Background and Goal of study
Blood products are usually ordered preoperatively by cardiac surgeons in our hospital. Platelet Concentrated (PC) costs 158,938 yen (€1,195) per 20 units in Japan. (One unit of blood product is made from 200mL of human blood.) Ten to 20 units of PC are minimally transfused for aortic surgery with deep hypothermic circulatory arrest (DHCA). Additionally, PC is expired within four days. So once ordered, PC could not be cancelled and had to be transfused even if the patients’ platelet counts were more than 100,000/ µL during operation. 
The aim of this study is seeking to reduce unnecessary PC products ordering. Therefore, we investigated changes of the platelet counts, and figured out the percentage of patients during cardiac surgery if their platelet counts were ≧ 100,000/ µL in the ICU.
Material and Methods
Fifty-six patients scheduled cardiac surgeries without PC transfusion during operations were recruited and withdrew blood samples for four times which were at induction of general anaesthesia (GA), beginning of cardio-pulmonary bypass (CPB), end of CPB and admitting to the ICU. We drew changes of the platelet counts for four points and plotted the percentage of patients whose platelet counts were ≧ 100,000/ µL in the ICU. 
Result
Patients were 69  ±9 (mean ±SD) years old. Thirty-six patients underwent single valve replacement or plasty, eight underwent double valves replacement or plasty, six did both single valve and CABG, four did aortic replacement, and two CABG. The figure showed the trends of platelet counts by bar graphs and percentage of patients whose platelet counts were≧ 100,000/ µL in the ICU by grey bars. We figured out if their platelet counts were≧ 300,000/ µL at the time of GA induction, 100% of patients were ≧ 100,000/ µL in the ICU.
Discussion and Conclusion
Cardiac surgeons generally prepare PC  based on the operative methods such as aortic replacement with DHAC or redo operation without considering preoperative platelet counts. Our research might suggest unnecessary PC ordering if the patients’ platelet counts ≧ 300,000/ µL, , because 66% of Japanese usually have ≧200,000/ µL of platelet counts 2).
Reference
1）www.mhlw.go.jp/new-info/kobetu/iyaku/kenketsugo/5tekisei3b.html
2）www.jpats.org/modules/investigation/index.php?content_id=6


08 / How would platelet counts have changed during cardiac surgery with cardiopulmonary bypass, if their postoperative platelet counts were =10×104/µL?
 
