Quantifiable Bleeding in Children Supported by Extracorporeal Membrane Oxygenation and Outcome

Use of Inhaled Tranexamic Acid for Pulmonary Hemorrhage in Pediatric Patients on Extracorporeal Membrane Oxygenation Support

Bleeding is a common complication of extracorporeal membrane oxygenation (ECMO), is multifactorial, and results in significant morbidity and mortality. Pulmonary hemorrhage represents a serious adverse event in pediatric patients on ECMO and remains a challenging complication to manage. Its occurrence highlights the importance of identifying treatments that address bleeding complications in this population. This retrospective cohort study, from January 2018 to August 2022, explores the use of inhaled tranexamic acid (TXA), a clot-stabilizing agent, in 53 pediatric ECMO patients with new pulmonary hemorrhage. Primary diagnoses included respiratory failure (34%) and structural abnormalities (34%), such as congenital heart defects, congenital diaphragmatic hernia, and tracheal stenosis, with viral pneumonia being the leading cause of respiratory failure (47%). Results indicated that 48 of 53 (91%) patients showed cessation of pulmonary hemorrhage within 48 hours of inhaled TXA administration as measured by a decrease in our institution-specific bleeding scale from moderate to minor or no bleeding. In ECMO-managed pediatric patients with pulmonary hemorrhage, treatment with inhaled TXA demonstrated safety, with no observed adverse effects, and showed promising signs of contributing to the cessation of bleeding.

Clinical outcomes in critically ill children on extracorporeal membrane oxygenation with severe thrombocytopenia

IntroductionAs international guidelines suggest keeping the platelet count between 50 and 100 × 109 cells/L in children on extracorporeal membrane oxygenation (ECMO), platelet transfusions are administered to two-thirds of ECMO days, and up to 70% of these patients still bleed. We aim to describe outcomes in critically ill children who develop severe thrombocytopenia on ECMO.MethodsSingle-center retrospective study, enrolling critically ill children on ECMO admitted at Children's Memorial Hermann, TX, between 1/2018 and 12/2022, with at least one platelet count below 50 × 109 cells/L (severe thrombocytopenia). Platelet counts were measured four times a day. We report platelet transfusion, bleeding, hemolysis, and clotting events within 6 h after transfusion, as well as ECMO duration and mortality.ResultsWe enrolled 54 patients representing 337 ECMO days and 1190 platelet counts. Median weight was 3.7 kg and 54% were male. Severe thrombocytopenia was observed in 56% of platelet counts. Severe thrombocytopenia was not associated with bleeding in the subsequent 6 h (18% vs 20%, p = .95), but was associated with more frequent platelet transfusions (18% vs 11%, p = .001). There was no correlation between time spent with severe thrombocytopenia and the duration of ECMO (R2 = 0.03). While the time spent with severe thrombocytopenia was not associated with on-ECMO mortality rate (p = .36), there was an association with in-hospital mortality rate (p = .003).ConclusionsOur results indicate a restrictive platelet transfusion strategy is not associated with higher proportions of subsequent bleeding, duration of ECMO, or on-ECMO mortality rate. Multicenter studies are needed to evaluate further the appropriateness of this strategy.

Trauma-related psychopathologies after extracorporeal membrane oxygenation support: A systematic review and meta-analysis

Extracorporeal Membrane Oxygenation (ECMO) use is associated with substantial psychiatric morbidity in patients and their families. This systematic review and meta-analysis quantifies the prevalence of post-traumatic stress disorder (PTSD), anxiety, and depression among ECMO survivors and their families. Included studies enrolled patients on ECMO or their families and reported at least one trauma-related psychopathology. Of 1767 screened studies, 55 were included (5146 participants): 50 in adult ECMO survivors, one in pediatric ECMO survivors, and four in families of ECMO patients (two adult, two pediatric.). The pooled prevalence of PTSD was 19% in adult ECMO survivors, 20% in pediatric ECMO survivors, 25% in families of adult ECMO patients, and 21% in families of pediatric ECMO patients. The pooled prevalence of anxiety was 30% in adult ECMO survivors, 8% in pediatric ECMO survivors, 67% in families of adult ECMO patients, and 46% in families of pediatric ECMO patients. The pooled prevalence of depression was 24% in adult ECMO survivors, 8% in pediatric ECMO survivors, 50% in families of adult ECMO patients, and 32% in families of pediatric ECMO patients. This meta-analysis demonstrates a high prevalence of trauma-related psychopathologies surrounding ECMO use, highlighting the need for interventions to improve post-ECMO outcomes.

Assessing the Reliability of the Bleeding Assessment Scale in Critically Ill Children (BASIC) Definition: A Prospective Cohort Study

OBJECTIVES

To determine the reliability of the Bleeding Assessment Scale in critically Ill Children (BASIC) definition of bleeding severity in a diverse cohort of critically ill children.

DESIGN

Prospective cohort study.

SETTING

Eight mixed PICUs in the Netherlands, Israel, and the United States.

