative LTOWB for females although they are often ineligible to receive RhD-negative LTOWB due to supply constraints. The risk and benefits of LTOWB compared to the rare occurrence of hemolytic disease of the fetus/newborn (HDFN) need further examination in the context of withholding a therapy for females that has the potential for improved outcomes.

Analyzing and modeling massive transfusion strategies and the role of fibrinogen-How much is the patient actually receiving?

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma, cardiac surgery, liver transplant, and childbirth. While emphasis on protocolization and ratio of blood product transfusion improves ability to treat hemorrhage rapidly, tools to facilitate understanding of the overall content of a specific transfusion strategy are lacking. Medical modeling can provide insights into where deficits in treatment could arise and key areas for clinical study. By using a transfusion model to gain insight into the aggregate content of massive transfusion protocols (MTPs), clinicians can optimize protocols and create opportunities for future studies of precision transfusion medicine in hemorrhage treatment.

METHODS

The transfusion model describes the individual round and aggregate content provided by four rounds of MTP, illustrating that the total content of blood elements and coagulation factor changes over time, independent of the patient's condition. The configurable model calculates the aggregate hematocrit, platelet concentration, percent volume plasma, total grams and concentration of citrate, percent volume anticoagulant and additive solution, and concentration of clotting factors: fibrinogen, factor XIII, factor VIII, and von Willebrand factor, provided by the MTP strategy.

RESULTS

Transfusion strategies based on a 1:1:1 or whole blood foundation provide between 13.7 and 17.2 L of blood products over four rounds. Content of strategies varies widely across all measurements based on base strategy and addition of concentrated sources of fibrinogen and other key clotting factors.

DISCUSSION

Differences observed between modeled transfusion strategies provide key insights into potential opportunities to provide patients with precision transfusion strategy.

Maternal and child life years gained by transfusing low titer group O whole blood in trauma: A computer simulation

BACKGROUND

Using low titer group O whole blood (LTOWB) is increasingly popular for resuscitating trauma patients. LTOWB is often RhD-positive, which might cause D-alloimmunization and hemolytic disease of the fetus and newborn (HDFN) if transfused to RhD-negative females of childbearing potential (FCP). This simulation determined the number of life years gained by the FCP and her future children if she was resuscitated with LTOWB compared with conventional component therapy (CCT).

METHODS

The model simulated 500,000 injured FCPs of each age between 0 and 49 years with LTOWB mortality relative reductions (MRRs) compared with components between 0.1% and 25%. For each surviving FCP, number of life years gained was calculated using her age at injury and average life expectancy for American women. The number of expected future pregnancies for FCPs that did not survive was also based on her age at injury; each future child was assigned the maximum lifespan unless they suffered perinatal mortality or serious neurological events from HDFN.

RESULTS

The LTOWB group with an MRR 25% compared with CCT had the largest total life years gained. The point of equivalence for RhD-positive LTOWB compared to CCT, where life years lost due to severe HDFN was equivalent to life years gained due to FCP survival/future childbearing, occurred at an MRR of approximately 0.1%.

CONCLUSION

In this model, RhD-positive LTOWB resulted in substantial gains in maternal and child life years compared with CCT. A >0.1% relative mortality reduction from LTOWB offset the life years lost to HDFN mortality and severe neurological events.

Transforming research to improve therapies for trauma in the twenty-first century

Improvements have been made in optimizing initial care of trauma patients, both in prehospital systems as well as in the emergency department, and these have also favorably affected longer term outcomes. However, as specific treatments for bleeding are largely lacking, many patients continue to die from hemorrhage. Also, major knowledge gaps remain on the impact of tissue injury on the host immune and coagulation response, which hampers the development of interventions to treat or prevent organ failure, thrombosis, infections or other complications of trauma. Thereby, trauma remains a challenge for intensivists. This review describes the most pressing research questions in trauma, as well as new approaches to trauma research, with the aim to bring improved therapies to the bedside within the twenty-first century.

Use of whole blood in pediatric trauma: a narrative review

Balanced hemostatic resuscitation has been associated with improved outcomes in patients with both pediatric and adult trauma. Cold-stored, low-titer group O whole blood (LTOWB) has been increasingly used as a primary resuscitation product in trauma in recent years. Benefits of LTOWB include rapid, balanced resuscitation in one product, platelets stored at 4°C, fewer additives and fewer donor exposures. The major theoretical risk of LTOWB transfusion is hemolysis, however this has not been shown in the literature. LTOWB use in injured pediatric populations is increasing but is not yet widespread. Seven studies to date have described the use of LTOWB in pediatric trauma cohorts. Safety of LTOWB use in both group O and non-group O pediatric patients has been shown in several studies, as indicated by the absence of hemolysis and acute transfusion reactions, and comparable risk of organ failure. Reported benefits of LTOWB included faster resolution of shock and coagulopathy, lower volumes of transfused blood products, and an independent association with increased survival in massively transfused patients. Overall, pediatric data are limited by small sample sizes and mostly single center cohorts. Multicenter randomized controlled trials are needed.

Optimizing Mass Casualty Triage: Using Discrete Event Simulation to Minimize Time to Resuscitation

BACKGROUND

Urban areas in the US are increasingly focused on mass casualty incident (MCI) response. We simulated prehospital triage scenarios and hypothesized that using hospital-based blood product inventories for on-scene triage decisions would minimize time to treatment.

STUDY DESIGN

Discrete event simulations modeled MCI casualty injury and patient flow after a simulated blast event in Boston, MA. Casualties were divided into moderate (Injury Severity Score 9 to 15) and severe (Injury Severity Score >15) based on injury patterns. Blood product inventories were collected from all hospitals (n = 6). The primary endpoint was the proportion of casualties managed with 1:1:1 balanced resuscitation in a target timeframe (moderate, 3.5 U red blood cells in 6 hours; severe, 10 U red blood cells in 1 hour). Three triage scenarios were compared, including unimpeded casualty movement to proximate hospitals (Nearest), equal distribution among hospitals (Equal), and blood product inventory-based triage (Supply-Guided).

