Sanne de Bruin

205 General summary General summary In summary, this thesis focussed on several aspects of transfusion medicine. In chap- ter 2-4 current transfusion practice was assessed in critically ill patients. In chapter 5 metabolic changes in red blood cells (RBCs) were reviewed, including changes during physiologically aging in vivo, aging during storage and in donor RBCs after transfusion. Followed by chapter 6 in which themetabolic state and post transfusion recovery (PTR) was assessed in RBCs that were stored in a new alkaline additive solution. Finally, in chapter 7 we described a method to label platelets with biotin as an alternative for radioactive labelling. Due to the lack of international guidelines specific for critically ill patients, we hypothe- sized that we would find large heterogeneity in transfusion practice. To assess current transfusion practices and identifying knowledge gaps, we conducted two online sur- veys, which are described in chapter 2 and chapter 3. In these surveys transfusion prac- tice was assessed in non-bleeding and bleeding critically ill patients, respectively. The surveys included questions on RBC, platelet and plasma transfusion practices, trans- fusion triggers, the use of coagulation factors and the use of transfusion guidelines. The most important findings were that RBC transfusion is restrictive in most critically ill subpopulations. For both bleeding and non-bleeding critically ill patients the median reported haemoglobin (Hb) threshold was 7 g/dL. RBC transfusion thresholds were most variable for patients on extracorporeal membrane oxygenation (ECMO): 7[7-9] g/dL in bleeding patients and 8[7-9] g/dL in non-bleeding patients. Some populations, including non-bleeding patients with acute myocardial infarction and bleeding patients after cardiothoracic surgery, were transfused at significantly higher Hb levels compared to other patient categories: 9.0 [8-9.7] g/dL and 8 [7-9] g/dL respectively. The clinical practices of platelet and plasma transfusions was more heterogeneous and less restrictive than RBC transfusion. About 60% of the respondents would consider plasma transfusion to correct vitamin K induced prolonged international normalized ratio (INR) prior to an invasive procedure. The presence of local transfusion guidelines influenced the transfusion practice of the respondents. We found that RBC transfusion was more restrictive in non-bleeding pa- tients when a local transfusion guideline was available. Furthermore, the presence of a massive transfusion protocol was associated with a more frequent use of fixed transfu- 8