Perioperative haemotherapy: II. Risks and complications of blood transfusion.

Major life-threatening complications following blood transfusion are rare and human error remains an important aetiological factor in many. The infectious risk from blood transfusion is predominantly hepatitis, and non-A, non-B and hepatitis C (HCV) are the most common subtypes noted. The risk of post-transfusion hepatitis (PTH) appears to be decreasing and this is attributed to both deferral of high-risk donors and more aggressive screening of donated blood. Screening for HCV is expected to decrease this risk further. The risk of HIV transmission following blood transfusion is negligibly small. There are data to suggest that perioperative blood transfusion results in suppression of the recipient's immune system. Earlier recurrence of cancer and an increased incidence of postoperative infection have been associated with perioperative blood transfusion although the evidence is not persuasive. Microaggregate blood filters are not recommended for routine blood transfusion but do have a role in the prophylaxis of non-haemolytic febrile reactions caused by platelet and granulocyte debris in the donor blood. Patients should be advised when there is likely to be a requirement for perioperative blood transfusion and informed consent for transfusion should be obtained.