Transfusion practices in high-risk patients in the intensive care unit

Transfusion has been a topic of interest for centuries. Nowadays, it is one of the key treatments in patients admitted to the intensive care unit (ICU). Researchers have tried to find the optimal indications for transfusion in different settings (e.g., trauma vs. non-trauma), subpopulations (e.g., sepsis, post-cardiothoracic surgery) as well as the specifics of transfusion itself (e.g., blood vs. components, storage times). In the past decades, there has been increasing attention to the potential downsides of transfusion. These include patient-level factors, such as short- and long-term side-effects, as well as system-level factors such as donor shortages and increasing healthcare costs. This has led to different international non-inferiority randomized trials investigating whether it is safe to apply a restrictive transfusion policy. Overall, this has resulted in guidelines moving towards a more restrictive transfusion policy in ICU patients. While these data are important for the patient population as a whole, the individual patient may benefit from a personalized approach. The work in this thesis forms an epidemiological overview of transfusion practices in two domains: on one hand, the global mixed population in the ICU; on the other hand, patients supported with extracorporeal membrane oxygenation (ECMO). The different presented studies each highlighted a different aspect of transfusion. By focusing on actual transfusion behavior, we aimed to improve our understanding of how clinical studies and guideline recommendations are translated into clinical practice. Ultimately, the goal of this work was to provide a foundation for future research, implementation and education.