Reduction in blood product usage associated with routine use of mini bypass systems in extracorporeal circulation.

Objective: The objective of this study is to investigate the hypothesis that a reduced prime extracorporeal circulation (ECC) system and ensuing reduction in patient hemodilution can affect blood product use.

Methods: We performed a prospective, randomized study from a group of 60 consecutive coronary artery bypass graft (CABG) patients, comparing blood product usage and postoperative bleeding in 30 mini bypass systems (n = 30) to 30 conventional systems (n = 30). The patient demographics in terms of patient weight, height, age, preoperative hemoglobin, preoperative hematocrit, BSA, ejection fraction, and NYHA were not statistically significant.

Results: Blood product use, including fresh frozen plasma (FFP) and homolgous blood transfusions was tracked through the operating theater and into the intensive care unit. In the mini bypass group, while no homologous blood transfusions were given in the OR, 27% of the patients received at least one unit of homologous blood. In the control group, 43% of the patients received at least one unit of blood in the OR or in the ICU and there was a stastistically-significant 38% reduction in homologous blood product use (p = 0.05). For the patients who received homologous blood, there was also a significant reduction in transfused volume (0.53 +/- 0.90 units blood mini bypass vs 1.3 +/- 1.93 units conventional, p < 0.05). In terms of FFP, there was also a stastistically significant difference between the two groups (0 units transfused in mini bypass group vs 3 patients receiving one unit FFP in the control group, p < 0.001). Cumulative postoperative bleeding during the ICU stay was also evaluated, yielding a significant reduction (365 +/- 495 ml mini bypass vs 825 +/- 975 ml conventional, p < 0.05).

Conclusion: Mini bypass reduces on-pump hemodilution and, therefore, donor blood usage in routine CABG patients as compared to conventional ECC circuits and can reduce postoperative bleeding as compared to a traditional system. The mini bypass system is safe in routine clinical use and can manage easily the same number of anastomoses as a traditional system and should be considered a favorable alternative to conventional ECC in all revascularization cases.