Rapid infusion of blood is needed occasionally for control massive bleeding. For rapid infusion, external pressure can be used which cause hemolysis and alteration of red blood cell. The investigators will study correlation between variable external pressure and hemolysis and deformability of red blood cell. Differ from previous study, the investigator will use scanning electron microscope for observation red blood cell.
Rapid infusion of blood is needed occasionally for control massive bleeding. For rapid infusion, external pressure can be used. The investigators will study correlation between external pressure and hemolysis and deformability of red blood cell.