SUBJECTS

Children ages 0-18 years admitted to participating PICUs from January 1, 2020, to December 31, 2022, with bleeding noted by bedside nurse.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The bleeding events were classified as minimal, moderate, or severe, according to the BASIC definition, by two independent physicians at two different time points. Patient demographic data, laboratory values, and clinical outcomes were collected. Three hundred twenty-eight patients were enrolled. The overall inter-rater reliability was substantial (weighted kappa coefficient, 0.736; 95% CI, 0.683-0.789), and the intra-rater reliability was "almost-perfect" (weighted kappa coefficient, 0.816; 95% CI, 0.769-0.863). The platelet count ( p = 0.008), prothrombin time ( p = 0.004), activated partial thromboplastin time ( p = 0.025), and fibrinogen levels ( p = 0.035) were associated with the bleeding severity, but the international normalized ratio was not ( p = 0.195). Patients were transfused blood components in response to any bleeding in 31% of cases and received hemostatic medications in 9% of cases. More severe bleeding was associated with increased 28-day mortality, longer hospital length of stay, and more days receiving inotropic support.

CONCLUSIONS

The BASIC definition is a reliable tool for identifying and classifying bleeding in critically ill children. Implementing this definition into clinical and research practice may provide a consistent and reliable evaluation of bleeding.

Analysis of platelet transfusion efficacy during extracorporeal membrane oxygenation (ECMO) treatment in pediatric patients post-cardiac surgery-a retrospective cohort study

BACKGROUND

Postoperative extracorporeal membrane oxygenation (ECMO) may be necessary for pediatric patients following cardiac surgery, with associated risks of thrombocytopenia and bleeding. Prophylactic platelet transfusions are utilized to mitigate these risks, but the effectiveness of platelet transfusion cannot be reliably predicted. The aim of this study was to investigate the effect of platelet transfusion during postoperative treatment with ECMO in children undergoing cardiac surgery and to explore the optimal transfusion thresholds to reduce the number of platelet transfusions in patients and reduce the risk of death.

METHODS

We included in our study patients from the Pediatric Cardiac Surgery Department at the First Affiliated Hospital of Tsinghua University who underwent cardiac surgery and received ECMO treatment from January 1, 2019, to December 31, 2023, and received platelets transfusion at least once during the ECMO therapy. The platelet counts were determined both before and 24 hours posttransfusion of the platelet product. The corrected count increment (CCI) was calculated for the effectiveness estimation of platelet transfusion. The research subjects were divided into 3 groups based on the platelet count before transfusion (pretransfusion platelet count ≤30×109/L was the low-threshold group, pretransfusion count 31-50×109/L was the medium-threshold group, and ≥51×109/L was the high-threshold group) and the effective rates of each group were calculated.

RESULTS

A total of 11 patients received 47 platelet transfusions, an average of 4.27 ± 1.67 per patient. According to the 24-hour postinfusion platelet (Plt) corrected critical control increase index (24-hour CCI) ≥4500, the infusion was considered to be effective, and ineffective when the CCI was <4500. Out of these, 22 transfusions (46.8%) proved effective, whereas 25 (53.2%) were deemed ineffective. The effective transfusion rates across the 3 groups were 69.2%, 50%, and 27.7%, respectively.

CONCLUSION

The efficacy of platelet transfusion may be higher if a low threshold of platelet transfusion is chosen during ECMO treatment, on the premise of ensuring life safety.

Short-term neurologic outcomes in pediatric extracorporeal membrane oxygenation are proportional to bleeding severity graded by a novel bleeding scale

INTRODUCTION

This study aimed to characterize the severity of bleeding and its association with short-term neurologic outcomes in pediatric ECMO.

METHODS

Multicenter retrospective cohort study of pediatric ECMO patients at 10 centers utilizing the Pediatric ECMO Outcomes Registry (PEDECOR) database from December 2013-February 2019. Subjects excluded were post-cardiac surgery patients and those with neonatal pathologies. A novel ECMO bleeding scale was utilized to categorize daily bleeding events. Poor short-term neurologic outcome was defined as an unfavorable Pediatric Cerebral Performance Category (PCPC) or Pediatric Overall Performance Category (POPC) (score of >3) at hospital discharge.

RESULTS

This study included 283 pediatric ECMO patients with a median (interquartile range [IQR]) age of 1.3 years [0.1, 9.0], ECMO duration of 5 days [3.0, 9.5], and 44.1% mortality. Unfavorable PCPC and POPC were observed in 48.4% and 51.3% of patients at discharge, respectively. Multivariable logistic regression analysis included patient's age, cannulation type, duration of ECMO, need for cardiopulmonary resuscitation, acute kidney injury, new infection, and vasoactive-inotropic score. As the severity of bleeding increased, there was a corresponding increase in the likelihood of poor neurologic recovery, shown by increasing odds of unfavorable neurologic outcome (PCPC), with an adjusted odds ratio (aOR) of 0.77 (confidence interval [CI] 0.36-1.62), 1.87 (0.54-6.45), 2.97 (1.32-6.69), and 5.56 (0.59-52.25) for increasing bleeding severity (grade 1 to 4 events, respectively). Similarly, unfavorable POPC aOR (CI) was 1.02 (0.48-2.17), 2.05 (0.63-6.70), 5.29 (2.12-13.23), and 5.11 (0.66-39.64) for bleeding grade 1 to 4 events.

