transfusion

Intravenous delivery of blood or blood products (plasma, red cells) into a patient's circulation to make up for deficiencies due to disease, injury, or surgical intervention.

Cross-matching is carried out to ensure the patient receives the right blood group. Because of worries about blood-borne disease, there is a growing interest in autologous transfusion with units of the patient's own blood ‘donated’ over the weeks before an operation.

Blood is rarely transfused whole. Blood cells and platelets are separated and resuspended in solution. Plasma can be frozen and is used to treat clotting deficiencies.

Blood transfusion, first successfully pioneered in humans in 1818, remained a high risk until the discovery of blood groups, by Austrian-born immunologist Karl Landsteiner in 1900, which indicated the need for compatibility of donated blood.

In May 2001, the American Red Cross announced that it would ban blood donations from anyone who has lived in the United Kingdom since 1980 for three months or in continental Europe for six months. The restriction is an attempt to stop the spread of bovine spongiform encephalopathy (BSE) and Creutzfeldt–Jakob disease (CJD) through blood transfusions. The organization also announced it would not allow anyone who has had a blood transfusion in the UK to give blood to the Red Cross.

In 2007, US researchers reported that the loss of nitric oxide (NO) from the haemoglobin of blood samples stored according to current US regulations was responsible for adverse effects observed in some cases where a lot of donated blood was either needed or given ‘too generously’. The researchers found that NO in fresh blood serves as a signal that encourages widening of blood vessels. Within hours after blood donation, the NO content is lost, but it can be restored prior to a transfusion.

Also in 2007, French and Danish researchers reported a new way of converting red blood cells of group A, B, or AB into ‘universal’ blood cells (group 0), which can be given to any patient. Once established in the clinic, this method could remove bottlenecks in the supply of donor blood for patients of specific blood groups.