Fifty percent of children are anemic after a critical illness. Iatrogenic blood testing may be a contributor to this problem. The objectives of this study were to describe blood sampling practice in a PICU, determine patient factors associated with increased sampling, and examine the association among blood sampling volume, anemia at PICU discharge, and change in hemoglobin from PICU entry to PICU discharge.

Blood sampling is a recognized contributor to hospital-acquired anemia. We aimed to bundle all published neonatal, pediatric, and adult data regarding clinical interventions to reduce diagnostic blood loss.DATA SOURCES: Four electronic databases were searched for eligible studies from inception until May 2021.STUDY SELECTION: Two reviewers independently selected studies, using predefined criteria. DATA EXTRACTION:One author extracted data, including study design, population, period, intervention type and comparator, and outcome variables (diagnostic blood volume and frequency, anemia, and transfusion).DATA SYNTHESIS: Of 16,132 articles identified, we included 39 trials; 12 (31%) were randomized controlled trials. Among six types of interventions, 27 (69%) studies were conducted in adult patients, six (15%) in children, and six (15%) in neonates. Overall results were heterogeneous. Most studies targeted a transfusion reduction (n = 28; 72%), followed by reduced blood loss (n = 24; 62%) and test frequency (n = 15; 38%). Small volume blood tubes (n = 7) and blood conservation devices (n = 9) lead to a significant reduction of blood loss in adults (8/9) and less transfusion of adults (5/8) and neonates (1/1). Point-of-care testing (n = 6) effectively reduced blood loss (4/4) and transfusion (4/6) in neonates and adults. Bundles including staff education and protocols reduced blood test frequency and volume in adults (7/7) and children (5/5). CONCLUSIONS:Evidence on interventions to reduce diagnostic blood loss and associated complications is highly heterogeneous. Blood conservation devices and smaller tubes appear effective in adults, whereas point-of-care testing and bundled interventions including protocols and teaching seem promising in adults and children.

Anemia is a common complication of pediatric critical illness; close to 75% of children that are admitted to the pediatric intensive care unit (PICU) are anemic at some point during their stay. The causes of anemia of critical illness are multifactorial and are most often attributable to inflammation and/or blood losses (iatrogenic or disease-related). The impact of anemia in critically ill children is unclear but given that hemoglobin is an important factor in the body's oxygen-carrying capacity, low hemoglobin can result in insufficient oxygen delivery to vital organs and tissues especially in the context of an acute illness. The management of anemia of critical illness is yet to be developed. Transfusions of red blood cells are the fastest way to increase hemoglobin; however, they are associated with adverse events. Current recommendations suggest limiting transfusions to hemoglobin levels below 7g/dL in hemodynamically stabilized children. Iron and erythropoietin have been investigated to manage and/or prevent anemia; yet studies on these two therapeutic options have been either negative or inconclusive. Another approach to reduce or prevent anemia is to reduce blood testing and iatrogenic blood losses. Multiples strategies have shown promising results, such as small-volume phlebotomy, in-line blood testing and modifying physician behavior with regard to blood testing orders. Further studies are required to determine how efficient these interventions are to reduce the prevalence of anemia at PICU discharge. Anemia is a significant complication of critical illness and 50% of children are discharged from the PICU anemic. The long-term impact of this complication on these children is unknown, in particular the impact on their long-term neurocognitive development. Structured follow-up is required to understand the trajectory and consequences of anemia in this particular population.