Red blood cell transfusions

Approximately 13,000,000 units of blood are transfused annually in the U.S.

More than 100 million units of blood are obtained from donors worldwide each year.

The most common procedure performed in hospitals.

See transfusion.

In 2011, 9.2 million people donated 15.7 million units of red blood cells and 6.7% of these donors were deferred for not having minimal hemoglobin levels.

Occurs in 11% of hospital stays requiring at least one procedure.

7.6% of all hospitalized patients receive at least one red blood transfusion during their hospitalization.

Approximately 14 million RBC units transfused in 2011, 84.8% were leukocyte reduced (Whitaker BI, Hinkins S).

Hospital acquisition cost for a unit of RBCs $122.

One unit of red blood cell transfusion increases the hemoglobin concentration by 1g/dL in the average sized adult.

No universal RBC transfusion criteria exists, and a restrictive transfusion strategy is as at least as good as a liberal transfusion strategy in the majority of clinical situations.

RBC transfusions may be indicated for a patient with symptoms due to anemia and a hemoglobin level below 7 g/dL.

Transfusions with a hemoglobin concentration between 7-10 g/L may be indicated if there are significant underlying comorbidities such as heart disease, respiratory disease, bone marrow failure or other hematological diseases.

Single unit transfusions traditionally were not recommended, but as transfusion requirements have become more conservative transfusions of one unit can be effective and sufficient.

Improved safety of the blood supply has resulted in the lowest rates of transfusion-transmissible infection and disease ever.

Stored red blood cells retain their shape, mass, and hemoglobin content over time, but the red blood cell membrane eventually become stiffer, less elastic, and makes them less capable of transporting oxygen.

Duration of blood cells storage is not associated with significant differences in the change in multiple organ dysfunction score: transfusion of RBCs stored for 10 days or less is not superior to the transfusion od RBCs stored for 21 days or more among patients undergoing complex cardiac surgery (Steiner ME et al).

60-70% of RBC units transfused are for surgical patients.

Use of transfusions in patients in the ICU is associated with an increased morbidity and mortality.

Post transfusion transmission rates of hepatitis B and C viruses result in about one case per million units transfused.

Post transfusion risk of HIV less than 1 per 1 million units transfused.

Single RBC unit transfusions the present standard for hospitalized patients without bleeding.

The rates of non-viral transfusion adverse events currently averages less than 1%.

The use of leukocyte reduction, gamma irradiation, and the use of male-only donor plasma have low at the risk of human leukocyte antigen (HLA) alloimmunization, transfusion associated graft-versus-host disease and transfusion related acute lung injury.

Retrospective studies suggest that colorectal, cervical, laryngeal, and lung cancer patients that receive transfusions during antineoplastic treatment have a higher rate of recurrence and decreased survival.

RBC transfusion associated with increased morbidity and reduced survival after cardiac surgery.

Increase risk of death with decreased preoperative hemoglobin level in patients with underlying cardiovascular disease compared with other patients.

Blood transfusions or a liberal blood transfusion strategy compared with no blood transfusions or a restricted blood transfusion strategy is associated with higher all cause mortality rates in patients with acute myocardial infarction (Chatterjee S et al).

Meta-analysis of 18 trials among 7593 patients, the absolute rates of hospital associated infection were 16.9% in the liberal transfusion group and 11.8% in the restrictive transfusion group (Rohde et al).

In the above study liberal transfusion policy was associated with increased risk of subsequent myocardial infarction.

Red blood cell transfusion in the setting of acute coronary syndromes and in hospitalized patients with a history of coronary artery disease is associated with increased risk of myocardial infarction and death.

Observational studies show high-risk of infections associated with red blood cell transfusions.

A meta-analysis found significant reduction in mortality associated with a restrictive transfusion approach (Carson JL et al).

A trial of upper G.I. bleeding management found a significant lower risk of of death at 45 days in the restrictive transfusion group compared to a liberal transfusion group (Villanueva C et al).

With gastrointestinal tract bleeding patients may rebleed more frequently as a result of higher portal pressures from liberal transfusion policy.

Presently, there is insufficient evidence to establish appropriate transfusion threshold for patients with myocardial infarction.

Clinical trials do not indicate a benefit to post transfusion hemoglobin concentrations above 10 g/L.

