The patient receives a blood transfusion through the cannula. Canned blood during the blood transfusion process<unk>  are used to restore oxygen-carrying capacity in people with anemia due to trauma or other medical problems, and are by far the most common blood component used in transfusion medicine. Historically they were transfused as part of whole blood, but are now typically used separately as<unk>  and plasma components. More than 100 million units of blood are collected each year around the world, and about 50% of these are given to people in high income countries. In low-income countries, the majority of blood transfusions (up to 65%) are given to children under 5 years of age to treat severe childhood anemia. Another major use of blood in low income countries is to treat pregnancy-related complications. Whereas in high-income countries, most blood transfusions are given to people over 65 years of age (up to 76%). In these countries transfusion are most commonly used for supportive care in heart surgery, transplant surgery, massive trauma, and therapy for solid and blood cancers. Due to changes in surgical practices, medical use of blood is now the major use of red blood cells in high-income countries. Whenever a red cell transfusion is being considered for an individual patient it is good practice to consider not only the hemoglobin level, but also the overall clinical context, patient preferences, and whether there are alternative treatments. If a person is stable and has a hematinic deficiency they should be treated for the deficiency (iron deficiency, B12 deficiency, or folate deficiency) rather than being given a red cell transfusion. In adults blood transfusion is typically recommended when hemoglobin levels reach 70 g/L (7 g/dL) in those who have stable vital signs, unless they have anemia due to a hematinic deficiency. Transfusing at a restrictive hemoglobin threshold of between 70 g/L to 80 g/L (7 to 8g/dL) decreased the proportion of people given a red blood cell transfusion by 41% across a broad range of clinical specialties, including those people who are critically ill. There is no evidence that a restrictive transfusion strategy affects death or major adverse events (e.g. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. There is not enough information in some patient groups to say whether a restrictive or liberal transfusion threshold is better. Single unit transfusion This refers to transfusing a single unit or bag of red blood cells to a person who is not bleeding and haemodynamically stable followed by an assessment to see if further transfusion is required. The benefits of single unit transfusion include reduced exposure to blood products. Each unit transfused increases the associated risks of transfusion such as infection, transfusion associated circulatory overload and other side effects. Transfusion of a single unit also encourages less wastage of red blood cells. Upper gastrointestinal bleeding In adults with upper gastrointestinal bleeding transfusing at a higher threshold caused harm (increased risk of death and bleeding). Heart surgery A review established that in patients undergoing heart surgery a restrictive transfusion strategy of 70 to 80g/L (7 to 8g/dL) is safe and decreased red cell use by 24%. Heart disease There is less evidence available for the optimal transfusion threshold for people with heart disease, including those who are having a heart attack. Guidelines recommend a higher threshold for people with heart disease of 80g/L (8 g/dL) if they are not undergoing cardiac surgery. Blood cancers There is insufficient evidence to suggest how to manage anemia in people with blood cancers in terms of transfusion thresholds. Transfusion–dependent anemia People with thalassaemia who are transfusion dependent require a higher hemoglobin threshold to suppress their own red cell production. To do this their hemoglobin levels should not be allowed to drop below 90 to 105g/L (9 to 10.5g/dL). There is insufficient evidence to recommend a particular hemoglobin threshold in people with myelodysplasia or aplastic anemia, and guidelines recommend an individualized approach to transfusion. Children There is less evidence for specific transfusion thresholds in children compared to adults. There has only been one randomized trial assessing different thresholds in children, and this showed no difference between a restrictive or liberal transfusion strategy. This trial used similar thresholds to the adult studies, and transfusing when the hemoglobin is less than 70g/L is also recommended in children. Neonates Neonatal red cell transfusion, and when it is appropriate depends on: the gestational age of the baby; how long since the baby had been born; and also on whether the baby is well or ill.
Packed red blood cells
Cryoprecipitate
Whole blood
Neohemocyte
Fresh frozen plasma
Washed red blood cells
Platelet transfusion
Platelet-rich plasma