CONCLUSION

Short-term neurologic outcomes in pediatric ECMO are proportional to the severity of bleeding events. Strategies to mitigate bleeding events could improve neurologic recovery in pediatric ECMO.

Definitions of adverse events associated with extracorporeal membrane oxygenation in children: results of an international Delphi process from the ECMO-CENTRAL ARC

Extracorporeal membrane oxygenation (ECMO) is a high-risk and low-volume life support with increasing clinical study. However, heterogenous outcome definitions impede data assimilation into evidence to guide practice. The Academic Research Consortium (ARC), an international collaborative forum committed to facilitating the creation of stakeholder-driven consensus nomenclature and outcomes for clinical trials of medical devices, supported the ECMO Core Elements Needed for Trials Regulation And quality of Life (ECMO-CENTRAL) ARC. The ECMO-CENTRAL ARC was assembled to develop definitions of paediatric ECMO adverse events for use in clinical trials and regulatory device evaluation. An initial candidate list of ECMO adverse events derived from the mechanical circulatory support ARC was supplemented with a review of ECMO-relevant adverse event definitions collated from literature published between Jan 1, 1988, and Feb 20, 2023. Distinct teams of international topic experts drafted separate adverse event definitions that were harmonised to existing literature when appropriate. Draft definitions were revised for paediatric ECMO relevance with input from patients, families, and an international expert panel of trialists, clinicians, statisticians, biomedical engineers, device developers, and regulatory agencies. ECMO-CENTRAL ARC was revised and disseminated across research societies and professional organisations. Up to three rounds of internet-based anonymous surveys were planned as a modified Delphi process. The expert panel defined 13 adverse event definitions: neurological, bleeding, device malfunction, acute kidney injury, haemolysis, infection, vascular access-associated injury, non-CNS thrombosis, hepatic dysfunction, right heart failure, left ventricular overload, lactic acidaemia, and hypoxaemia. Definitional structure varied. Among 165 expert panel members, 114 were eligible to vote and 111 voted. Consensus was achieved for all proposed definitions. Agreement ranged from 82% to 95%. ECMO-CENTRAL ARC paired rigorous development with methodical stakeholder involvement and dissemination to define paediatric ECMO adverse events. These definitions will facilitate new research and the assimilation of data across clinical trials and ECMO device evaluation in children.

Recommendations on Monitoring and Replacement of Antithrombin, Fibrinogen, and Von Willebrand Factor in Pediatric Patients on Extracorporeal Membrane Oxygenation: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic review informed, modified Delphi consensus regarding monitoring and replacement of specific coagulation factors during pediatric extracorporeal membrane oxygenation (ECMO) support for the Pediatric ECMO Anticoagulation CollaborativE.

DATA SOURCES

A structured literature search was performed using PubMed, Embase, and Cochrane Library (CENTRAL) databases from January 1988 to May 2020, with an update in May 2021.

STUDY SELECTION

Included studies assessed monitoring and replacement of antithrombin, fibrinogen, and von Willebrand factor in pediatric ECMO support.

DATA EXTRACTION

Two authors reviewed all citations independently, with conflicts resolved by a third reviewer if required. Twenty-nine references were used for data extraction and informed recommendations. Evidence tables were constructed using a standardized data extraction form.

DATA SYNTHESIS

Risk of bias was assessed using the Quality in Prognosis Studies tool. The evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation system. A panel of 48 experts met over 2 years to develop evidence-based recommendations and, when evidence was lacking, expert-based consensus statements. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was defined as greater than 80% agreement. We developed one weak recommendation and four expert consensus statements.

CONCLUSIONS

There is insufficient evidence to formulate recommendations on monitoring and replacement of antithrombin, fibrinogen, and von Willebrand factor in pediatric patients on ECMO. Optimal monitoring and parameters for replacement of key hemostasis parameters is largely unknown.

Prophylactic Transfusion Strategies in Children Supported by Extracorporeal Membrane Oxygenation: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic-review informed, modified Delphi consensus regarding prophylactic transfusions in neonates and children supported with extracorporeal membrane oxygenation (ECMO) from the Pediatric ECMO Anticoagulation CollaborativE.

DATA SOURCES

A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2020, with an update in May 2021.

STUDY SELECTION

Included studies assessed use of prophylactic blood product transfusion in pediatric ECMO.

DATA EXTRACTION

Two authors reviewed all citations independently, with a third independent reviewer resolving conflicts. Thirty-three references were used for data extraction and informed recommendations. Evidence tables were constructed using a standardized data extraction form.