RESULTS

Simulated MCIs generated a mean ± SD of 302 ± 7 casualties, including 57 ± 2 moderate and 15 ± 2 severe casualties. Nearest triage resulted in significantly fewer overall casualties treated in the target time (55% vs Equal 86% vs Supply-Guided 91%, p < 0.001). These differences were principally due to fewer moderate casualties treated, but there was no difference among strategies for severe casualties.

CONCLUSIONS

In this simulation study comparing different triage strategies, including one based on actual blood product inventories, nearest hospital triage was inferior to equal distribution or a Supply-Guided strategy. Disaster response leaders in US urban areas should consider modeling different MCI scenarios and casualty numbers to determine optimal triage strategies for their area given hospital numbers and blood product availability.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Not as "D"eadly as once thought - the risk of D-alloimmunization and hemolytic disease of the fetus and newborn following RhD-positive transfusion in trauma

The use of blood products to resuscitate injured and massively bleeding patients in the prehospital and early in-hospital phase of the resuscitation is increasing. Using group O red blood cells (RBC) and low titer group O whole blood (LTOWB) avoids an immediate hemolytic reaction from recipient's naturally occurring anti-A and - B, but choosing the RhD type for these products is more nuanced and requires the balancing of product availability and survival benefit against the risk of D-alloimmunization, especially in females of childbearing potential (FCP) due to the possible future occurrence of hemolytic disease of the fetus and newborn (HDFN). Recent models have estimated the risk of fetal/neonatal death from HDFN resulting from D-alloimmunization of an FCP during her trauma resuscitation at between 0-6.5% depending on her age at the time of the transfusion and other societal factors including trauma mortality, her age when she becomes pregnant, frequency of different RHD genotypes in the population, and the probability that the woman will have children with different fathers; this is counterbalanced by an approximately 24% risk of death from hemorrhagic shock. This review will discuss the different models of HDFN outcomes following RhD-positive transfusion as well as the results of recent surveys where the public was asked about their preferences for urgent transfusion in light of the risks of fetal/neonatal adverse events.

Optimizing RBC Transfusion Outcomes in Patients with Acute Illness and in the Chronic Transfusion Setting

Red blood cell (RBC) transfusion is a common clinical intervention used to treat patients with acute and chronic anemia. The decision to transfuse RBCs in the acute setting is based on several factors but current clinical studies informing optimal RBC transfusion decision making (TDM) are largely based upon hemoglobin (Hb) level. In contrast to transfusion in acute settings, chronic RBC transfusion therapy has several different purposes and is associated with distinct transfusion risks such as iron overload and RBC alloimmunization. Consequently, RBC TDM in the chronic setting requires optimizing the survival of transfused RBCs in order to reduce transfusion exposure over the lifespan of an individual and the associated transfusion complications mentioned. This review summarizes the current medical literature addressing optimal RBC-TDM in the acute and chronic transfusion settings and discusses the current gaps in knowledge which need to be prioritized in future national and international research initiatives.

Damage-control resuscitation in pediatric trauma: What you need to know

ABSTRACT

Damage-control resuscitation (DCR) consists of rapid control of bleeding, avoidance of hemodilution, acidosis, and hypothermia; early empiric balanced transfusions with red blood cells, plasma and platelets, or whole blood when available, and the use of intravenous or mechanical hemostatic adjuncts when indicated. The principles used in pediatric and adult trauma patients are quite similar. There are very important recognized physiologic differences in children with traumatic hemorrhagic shock that warrant slight variations in DCR. In pediatric trauma patients, early physiologic signs of shock may be different from adults and the early recognition of this is critical to enable prompt resuscitation and utilization of damage control principles. This review details the current principles of pediatric DCR based on the best available literature, expert consensus recommendations, and also describes a practical guide for implementation of DCR strategies for pediatric trauma patients.

Cold-stored platelets for acute bleeding in cardiac surgical patients: a narrative review

PURPOSE

Cold-stored platelets (CSP) are an increasingly active topic of international research. They are maintained at 1-6 °C, in contrast to standard room-temperature platelets (RTP) kept at 20-24 °C. Recent evidence suggests that CSP have superior hemostatic properties compared with RTP. This narrative review explores the application of CSP in adult cardiac surgery, summarizes the preclinical and clinical evidence for their use, and highlights recent research.

SOURCE

A targeted search of MEDLINE and other databases up to 24 February 2022 was conducted. Search terms combined concepts such as cardiac surgery, blood, platelet, and cold-stored. Searches of trial registries ClinicalTrials.gov and WHO International Clinical Trials Registry Platform were included. Articles were included if they described adult surgical patients as their population of interest and an association between CSP and clinical outcomes. References of included articles were hand searched.

PRINCIPAL FINDINGS

When platelets are stored at 1-6 °C, their metabolic rate is slowed, preserving hemostatic function for increased storage duration. Cold-stored platelets have superior adhesion characteristics under physiologic shear conditions, and similar or superior aggregation responses to physiologic agonists. Cold-stored platelets undergo structural, metabolic, and molecular changes which appear to "prime" them for hemostatic activity. While preliminary, clinical evidence supports the conduct of trials comparing CSP with RTP for patients with platelet-related bleeding, such as those undergoing cardiac surgery.

CONCLUSION

Cold-stored platelets may have several advantages over RTP, including increased hemostatic capacity, extended shelf-life, and reduced risk of bacterial contamination. Large clinical trials are needed to establish their potential role in the treatment of acutely bleeding patients.

Effect of red blood cell storage time in pediatric cardiac surgery patients: A subgroup analysis of a randomized controlled trial

Objective

This study aimed to determine whether or not transfusion of fresh red blood cells (RBCs) reduced the incidence of new or progressive multiple organ dysfunction syndrome compared with standard-issue RBCs in pediatric patients undergoing cardiac surgery.

