Observational study of blood transfusions in European preterm infants

1. The prevalence and incidence of RBC, platelet, and plasma transfusions in neonates with a gestational age of less than 32 weeks at birth, admitted to a tertiary-level NICU:
1.1. The prevalence is calculated by dividing the number of transfusions of the respective transfusion type by the total sum of neonate study days
1.2. The incidence of receiving at least one transfusion, both for any transfusion as per transfusion type, is calculated by dividing the number of neonates receiving at least one transfusion by the total sum of neonate study days

Each participating center will collect data during a 6-week period, in which they will screen all 7 days of these weeks for the study outcomes in the included neonates. For neonates already admitted at the start of the study, the start of patient follow-up in the study is equal to the first day of the study period in the participating center. For all other included infants, the start of patient follow-up equals the day of admission. The end of patient follow-up in the study is equal to the day of death, the day of transfer, the day of discharge, or the last day of the study period in the center (whichever occurs first).

1. Variations in prevalence rates of RBC, platelet, and plasma transfusions. Data analysis will be predominantly descriptive, comparing both participating countries and different types of NICUs. Types of NICUs will be defined based on unit size and whether surgical procedures are being performed.
2. Indications for transfusion: the primary indication for which the transfusion is prescribed by the treating physician will be collected. If applicable, the secondary and tertiary indications will also be registered, as clinicians may consider multiple factors when deciding to give a transfusion. For each transfusion, the prescribing physician must choose from a list of predefined indications (up to three options can be selected, ranked primary to tertiary indication). The primary indication is the indication that has the most weight in the decision to prescribe a transfusion. If the indication for transfusion is registered by someone other than the prescribing physician, the prescribing physician must confirm the correctness of these data.
3. Duration, volume, and transfusion rate of the prescribed RBC, platelet, and plasma transfusions
4. Guideline use: data is collected on whether centers have guidelines in place regarding RBC, platelet, and plasma transfusion for neonates. Following the implementation model by Wensing and Grol, information is gathered on the implementation of transfusion guidelines. Additionally, the researchers will ask centers with established guidelines to provide the guidelines in place at the start of data collection. The researchers will analyse how many of the RBC and platelet guidelines have already incorporated the results of recent clinical trials. They will categorize the existing RBC guidelines into “TOP and/or ETTNO incorporated” and “TOP and/or ETTNO not incorporated”. They will categorize the existing platelet guidelines into “PlaNeT-2/MATISSE incorporated” and “PlaNeT-2/MATISSE not incorporated”. They will assess to what extent centers follow their own local and/or national guidelines.
5. Evidence-basedness of practice: before the start of data collection, the researchers will collaborate with various experts to define what they view as high-quality evidence regarding RBC and platelet transfusion practices in neonates, using the best available evidence including the TOP, ETTNO, and PlaNeT-2/MATISSE trials. They will assess if the RBC and platelet transfusions were prescribed following the best available evidence, by categorizing the prescribed transfusions into different levels of certainty in evidence. They will assign a panel review by three ‘blinded’ experts to discuss cases where there may be ambiguity on the certainty of evidence to support transfusion practice. Transfusion events in clinical scenarios that were not addressed in randomized trials will not be assessed.
6. Transfusion-associated adverse effects: in the absence of clear definitions of transfusion-associated side effects in neonates, the researchers will ask participating centers to register any perceived transfusion-associated adverse effects if the local investigators consider the adverse event to be potentially associated with the preceding transfusion. With this they hope to gain insight into what adverse effects neonatologists identify in clinical practice, despite the lack of well-defined descriptions.
7. Component specifications: the researchers will perform an online survey among transfusion experts in which they explore variations in transfusion component characteristics. They chose this strategy because neonatologists may not be aware of all relevant component specifications. The survey will be sent to transfusion experts in all countries participating in this study during the data collection period. The researchers will record the blood banks from which each participating NICU receives their blood products, which will allow them to link the NICU clinical data to the component specifications reported by the transfusion specialists. They aim to include all blood banks that provide blood products to participating NICUs in the survey.
8. Transfusion with blood products other than RBC, platelet, and plasma or agents that promote or reduce coagulation. The researchers will collect data on transfusions of blood products other than RBC, platelet, and plasma transfusions or agents that promote or reduce coagulation, such as erythropoietin. They will describe these treatments and the indications for which they were prescribed.

Each participating center will collect data during a 6-week period, in which they will screen all 7 days of these weeks for the study outcomes in the included neonates. For neonates already admitted at the start of the study, the start of patient follow-up in the study is equal to the first day of the study period in the participating center. For all other included infants, the start of patient follow-up equals the day of admission. The end of patient follow-up in the study is equal to the day of death, the day of transfer, the day of discharge, or the last day of the study period in the center (whichever occurs first).