[Supply of blood to heart surgery patients. Can transfusion habits be changed?].

Objective: In cardiac surgery, patients might receive unnecessary blood transfusions, due to the lack of a uniform criteria for blood replacement. We set out to evaluate the effect of a transfusion education program on the homologous blood requirements of subjects undergoing cardiac surgery.

Methods: In June of 1993 a transfusion education program based on international criteria was designed and put into effect in the intensive care unit. Since that date, 133 patients (group 1), on whom we attempted to evaluate the effects of the program, were included, comparing them with 150 control patients (group 2) from the previous year. Multiple variables were analyzed, in order to confirm that the factors that could affect the use of blood did not differ between the two groups. The impact of these variables and the program on the homologous blood expenditures was measured with uni and multivariant analyses.

Results: Blood requirements of the patients during the first day of the postoperative period were 0.9 +/- 0.1 U in group 1 versus 1.8 +/- 0.1 U in group 2 (p < 0.001) and the requirements during their entire stay in ICU were 1.8 +/- 0.1 versus 2.6 +/- 0.1 (p < 0.005). There were significant differences between both groups: Hemoglobin level at the admission in ICU, anoxia time, extracorporal circulation time, and blood losses in the first 24 hours of their stay in ICU. However, the analysis of covariance showed that the transfusion program exerted an independent influence, apart from other variables, over the decrease of blood transfusions. Morbidity and mortality were similar in both groups.

Conclusions: Transfusion habits can be modified, permitting a lesser consumption of homologous blood through the adoption of education programs adapted to the diseases in which they will be applied.