Managing anaemia in critically ill adults

#### Summary points Anaemia (haemoglobin <120 g/l for women, and <130 g/l for men) is common in acutely unwell patients. Maintaining sufficient oxygen transport to the tissues is fundamental to survival and recovery from acute illness, and in the United Kingdom 8-10% of the blood supply is used to treat patients in intensive care.1 Red blood cells transport more than 97% of the oxygen content of blood—about 200 ml/l—and anaemia greatly reduces oxygen delivery, especially if patients also have cardiovascular and respiratory compromise.2 Transfusion of donor (allogeneic) red blood cells is the standard method for rapidly correcting anaemia in acutely unwell patients, but the risk-benefit balance of this intervention is a subject of continuing debate, controversy, and concern.3 We highlight uncertainties in the management of anaemia in critically ill patients, especially in relation to the use of red cells, and summarise current evidence from observational studies and randomised trials. We focus on the management of anaemia in critically ill patients without active bleeding, such as those who are in adult medical and surgical intensive care units, high dependency units, and other acute units. We do not discuss the management of patients …