MEASUREMENTS AND MAIN RESULTS

The evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. Forty-eight experts met over 2 years to develop evidence-informed recommendations and, when evidence was lacking, expert-based consensus statements or good practice statements for prophylactic transfusion strategies for children supported with ECMO. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was based on a modified Delphi process with agreement defined as greater than 80%. We developed two good practice statements, 4 weak recommendations, and three expert consensus statements.

CONCLUSIONS

Despite the frequency with which pediatric ECMO patients are transfused, there is insufficient evidence to formulate evidence-based prophylactic transfusion strategies.

Patient-tailored platelet transfusion practices for children supported by extracorporeal membrane oxygenation

BACKGROUND AND OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) serves as cardiopulmonary therapy in critically ill patients with respiratory/heart failure and often necessitates multiple blood product transfusions. The administration of platelet transfusions during ECMO is triggered by the presence or risk of significant bleeding. Most paediatric ECMO programmes follow guidelines that recommend a platelet transfusion threshold of 80-100 × 109/L. To reduce exposure to platelets, we developed a practice to dynamically lower the threshold to ~20 × 109/L. We describe our experience with patient-tailored platelet thresholds and related bleeding outcomes.

MATERIALS AND METHODS

We retrospectively evaluated our platelet transfusion policy, bleeding complications and patient outcome in 229 ECMO-supported paediatric patients in our unit.

RESULTS

We found that more than 97.4% of patients had a platelet count <100 × 109/L at some point during their ECMO course. Platelets were transfused only on 28.5% of ECMO days; and 19.2% of patients never required a platelet transfusion. The median lowest platelet count in children who had bleeding events was 25 × 109/L as compared to 33 × 109/L in children who did not bleed (p < 0.001). Our patients received fewer platelet transfusions and did not require more red blood cell transfusions, nor did they experience more haemorrhagic complications.

CONCLUSION

We have shown that a restrictive, 'patient-tailored' rather than 'goal-directed' platelet transfusion policy is feasible and safe, which can greatly reduce the use of platelet products. Although there was a difference in the lowest platelet counts in children who bled versus those who did not, the median counts were much lower than current recommendations.

Bleeding in Critically Ill Children With Malignancy or Hematopoietic Cell Transplant: A Single-Center Prospective Cohort Study

OBJECTIVES

To determine the incidence of bleeding in critically ill children with malignancy and to describe associated patient characteristics, interventions, and clinical outcomes.

DESIGN

Prospective cohort study.

SETTING

PICU in a specialized cancer hospital.

PATIENTS

Children with malignancy or hematopoietic cell transplant 0-18 years of age were admitted to the PICU from November 2020 to November 2021.

INTERVENTIONS

None.

MEASUREMENTS

Patient demographic data, laboratory values, and PICU outcome data were collected. Bleeding was classified according to the Bleeding Assessment Scale in Critically Ill Children.

MAIN RESULTS

Ninety-three bleeding patients were enrolled, and a total of 322 bleeding days were recorded. The median (interquartile range [IQR]) age was 5.8 (2.9-11.8) years and 56% (52/93) of the patients were male. There were 121 new bleeding episodes, in 593 at-risk person-days, translating into a 20% incidence rate per day (95% CI, 17-24%). The incidence of severe, moderate, and minimal bleeding was 2% (95% CI, 1-3), 4% (95% CI, 3-6), and 14% (95% CI, 12-17), respectively. Of the new bleeding episodes, 9% were severe, 25% were moderate and 66% were minimal. Thrombocytopenia was the only laboratory value independently associated with severe bleeding ( p = 0.009), as compared to minimal and moderate bleeding episodes. History of radiation therapy was independently associated with severe bleeding ( p = 0.04). We failed to identify an association between a history of stem cell transplant ( p = 0.49) or tumor type ( p = 0.76), and bleeding severity. Patients were transfused any blood product on 28% (95% CI, 22-34) of the bleeding days. Severe bleeding was associated with increased length of mechanical ventilation ( p = 0.003), longer PICU stays ( p = 0.03), and higher PICU mortality ( p = 0.004).

CONCLUSIONS

In this prospective cohort of children with malignancy, the incidence rate of bleeding was 20%. Most events were classified as minimal bleeding. Low platelet count and radiation therapy were variables independently associated with severe bleeding episodes.

Epidemiology of severe bleeding in children following cardiac surgery involving cardiopulmonary bypass: use of Bleeding Assessment Scale for critically Ill Children (BASIC)

OBJECTIVES

To describe the epidemiology of severe bleeding in the immediate post-operative period in children who undergo cardiopulmonary bypass surgery using the Bleeding Assessment Scale for critically Ill Children (BASIC).

STUDY DESIGN

Retrospective cohort study in a paediatric ICU from 2015 to 2020.

