Recommendations for the transfusion of red blood cells.

The transfusion of red cell concentrates (RCC) is indicated in order to achieve a fast increase in the supply of oxygen to the tissues, when the concentration of haemoglobin (Hb) is low and/or the oxygen carrying capacity is reduced, in the presence of inadequate physiological mechanisms of compensation (table I)1–14. Table I Mechanisms of adaptation to anaemia Tissue oxygenation depends on various factors - the concentration of Hb; - the saturation of Hb, which, in turn, depends on the O2 tension and the affinity of the Hb for O2; - the O2 requirement, that is, the volume of oxygen needed by the tissues to carry out their aerobic function. Clinical factors that affect the physiological mechanisms of adaptation to anaemia5–8,15–19 - a reduced increase in cardiac output: hypovolaemia, coronary artery disease, disorders of heart valves, congestive heart disease, negative inotropic drugs; - decreased capacity to increase the extraction of O2: acute respiratory distress syndrome (ARDS), sepsis, systemic inflammatory response syndrome (SIRS), traumatic ischaemia-reperfusion damage syndrome; - altered gas exchange: chronic obstructive pulmonary disease (COPD), ARDS; - increased consumption of O2: fever, pain, stress, sepsis, SIRS, hyperventilation syndromes. When there is an indication to correct anaemia, but the situation is not urgent, strategies other than transfusion are preferred, such as the use of haematopoietic drugs (iron, vitamin B12, folic acid, recombinant erythropoietin)5–8,20. In order to reduce perioperative bleeding, it is important to suspend treatment with platelet anti-aggregants, adapt/neutralise anticoagulant therapy and use drugs such as antifibrinolytics and desmopressin9,20–23. Autotransfusion, carried out according to the criteria set out in the appropriate pre-operative request schemes (maximum surgical blood order schedule -MSBOS), and surgical and anaesthetic techniques to limit blood loss are useful strategies for decreasing the use of homologous blood (Grade of recommendation: 1C+)5,6,13,14,20–24.