Methods

Preplanned secondary analysis of the Age of Blood in Children in Pediatric Intensive Care Unit study, an international randomized controlled trial. This study included children enrolled in the Age of Blood in Children in Pediatric Intensive Care Unit trial and admitted to a pediatric intensive care unit after cardiac surgery with cardiopulmonary bypass. Patients were randomized to receive either fresh (stored ≤7 days) or standard-issue RBCs. The primary outcome measure was new or progressive multiple organ dysfunction syndrome, measured up to 28 days postrandomization or at pediatric intensive care unit discharge, or death.

Results

One hundred seventy-eight patients (median age, 0.6 years; interquartile range, 0.3-2.6 years) were included with 89 patients randomized to the fresh RBCs group (median length of storage, 5 days; interquartile range, 4-6 days) and 89 to the standard-issue RBCs group (median length of storage, 18 days; interquartile range, 13-22 days). There were no statistically significant differences in new or progressive multiple organ dysfunction syndrome between fresh (43 out of 89 [48.3%]) and standard-issue RBCs groups (38 out of 88 [43.2%]), with a relative risk of 1.12 (95% CI, 0.81 to 1.54; P = .49) and an unadjusted absolute risk difference of 5.1% (95% CI, -9.5% to 19.8%; P = .49).

Conclusions

In neonates and children undergoing cardiac surgery with cardiopulmonary bypass, the use of fresh RBCs did not reduce the incidence of new or progressive multiple organ dysfunction syndrome compared with the standard-issue RBCs. A larger trial is needed to confirm these results.

Factors influencing pediatric transfusion: A complex decision impacting quality of care

BACKGROUND

The risks of red blood cell transfusion may outweigh the benefits for many patients in pediatric intensive care units (PICUs), but guidelines from the Transfusion and Anemia eXpertise Initiative (TAXI) have not been consistently adopted. We sought to identify factors that influenced transfusion decision-making in PICUs to explore potential barriers and facilitators to implementing the guidelines.

STUDY DESIGN AND METHODS

A total of 50 ICU providers working in eight US ICUs of different types (non-cardiac PICUs, cardiovascular ICUs, combined units) and variable sizes (11-32 beds) completed semi-structured interviews. Providers included ICU attendings and trainees, nurse practitioners, nurses, and subspecialty physicians. Interviews examined factors that influenced transfusion decisions, transfusion practices, and provider beliefs. Qualitative analysis utilized a Framework Approach. Summarized data was compared between provider roles and units with consideration to identify patterns and unique informative statements.

RESULTS

Providers cited clinical, physiologic, anatomic, and logistic factors they considered in making transfusion decisions. Improving oxygen carrying capacity, hemodynamics and perfusion, respiratory function, volume deficits, and correcting laboratory values were among the reasons given for transfusion. Other sought-after benefits included alleviating symptoms of anemia, improving ICU throughput, and decreasing blood waste. Providers in different roles approached transfusion decisions differently, with the largest differences noted between nurses and subspecialists as compared with other ICU providers. While ICU attendings most often made the decision to transfuse, all providers influenced the decision-making.

DISCUSSION

Implementation of transfusion guidelines requires multi-professional approaches that emphasize the known risks of transfusion, its limited benefits, and highlight evidence around the safety and benefit of restrictive approaches.

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.

Cryoprecipitate for the treatment of life-threatening hemorrhage in children

BACKGROUND

Hypofibrinogenemia is an important risk factor for poor outcomes in children with severe bleeding. There is a paucity of data on the impact of cryoprecipitate transfusion on outcomes in pediatric patients with life-threatening hemorrhage (LTH).

STUDY DESIGN AND METHODS

This secondary analysis of a multicenter prospective observational study of children with LTH investigated subjects who were categorized by receipt of cryoprecipitate during their resuscitation and according to the etiology of their bleeding: trauma, operative, and medical. Bivariate analysis was performed to identify variables associated with 6-hour, 24-hour and 28-day mortality. Cox Hazard regression models were generated to adjust for potential confounders.

RESULTS

Cryoprecipitate was transfused to 33.9% (152/449) of children during LTH. The median (Interquartile range) time to cryoprecipitate administration was 108 (47-212) minutes. Children in the cryoprecipitate group were younger, more often female, with higher BMI and pre-LTH PRISM score and lower platelet counts. After adjusting for PRISM score, bleeding etiology, age, sex, red blood cell volume, platelet volume, antifibrinolytic use and cardiac arrest, cryoprecipitate administration was independently associated with lower 6-hour mortality, Hazard Ratio (95% CI), 0.41 (0.19-0.89), (p=0.02) and 24-hour mortality, Hazard Ratio (95% CI), 0.46 (0.24-0.89), (p=0.02).

CONCLUSION

Cryoprecipitate transfusion to children with LTH was associated with reduced early mortality. A prospective randomized trial is needed to determine if cryoprecipitate can improve outcomes in children with LTH. This article is protected by copyright. All rights reserved.

Epsilon aminocaproic acid is associated with acute kidney injury after life-threatening hemorrhage in children

BACKGROUND

Antifibrinolytic medications have been associated with reduced mortality in pediatric hemorrhage but may contribute to adverse events such as acute kidney injury (AKI).

STUDY DESIGN AND METHODS

We conducted a secondary analysis of the MAssive Transfusion in Children (MATIC), a prospectively collected database of children with life-threatening hemorrhage (LTH), and evaluated for risk of adverse events with either antifibrinolytic treatment, epsilon aminocaproic acid (EACA) or tranexamic acid (TXA). The primary outcome was AKI and secondary outcomes were acute respiratory distress syndrome (ARDS) and sepsis.

RESULTS

Of 448 children included, median (interquartile range) age was 7 (2-15) years, 55% were male, and LTH etiology was 46% trauma, 34% operative, and 20% medical. Three hundred and ninety-three patients did not receive an antifibrinolytic (88%); 37 (8%) received TXA and 18 (4%) received EACA. Sixty-seven (17.1%) patients in the no antifibrinolytic group developed AKI, 6 (16.2%) patients in the TXA group, and 9 (50%) patients in the EACA group (p = 0.002). After adjusting for cardiothoracic surgery, cyanotic heart disease, pre-existing renal disease, lowest hemoglobin pre-LTH, and total weight-adjusted transfusion volume during the LTH, the EACA group had increased risk of AKI (adjusted odds ratio 3.3 [95% CI 1.0 - 10.3]) compared to no antifibrinolytic. TXA was not associated with AKI. Neither antifibrinolytic treatment was associated with ARDS or sepsis.

