Sanne de Bruin

213 General discussion study in chapter 4. In this international study, the use of other transfusion triggers than Hb levels will be assessed. Although so far no study showed other transfusion triggers than Hb levels to be superior to determine the need for RBC transfusion, the additive value of other triggers besides the use of Hb levels can be a step towards personalized medicine. In recent transfusion guidelines, recommendations are based on a combi- nation of underlying illness and Hb levels 3,6 . Possibly, a combination of physiological changes, comorbidities, underlying disease and Hb levels will guide in the future the decision to transfuse or not. The international study will also reveal potential imple- mentation issues of current evidence regarding transfusion in the critically ill patients. This could be a starting point for focussed education and implementation projects. Platelet and plasma transfusion practice in non-bleeding patients is far more hetero- geneous. This is observed in chapter 2 and 3. For these products it is recognized that INR/PT and platelet count are not the only determinants in the decision to transfuse a patient. Two RCTs in other vulnerable patient populations have shown that liberal platelet transfusion strategies resulted in worse clinical outcomes: neonates who were randomized to a platelet threshold of 50 x 10 9 cells/L died or suffered more often from major bleeding significantly than neonates who were allocated to a threshold of 10 x 10 9 cells/L 7 . Furthermore, patients with a haemorrhagic stroke who used antiplatelet therapy, showed a higher mortality and dependency rate when they were allocated to platelet transfusion 8 . Even though these studies included different patient cohorts, they hint at potential harmful side effects of platelet transfusion. These trials were investi- gating prophylactic platelet transfusion. The next step is whether platelet transfusion is needed in severe thrombopenic patients undergoing an invasive procedure. Although small underpowered studies have been performed, the PACER trial will be the first large well powered non-inferiority RCT in critical ill patients, the PACER trial, which compares different platelet thresholds in severe thrombopenic patients undergoing an ultrasound guided central venous catheter (CVC) placement, is currently recruiting 9 . If the PACER study provides conclusive results, showing the safety of lower platelet count transfusion thresholds during CVC placement, it would pave the way to study lower platelet count transfusion thresholds during more invasive interventions. This could be the start of a shift towards a more restrictive platelet transfusion practice in thrombopenic critically ill patients. Furthermore the PACER trial only allows enrolment when the physician is experienced and uses ultrasound during the CVC placement procedure. Hence, instead of preparing the thrombopenic patient with platelet transfusion for a less experienced physician the trial applies a personalized strategy in severe thrombopenic critically ill patients hopefully preventing allogenic platelet transfusion. 9