在現今社會心血管疾病是造成國人死因的前幾名，為了改善疾病，人們開發了人工器官，如心室輔助器、人工心瓣、導管等，但心血管中會造成非生理性的流況，其流況所產生的血流應力會引發血液的破壞，特別是紅血球的損傷，稱為溶血。真實流場應包含有剪應力和拉伸應力。本研究以突縮之微細短毛細管做為實驗流場，其在進口端會產生一強烈的拉伸應力場，此流場先經由CFD的計算，求出其應力值，然後採用豬的新鮮紅血球，進行溶血的測試，以了解拉伸應力對溶血的影響。結果顯示和先前的研究結果是一致的，拉伸應力為影響紅血球破壞的主要機械力，且其閥值約為1000Pa。 Cardiovascular disease is the major leading cause of death in nowadays society. For cure the disease, people have developed artificial organs, such as ventricular assist devices, artificial heart valves,catheters. But tubing can create non-physiologic flow conditions within the cardiovascular system. The stress forces generated in these flow fields can induce blood cell damage, particularly red blood cell damage or hemolysis. However, actual flow field forces include both shear stress and extensional stress. In this study, we created a strong extensional stress flow field with the sharp contraction of a short capillary. The flow field generated at the entrance of the capillary was calculated with CFD to determine the stress values, which was followed by hemolysis experiments with porcine red blood cells to determine the effects of extensional stress on hemolysis. Our results were consistent with prior studies in that the extensional stress was the primary mechanical force involved in hemolysis with a threshold value of 1000 Pa.
