Bull Brian S, Hay Karen L, Herrmann Paul C
School of Medicine, Department of Pathology and Human Anatomy, Loma Linda University, Loma Linda, CA 92350, USA.
Blood Cells Mol Dis. 2009 Nov-Dec;43(3):256-9. doi: 10.1016/j.bcmd.2009.07.002. Epub 2009 Aug 21.
A number of associations with post-bypass bleeding have been described in the accompanying paper. Herein we hypothesize that dilution is an underlying cause through a malign series of bypass-associated events. Heparinized blood behaves anomalously when diluted. Clotting times first shorten somewhat, then--as the dilution of whole blood approaches 50%--rapidly lengthen to unclottability. During cardiopulmonary bypass, low blood volume patients are at a significant risk of clotting factor dilution which will always be more severe than the level of whole blood dilution. If severe enough, this dilution may lower plasma clotting factors to a critical level and may result in excess protamine administration, secondary to overestimation of heparin. The presence of un-neutralized protamine combined with critically lowered clotting factors leads to marked coagulopathy.
随附论文中描述了许多与体外循环后出血相关的关联。在此我们假设，稀释是一系列与体外循环相关的不良事件背后的一个原因。肝素化血液在稀释时表现异常。凝血时间首先会有所缩短，然后——当全血稀释接近50%时——迅速延长至无法凝血。在体外循环期间，低血容量患者有凝血因子稀释的显著风险，这种稀释总是比全血稀释的程度更严重。如果足够严重，这种稀释可能会将血浆凝血因子降低到临界水平，并可能导致因对肝素估计过高而过量使用鱼精蛋白。未中和的鱼精蛋白与严重降低的凝血因子共同导致明显的凝血病。