RESULTS

356 children were enrolled; 59% were male with median (IQR) age 2.1 (0.5-8) years. Fifty-seven patients (16%) had severe bleeding in the first 24 hours post-operatively. Severe bleeding was observed more frequently in younger and smaller children with longer bypass and cross-clamp times (p-values <0.001), in addition to higher surgical complexity (p = 0.048). Those with severe bleeding received significantly more red blood cells, platelets, plasma, and cryoprecipitate in the paediatric ICU following surgery (all p-values <0.001). No laboratory values obtained on paediatric ICU admission were able to predict severe post-operative bleeding. Those with severe bleeding had significantly less paediatric ICU-free days (p = 0.010) and mechanical ventilation-free days (p = 0.013) as compared to those without severe bleeding.

CONCLUSIONS

Applying the BASIC definition to our cohort, severe bleeding occurred in 16% of children in the first day following cardiopulmonary bypass. Severe bleeding was associated with worse clinical outcomes. Standard laboratory assays do not predict bleeding warranting further study of available laboratory tests.

Causes of red blood cell loss during extracorporeal membrane oxygenation

BACKGROUND

Pediatric patients on extracorporeal membrane oxygenation (ECMO) often receive repeated red blood cell (RBC) transfusions. This study aims to quantify and characterize causes of RBC loss on ECMO.

METHODS

This retrospective, single-center, observational study includes 91 ECMO patients (age 1 day-20 years). An RBC loss index (RLI), equal to ml RBCs lost per liter of patient + circuit volume per hour, was calculated from the changes in hematocrit and transfused RBCs. To measure the contribution of RBC injury/activation, RBC extracellular vesicle (REV) generation was measured by flow cytometry.

RESULTS

Median RLI on ECMO was 1.9 ml/L/h, 13-fold higher than normal RBC production rate (0.15 ml/L/h) and equivalent to a 4.6 drop in hematocrit/day. Median RBC loss was higher in patients who died (2.95 ml/L/h) versus survived (1.70 ml/L/h, p = .0008). RLI correlated with transfusion rate (r2  = 0.71); however, transfusion rate (ml/kg) underestimated RBC loss in patients with large changes in hematocrit and over-estimated RBC loss in neonates where the circuit volume is greater than the patient blood volume. In non-bleeding patients, intravascular hemolysis represented 16% of total RBC loss and diagnostic phlebotomy 24%, suggesting that ~60% of RBC loss was due to other causes. REV generation was increased sevenfold to ninefold during ECMO.

DISCUSSION

RLI (ml/L/h) is a more reliable quantitative indicator of RBC loss than transfusion rate (ml/kg) for pediatric patients on ECMO. Phlebotomy and intravascular hemolysis only account for 40% of RBC loss in non-bleeding ECMO patients. High REV generation suggests sublethal damage and extravascular clearance may be a cause of RBC loss on ECMO.

Anticoagulation practices associated with bleeding and thrombosis in pediatric extracorporeal membrane oxygenation; a multi-center secondary analysis

To determine associations between anticoagulation practices and bleeding and thrombosis during pediatric extracorporeal membrane oxygenation (ECMO), we performed a secondary analysis of prospectively collected data which included 481 children (<19 years), between January 2012 and September 2014. The primary outcome was bleeding or thrombotic events. Bleeding events included a blood product transfusion >80 ml/kg on any day, pulmonary hemorrhage, or intracranial bleeding, Thrombotic events included pulmonary emboli, intracranial clot, limb ischemia, cardiac clot, and arterial cannula or entire circuit change. Bleeding occurred in 42% of patients. Five percent of subjects thrombosed, of which 89% also bled. Daily bleeding odds were independently associated with day prior activated clotting time (ACT) (OR 1.03, 95% CI= 1.00, 1.05, p=0.047) and fibrinogen levels (OR 0.90, 95% CI 0.84, 0.96, p <0.001). Thrombosis odds decreased with increased day prior heparin dose (OR 0.88, 95% CI 0.81, 0.97, p=0.006). Lower ACT values and increased fibrinogen levels may be considered to decrease the odds of bleeding. Use of this single measure, however, may not be sufficient alone to guide optimal anticoagulation practice during ECMO.

Causes of platelet loss during extracorporeal life support

BACKGROUND

Most pediatric patients show a decline in platelet counts while on extracorporeal life support (ECLS) and require multiple platelet transfusions. To better understand platelet loss during ECLS, this study estimated platelet loss rates due to diagnostic phlebotomy, platelet activation, bleeding and other causes.

METHODS

We collected data on 91 patients (1d-20y, 50 M, 41F). Platelet losses were estimated based on changes in platelet count, patient+circuit blood volume, and transfused platelet volumes. Platelet extracellular vesicles were measured by flow cytometry.

RESULTS

Median platelet loss was 2.8 × 10⁹ /L/hr, more than twice the normal rate of platelet removal and equivalent to a 67 000/μl decrease in platelet count per day. While platelet loss was correlated with platelet transfusion (r²  = 0.51), transfusion underestimated platelet loss in patients with large decreases in platelet count and over-estimated platelet loss in neonates where the circuit volume > patient blood volume. Patients with disseminated intravascular coagulation before or significant bleeding during ECLS have double the rate of platelet loss. Platelet activation accounted for ~32% of total platelet loss, bleeding ~36% and phlebotomy 4%, with the remaining one-third due to other causes. Annexin-negative platelet extracellular vesicle release, a measure of platelet damage, was increased 9-fold during ECLS.

