Transfusion Practices in Pediatric Cardiac Surgery Requiring Cardiopulmonary Bypass: A Secondary Analysis of a Clinical Database

Blood products for paediatric patients in congenital heart surgery: A retrospective, single- centre study

IntroductionBlood transfusions during paediatric cardiac surgery with (cardiopulmonary bypass) CPB carry increased risks, including infection and immunological complications. This study evaluates blood product use in the Clinic for Paediatric Cardiology and Cardiac Surgery at the Children's University Hospital following the implementation of a revised blood management protocol from 2020 to 2023.MethodsA retrospective review of 135 paediatric patients who underwent congenital cardiac surgery with CPB was conducted. Patients were categorized into three age groups: Group 1 (<1 year), Group 2 (1 - 4 years), and Group 3 (>4 years). Data on erythrocyte, fresh frozen plasma (FFP), cryoprecipitate, and platelet use were analysed using the Kruskal-Wallis and Spearman's rho tests, with significance set at p < .05, and confidence interval (CI) of 95% quoted when applicable.ResultsErythrocyte use significantly declined over 4 years, with the largest reductions observed from 2020 to 2023 [p < .0001]. Older and heavier patients required fewer transfusions, with a significant inverse correlation between weight and erythrocyte use [Spearman's rho = -0.29, p = .001]. Platelet use also decreased significantly from 2020 to 2023 [p = .04], while FFP and cryoprecipitate use declined notably over the same period [p < 0.01].ConclusionOver 4 years, significant reductions in blood product use were observed, particularly for erythrocytes and platelets. Patients' age and weight were inversely related to erythrocyte transfusion needs. These trends may reflect improvements in surgical techniques and blood management protocols, with potential benefits for patient outcomes.

Prothrombotic Microvesicle Generation in Pediatric Cardiopulmonary Bypass: A Pilot Observational Study

IMPORTANCE

Over 10% of children develop thrombosis after cardiac surgery for congenital heart disease. Children with a single ventricle physiology have the highest risk of thrombosis associated with increased length of the postoperative stay, neurologic complications, and mortality. To decrease these complications, research is needed to understand the mechanisms that promote cardiopulmonary bypass (CPB) surgery-induced thrombin generation and clot formation.

OBJECTIVES

The objective of this pilot observational study was to measure the generation of prothrombotic microvesicles (MVs) and thrombin generation in 21 children collected 5 minutes after initiation of CPB, at the end of CPB, upon arrival in the pediatric congenital cardiac unit (PCCU), and 20 to 24 hours after arrival in the PCCU.

DESIGN, SETTING, AND PARTICIPANTS

An observational pilot study measured platelet and leukocyte MV, platelet aggregation, coagulation, and thrombin generation in 21 children undergoing CPB surgery. The study setting was a tertiary pediatric hospital. Inclusion criteria included age between birth to 5 years and weight on the day of surgery greater than three kilograms.

MAIN OUTCOMES AND MEASURES

Bleeding outcomes were measured by chest tube output and thrombotic outcomes were measured by surveillance ultrasound. Laboratory outcomes of prothrombotic MVs and thrombin generation were measured by high-resolution flow cytometry and calibrated automated thrombogram, respectively.

RESULTS

Time on CPB correlated with a significant increase in WBCs and phosphatidylserine-expressing MVs. Children with single ventricle physiology had increased levels of prothrombotic MVs (p = 0.017), platelet aggregation, peak thrombin (p = 0.019), and d-dimer (p = 0.029) upon arrival to the ICU compared with children with a dual ventricle. Only single ventricle children had a positive correlation between generation of platelet MV with peak thrombin (p = 0.010).

CONCLUSIONS AND RELEVANCE

Larger prospective studies are needed to determine if prothrombotic MVs can predict children with congenital heart disease at risk for thrombotic events.

The Association Between Platelet Transfusion and Acute Kidney Injury Following Fontan Surgery

