The transfusion of allogeneic red blood cell (RBC) concentrates is common practice in critical care medicine: up to 45% of critically ill patients are transfused during their stay in an intensive care unit (ICU)10,53. Generally, RBC transfusions are performed with the intention to increase arterial oxygen content and thus oxygen delivery to the tissues.
To this end, RBC transfusions have undoubtedly been proven effective in many medical and surgical conditions, thereby particularly improving the survival of patients with critical impairment of tissue oxygenation, i.e. those with profound anaemia or circulatory shock.
Nevertheless, systematic evidence about the clinical effectiveness of blood transfusions is still difficult to obtain. The most relevant clinical studies report inconsistent effects of blood transfusion on morbidity and mortality as primary outcome parameters (...).