Every year over 14 million units of blood are donated in the US and used to treat 4 million people. Blood is tested for infectious diseases like HIV and hepatitis. The most common complication is fever without hemolysis due to antibodies against donor white blood cells. The most serious risks are acute hemolytic reaction from ABO incompatibility and transfusion-related acute lung injury, which have high mortality. Proper screening, testing, and transfusion practices have made the blood supply safer but risks remain.

1. Infectious Risks and Complications of Blood Transfusions. Sheree L. Starr Leadership Practicum 2010 1

4. In 2002, the Centers for Disease Control and Prevention reported the first known cases of West Nile Virus (WNV) transmission through organ transplantation and blood transfusion.

5. When it was discovered that WNV could be transmitted in blood, CADC, FDA, manufactures of test kits, and other combined efforts to develop a WNV blood test. By 2003 only 1 year after the first cases of transfusion- transmitted WNV infection were reported- screening test for WNV became available, and are now used by all U.S. Blood banks to screen blood donors.3

7. The risk of transfusion related infection per unit of platelets is 50 to 250 times higher than the risk associated with HIV-1, HCV, HBV, and HTLV-1/11 ( America’s Blood Centers, 2008)

8. When infused, bacterially containminated platelets can cause sepsis or endotoxic shock.

9. The major sources of platelet contamination are believed to be from transient bacteria's in donors and the introduction of skin organisms into the units of blood at the phlebotomy site ( American’s Blood Centers, 2008)4

11. Other approaches under investigation focus on reducing the bacterial load in blood components or inactivating bacteria without destroying the biologic function of the blood components.5

12. Transfusions Practices Overall, the risk of transfusion- related infectious diseases has significantly decreased over the past several years, and the blood supply is safer than it has ever been. Donor screening, serologic testing, and transfusion practices are continually being improved and refined to prevent diseases from being transmitted by blood transfusions. 6

13. Common Complications. The most common complications of transfusion are febrile nonhemolytic and chill-rigor reactions. The most serious complications are acute hemolytic reaction due to ABO incompatible transfusion and transfusion-related acute lung injury, which have very high mortality rates 7

14. What is the action ? Early recognition of symptoms suggestive of a transfusion reaction and prompt reporting to the blood bank are essential. The most common symptoms are chills, rigors, fever, dyspnea, light-headedness, urticaria, itching, and flank pain. If any of these symptoms (other than localized urticaria and itching) occur, the transfusion should be stopped immediately and the IV line kept open with normal saline. The remainder of the blood product and clotted and anticoagulated samples of the patient's blood should be sent to the blood bank for investigation 8

15. Delayed hemolytic transfusion reaction Occasionally, a patient who has been sensitized to an RBC antigen has very low antibody levels and negative pretransfusion tests. After transfusion with RBCs bearing this antigen, a primary or anamnestic response may result (usually in 1 to 4 wk) and cause a delayed hemolytic transfusion reaction. Delayed hemolytic transfusion reaction usually does not manifest as dramatically as AHTR. Patients may be asymptomatic or have a slight fever. Rarely, severe symptoms occur. Usually, only destruction of the transfused RBCs (with the antigen) occurs, resulting in a falling Hct and a slight rise in LDH and bilirubin. Because delayed hemolytic transfusion reaction is usually mild and self-limited, it is often unidentified, and the clinical clue may be an unexplained drop in Hb to the pretransfusion level occurring 1 to 2 wk posttransfusion. Severe reactions are treated similarly to acute reactions. 9

16. Febrile nonhemolytic transfusion reaction Febrile reaction may occur without hemolysis. Antibodies directed against WBC HLA from otherwise compatible donor blood are one possible cause. This cause is most common in multitransfused or multiparous patients. Cytokines released from WBCs during storage, particularly in platelet concentrates, is another possible cause. Clinically, febrile reactions consist of a temperature increase of ≥ 1° C, chills, and sometimes headache and back pain. Simultaneous symptoms of allergic reaction are common. Because fever and chills also herald a severe hemolytic transfusion reaction, all febrile reactions must be investigated as above, as with any transfusion reaction. 10

17. Allergic reactions Allergic reactions to an unknown component in donor blood are common, usually due to allergens in donor plasma or, less often, to antibodies from an allergic donor. These reactions are usually mild, with urticaria, edema, occasional dizziness, and headache during or immediately after the transfusion. Simultaneous fever is common 11