CONCLUSION

Our study is the first to quantitate total, phlebotomy and activation related platelet loss during ECLS. Platelet activation accounts for ~32% of total platelet loss, while bleeding doubles the platelet loss rate. The etiology of the remaining platelet loss is unknown.

Transfusion Strategies for Hemostatic Blood Products in Critically Ill Children: A Narrative Review and Update on Expert Consensus Guidelines

Critically ill children commonly receive coagulant products (plasma and/or platelet transfusions) to prevent or treat hemorrhage or correct coagulopathy. Unique aspects of pediatric developmental physiology, and the complex pathophysiology of critical illness must be considered and balanced against known transfusion risks. Transfusion practices vary greatly within and across institutions, and high-quality evidence is needed to support transfusion decision-making. We present recent recommendations and expert consensus statements to direct clinicians in the decision to transfuse or not to transfuse hemostatic blood products, including plasma, platelets, cryoprecipitate, and recombinant products to critically ill children.

Hemostatic complications and systemic heparinization in pediatric post-cardiotomy veno-arterial extracorporeal membrane oxygenation failed to wean from cardiopulmonary bypass

BACKGROUND

Hemostatic complications and the need for large amounts of blood products are major obstacles during veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Additionally, the occurrence of coagulopathy after cardiopulmonary bypass (CPB) affects systemic heparinization in pediatric post-cardiotomy patients. This study compares hemostatic complications in pediatric post-cardiotomy VA-ECMO patients for failure to wean from CPB with those who received post-cardiotomy VA-ECMO for other indications, while also exploring the relationship between different stages-hemostatic complications and the timing of systemic heparinization.

METHODS

We retrospectively analyzed 146 pediatric patients who received post-cardiotomy VA-ECMO support (CPB-ECMO, n=96 vs. non-CPB-ECMO, n=50) from January 2005 to June 2020. Patients were divided into survivors (n=46) and non-survivors (n=50) according to in-hospital mortality in the CPB-ECMO group. We compared clinical outcomes between the groups, then examined the associations between the timing of systemic heparinization after ECMO implantation and different stages-hemostatic complications, in the CPB-ECMO group.

RESULTS

We found that the risk of early bleeding was significantly increased in patients who failed to wean from CPB. The presence of early bleeding was accompanied by the higher demand for blood products transfusion in the CPB-ECMO group, and for treatment the patients received a longer delayed continuous heparin infusion. As a result of using delayed systemic heparinization to avoid early bleeding, early hemolysis increased in the CPB-ECMO group. A delayed systemic heparinization of 9.5 hours showed the best Youden index results and the overall greatest accuracy in predicting early hemolysis.

CONCLUSIONS

A direct transition from CPB to ECMO in pediatric post-cardiotomy patients significantly increases early bleeding. Delayed systemic heparinization to reduce early bleeding has good discrimination for predicting early hemolysis in the CPB-ECMO group. Coagulopathy is complex in pediatric post-cardiotomy VA-ECMO patients who failed to wean from CPB, and, as such, it is extremely important to monitor coagulation-related indicators in multiple dimensions to determine the timing of systemic heparinization.

Risk Factors Associated With Bleeding in Children With Cardiac Disease Receiving Extracorporeal Membrane Oxygenation: A Multi-Center Data Linkage Analysis

Background: Bleeding is a common complication of extracorporeal membrane oxygenation (ECMO) for pediatric cardiac patients. We aimed to identify anticoagulation practices, cardiac diagnoses, and surgical variables associated with bleeding during pediatric cardiac ECMO by combining two established databases, the Collaborative Pediatric Critical Care Research Network (CPCCRN) Bleeding and Thrombosis in ECMO (BATE) and the Extracorporeal Life Support Organization (ELSO) Registry.

Methods: All children (<19 years) with a primary cardiac diagnosis managed on ECMO included in BATE from six centers were analyzed. ELSO Registry criteria for bleeding events included pulmonary or intracranial bleeding, or red blood cell transfusion >80 ml/kg on any ECMO day. Bleeding odds were assessed on ECMO Day 1 and from ECMO Day 2 onwards with multivariable logistic regression.

Results: There were 187 children with 114 (61%) bleeding events in the study cohort. Biventricular congenital heart disease (94/187, 50%) and cardiac medical diagnoses (75/187, 40%) were most common, and 48 (26%) patients were cannulated directly from cardiopulmonary bypass (CPB). Bleeding events were not associated with achieving pre-specified therapeutic ranges of activated clotting time (ACT) or platelet levels. In multivariable analysis, elevated INR and fibrinogen were associated with bleeding events (OR 1.1, CI 1.0–1.3, p = 0.02; OR 0.77, CI 0.6–0.9, p = 0.004). Bleeding events were also associated with clinical site (OR 4.8, CI 2.0–11.1, p < 0.001) and central cannulation (OR 1.75, CI 1.0–3.1, p = 0.05) but not with cardiac diagnosis, surgical complexity, or cannulation from CPB. Bleeding odds on ECMO day 1 were increased in patients with central cannulation (OR 2.82, 95% CI 1.15–7.08, p = 0.023) and those cannulated directly from CPB (OR 3.32, 95% CI 1.02–11.61, p = 0.047).

