Trends in the utilization of blood components in San Pablo Hospital; 1991-1996

The purpose of this paper was to evaluate the trends in the use of blood products in our hospital during the last six years. We selected for the study packed red cells and platelet products since they are the most frequently used, on a unit per unit basis they represent a larger component of the transfusion service budget and finally are the most frequent units involved in transfusion reactions.

The variables in the data bank that were utilized to study included, patients transfused, patients operated, units transfused, units prepared, and units discarded. From these variables we constructed the following new variables, Cross match to Transfusion ratio, units transfused to patients transfused ratio, units transfused to patients operated ratio, and finally patients operated to patients transfused ratio. The data was then organized by year and transported to SPSS software where the null hypothesis was tested through an analysis of the variance (ANOVA).

The number of patients who underwent coronary artery bypass surgery increased over the last six years. An average increase of six additional patients per month was documented. An increase in the total number of packed Red Cells units transfused was seen with a mean of 167 units per month in 1992, 182 units in 1994 and 187 units in 1996. (p = .425). A mean of 45 patients per month were transfused in 1992 as compared to 55 and 56 in 1994 and 1996 respectively. (p = .009). The ratio of patients operated to patients transfused decreased from 1.65 in 1992 to 1.3 and 1.4 in 1992 and 1996. (p = .021) The intensity of Red Cell use in patients undergoing surgery was analyzed by using the ratio of number of red cell units transfused by the number of patients operated and transfused. This ratio was 3.7 in 1992, 3.2 in 1994 and 3.3 in 1996. (p = .032) The use of platelets transfusion in the cardiovascular surgery arena appears to have changed very slightly over the five years in our institution. A non-significant trend in the number of patients who are operated and are transfused with platelets is noted, along with a mild decrease in the intensity of platelet use per patient transfused. NON CARDIOVASCULAR SERVICE: The number of patients transfused with packed Red Cells has not changed significantly in this service since 1992. The mean number of units transfused per month in 1992 and in 1994 was close to 222. In 1996, a mean number of 230 units per month were transfused. (p = .172) The mean number of patients transfused increased slightly from 74.5 patients per month in 1992 to 77.5 in 1994 and 77.7 in 1996. (p = .585) The intensity of Red Cell transfusion support decreased somewhat with 2.98 in 1992 to 2.87 and 2.95 in 1994 and 1996. (p = .806) A marked increase in the number of platelet transfusion was documented. A mean number of 192 units were transfused in 1992 per month as compared to 333 and 360 in 1994 and 1996. (p = .27) This increase in platelet use was associated to an increase in the number of patients who were transfused with 9 per month in 1992 and 16.5 and 16.4 in 1994 and 1996. (p = .005) The mean number of platelet transfused per patient decreased in a non significant fashion with 19.9 units and 20.6 units per transfused patient in 1992 and in 1994 to 19.2 units in 1996. (p = .861).

We have been able to define distinct changes in the trends of blood product utilization in our institution.