CONCLUSION

Administration of EACA during LTH may increase the risk of AKI. Additional studies are needed to compare the risk of AKI between EACA and TXA in pediatric patients. This article is protected by copyright. All rights reserved.

A rapid ABO and RhD test demonstrates high fidelity to blood bank testing for RhD typing

BACKGROUND

The rapid provision of blood products is life-saving for patients with massive hemorrhage. Ideally, RhD-negative blood products would be supplied to a woman of childbearing potential whose Rh type is unknown due to the risk of D-alloimmunization and the potential for hemolytic disease of the fetus and newborn to occur if RhD-positive blood products are transfused. Therefore, there is a need for a test that rapidly determines her RhD type. This study compared the RhD type determined using a rapid ABO and RhD test to the RhD type determined by an immunohematology reference laboratory.

METHODS

After receiving ethics review board approval, 200 random, unique, deidentified patient samples that had undergone routine pretransfusion testing in an immunohematology reference laboratory using column agglutination technology were collected and tested using a rapid ABO and RhD test (Eldoncard Home kit 2511). The RhD typing results from these two methods were compared to determine the accuracy of the rapid ABO and RhD test.

RESULTS

The rapid ABO and RhD test produced results that were concordant with the transfusion service's results in 199/200 (99.5%) of cases, with a negative predictive value of 98.2% and 99.3% sensitivity. The single outlier was likely an RhD variant due to its serological characteristics.

DISCUSSION

These data indicate that this rapid ABO and RhD test could be used for the rapid determination of a patient's RhD type, perhaps even in the emergency department, which could guide the selection of blood products provided during their resuscitation.

Timing of RhD-positive red blood cell administration is associated with D-alloimmunization in injured patients

BACKGROUND

The D-alloimmunization rate in trauma patients does not appear to depend on the number of RhD-positive units transfused. The effect of the timing and pattern of RhD-positive transfusions has not been evaluated.

METHODS

RhD-negative trauma patients who were transfused with RhD-positive red blood cells (RBC) or low titer group O whole blood (collectively called RBCs) on at least two separate calendar days and who had antibody detection tests performed at least 14 days after the second RhD-positive RBC transfusion without receiving RhIg were included in the analysis. Patients whose anti-D was detected within 14 days of the index RhD-positive RBC transfusion were excluded. Patient demographics and the dates of RhD-positive RBC transfusions and results of antibody detection tests performed after the index transfusion were collected on eligible patients.

RESULTS

There were 44/61 (72.1%) patients in whom anti-D was not detected (non-alloimmunized) and 17/61 (27.9%) in whom anti-D was detected (alloimmunized). The patients had similar demographics with trends towards higher median admission heart rates and lower median admission Glasgow Coma Scale values in the alloimmunized group. Both groups received statistically identical median quantities of RhD-positive RBCs (non-alloimmunized 5 vs. alloimmunized 4 units, p = .53), however, the alloimmunized group received all their RhD-positive RBCs over a significantly shorter period of time compared to the non-alloimmunized (median 4 vs. 15 days, respectively, p = .01).

CONCLUSION

Receipt of all RhD-positive RBCs over a shorter period of time was associated with higher D-alloimmunization rates. These results need to be confirmed in larger studies.

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.

Parent Perceptions of Emergent Blood Transfusion in Children

BACKGROUND

RhD-negative blood products are in chronic short supply leading to renewed interest in utilizing RhD-positive blood products for emergency transfusions. This study assessed parental perceptions of emergency RhD-positive blood use in children.

METHODS

A survey of parents/guardians was conducted on their tolerance of transfusing RhD-positive blood to RhD-negative female children ≤17 years old at four level 1 pediatric hospitals.

RESULTS

In total, 621 parents/guardians were approached of whom 378/621 (61%) completed the survey in its entirety and were included in the analysis. Respondents were mostly females [295/378 (78%)], White [242/378 (64%)], had some college education [217/378 (57%)] and less than $60,000 annual income [193/378 (51%)]. Respondents had a total of 547 female children. Most children's ABO [320/547 (59%)] and RhD type [348/547 (64%)] were not known by their parents; of children with known RhD type, 58/186 (31%) were RhD-negative. When the risk of harm to a future fetus was given as 0-6%, more than 80% of respondents indicated that they were likely to accept RhD-positive blood transfusions on behalf of RhD-negative female children in a life-threatening situation. The rate of willingness to accept emergent RhD-incompatible blood transfusions significantly increased as the potential survival benefit of the transfusion increased.

CONCLUSION

Most parents were willing to accept RhD-positive blood products on behalf of RhD-negative female children in an emergency situation. Further discussions and evidence-based guidelines on transfusing RhD-positive blood products to RhD-unknown females in emergency settings are needed.

The role of sodium citrate during extended cold storage of platelets in platelet additive solutions

BACKGROUND

Cold-stored platelets are increasingly being used to treat bleeding. Differences in manufacturing processes and storage solutions can affect platelet quality and may influence the shelf life of cold-stored platelets. PAS-E and PAS-F are approved platelet additive solutions (PAS) in Europe and Australia, or the United States respectively. Comparative data are required to facilitate international transferability of laboratory and clinical data.

STUDY DESIGN AND METHODS

Single apheresis platelets from matched donors (n = 8) were collected using the Trima apheresis platform and resuspended in either 40% plasma/60% PAS-E or 40% plasma/60% PAS-F. In a secondary study, platelets in PAS-F were supplemented with sodium citrate, to match the concentration in PAS-E. Components were refrigerated (2-6°C) and tested over 21 days.