Objectives: Previous studies have demonstrated an association between transfusion and increased organ dysfunction. We sought to determine the association between transfusion of blood components (red blood cell [RBC], plasma, platelet, and cryoprecipitate transfusions) with development of acute kidney injury (AKI) in children following the Fontan procedure. Methods: This is a single center, retrospective cohort study from 2009 to 2016. All children who underwent the Fontan procedure during the prescribed period who had transfusion and laboratory data available were included. Results: Eighty-eight children were enrolled. The median (interquartile range [IQR]) age was 4.5 (3.3-6.0) years, and median (IQR) weight was 14.8 (13.0-18.8) kg. The median (IQR) cardiopulmonary bypass (CPB) time was 62 (47-89) minutes. Following surgery, according to Kidney Disease Improving Global Outcomes criteria, 41% (36/88) had stage 1 AKI, 23% (20/88) stage 2 AKI, and 15% (13/88) stage 3 AKI. Fifty-eight percent (51/88) of children received at least one RBC transfusion, 73% (64/88) received at least one plasma transfusion, 47% (41/88) received at least one platelet transfusion, and 28% (25/88) received at least one cryoprecipitate transfusion. Children with severe AKI received more of each blood component. After adjusting for age, weight, pre-Fontan pulmonary vascular resistance, pre-Fontan dominant ventricular end-diastolic pressure, CPB time, RBC dose, plasma dose, and cryoprecipitate dose, each 1 mL/kg of platelet transfusion was associated with an increased risk in development of severe AKI (odds ratio: 1.160, 95%CI 1.006-1.339, P = .041). Conclusions: In our cohort of children undergoing the Fontan procedure, platelet transfusion was independently associated with an increased risk of severe AKI postoperatively. The risks, benefits, and alternatives to transfusion should be carefully weighed in this patient population.

Fluid bolus resuscitation with hypertonic saline albumin solution in critically ill children: a prospective observational pilot study

To evaluate the hemodynamic effects and the safety profile of fluid bolus resuscitation with hypertonic saline albumin (HSA) in critically ill children, we performed a prospective observational pilot study between October 2018 and May 2021 in the pediatric intensive care unit (PICU) in a tertiary hospital in Madrid, Spain. Sixty-four HSA boluses were analyzed in 23 patients. A mean volume of 5.7 ml/kg (Standard Deviation, SD 2.3 ml/kg) per bolus was infused. Acute hypotension was the main indication. 91% of the patients had a cardiac disease, 56% of them had undergone cardiac surgery in the previous 72 h, and 47.8% associated right ventricular dysfunction. A significant increase in systolic, mean, and diastolic blood pressure and a decrease in the vasoactive index was observed after the infusion of HSA. This effect lasted for twenty-four hours (p < 0.05). Moreover, the amount of fluid requirements decreased significantly in the 6 h following HSA infusion [8.7 ml/kg (SD 9.6) vs. 15.1 ml/kg (SD 13.6) in the previous 6 h (p < 0.05)]. Serum levels of sodium and chloride increased after the infusion, reaching their peak concentration after one hour (143 mEq/L (SD 3.5) and 109.7 mEq/L (SD 6) respectively). HSA-related metabolic acidosis or acute kidney injury were not observed in this study. Hypertonic saline albumin is safe and effective when infused at a dose of 5 ml/kg in critically ill children. However, further research is required to confirm our findings.

Pilot Assessment of Platelet Thrombus Area and Contractile Force in Pediatric Congenital Heart Surgery Patients Using a Microfluidic Device

OBJECTIVES

This work was designed to evaluate maximum platelet contractile force and thrombus area before and after cardiopulmonary bypass (CPB) in pediatric patients having congenital heart disease (CHD) surgery using a microfluidic device.

DESIGN

A prospective cohort study was designed.

SETTING

The work took place at an academic medical center.

PARTICIPANTS

Twenty pediatric CHD patients ≤8 years of age with expected CPB time >30 minutes were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood was collected at baseline and post-CPB. Maximum platelet contractile force and thrombus area were evaluated in vitro using a microfluidic device (ATLAS PST). Post-CPB samples were supplemented with recombinant von Willebrand factor (rVWF) to explore the impact on contractile force and thrombus area. At baseline, the maximum thrombus area was 0.06 (0.05, 0.07), and the maximum force was 123.3 nN (68.4, 299.5). Linear mixed-effects regression models showed that the maximum thrombus area was larger post-CPB and post-CPB + rVWF compared with pre-CPB (estimated coefficient [Est] = 0.04, p = 0.002; Est = 0.09, p < 0.001, respectively). The maximum thrombus area was also larger post-CPB + rVWF compared with post-CPB (Est = 0.04, p = 0.001). Force was higher post-CPB + rVWF compared with pre-CPB (Est = 173.32, p = 0.044).

CONCLUSIONS

In pediatric CHD patients, microfluidic testing demonstrated that platelet thrombus area increased slightly after CPB, while platelet contractile force did not change. In vitro addition of rVWF further increased thrombus area, suggesting augmentation of primary hemostasis. Microfluidic assessment of platelet contractile force and thrombus area in pediatric CHD patients appears feasible and can demonstrate changes after CPB. Further studies are needed to determine its accuracy, clinical utility, and normal values for pediatric patients.

Analysis of haemodynamics surrounding blood transfusions after the arterial switch operation: a pilot study utilising real-time telemetry high-frequency data capture

BACKGROUND

Packed red blood cell transfusions occur frequently after congenital heart surgery to augment haemodynamics, with limited understanding of efficacy. The goal of this study was to analyse the hemodynamic response to packed red blood cell transfusions in a single cohort, as "proof-of-concept" utilising high-frequency data capture of real-time telemetry monitoring.

