Department of Anesthesia, Toronto General Hospital, 200 Elizabeth St., EN3-402, Toronto, ON, Canada M5G 2C4.
Anesth Analg. 2010 Jun 1;110(6):1533-40. doi: 10.1213/ANE.0b013e3181db7991. Epub 2010 Apr 30.
Coagulopathy leading to excessive blood loss is a serious complication of cardiac surgery. In this prospective cohort study, we measured patients' coagulation status before and after cardiopulmonary bypass (CPB) and examined their relationships with postoperative blood loss.
Patients undergoing complex cardiac surgery with CPB who did not have preexisting coagulopathy were eligible. Detailed clinical and coagulation data were prospectively collected on all patients. Coagulation testing was performed before and after CPB, and included measures of thrombin generation, clotting factor consumption and dilution, clot stabilization, and fibrinolysis. The associations of variables with post-CPB blood loss (estimated loss from CPB to intensive care unit admission and 24-hour chest tube drainage) were assessed with the Spearman rank correlation test and multivariable linear regression.
The median blood loss among the 101 study patients was 952 mL (interquartile range, 601-1553 mL). Variables independently associated with increasing blood loss were as follows: previous sternotomies (P = 0.01), lower pre-CPB prothrombin fragment F1 + 2 levels (measure of thrombin generation; P = 0.001), lower post-CPB platelet counts (P = 0.01), larger percent decrease in fibrinogen levels (P = 0.05), and higher post-CPB soluble fibrin monomer levels (measure of thrombin activity and clot stabilization; P < 0.0001) (model R(2) = 0.43).
In complex cardiac surgery, blood loss is directly influenced by reduced pre-CPB thrombin generation rate, increased post-CPB consumption and dilution of clotting factors, as well as inadequate post-CPB clot stabilization. This information can aid in identifying patients at high risk for excessive blood loss and testing new interventions aimed at reducing the burden of this complication. The validity and generalizability of these findings need to be assessed by other studies.
导致过度失血的凝血功能障碍是心脏手术的严重并发症。在这项前瞻性队列研究中，我们测量了体外循环（CPB）前后患者的凝血状态，并检查了它们与术后失血的关系。
纳入接受 CPB 复杂心脏手术且无预先存在凝血功能障碍的患者。所有患者均前瞻性收集详细的临床和凝血数据。在 CPB 前后进行凝血检测，包括凝血酶生成、凝血因子消耗和稀释、血凝块稳定和纤维蛋白溶解的测量。使用 Spearman 秩相关检验和多变量线性回归评估变量与 CPB 后失血（从 CPB 到重症监护病房入院和 24 小时胸腔引流管的估计失血）的相关性。
101 例研究患者的中位失血量为 952 毫升（四分位距 601-1553 毫升）。与失血增加相关的变量如下：先前的胸骨切开术（P = 0.01）、CPB 前较低的凝血酶原片段 F1 + 2 水平（凝血酶生成的测量值；P = 0.001）、CPB 后较低的血小板计数（P = 0.01）、纤维蛋白原水平下降幅度较大（P = 0.05）和 CPB 后可溶性纤维蛋白单体水平升高（凝血酶活性和血凝块稳定的测量值；P < 0.0001）（模型 R²= 0.43）。
在复杂的心脏手术中，失血直接受到 CPB 前凝血酶生成率降低、CPB 后凝血因子消耗和稀释增加以及 CPB 后血凝块稳定不足的影响。这些信息可以帮助识别高失血风险的患者，并测试旨在减少这种并发症负担的新干预措施。这些发现的有效性和普遍性需要通过其他研究来评估。