RESULTS

Cold-stored platelets in PAS-F had a lower pH, a greater propensity to form visible (and micro-) aggregates, and higher activation markers compared to PAS-E. These differences were most pronounced during extended storage (14-21 days). While the functional capacity of cold-stored platelets was similar, the PAS-F group displayed minor improvements in ADP-induced aggregation and TEG parameters (R-time, angle). Supplementation of PAS-F with 11 mM sodium citrate improved the platelet content, maintained the pH above specifications and prevented aggregate formation.

DISCUSSION

In vitro parameters were similar during short-term cold storage of platelets in PAS-E and PAS-F. Storage in PAS-F beyond 14 days resulted in poorer metabolic and activation parameters. However, the functional capacity was maintained, or even enhanced. The presence of sodium citrate may be an important constituent in PAS for extended cold storage of platelets.

Receipt of low titer group O whole blood does not lead to hemolysis in children weighing less than 20 kilograms

OBJECTIVE

The safety of Low Titer Group O Whole Blood (LTOWB) transfusion has not been well-studied in small children.

METHODS

This is a single-center retrospective cohort study of pediatric recipients of RhD-LTOWB (June 2016-October 2022) who weigh less than 20 kilograms. Biochemical markers of hemolysis (lactate dehydrogenase, total bilirubin, haptoglobin, and reticulocyte count) and renal function (creatinine and potassium) were recorded on the day of LTOWB transfusion and post-transfusion days 1 and 2. Group O and non-Group O recipients were compared.

RESULTS

Twenty-one children were included. Their median (interquartile range [IQR]) weight was 12 kg (12-18) with minimum 2.8 kg, and median (IQR) age was 3 years (1.75-5.00) with minimum 0.08 years (29 days old). The most common indication for transfusion was trauma (17/21; 81%). The median (IQR) volume of LTOWB transfused was 30 mL/kg (20-42). There were 9 non-group O and 12 group O recipients. There were no statistically significant differences in the median concentrations of any of the biochemical markers of hemolysis or the renal function markers between the non-group O and the group O recipients at any of the three time points (p > 0.05 for all comparisons). There were also no statistically significant differences in demographic parameters or clinical outcomes including 28-day mortality, length of stay, ventilator days, and venous thromboembolism between the groups. No transfusion reactions were reported in either group.

CONCLUSION

These data suggest LTOWB use is safe in children weighing less than 20 kg. Further multi-center studies and larger cohorts are needed to confirm these results.

Community-Onset Bacterial Coinfection in Children Critically Ill With Severe Acute Respiratory Syndrome Coronavirus 2 Infection

Background

Community-onset bacterial coinfection in adults hospitalized with coronavirus disease 2019 (COVID-19) is reportedly uncommon, though empiric antibiotic use has been high. However, data regarding empiric antibiotic use and bacterial coinfection in children with critical illness from COVID-19 are scarce.

Methods

We evaluated children and adolescents aged <19 years admitted to a pediatric intensive care or high-acuity unit for COVID-19 between March and December 2020. Based on qualifying microbiology results from the first 3 days of admission, we adjudicated whether patients had community-onset bacterial coinfection. We compared demographic and clinical characteristics of those who did and did not (1) receive antibiotics and (2) have bacterial coinfection early in admission. Using Poisson regression models, we assessed factors associated with these outcomes.

Results

Of the 532 patients, 63.3% received empiric antibiotics, but only 7.1% had bacterial coinfection, and only 3.0% had respiratory bacterial coinfection. In multivariable analyses, empiric antibiotics were more likely to be prescribed for immunocompromised patients (adjusted relative risk [aRR], 1.34 [95% confidence interval {CI}, 1.01-1.79]), those requiring any respiratory support except mechanical ventilation (aRR, 1.41 [95% CI, 1.05-1.90]), or those requiring invasive mechanical ventilation (aRR, 1.83 [95% CI, 1.36-2.47]) (compared with no respiratory support). The presence of a pulmonary comorbidity other than asthma (aRR, 2.31 [95% CI, 1.15-4.62]) was associated with bacterial coinfection.

Conclusions

Community-onset bacterial coinfection in children with critical COVID-19 is infrequent, but empiric antibiotics are commonly prescribed. These findings inform antimicrobial use and support rapid de-escalation when evaluation shows coinfection is unlikely.

Life-Threatening Complications of Influenza vs Coronavirus Disease 2019 (COVID-19) in US Children

BACKGROUND

Clinical differences between critical illness from influenza infection vs coronavirus disease 2019 (COVID-19) have not been well characterized in pediatric patients.

METHODS

We compared demographics, clinical characteristics, and outcomes of US children (aged 8 months to 17 years) admitted to the intensive care or high-acuity unit with influenza or COVID-19. Using mixed-effects models, we assessed the odds of death or requiring life support for influenza vs COVID-19 after adjustment for age, sex, race and Hispanic origin, and underlying conditions including obesity.

RESULTS

Children with influenza (n = 179) were younger than those with COVID-19 (n = 381; median, 5.2 years vs 13.8 years), less likely to be non-Hispanic Black (14.5% vs 27.6%) or Hispanic (24.0% vs 36.2%), and less likely to have ≥1 underlying condition (66.4% vs 78.5%) or be obese (21.4% vs 42.2%), and a shorter hospital stay (median, 5 days vs 7 days). They were similarly likely to require invasive mechanical ventilation (both 30.2%), vasopressor support (19.6% and 19.9%), or extracorporeal membrane oxygenation (2.2% and 2.9%). Four children with influenza (2.2%) and 11 children with COVID-19 (2.9%) died. The odds of death or requiring life support in children with influenza vs COVID-19 were similar (adjusted odds ratio, 1.30; 95% confidence interval, .78-2.15; P = .32).

CONCLUSIONS

Despite differences in demographics and clinical characteristics of children with influenza or COVID-19, the frequency of life-threatening complications was similar. Our findings highlight the importance of implementing prevention measures to reduce transmission and disease severity of influenza and COVID-19.

