Sanne de Bruin

206 Chapter 8 sion ratio’s inmassively bleeding patients. In non-bleeding patients, also an association between transfusion practices and base specialty was found. Physicians with a base specialty in internal medicine transfused relatively more restric- tive than physicians with a base specialty in anaesthesiology. Furthermore, the use of other transfusion triggers than Hb levels was common for RBC transfusion according to our survey. More than 50% of the respondents always or most of the time use other triggers than Hb levels. While surveys provide insights how physicians believe patients are currently trans- fused, they don’t reveal how patients are actually transfused in daily practice. For this, a large prospective observational study is necessary. To optimize this trial, a feasibility prospective observational study on transfusion practice was performed. This study was described in chapter 4. We conducted a prospective observational single centre study, in which for seven consecutive days all newly admitted patients were followed until ICU discharge. Information on baseline characteristics, daily clinical and laboratory values, data on each transfusion event (including a questionnaire for the physician why a transfusion was ordered) and 28-day mortality were collected. Workload was scored to assess study feasibility. We included 48 patients in this single centre study. During the study period 30 transfusion events were reported in eight patients including 17 RBC transfusions, 11 platelet transfusions and two plasma transfusions. The average time of data collection was three hours per patient. This study showed that the large prospective study is feasible, and currently this study is enrolling worldwide. In chapter 5 the metabolic changes in vivo of RBCs, in vitro during storage, and the metabolic changes of RBCs after transfusion were reviewed. Several similarities exist between aging in vivo and in vitro during storage. Glycolysis and pentose phosphate pathway (PPP) metabolism slow down during physiological aging, but not as prominent during storage. Mainly due to the decrease in pH, ATP and 2,3-DPG levels decrease significantly during storage. Also, PPP activity decreases during storage. The degree of changes depends on the composition of the additive solution that is used to preserve the RBC. Alkaline, chloride-free, additive solutions are designed to counteract the inhibi- tion of rate limiting enzyme activity in these pathways. Consequently, 2,3-DPG and ATP levels are better preserved in these additive solutions. In addition, the redoxmetabolism remains more active when RBCs are stored under alkaline conditions. Literature on metabolic restoration after transfusion was limited, but it was observed that ATP and 2,3-DPG levels restore within 72 hours after transfusion. Other pathways, such as the PPP have not been studied after transfusion.