METHODS

Retrospective review of patients after the arterial switch operation receiving packed red blood cell transfusions from 15 July 2020 to 15 July 2021. Hemodynamic parameters were collected from a high-frequency data capture system (SickbayTM) continuously recording vital signs from bedside monitors and analysed in 5-minute intervals up to 6 hours before, 4 hours during, and 6 hours after packed red blood cell transfusions-up to 57,600 vital signs per packed red blood cell transfusions. Variables related to oxygen balance included blood gas co-oximetry, lactate levels, near-infrared spectroscopy, and ventilator settings. Analgesic, sedative, and vasoactive infusions were also collected.

RESULTS

Six patients, at 8.5[IQR:5-22] days old and weighing 3.1[IQR:2.8-3.2]kg, received transfusions following the arterial switch operation. There were 10 packed red blood cell transfusions administered with a median dose of 10[IQR:10-15]mL/kg over 169[IQR:110-190]min; at median post-operative hour 36[IQR:10-40]. Significant increases in systolic and mean arterial blood pressures by 5-12.5% at 3 hours after packed red blood cell transfusions were observed, while renal near-infrared spectroscopy increased by 6.2% post-transfusion. No significant changes in ventilation, vasoactive support, or laboratory values related to oxygen balance were observed.

CONCLUSIONS

Packed red blood cell transfusions given after the arterial switch operation increased arterial blood pressure by 5-12.5% for 3 hours and renal near-infrared spectroscopy by 6.2%. High-frequency data capture systems can be leveraged to provide novel insights into the hemodynamic response to commonly used therapies such as packed red blood cell transfusions after paediatric cardiac surgery.

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.

Transfusion Strategies in the 21st Century: A Case-Based Narrative Report

The transfusion of all blood components (red blood cells, plasma, and platelets) has been associated with increased morbidity and mortality in children. It is essential that pediatric providers weigh the risks and benefits before transfusing a critically ill child. A growing body of evidence has demonstrated the safety of restrictive transfusion practices in critically ill children.

Assessment of haemostatic function in paediatric surgical patients: 'if you prick us, do we not bleed?'

Healthy babies have ∼50% of adult procoagulant factor levels, but without an increased risk of bruising or bleeding. The preoperative clotting tests, prothrombin time and partial thromboplastin time, are frequently performed in infants and children. However, the clinical usefulness of screening coagulation tests remains controversial. Viscoelastic coagulation tests are increasingly used to guide perioperative haemostatic interventions. Enhanced coagulability was previously demonstrated on some viscoelastic testing devices using blood from younger infants. This editorial focuses on several key findings from the paediatric reference range study using a new whole blood viscoelastic coagulation test system, ClotPro® (Haemonetics, Boston, MA, USA). Altered clotting patterns in younger infants, underlying mechanisms of coagulation, and potential clinical implications are discussed.

Intraoperative blood product transfusion in pediatric cardiac surgery patients: A retrospective review of adverse outcomes

BACKGROUND

Resuscitation with blood products is often required for pediatric cardiac surgery patients following cardiopulmonary bypass. However, data suggest that blood product transfusion is an independent predictor of adverse outcomes. Most studies have specifically found detrimental effects of overall transfusion of red blood cells in particular, but few have analyzed outcomes by the other specific blood product components.

AIMS

The objective of this study is to analyze adverse outcomes associated with intraoperative transfusion of specific blood product components.

METHODS

A retrospective review was performed on 643 pediatric patients who underwent cardiac surgery requiring cardiopulmonary bypass to evaluate the risk of selected adverse outcomes associated with intraoperative blood product transfusion. Adverse outcomes included thrombotic complications, stroke, acute kidney injury, prolonged mechanical ventilation, and death. Univariate logistic and linear regression analyses were performed to explore the association between various blood products and the occurrence of postoperative complications. Multiple logistic and linear regression analyses were performed adjusting for age, cyanotic status, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Score (STAT score), and cardiopulmonary bypass time.

RESULTS

Unadjusted analysis using univariate logistic and linear regressions showed statistically significant associations of almost all blood components (per 10 mL/kg dose increments) with multiple postoperative complications, including mortality, thrombotic complications, stroke, and days of mechanical ventilation. After adjusting for patient age, cyanotic status, STAT score, and cardiopulmonary bypass time, multivariable logistic and linear regression analyses revealed no association between transfusion of blood products with acute kidney injury and stroke. Administration of red blood cells was the only category significantly correlated with increased days of mechanical ventilation (0.5 days increase in mechanical ventilation per 10 mL/kg transfusion of red blood cells). The only blood product to show complete lack of a statistically significant association with any of the studied outcomes was cryoprecipitate.