Design and logistical considerations for the randomized adaptive non-inferiority storage-duration-ranging CHIlled Platelet Study

BACKGROUND

Platelet transfusion is a potentially life-saving therapy for actively bleeding patients, ranging from those undergoing planned surgical procedures to those suffering unexpected traumatic injuries. Platelets are currently stored at room temperature (20°C-24°C) with a maximum storage duration of 7 days after donation. The CHIlled Platelet Study trial will compare the efficacy and safety of standard room temperature-stored platelets with platelets that are cold-stored (1°C-6°C), that is, chilled, with a maximum of storage up to 21 days in adult and pediatric patients undergoing complex cardiac surgical procedures.

METHODS/RESULTS

CHIlled Platelet Study will use a Bayesian adaptive design to identify the range of cold storage durations for platelets that are non-inferior to standard room temperature-stored platelets. If cold-stored platelets are non-inferior at durations greater than 7 days, a gated superiority analysis will identify durations for which cold-stored platelets may be superior to standard platelets. We present example simulations of the CHIlled Platelet Study design and discuss unique challenges in trial implementation. The CHIlled Platelet Study trial has been funded and will be implemented in approximately 20 clinical centers. Early randomization to enable procurement of cold-stored platelets with different storage durations will be required, as well as a platelet tracking system to eliminate platelet wastage and maximize trial efficiency and economy.

DISCUSSION

The CHIlled Platelet Study trial will determine whether cold-stored platelets are non-inferior to platelets stored at room temperature, and if so, will determine the maximum duration (up to 21 days) of storage that maintains non-inferiority.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04834414.

Blood component ratios in children with non-traumatic life-threatening bleeding

BACKGROUND AND OBJECTIVES

In paediatric trauma patients, there are limited prospective data regarding blood components and mortality, with some literature suggesting decreased mortality with high ratios of plasma and platelets to red blood cells (RBCs) in massive transfusions; however, most paediatric massive transfusions occur for non-traumatic aetiologies and few studies assess blood product ratios in these children. This study's objective was to evaluate whether high blood product ratios or low deficits conferred a survival benefit in children with non-traumatic life-threatening bleeding.

MATERIALS AND METHODS

This is a secondary analysis of the five-year, multicentre, prospective, observational massive transfusion epidemiology and outcomes in children study of children with life-threatening bleeding from US, Canadian and Italian medical centres. Primary interventions were plasma:RBC and platelets:RBC (high ratio ≥1:2 ml/kg) and plasma and platelet deficits. The primary outcome was mortality at 6 h, 24 h and 28 days. Multivariate logistic regression models were used to determine independent associations with mortality.

RESULTS

A total of 222 children were included from 24 medical centres: 145 children (median [interquartile range] age 2.1 years [0.3-11.8]) with operative bleeding and 77 (8.0 years [1.2-14.7]) with medical bleeding. In adjusted analyses, neither blood product ratios nor deficits were associated with mortality at 6 h, 24 h or 28 days.

CONCLUSION

This paper addresses a lack of prospective data in children regarding optimal empiric massive transfusion strategies in non-traumatic massive haemorrhage and in finding no decrease in mortality with high plasma or platelet to RBC ratios or lower deficits supports an exploratory analysis for mortality.

Pediatric traumatic hemorrhagic shock consensus conference research priorities

BACKGROUND

Traumatic injury is the leading cause of death in children and adolescents. Hemorrhagic shock remains a common and preventable cause of death in the pediatric trauma patients. A paucity of high-quality evidence is available to guide specific aspects of hemorrhage control in this population. We sought to identify high-priority research topics for the care of pediatric trauma patients in hemorrhagic shock.

METHODS

A panel of 16 consensus multidisciplinary committee members from the Pediatric Traumatic Hemorrhagic Shock Consensus Conference developed research priorities for addressing knowledge gaps in the care of injured children and adolescents in hemorrhagic shock. These ideas were informed by a systematic review of topics in this area and a discussion of these areas in the consensus conference. Research priorities were synthesized along themes and prioritized by anonymous voting.

RESULTS

Eleven research priorities that warrant additional investigation were identified by the consensus committee. Areas of proposed study included well-designed clinical trials and evaluations, including increasing the speed and accuracy of identifying and treating hemorrhagic shock, defining the role of whole blood and tranexamic acid use, and assessment of the utility and appropriate use of viscoelastic techniques during early resuscitation. The committee recommended the need to standardize essential definitions, data elements, and data collection to facilitate research in this area.

CONCLUSION

Research gaps remain in many areas related to the care of hemorrhagic shock after pediatric injury. Addressing these gaps is needed to develop improved evidence-based recommendations for the care of pediatric trauma patients in hemorrhagic shock.

Pediatric traumatic hemorrhagic shock consensus conference recommendations

ABSTRACT

Hemorrhagic shock in pediatric trauma patients remains a challenging yet preventable cause of death. There is little high-quality evidence available to guide specific aspects of hemorrhage control and specific resuscitation practices in this population. We sought to generate clinical recommendations, expert consensus, and good practice statements to aid providers in care for these difficult patients.The Pediatric Traumatic Hemorrhagic Shock Consensus Conference process included systematic reviews related to six subtopics and one consensus meeting. A panel of 16 consensus multidisciplinary committee members evaluated the literature related to 6 specific topics: (1) blood products and fluid resuscitation for hemostatic resuscitation, (2) utilization of prehospital blood products, (3) use of hemostatic adjuncts, (4) tourniquet use, (5) prehospital airway and blood pressure management, and (6) conventional coagulation tests or thromboelastography-guided resuscitation. A total of 21 recommendations are detailed in this article: 2 clinical recommendations, 14 expert consensus statements, and 5 good practice statements. The statement, the panel's voting outcome, and the rationale for each statement intend to give pediatric trauma providers the latest evidence and guidance to care for pediatric trauma patients experiencing hemorrhagic shock. With a broad multidisciplinary representation, the Pediatric Traumatic Hemorrhagic Shock Consensus Conference systematically evaluated the literature and developed clinical recommendations, expert consensus, and good practice statements concerning topics in traumatically injured pediatric patients with hemorrhagic shock.

