Best practice & research. Clinical anaesthesiology
-
Best Pract Res Clin Anaesthesiol · Jun 2007
ReviewAllogeneic red blood cell transfusion: physiology of oxygen transport.
Allogeneic red blood cell (RBC) transfusions have been shown to be associated with considerable risks. While their efficiency in many clinical situations has not been proven, the number of studies finding adverse outcomes in terms of morbidity (e.g. postoperative infections) and mortality continues to rise. ⋯ Only a thorough knowledge of the physiology and pathophysiology of oxygen transport can be a solid base for meaningful transfusion decisions. Therefore, the goal of this article is to review the basics of oxygen transport and normovolaemic anaemia.
-
The majority of intensive care unit (ICU) patients will receive a blood transfusion at some point during the course of their ICU stay, generally in an attempt to increase oxygen delivery and hence tissue oxygenation. The efficacy of red blood cell (RBC) transfusion can be evaluated through its effects on patient mortality or morbidity, or more simply by its effects on tissue oxygenation. ⋯ The true challenge lies in determining which patients will benefit from transfusion and those in whom it may be safe to delay or withhold transfusion. In this article, several key factors influencing the systemic and regional efficacy of blood transfusion will be reviewed.
-
According to the global study of the burden of disease, violence and accidental injury account for 12% of deaths worldwide; 30-40% of trauma mortality is attributable to haemorrhage. The highly complex haemostatic system is severely impaired as a result of haemorrhagic shock, acidosis, hypothermia, haemodilution, hyperfibrinolysis, and consumption of clotting factors. Thus it is important to prioritize the prevention of the development of coagulopathy. ⋯ In the absence of international guidelines, there is an ongoing debate about a generally accepted treatment algorithm, mass transfusion protocols, and adverse events that have been observed as a result of transfusion. Thus many recommendations are based upon expert opinion rather than on evidence. In this chapter we address key issues of transfusions of red blood cells and plasma products in the acute control of bleeding in traumatized patients.
-
Inherent risks and increasing costs of allogeneic transfusions underline the socioeconomic relevance of safe and effective alternatives to banked blood. The safety limits of a restrictive transfusion policy are given by a patient's individual tolerance of acute normovolaemic anaemia. latrogenic attempts to increase tolerance of anaemia are helpful in avoiding premature blood transfusions while at the same time maintaining adequate tissue oxygenation. Autologous transfusion techniques include preoperative autologous blood donation (PAD), acute normovolaemic haemodilution (ANH), and intraoperative cell salvage (ICS). ⋯ Currently, some controversy regarding contraindications of ICS needs to be resolved. Artificial oxygen carriers based on perfluorocarbon (PFC) or haemoglobin (haemoglobin-based oxygen carriers, HBOCs) are attractive alternatives to allogeneic red blood cells. Nevertheless, to date no artificial oxygen carrier is available for routine clinical use, and further studies are needed to show the safety and efficacy of these substances.