Sanne de Bruin

18 Chapter 1 Currently, the gold standard for calculating the PTR, is using labelled cells. The most applied method of labelling is radioactive labelling with 111 Indium or 51 Chromium. This is both used in platelets and RBCs but has several disadvantages. Recipients are exposed to harmful Ionizing radiation and so this method is not applicable in vulnerable patient categories. Furthermore, radioactively labelled cells cannot be separately isolated from the circulation after transfusion and it is also not possible to trace different platelet populations simultaneously after transfusion. Recently, biotin labelling is used as an alternative for radioactive labelling. Biotin, also called vitamin B7, has several advantages, including the possibility to isolate the trans- fused cells from the already circulating cells. This method has been validated extensive- ly for RBCs. On a smaller scale biotinylation is also tested in platelets, but it is not yet validated on a larger scale. For platelets, the biotinylation process is more complicated as platelets are easily activated when manipulated. Currently, a standardized method for biotin labelling on a large scale would be desirable. Aims of this thesis This thesis focusses on three topics. First, current clinical transfusion practice is as- sessed in critically ill patients. Second, the application of a new additive solution is tested in healthy volunteers, assessing the RBC survival after transfusion and the met- abolic recovery from the storage lesion after transfusion. And lastly, a newmethod for platelet labelling on a large scale is developed. Short outline of the thesis In Chapter 2 and Chapter 3 clinical transfusion practice is assessed with an online questionnaire regarding non-bleeding and bleeding patients, respectively. In Chapter 4 we performed a pilot study, assessing clinical practice in an academic intensive care unit and testing this study protocol prior to enrolling this worldwide. In Chapter 5 we reviewed the metabolic changes in erythrocytes in vivo, during storage and after transfusion. In Chapter 6 we assessed the effect of storage time and additive solution on post trans- fusion recovery and metabolic recovery of RBCs after transfusion.