Dose-Dependent Von Willebrand Factor Inhibition by Aptamer BB-031 Correlates with Thrombolysis in a Microfluidic Model of Arterial Occlusion

Von Willebrand Factor (VWF) plays a critical role in thrombus formation, stabilization, and propagation. Previous studies have demonstrated that targeted inhibition of VWF induces thrombolysis when administered in vivo in animal models of ischemic stroke. The study objective was to quantify dose-dependent inhibition of VWF-platelet function and its relationship with thrombolysis using BB-031, an aptamer that binds VWF and inhibits its function. VWF:Ac, VWF:RCo, T-TAS, and ristocetin-induced impedance aggregometry were used to assess BB-031-mediated inhibition of VWF. Reductions in original thrombus surface area and new deposition during administration of treatment were measured in a microfluidic model of arterial thrombolysis. Rotational thromboelastometry was used to assess changes in hemostasis. BB-031 induced maximal inhibition at the highest dose (3384 nM) in VWF:Ac, and demonstrated dose-dependent responses in all other assays. BB-031, but not vehicle, induced recanalization in the microfluidic model. Maximal lytic efficacy in the microfluidic model was seen at 1692 nM and not 3384 nM BB-031 when assessed by surface area. Minor changes in ROTEM parameters were seen at 3384 nM BB-031. Targeted VWF inhibition by BB-031 results in clinically measurable impairment of VWF function, and specifically VWF-GPIb function as measured by VWF:Ac. BB-031 also induced thrombolysis as measured in a microfluidic model of occlusion and reperfusion. Moderate correlation between inhibition and lysis was observed. Additional studies are required to further examine off-target effects of BB-031 at high doses, however, these are expected to be above the range of clinical targeted dosing.

Extracorporeal Membrane Oxygenation Outcomes in Children With Preexisting Neurologic Disorders or Neurofunctional Disability

OBJECTIVE

Patient selection for pediatric extracorporeal membrane oxygenation (ECMO) support has broadened over the years to include children with pre-existing neurologic morbidities. We aimed to determine the prevalence and nature of pre-ECMO neurologic disorders or disability and investigate the association between pre-ECMO neurologic disorders or disability and mortality and unfavorable neurologic outcome.

DESIGN

Multicenter retrospective observational cohort study.

SETTING

Eight hospitals reporting to the Pediatric ECMO Outcomes Registry between October 2011 and June 2019.

PATIENTS

Children younger than 18 years supported with venoarterial or venovenous ECMO.

INTERVENTIONS

The primary exposure was presence of pre-ECMO neurologic disorders or moderate-to-severe disability, defined as Pediatric Cerebral Performance Category (PCPC) or Pediatric Overall Performance Category (POPC) 3-5. The primary outcome was unfavorable outcome at hospital discharge, defined as in-hospital mortality or survival with moderate-to-severe disability (discharge PCPC 3-5 with deterioration from baseline).

MEASUREMENTS AND MAIN RESULTS

Of 598 children included in the final cohort, 68 of 598 (11%) had a pre-ECMO neurologic disorder, 70 of 595 (12%) had a baseline PCPC 3-5, and 189 of 592 (32%) had a baseline POPC 3-5. The primary outcome of in-hospital mortality ( n = 267) or survival with PCPC 3-5 with deterioration from baseline ( n = 39) was observed in 306 of 598 (51%). Overall, one or more pre-ECMO neurologic disorders or disability were present in 226 of 598 children (38%) but, after adjustment for age, sex, diagnostic category, pre-ECMO cardiac arrest, and ECMO mode, were not independently associated with increased odds of unfavorable outcome (unadjusted odds ratio [OR], 1.34; 95% CI, 1.07-1.69; multivariable adjusted OR, 1.30; 95% CI, 0.92-1.82).

CONCLUSIONS

In this exploratory study using a multicenter pediatric ECMO registry, more than one third of children requiring ECMO support had pre-ECMO neurologic disorders or disability. However, pre-existing morbidities were not independently associated with mortality or unfavorable neurologic outcomes at hospital discharge after adjustment for diagnostic category and other covariates.

Cold-stored platelet function is not significantly altered by agitation or manual mixing

BACKGROUND

Cold storage of platelets (CS-PLT), results in better maintained hemostatic function compared to room-temperature stored platelets (RT-PLT), leading to increased interest and use of CS-PLT for actively bleeding patients. However, questions remain on best storage practices for CS-PLT, as agitation of CS-PLT is optional per the United States Food and Drug Administration. CS-PLT storage and handling protocols needed to be determined prior to upcoming clinical trials, and blood banking standard operating procedures need to be updated accordingly for the release of units due to potentially modified aggregate morphology without agitation.

STUDY DESIGN AND METHODS

We visually assessed aggregate formation, then measured surface receptor expression (GPVI, CD42b (GPIbα), CD49 (GPIa/ITGA2), CD41/61 (ITGA2B/ITGB3; GPIIB/GPIIIA; PACI), CD62P, CD63, HLAI), thrombin generation, aggregation (collagen, adenosine diphosphate [ADP], and epinephrine activation), and viscoelastic function (ExTEM, FibTEM) in CS-PLT (Trima collection, 100% plasma) stored for 21 days either with or without agitation (Phase 1, n = 10 donor-paired units) and then without agitation with or without daily manual mixing to minimize aggregate formation and reduce potential effects of sedimentation (Phase 2, n = 10 donor-paired units).

RESULTS

Agitation resulted in macroaggregate formation, whereas no agitation caused film-like sediment. We found no substantial differences in CS-PLT function between storage conditions, as surface receptor expression, thrombin generation, aggregation, and clot formation were relatively similar between intra-Phase storage conditions.

DISCUSSION

Storage duration and not condition impacted phenotype and function. CS-PLT can be stored with or without agitation, and with or without daily mixing and standard metrics of hemostatic function will not be significantly altered.

