Study Design and Methods: This epidemiological study is a follow-up of a study that is already being carried out in four German university hospitals. This new prospective, multi-centre trial comprises approximately 20 different hospitals of varying size and levels of patient care. A patient-centred, evidence-based Patient Blood Management program will be enrolled in each of these hospitals reforming the care of adult patients undergoing any type of surgery. This PBM program includes the following three main pillars: 1) preoperative optimization of hemoglobin levels in high-risk patients with anaemia, 2) standardization of transfusion practice and transfusion triggers according to evidence-based guidelines and 3) alternatives to transfusion of allogeneic RBC concentrates and blood-sparing techniques (like routine use of cell saver systems, point-of-care diagnostics, optimized coagulation management, restrictive blood sampling).