Transfusion: morbidity and mortality.

Homologous, and to a significantly lesser extent, autologous blood transfusion is associated with definable and potentially serious risk. The increasing professional and public awareness has led to a critical evaluation of transfusion practices and a change in transfusion philosophy towards optimising transfusion therapy for individual patients. This involves the provision of the safest blood and the minimisation of homologous blood exposure. Autologous blood transfusion is not without risk as misidentification of patient or unit, bacterial contamination and volume overload can occur; consequently, the indications for the transfusion of autologous blood, as per homologous units, must be appropriate to the clinical circumstances. Appropriate transfusion criteria are being developed and lower haemoglobin levels are becoming accepted. Transfusion-related mortality and morbidity data is infrequently reported. Ongoing transfusion surveillance programs have reported adverse reactions in 3.5% of transfusion episodes and fatalities have resulted from ABO-incompatible acute haemolytic transfusion reactions, most commonly with group O recipients of group A or B red cells. A significant number of such deaths are attributable to misidentification of patient or units and are preventable by obsessional attention to clerical details. The risks should be considered in the evaluation of the risk-benefit equation and in the resultant decision to administer blood.