Pediatric Hemovigilance and Adverse Transfusion Reactions

Some types of transfusion reactions occur more frequently in the pediatric than the adult population. Allergic reactions are the most common, followed by nonhemolytic transfusion reactions; male children seem most susceptible to such reactions. Platelets are often implicated and pulmonary reactions are understudied in children. Clinical sequelae in neonates, such as bronchopulmonary dysplasia/chronic lung disease and intraventricular hemorrhage, have received increasing attention in relation to transfusion. There is a need to better understand the pathophysiology of transfusion reactions in neonatal and pediatric populations so preventive strategies can be undertaken. There is also a need for robust hemovigilance systems.

Key points

• Pediatric patients have a disproportionately high risk of transfusion reactions compared with adults.
• Allergic transfusion reactions are the most common reactions in children, with platelets being the component most likely to result in such reactions.
• Febrile nonhemolytic transfusion reactions are the second most common reactions in children, with more cases associated with red blood cells than any other blood products.
• Besides classic transfusion reactions, other posttransfusion sequelae should be considered in future studies in neonates and children.
• Collecting accurate statistics on pediatric transfusion reactions relies on hemovigilance systems, with some countries better equipped to gather these data than others.

Introduction

Pediatricians are taught very early in their training that neonates and children are not simply small adults. A large percentage of extremely low birth weight and very low birth weight neonates are transfused, with neonates accounting for between one-third and one-half of all pediatric transfusions. 1 , 2 The complexity of clinical presentation in combination with human errors, such as overtransfusion and a lack of knowledge about certain component modifications (eg, irradiation), affect transfusion outcomes in children. 3 Data from hemovigilance systems as well as single-center studies suggest that a disproportionate number of transfused children (compared with adults) experience transfusion reactions. 3456 Despite data showing a decrease in blood transfusions across the United States in adults, 2 , 7 the 2017 National Blood Collection and Utilization Survey (NBCUS) showed a 7% to 14% increase in the number of red blood cell (RBC), platelet, and plasma units transfused in neonates and children compared with 2015 using matched facility data. 2 As such, the total number of transfusion reactions in children would be expected to increase accordingly. This article reviews what is known about transfusion reactions in neonates and children, with a focus on definitions, pathophysiology, statistics, and mitigation strategies for the most common reactions.

Hemovigilance systems

According to The International Hemovigilance Network (IHN) Web site, 8 the word hemovigilance means “a set of surveillance procedures covering the whole transfusion chain (from the collection of blood and its components to the follow-up of recipients), intended to collect and assess information on unexpected or undesirable effects resulting from the therapeutic use of labile blood products, and to prevent their occurrence or recurrence.” Hemovigilance exists on local, national, and international levels, with groups from multiple countries having made extremely significant contributions over the past few decades. 9 The United Kingdom’s Serious Hazards of Transfusion (UK-SHOT) reporting system 10 is one such notable example. The United States system is voluntary and relies on passive reporting using the Hemovigilance Module of the National Healthcare Safety Network (NHSN), initiated in 2009 to 2010. 11

Although some hemovigilance systems (such as UK-SHOT) evaluate pediatric-specific data, systems in many other countries do not. Reporting systems’ inconsistencies in combination with variability in reporting practices (ie, passive vs active), in addition to the retrospective nature of most studies, make studying trends in serious hazards of transfusion experienced by pediatric patients difficult. For example, as a part of the National Heart, Lung, and Blood Institute REDS-III (Recipient Epidemiology and Donor Evaluation Study) multicenter study, each participating US hospital identified significant underreporting in passive systems in adult transfusion recipients: fewer than 10% of pulmonary transfusion reactions identified by the clinical teams were reported to the transfusion service.