CONCLUSIONS

Transfusion of blood products following cardiopulmonary bypass is associated with postoperative adverse outcomes. Future studies aimed at strategies to reduce intraoperative bleeding and decrease the amount of blood products administered are warranted.

Use of Fresh-frozen Plasma in Newborn Infants

Nearly 10% of premature and critically ill infants receive fresh-frozen plasma (FFP) transfusions to reduce their high risk of bleeding. The authors have only limited data to identify relevant clinical predictors of bleeding and to evaluate the efficacy of FFP administration. There is still no consensus on the optimal use of FFP in infants who have abnormal coagulation parameters but are not having active bleeding. The aims of this review are to present current evidence derived from clinical studies focused on the use of FFP in neonatology and then use these data to propose best practice recommendations for the safety of neonates receiving FFP.

Current advances in transfusion medicine 2021: A critical review of selected topics by the AABB Clinical Transfusion Medicine Committee

BACKGROUND

Each year the AABB Clinical Transfusion Medicine Committee (CTMC) procures a synopsis highlighting new, important, and clinically relevant studies in the field of transfusion medicine (TM). This has been made available as a publication in Transfusion since 2018.

METHODS

CTMC members reviewed and identified original manuscripts covering TM-related topics published electronically (ahead-of-print) or in print from December 2020 to December 2021. Selection of publications was discussed at committee meetings and chosen based on perceived relevance and originality. Next, committee members worked in pairs to create a synopsis of each topic, which was then reviewed by additional committee members. The first and senior authors assembled the final manuscript. Although this synopsis is extensive, it is not exhaustive, and some articles may have been excluded or missed.

RESULTS

The following topics are included: blood products; convalescent plasma; donor collections and testing; hemoglobinopathies; immunohematology and genomics; hemostasis; patient blood management; pediatrics; therapeutic apheresis; and cell therapy.

CONCLUSIONS

This synopsis highlights and summarizes recent key developments in TM and may be useful for educational purposes.

Pediatric platelet transfusions in critical illness: a narrative review of recent studies

PURPOSE OF REVIEW

We sought to describe the current use of platelet transfusions, harms associated with platelet transfusion, new methods of platelet processing that attempt to address these harms, and recent platelet transfusion guidance specific to critically ill children.

RECENT FINDINGS

Platelet transfusions have been associated with significant morbidity and mortality. New processing techniques, such as pathogen reduction, have been developed to combat infectious risks but in a recent trial of platelet transfusion thresholds in neonates, transfusing platelets more liberally was associated with increased bleeding and mortality.

SUMMARY

Recent efforts to develop evidence-based guidelines for platelet transfusion in critically ill children were limited by the lack of evidence. However, given the significant risks, restrictive transfusion thresholds should be considered.

The Year in Review: Anesthesia for Congenital Heart Disease 2021

This review focuses on the literature published during the calendar year 2021 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Four major themes are discussed, including cardiovascular disease in children with COVID-19, aortic valve repair and replacement, bleeding and coagulation, and enhanced recovery after surgery (ERAS).

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P): A research program striving to improve blood donor safety and optimize transfusion outcomes across the lifespan

BACKGROUND

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P) is a new iteration of prior National Heart, Lung, and Blood Institute (NHLBI) REDS programs that focus on improving transfusion recipient outcomes across the lifespan as well as the safety and availability of the blood supply.

STUDY DESIGN AND METHODS

The US program includes blood centers and hospitals (22 including 6 free-standing Children's hospitals) in four geographic regions. The Brazilian program has 5 participating hemocenters. A Center for Transfusion Laboratory Studies (CTLS) and a Data Coordinating Center (DCC) support synergistic studies and activities over the 7-year REDS-IV-P program.

RESULTS

The US is building a centralized, vein-to-vein (V2V) database, linking information collected from blood donors, their donations, the resulting manufactured components, and data extracts from hospital electronic medical records of transfused and non-transfused patients. Simultaneously, the Brazilian program is building a donor, donation, and component database. The databases will serve as the backbone for retrospective and prospective observational studies in transfusion epidemiology, transfusion recipient outcomes, blood component quality, and emerging blood safety issues. Special focus will be on preterm infants, patients with sickle cell disease, thalassemia or cancer, and the effect of donor biologic variability and component manufacturing on recipient outcomes. A rapid response capability to emerging safety threats has resulted in timely studies related to Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2).

CONCLUSIONS

The REDS-IV-P program endeavors to improve donor-recipient-linked research with a focus on children and special populations while also maintaining the flexibility to address emerging blood safety issues.