From the Departments of Anesthesia and Critical Care and.
Obstetrics and Gynecology, University of Chicago, Chicago, Illinois.
Anesth Analg. 2020 Nov;131(5):1373-1379. doi: 10.1213/ANE.0000000000004796.
Postpartum hemorrhage is a leading cause of maternal mortality. Antifibrinolytic therapy has the potential to influence outcomes in postpartum hemorrhage, but the incidence of elevated fibrinolytic activity in postpartum hemorrhage is unknown.
We retrospectively reviewed thromboelastography (TEG) results obtained for postpartum hemorrhage from 118 deliveries at The University of Chicago. TEG results were obtained as part of our postpartum hemorrhage protocol when blood loss exceeded 500 mL after vaginal delivery or 1000 mL after cesarean delivery. Our primary outcome was the incidence of elevated fibrinolytic activity, which we predefined as clot lysis ≥3% at 30 minutes (Ly30) on kaolin TEG. Platelet-mediated clot retraction can also lead to an elevated Ly30 on kaolin TEG. Therefore, to distinguish between fibrinolysis and clot retraction, we evaluated clot lysis using functional fibrinogen TEG, which contains a platelet inhibitor. We considered a kaolin TEG Ly30 ≥3% in conjunction with a nonzero functional fibrinogen TEG Ly30 suggestive of elevated fibrinolytic activity. We also recorded quantitative blood loss, primary etiology of hemorrhage, standard laboratory measurements of coagulation, and demographic and obstetric characteristics of the study population.
The median kaolin TEG Ly30 was 0.2% (interquartile range: 0%-0.8%). Fifteen of 118 women (12.7%; 95% confidence interval, 7.9%-19.9%) had kaolin TEG Ly30 values ≥3%. Of 15 patients with elevated Ly30 values, functional fibrinogen TEG Ly30 was available for 13, of which none demonstrated detectable clot lysis.
Our observation that none of the patients in our sample with kaolin TEG Ly30 values ≥3% had a nonzero functional fibrinogen TEG Ly30 value suggests that the observed elevations in kaolin TEG Ly30 may have been secondary to platelet-mediated clot retraction as opposed to fibrinolysis. Platelet-mediated clot retraction should be distinguished from fibrinolysis when assayed using viscoelastic techniques in postpartum hemorrhage. Further research is necessary to determine the optimal methods to assess fibrinolytic activity in postpartum hemorrhage.
产后出血是产妇死亡的主要原因。抗纤维蛋白溶解疗法有可能影响产后出血的结局，但产后出血时纤维蛋白溶解活性升高的发生率尚不清楚。
我们回顾性分析了在芝加哥大学进行的 118 例分娩时获得的血栓弹力图（TEG）结果。当阴道分娩后出血量超过 500 毫升或剖宫产术后出血量超过 1000 毫升时，我们会根据产后出血方案获得 TEG 结果。我们的主要结局是纤维蛋白溶解活性升高的发生率，我们将高岭土 TEG 上 30 分钟时的凝块溶解≥3%（Ly30）定义为纤维蛋白溶解活性升高。血小板介导的凝块回缩也可导致高岭土 TEG 上的 Ly30 升高。因此，为了区分纤维蛋白溶解和凝块回缩，我们使用含有血小板抑制剂的功能性纤维蛋白原 TEG 评估凝块溶解。我们认为高岭土 TEG Ly30≥3%并结合功能性纤维蛋白原 TEG Ly30 非零提示纤维蛋白溶解活性升高。我们还记录了定量失血量、出血的主要病因、凝血的标准实验室测量以及研究人群的人口统计学和产科特征。
中位数高岭土 TEG Ly30 为 0.2%（四分位距：0%-0.8%）。118 例女性中有 15 例（12.7%；95%置信区间，7.9%-19.9%）高岭土 TEG Ly30 值≥3%。在 15 例 Ly30 值升高的患者中，有 13 例可获得功能性纤维蛋白原 TEG Ly30，其中无一例检测到凝块溶解。
我们的观察结果表明，我们样本中高岭土 TEG Ly30 值≥3%的患者中，没有一个人的功能性纤维蛋白原 TEG Ly30 值不为零，这表明观察到的高岭土 TEG Ly30 值升高可能是血小板介导的凝块回缩而不是纤维蛋白溶解所致。在产后出血中使用粘弹性技术检测时，应将血小板介导的凝块回缩与纤维蛋白溶解区分开来。需要进一步研究以确定评估产后出血中纤维蛋白溶解活性的最佳方法。