The ideal transfusion threshold at which benefits outweigh risks differs depending on the predominant underlying pathophysiology of the disorder.

Hemoglobin levels of 10 g/dL threshold used is too high for most patients and is associated with increased rates of infection and other adverse effects.

Studies of patients with Jehovah witness faith suggest that mortality sharply increases when hemoglobin concentration declines to less than 5 g/dL, and it is suggested that 5-6 g/dL may be the optimal transfusion trigger. (Carson JL et al).

Jehovah’s Witnesses who refuse transfusion for cardiac surgery do not have increased risk for surgical complications or long-term mortality when comparisons were made by transfusions status (Pattakos G et al).

In the above study 322 Witnesses and 87,453 non-Witnesses underwent cardiac surgery: Witnesses had fewer acute complications, showed a length of stay within those who receive transfusions, and the better one years survival, but similar 20 years survival rates.

In a comparative trial of 428 patients undergoing CABG, reducing the hemoglobin trigger for blood transfusions to 8 g/dL does not adversely affect patient outcomes (Bracey AW et al).

All patients who require chronic transfusions should have extended red blood cell phenotype performed for antigens most likely to be implicated for alloantibody formation.

Extended phenotyping should be performed before the patient begins chronic transfusion therapy to make phenotype being easier.

Extended phenotyping allows laboratories to identify new antibodies and therefore provide better transfusion therapy.

In a study of 2016 patients over the age of 50 with a history of or risk factors for cardiovascular disease, and whose hemoglobin was less than 10 g/dL after hip fracture surgery randomized to liberal transfusion or transfusion restricted to symptomatic patients with a hemoglobin of less than 8 g/dL: primary outcome was death or inability to walk across a room on pay 60 of follow-up-there was no reduction in rates of death the inability to walk independently on day 60 or reduction in in-hospital mortality in elderly patients at high cardiovascular risk (FOCUS Investigators).

In patients with septic shock who underwent transfusion and hemoglobin threshold of 7 g/dL, as compared with those who underwent transfusion at hemoglobin threshold of 9g/dL received fewer transfusions and had similar mortality at 90 days, use of life support, number of days alive and out of the hospital, and the numbers of patients with ischemic events and severe adverse reactions to blood were similar in the two groups (Holst LB et al).

Febrile nonhemolytic transfusion reactions and allergic reactions are the most common adverse effects of transfusion.

To reduce febrile nonhemolytic transfusion reactions leukoreduced red blood cell transfusions are utilized.

Leuko-reduced red blood cells and platelets mitigate against the risk of cytomegalic virus transmission as they are CMV safe.

To prevent febrile nonhemolytic and allergic transfusion reactions antipyretics and antihistamines, usually acetaminophen and diphenhydramine, are used prior to transfusions in about 50% of cases of RBC transfusions.

Premedication with antipyretics and antihistamines routinely is of questionable value.

Life-threatening acute transfusion reactions include: acute hemolytic transfusion reactions, transfusion-associated circulatory overload, and transfusion related acute lung injury.

About 1-5% patients develop associated cardiac overload with heart failure after receiving a blood transfusion.

Based on their cardiac history diuretics can be admitted to see either before or after transfusion to prevent congestive changes.

Transfusion related acute lung injury occurs in one out of 5000 red blood transfusions.

There is a higher risk of bacterial infection in patients who to get more blood than those who get less.

RBC transfusions may be associated with increased risk of postoperative infections, longer duration of hospitalization, and increased stays in the ICU.

Linked to longer duration of mechanical ventilation, and increased incidence of multiple organ failures and increased health costs.

Blood donors are screened for syphilis, but no associated cases of systems had been transfused since the late 1960s.

Approximately 1 in 2 million transfusions may be contaminated with HIV.

Borrellia burgdorferi has not been transferred by blood transfusion.

Rickettsial diseases may be transmitted by blood transfusions as these obligate intracellular bacterial organisms can be viable up to 2 weeks of storage.

Rickettsial diseases associated with blood transfusion include: Anaplasma phagocytophilum, Coxiella burnetii, and Ricketsia rickettsii.

Malaria has rarely been associated with RBC transfusions.

Because of testing for anti-T cruzi antibodies to identify Chagas disease the risk of transmission via transfusion is now negligible.

The most frequent transmitted parasite via transfusion in the US is the tick-borne intraerythrocytic parasite Babesia microti.

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