18. Volume overload The high osmotic load of blood products draws volume into the intravascular space over the course of hours, which can cause volume overload in susceptible patients (eg, those with cardiac or renal insufficiency). RBCs should be infused slowly. The patient should be observed and, if signs of heart failure (eg, dyspnea, rales) occur, the transfusion should be stopped and treatment for heart failure begun. 12

19. Acute lung injury TRALI Transfusion-related acute lung injury is an infrequent complication caused by anti-HLA and/or anti-granulocyte antibodies in donor plasma that agglutinate and degranulate recipient granulocytes within the lung. Acute respiratory symptoms develop, and chest x-ray has a characteristic pattern of noncardiogenic pulmonary edema. After ABO incompatibility, this is the 2nd most common cause of transfusion-related death. Incidence is 1:5,000–10,000, but many cases are mild. Mild to moderate transfusion-related acute lung injury probably is commonly missed. 13

20. Actions ? If AHTR is suspected, one of the first steps is to recheck the sample and patient identifications. Diagnosis is confirmed by measuring urinary Hb, serum LDH, bilirubin, and haptoglobin. Intravascular hemolysis produces free Hb in the plasma and urine; haptoglobin levels are very low. Hyperbilirubinemia may follow. After the acute phase, the degree of acute renal failure determines the prognosis. Diuresis and a decreasing BUN usually portend recovery. Permanent renal insufficiency is unusual. Prolonged oliguria and shock are poor prognostic signs. 14

21. Graft-vs-host disease (GVHD) Transfusion-associated GVHD is usually caused by transfusion of products containing immunocompetent lymphocytes to an immunocompromised host. The donor lymphocytes attack host tissues. GVHD can occur occasionally in immunocompetent patients Symptoms and signs include fever, skin rash (centrifugally spreading rash becoming erythroderma with bullae), vomiting, watery and bloody diarrhea, lymphadenopathy, and pancytopenia due to bone marrow aplasia. Jaundice and elevated liver enzymes are also common. GVHD occurs 4 to 30 days after transfusion and is diagnosed based on clinical suspicion and skin and bone marrow biopsies. GVHD has > 90% mortality because no specific treatment is available. 15

22. Complications of massive transfusion 24 h (eg, 10 units in a 70-kg adult). When a patient receives stored blood in such large volume, the patient's own blood may be, in effect, “washed out.” In circumstances uncomplicated by prolonged hypotension or DIC, dilutional thrombocytopenia is the most likely complication. Platelets in stored whole blood are not functional. Clotting factors (except factor VIII) usually remain sufficient. Microvascular bleeding (abnormal oozing and continued bleeding from raw and cut surfaces) may result. Five to 8 (1 unit/10 kg) platelet concentrates are usually enough to correct such bleeding in an adult. Fresh frozen plasma and cryoprecipitate may be needed. 16

23. Infectious complications Bacterial contamination of packed RBCs occurs rarely, possibly due to inadequate aseptic technique during collection or to transient asymptomatic donor bacteremia. Refrigeration of RBCs usually limits bacterial growth except for cryophilic organisms such as Yersinia sp, which may produce dangerous levels of endotoxin. All RBC units are inspected before issue for bacterial growth, which is indicated by a color change. Because platelet concentrates are stored at room temperature, they have greater potential for bacterial growth and endotoxin production if contaminated. To minimize growth, storage is limited to 5 days. The risk of bacterial contamination of platelets is 1:2500. Therefore, platelets are routinely tested for bacteria 17

24. Lastly- malaria Malaria is transmitted easily through infected RBCs. Many donors are unaware that they have malaria, which may be latent and transmissible for 10 to 15 yr. Storage does not render blood safe. Prospective donors must be asked about malaria or whether they have been in a region where it is prevalent. Donors who have had a diagnosis of malaria or who are immigrants, refugees, or citizens from countries in which malaria is considered endemic are deferred for 3 yr; travelers to endemic countries are deferred for 1 yr. Babesiosis has rarely been transmitted by transfusion. 18

25. Acute hemolytic transfusion reaction (AHTR) usually results from recipient plasma antibodies to donor RBC antigens. ABO incompatibility is the most common cause of AHTR. Antibodies against blood group antigens other than ABO can also cause AHTR. Mislabeling the recipient's pretransfusion sample at collection or failing to match the intended recipient with the blood product immediately before transfusion is the usual cause, not laboratory error. Mainly due to Clerical errors 19