[Blood transfusion under cardiopulmonary bypass is a possible inducer for inflammation?]

To investigate that blood transfusion under cardiopulmonary bypass is a possible inducer for inflammation, a retrospective study was made with 20 adult patients who underwent coronary artery bypass grafting. The subjects were divided into two groups; transfusion group (group T) including 9 patients who received blood transfusion during cardiopulmonary bypass and the control group (group C) including 11 patients who did not undergo perioperative transfusion. Respiratory index as an indicator of respiratory functions was determined before and immediately after cardiopulmonary bypass, at the end of surgery and 4 hours thereafter. Cardiac index and arterial pressure were determined as the indicator of cardiac function. Moreover, interleukin 6 and 8 (IL-6 and IL-8), inflammatory cytokines were measured and compared between the two groups. The mean amount of blood transfusion was 2.1 units per individual of group T. The minimum value of hematocrit during cardiopulmonary bypass was significantly lower in group T (15.8 +/- 1.8%) than group C (19.1 +/- 1.4%), but the difference became not significant after cardiopulmonary bypass. There were no significant differences either in aortic pressure or cardiac index between two groups. The respiratory index at the end of surgery was higher in group T but the difference was not significant. Meanwhile IL-8 level at the end of cardiopulmonary bypass was significantly higher in group T (67.9 +/- 36 pg/ml) than group C (35.1 +/- 21 pg/ml). However, there was no difference in IL-6 level between the two. These results suggested that inflammation might be aggravated by an increase of IL-8 induced by blood transfusion.