Conclusions: Bleeding events in children with cardiac diagnoses supported on ECMO were associated with central cannulation strategy and coagulopathy, but were not modulated by achieving pre-specified therapeutic ranges of monitoring assays.

Coagulation Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference

CONTEXT

Previous criteria for coagulation dysfunction in critically ill children were based mainly on expert opinion.

OBJECTIVE

To evaluate current evidence regarding coagulation tests associated with adverse outcomes in children to inform criteria for coagulation dysfunction during critical illness.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from January 1992 to January 2020 by using a combination of medical subject heading terms and text words to define concepts of coagulation dysfunction, pediatric critical illness, and outcomes of interest.

STUDY SELECTION

Studies were included if critically ill children with coagulation dysfunction were evaluated, if performance characteristics of assessment and/or scoring tools to screen for coagulation dysfunction were evaluated, and if outcomes related to mortality or functional status, organ-specific outcomes, or other patient-centered outcomes were assessed.

DATA EXTRACTION

Data were abstracted from each eligible study into a standard data extraction form, along with risk of bias assessment, by a task force member.

RESULTS

The systematic review supports the presence of at least 2 of the following criteria reflecting coagulation dysfunction in the absence of liver dysfunction: platelet count <100 000 cells per μL, international normalized ratio >1.5, fibrinogen level <150 mg/dL, and D-dimer value above 10 times the upper limit of normal, or above the assay's upper limit of detection if this limit is below 10 times the upper limit of normal.

LIMITATIONS

The proposed criteria for coagulation dysfunction are limited by the available evidence and will require future validation.

CONCLUSIONS

Validation of the proposed criteria and identified scientific priorities will enhance our understanding of coagulation dysfunction in critically ill children.

Plasma and Platelet Transfusions Strategies in Neonates and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass or Neonates and Children Supported by Extracorporeal Membrane Oxygenation: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present the recommendations and consensus statements with supporting literature for plasma and platelet transfusions in critically ill neonates and children undergoing cardiac surgery with cardiopulmonary bypass or supported by extracorporeal membrane oxygenation 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 neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of nine experts developed evidence-based and, when evidence was insufficient, expert-based statements for plasma and platelet transfusions in critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation. 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 one good practice statement, two recommendations, and three expert consensus statements.

CONCLUSIONS

Whereas viscoelastic testing and transfusion algorithms may be considered, in general, evidence informing indications for plasma and platelet transfusions in neonatal and pediatric patients undergoing cardiac surgery with cardiopulmonary bypass or those requiring extracorporeal membrane oxygenation support is lacking.

Transfusion management for children supported by extracorporeal membrane oxygenation

Due to the patients' underlying illness, in combination with circuit-induced coagulopathy, as well as PLT dysfunction, children supported by ECMO are a risk of receiving large volumes of blood components. Given the increasing use of modified blood products and newer biologics, it is unknown whether these products have equal efficacy and safety, in ECMO. The majority of guidance for transfusion therapy is based on expert opinion alone, and research on indications for RBC, plasma, and PLT transfusions for children on ECMO should be a priority.

Epidemiology of the Use of Hemostatic Agents in Children Supported by Extracorporeal Membrane Oxygenation: A Pediatric Health Information System Database Study

Objectives: Children supported by extracorporeal membrane oxygenation (ECMO) are at high risk of bleeding. Though practitioners often prescribe blood components and/or medications to prevent or treat bleeding, the utilization of these hemostatic measures in children is not well-understood. We sought to evaluate the use of hemostatic blood products (platelet, plasma and cryoprecipitate transfusions) and medications [aminocaproic acid, tranexamic acid (TXA) and Factor VIIa] in children supported by ECMO. Design: Retrospective observational study using the Pediatric Health Information System (PHIS) database from 2011-2017. Setting: Fifty-one U.S. children's hospitals. Patients: Children (aged 0-18 years) supported by ECMO. Interventions: None. Measurements and Main Results: ECMO was employed in the care of 7,910 children for a total of 56,079 ECMO days. Fifty-five percent of the patients were male with a median (IQR) age of 0 (0-2) years. The median (IQR) length of ECMO was 5 (2-9) days with a hospital mortality rate of 34%. Platelets were transfused on 49% of ECMO days, plasma on 33% of ECMO days and cryoprecipitate on 17% of ECMO days. Twenty-two percent of children received TXA with the majority receiving it on the first day of ECMO and the use of TXA increased during the 6-year period studied (p < 0.001). Seven percent of children received aminocaproic acid and 3% received Factor VIIa. Conclusions: Children supported by ECMO are exposed to a significant number of hemostatic blood products. Antifibrinolytics, in particular TXA, are being used more frequently. Given the known morbidity and mortality associated with hemostatic blood products, studies are warranted to evaluate the effectiveness of hemostatic strategies.

