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IMMUNE COMPLICATION
Haemolytic transfusion reactions: Haemolysis following red cell transfusion occur in two forms. Acute haemolysis occurs within 24 hours, is more serious and usually intravascular. Delayed haemolysis occurs after the first 24 hours is more common, less serous and usually intravascular.
Febrile reaction: A rise of temperature usually with chills by more the 1°C after blood transfusion. Headache nausea and vomiting may be seen in serve reaction. Fever lasting more the 18 hours after transfusion are not likely to be febrile reactions. They are almost always seen with cellular components being most common with platelet transfusion.
Urticarial Reactions complicate about 1% of blood trasnfusions
Anaphylactic reactions occur in about 1:150,000 patinets. They are seen in patients with IgA deficiency. These patients have anti IgA antibodies that react to IgA in the transfused plasma. These patients must be transfused thoroughly washed RBCs.
Transfusion Induced Acute Lung Injury manifests as sudden deterioration of lung function shortly (2-6 hours) after a blood transfusion. It is treated by respiratory support with oxygenation and positive pressure ventillation.
Graft vs. Host disease is a rare but almost uniformly fatal complication of blood transfusion, usually from a close relative, that manifests as post transfusion fever, skin, liver, and gastrointestinal manifestations and pancytopenia.
Immune suppression caused by blood transfusion has been used in the past for decrease renal graft rejection. Today clinical relevance this effect is not clear.
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INFECTIONS
Hepatitis (B and C): The incidence of transfusion induced hepatitis has called because of testing of blood and blood products. HIV: HIV posed a major risk before testing became mandatory. Testing has substantially reduced but not eliminated the risk of HIV transmission. Other Viruses: Cytomegalovirus, Epstein-Barre virus, parvovirus b19, HTLV I, HTLV II can be transmitted by blood transfusion. Though some countries mandate testing for some of these viruses the practice, unlike that for HBV, HCV and HIV is not universal. Malaria and other parasitic diseases: Out of the parasitic diseases that can be transmitted by blood transfusion (malaria, filariasis, bebesiosis, toxiplasmosis, toxoplasmosis and trypanosomiasis (South American, African). Malaria because of it’s widespread distribution is the greatest concern. because of it’s wide spread distribution. Transfusion induced sepsis: Transfusion induced sepsis occurs as a result on bacterial growth during storage. It is most common with platelet transfusion as platelets are the only component stored at room temperature. |
MASSIVE TRANSFUSION
Coagulopathy: Dilutional coagulopathy due to degradation of labile coagulation factors like V and VIII on storage causes coagulopathy.
Citrate toxicity: Citrate used as an anticoagulant binds calcium and causes hypocalcaemia. Clinically significant hypocalcaemia is seen only with very rapid transfusion raters (more than one unit over less than 5 mins) and in patients with liver disease (because of impaired citrate metabolism). Treated with intravenous calcium.
Hypothermia: Blood is refrigerated for storage. In massive transfusion the urgency and the rapid rate of infusion may result in hypothermia that can be prevented by the use of blood warmers.
Acid-base imbalance: Patients needing massive transfusion are likely to be acidotic due to lactic acidosis. Citrate present in the transfused blood may aggregate acidosis. On recovery citrate and lactate are converted to bicarbonate resulting in metabolic alkalosis the commonest
Hyperkalaemia: Stored blood may have unto 80mEq/L of potassium which on transfusion cause lifethreatening hyperkalaemia
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Further Reading:
Vein to Vein: An online publication of the Canadian Blood Services
All About Blood 