Blood transfusions and clinical outcomes in neonates and infants undergoing cardiac surgery with cardiopulmonary bypass-A single centre prospective study

Abstract

Background: Approximately 3000 babies are born with congenital heart disease (CHD) each year in Australia. Children born with CHD often require surgery requiring cardiopulmonary bypass (CPB). While CPB has helped improve overall survival rates for children born with CHD, a major complication associated with CPB is bleeding. Bleeding leads to poorer health outcomes. The underlying mechanism of post-CPB bleeding is currently unknown. Bleeding post-CPB is primarily treated with broad-based high-volume blood component transfusions however these have their own risks such as acute volume overload. Understanding blood transfusion in the setting of paediatric CPB is important to optimise outcomes for these patients. Aim: To quantitate and describe blood transfusions and clinical outcomes in neonates and infants undergoing cardiac surgery with CPB at the Royal Children's Hospital (RCH), Melbourne. Method: Neonates and infants (0-1 year old) undergoing cardiac surgery with CPB at RCH were prospectively enrolled in this observational study from October 2021 to June 2023. This study was approved by the RCH Human Research Ethics Committee (HREC 74533) and parents/guardians provided informed consent. Detailed clinical data including patient demographics, surgery details, clinical blood tests, blood component and product transfusions and patient outcomes was collected for each participant. Results: 176 babies were enrolled with median age 1.8 months (IQR 0.3-4.6) and median weight 4.2kg (IQR 3.3-6.1). 83 (47.2%) patients were female. The median total CPB time was 139 mins (IQR 99.8- 190.0) and median time to leaving theatre after protamine administration was 104.5 mins (IQR 85.0-126.5). Blood transfusions received by each patient from pre-CPB through to 24 h post-PICU admission is shown in Table 1. The median total volume of Red Blood Cells, Platelets, Fresh Frozen Plasma and Cryoprecipitate received in theatre post-CPB were 16.7 (IQR 9.0- 24.5), 14.3 (IQR 10.3-17.7), 12.2 (IQR 7.1-20.0), 10 (IQR 7.8-14.3) ml/kg respectively. The median length of stay in the paediatric intensive care unit (PICU) and hospital post-surgery was 4 days (IQR 2-11) and 13 days (IQR 9- 32.5) respectively. 174 patients (98.9%) survived to hospital discharge. Summary/Conclusions: This is the largest single centre prospective study of babies undergoing cardiac surgery with CPB to date. Transfusion requirements were high, and we will analyse the relationship between pre-surgical/patient factors, blood transfusions and outcomes. This will provide insight into the impact of blood transfusions in paediatric CPB and guide future clinical protocols. Additionally, the blood samples collected from this patient cohort will allow mechanistic studies that may refine and reduce blood transfusions and improve clinical outcomes with reduced bleeding.