Bleeding in Critically Ill Children-Review of Literature, Knowledge Gaps, and Suggestions for Future Investigation

Clinically significant bleeding complicates up to 20% of admissions to the intensive care unit in adults and is associated with severe physiologic derangements, requirement for significant interventions and worse outcome. There is a paucity of published data on bleeding in critically ill children. In this manuscript, we will provide an overview of the epidemiology and characteristics of bleeding in critically ill children, address the association between bleeding and clinical outcomes, describe the current definitions of bleeding and their respective limitations, and finally provide an overview of current knowledge gaps and suggested areas for future research.

The Use of Hemostatic Blood Products in Children Following Cardiopulmonary Bypass and Associated Outcomes

To describe the use of hemostatic transfusions in children following cardiac surgery with cardiopulmonary bypass and the association of hemostatic transfusions postoperatively with clinical outcomes.

Epidemiology of Hemostatic Transfusions in Children Supported by Extracorporeal Membrane Oxygenation

OBJECTIVE

To evaluate the epidemiology of hemostatic transfusions (plasma, platelet, and cryoprecipitate) in children supported by extracorporeal membrane oxygenation.

DESIGN

Secondary analysis of a large observational cohort study.

SETTING

Eight pediatric institutions within the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Collaborative Pediatric Critical Care Research Network.

PATIENTS

Critically ill children supported by extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Extracorporeal membrane oxygenation was used in the care of 514 consecutive children. Platelets were transfused on 68% of extracorporeal membrane oxygenation days, plasma on 34% of the days on extracorporeal membrane oxygenation, and cryoprecipitate on 14%. Only 24% of the days on extracorporeal membrane oxygenation were free of any hemostatic transfusions. Daily platelet transfusion dose was independently associated with chest tube output (p < 0.001), other bleeding requiring RBC transfusion (p = 0.03), and daily set platelet goal (p = 0.009), but not with total platelet count (p = 0.75). Daily plasma transfusion dose was independently associated with chest tube output (p < 0.001), other bleeding requiring RBC transfusion (p = 0.01), activated clotting time (p = 0.001), and antithrombin levels (p = 0.02), but not with international normalized ratio (p = 0.99) or activated partial thromboplastin time (p = 0.29). Daily cryoprecipitate transfusion dose was independently associated with younger age (p = 0.009), but not with chest tube bleeding (p = 0.18), other bleeding requiring RBC transfusion (p = 0.75), fibrinogen level (p = 0.67), or daily fibrinogen goal (p = 0.81).

CONCLUSIONS

Platelets were transfused on two third of the days on extracorporeal membrane oxygenation, plasma on one third, and cryoprecipitate on one sixth of the days. Although most hemostatic transfusions were independently associated with bleeding, they were not independently associated with the majority of hemostatic testing. Further studies are warranted to evaluate the appropriateness of these transfusion strategies.

Bleeding Assessment Scale in Critically Ill Children (BASIC): Physician-Driven Diagnostic Criteria for Bleeding Severity

OBJECTIVE

Although bleeding frequently occurs in critical illness, no published definition to date describes the severity of bleeding accurately in critically ill children. We sought to develop diagnostic criteria for bleeding severity in critically ill children.

DESIGN

Delphi consensus process of multidisciplinary experts in bleeding/hemostasis in critically ill children, followed by prospective cohort study to test internal validity.

SETTING

PICU.

PATIENTS

Children at risk of bleeding in PICUs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-four physicians worldwide (10 on a steering committee and 14 on an expert committee) from disciplines related to bleeding participated in development of a definition for clinically relevant bleeding. A provisional definition was created from 35 descriptors of bleeding. Using a modified online Delphi process and conference calls, the final definition resulted after seven rounds of voting. The Bleeding Assessment Scale in Critically Ill Children definition categorizes bleeding into severe, moderate, and minimal, using organ dysfunction, proportional changes in vital signs, anemia, and quantifiable bleeding. The criteria do not include treatments such as red cell transfusion or surgical interventions performed in response to the bleed. The definition was prospectively applied to 40 critically ill children with 46 distinct bleeding episodes. The kappa statistic between the two observers was 0.74 (95% CI, 0.57-0.91) representing substantial inter-rater reliability.

CONCLUSIONS

The Bleeding Assessment Scale in Critically Ill Children definition of clinically relevant bleeding severity is the first physician-driven definition applicable for bleeding in critically ill children derived via international expert consensus. The Bleeding Assessment Scale in Critically Ill Children definition includes clear criteria for bleeding severity in critically ill children. We anticipate that it will facilitate clinical communication among pediatric intensivists pertaining to bleeding and serve in the design of future epidemiologic studies if it is validated with patient outcomes.