The publication impact of the first 100 THOR Network publications by bibliometric and social network analyses

BACKGROUND

A specialized international multidisciplinary group of investigators wanted to determine the performance and impact of publications presented at an annual conference over a 6 year period. Specifically, the group wanted to know if the influence of the conference publications extended beyond conference publication authors and attendees. Bibliometric methods and network analyses were used to evaluate the performance and impact of 100 peer-reviewed publications presented at the Trauma Hemostasis and Oxygenation Research (THOR) Network Remote Damage Control Resuscitation (RCDR) Symposia from 2012 to 2017 (published 2013-2018). Further analysis was performed on the affiliations of conference attendees who attended from the years of 2012 to 2017.

STUDY DESIGN AND METHODS

This project used normative and relative bibliometric measures and social network analysis to evaluate the performance and impact of 100 peer-reviewed publications presented at the Trauma Hemostasis and Oxygenation Research (THOR) Network RDCR Symposia from 2012 to 2017. Publication and citation data were from Elsevier Scopus, a bibliographic citation database. Metrics from Elsevier SciVal were selected for the project to normalize for group size, year of publication, and document type. A six-year period of publications presented at the Symposia, published from 2013 to 2018, was selected for analysis. The publication and citation data were further analyzed using Elsevier SciVal and the iCite database from the National Institutes of Health Office of Portfolio Analysis. Sci2, VOSviewer, and Gephi were used for social network analyses and visualization.

RESULTS

The 100 publications presented at the Trauma Hemostasis and Oxygenation Research (THOR) Network Remote Damage Control Resuscitation (RCDR) Symposia from 2012 to 2017 demonstrate reach and influence beyond the authors of the THOR publications or the THOR attendees. Citations to the THOR publications were published in 10 languages and 313 unique journals, with author affiliations from 62 countries. Citation metrics for the THOR publications exceed global averages with 65% of the THOR publications being in the 25% citation percentiles. When benchmarking the THOR publications using six homogenous comparator groups, the THOR publications demonstrate higher citation metrics than any of the comparator groups with more citations per publication, a higher average of cited publications, higher FWCI and outputs in the top citation percentiles among the six groups. The Office of Portfolio Analysis (OPA) iCite database was used to calculate potential to translate for the THOR publications with 57 of the THOR publications cited by clinical articles with an average approximate potential to translate score of 65.3%.

CONCLUSIONS

The value of international groups with sharing of research and knowledge are instrumental in enhancing the uptake for best practices for in medicine and treatment of hemorrhagic shock resuscitation. The use of bibliometric methods and network analyses, along with benchmarking, demonstrated reach and impact beyond the THOR Network. Limitations include use of a single source for analysis of publication and citation; and that publication data alone does not provide a full overview of research performance. Despite these limitations, bibliometric methods, social network analyses, and benchmarking can help centers better understand their impact.

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.

Attitudes of American adult women toward accepting RhD-mismatched transfusions in bleeding emergencies

BACKGROUND

There is an increasing literature demonstrating the benefits of prehospital and early in-hospital transfusions. RhD-positive products might only be available during these phases, which could pose consequences for future pregnancies if D-alloimmunization occurs. This survey measured the willingness of females to accept urgent but incompatible transfusions in light of the potential for future pregnancy complications.

METHODS

A survey was designed to assess the willingness of females ≥18 years of age to accept urgent incompatible transfusions when different absolute risk reductions in maternal mortality were presented along with a static rate of 0.3%-4.0% risk of harm to future pregnancies. The survey was sent electronically to women who are part of the Washington University Research Enhancement Core database.

RESULTS

A total of 4896 delivered survey email invitations were distributed and 325 (6.6%) responses were received; 16 responses were excluded leaving 309 responses for analysis. Most of the responding women were White, college-educated, and lived in Missouri. At least 90% of the respondents would accept an urgent incompatible transfusion when the absolute risk reduction in maternal mortality was ≥4%. Women without a college degree, who lived in Illinois, who were not able to have children appeared to be less willing than their counterparts to receive an incompatible transfusion when the absolute risk reduction in maternal mortality was low.

CONCLUSION

This survey demonstrated that adult women are highly likely to be open to accept urgent incompatible blood transfusions during a bleeding emergency when the absolute risk reduction in maternal mortality was ≥4%.

Low titer Group O whole blood utilization in pediatric trauma resuscitation: A National Survey

BACKGROUND

Renewed interest in low titer group O whole blood (LTOWB) transfusion has led to increased utilization in adult trauma centers; little is known regarding LTOWB use in pediatric centers.

STUDY DESIGN AND METHODS

A survey of LTOWB utilization at American pediatric level 1 trauma centers.

RESULTS

Responses were received from 43/72 (60%) centers. These institutions were primarily urban (84%) and pediatric-specific (58%). There were 16% (7/43) centers using LTOWB, 7% (3/43) imminently initiating an LTOWB program, 47% (20/43) with interest but no current plan to develop a LTOWB program, and 30% (13/43) with no immediate interest in an LTOWB program. For the hospitals actively or imminently using LTOWB, 70% (3/10) have a minimum recipient weight criterion, 60% (6/10) have a minimum age criterion, and 70% (7/10) restrict the maximum volume transfused. Before the patient's RhD type becomes known, 30% (3/10) use RhD negative LTOWB for males and females, 40% (4/10) use RhD positive LTOWB for males and RhD negative LTOWB for females, 20% (2/10) use RhD positive LTOWB for males and RhD negative RBCs for females, and 10% (1/10) use RhD positive LTOWB for both males and females. Maximum LTOWB storage duration was 14-35 days and units nearing expiration were used for non-trauma patients (40%), processed to RBC (40%), and/or discarded (40%). The most common barriers to implementation were concerns about inventory management (37%), wastage (35%), infrequent use (33%), cost (21%) and unclear efficacy (14%).

CONCLUSION

LTOWB utilization is increasing in pediatric level 1 trauma centers in the United States.

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.