[How Much Blood and What Components does the Patient need Intra- and Perioperatively?]

By the optimised availability of less expensive and safe red cell packs and other blood products over the last 20 years, numerous surgical interventions have become possible without any demand for comments on the precise need. However, a number of publications indicates that blood transfusion may also induce disadvantageous effects on the postoperative course by immunomodulation, which requires a rather restrictive indication for transfusion. Furthermore, demographic development leads to a decrease in that portion of the population with the potential for blood donation accompanied simultaneously by an increase of the percentage of older patients with more need of blood products during medical treatment. This makes blood-sparing measures necessary. In addition, costs for red cell packs have increased, in particular, for the generally compatible blood group 0 - an extra amount for rhesus negative blood. The present narrative review highlights, therefore, important news from the clinical transfusion medicine, immunohaematology and haemostaseology and their impact on daily transfusion practice. In this context, "blood management" is considered as one of the very effective blood-sparing measures, which focusses especially i) on the substitution of iron in case of depressed preoperative haemoglobin as well as ii) to elucidate disorders of coagulation by structured medical history and, subsequently, to balance possible need by a specific plan for substitution. Simultaneously, prospective studies are initiated to investigate how far the transfusion trigger of a patient can be lowered down to a still appropriate level. As far as consolidated findings are already available, they are described with regard to the single blood components and taking into account the cross-sectional guidelines of the "Bundesärztekammer" (Federal Physicians Chamber). Finally, initial evidence is provided characterising patient- and blood donor-specific, blood group-dependent features of a reasonable haemotherapy.