[Perioperative Restrictive Red Blood Cell Transfusion:Recent Advances in Research and Clinical Guidelines]

Perioperative restrictive red blood cell(RBC)transfusion strategy,in which a trigger of hemoglobin(Hb)<7 g/dl is used,is of great benefits to save blood storage and reduce transfusion-related adverse events including infections,immunologic risks,and circulatory overload.Human body can display a series of compensatory mechanisms to acute anemia,including increased cardiac output,favored oxyhemoglobin dissociation,and lung vascular dilation.Therefore,moderate Hb decrease does not necessarily lead to hypoxemia.Patients undergoing hip surgery or suffering from septic shock and/or upper gastrointestinal bleeding can benefit from restrictive RBC transfusion;however,restrictive transfusion may be associated with adverse outcomes in patients with coronary heart disease or undergoing cardiac surgery.Restrictive RBC transfusion strategies have been included in described in many different guidelines.Most of them recommended Hb<7 g/dl to be a trigger for allogeneic RBC transfusion.For patients with an Hb of 7-10 g/dl,the application of restrictive RBC transfusion should be based on the expected blood loss,compensatory ability,and metabolic rate.