Reducing red blood cell transfusion in elective surgical patients: the role of audit and practice guidelines.

In 1996, we prospectively audited peri-operative transfusion practice in elective surgical patients over a 3-month period. Two-unit transfusions represented 60% of all transfusions. Haemoglobin was measured infrequently prior to transfusion and the main 'trigger' for transfusion was an estimated blood loss in excess of 500 ml. Transfusion guidelines that required the haemoglobin level to be measured immediately before transfusion were introduced. The audit was repeated in 1998; transfusion 'triggers' and the number of transfusions for the two periods were compared. In the second audit, the total number of transfusions decreased by 43%. The mean estimated blood loss associated with a 2-unit transfusion had increased from 608 (373) ml to 1320 (644) ml (p < 0.01) and the estimated haemoglobin concentration after transfusion had decreased from 12.4 (1.8) g.dl-1 to 9.9 (2.4) g.dl-1 (p < 0.01). These results suggest that transfusion guidelines can have a significant impact on clinical practice.