做不做TEG，这是个问题

Despite numerous advances in trauma care, injuries are the leading cause of death in Americans<46 years age.1 Acute blood loss and its adverse consequences remain the main etiology of ‘‘preventable’’ deaths in these patients. As most of the deaths due to bleeding are early, prompt hemorrhage control, along with balanced resuscitation, remains the cornerstone of acute trauma care. Development of trauma-associated coagulopathy in the severely injured patients is often a major barrier to achieving effective hemostasis. The normal coagulation system depends on a delicate balance between clot formation and breakdown. Injuries typically tilt the balance in favor of clot formation at the site of injuries to stop the bleeding. However, major tissue damage, excessive blood loss, prolonged tissue hypoperfusion, and traumatic brain injury with disruption of the blood-brain barrier have all been shown to upset the normal coagulation homeostasis, resulting in development of coagulopathy.2,3 This can manifest as abnormal clot formation and/or excessive or rapid clot breakdown (fibrinolysis). Unless treated promptly, this coagulopathy leads to further bleeding. This vicious cycle can result in the development of the ‘‘lethal triad’’ of coagulopathy, acidosis, and hypothermia, which is associated with an extremely high mortality. An analysis of the traumaassociated coagulopathy suggests that it is a complicated process with numerous phenotypes. For example, depletion coagulopathy results in abnormalities of traditional coagulation parameters (international normalized ratio, partial thromboplastin time) and predicts mortality, whereas fibrinolytic coagulopathy predicts infection, end-organ failure, and mortality, without a detectable difference in international normalized ratio or partial thromboplastin time.4 There is considerable controversy about the most effective strategies for treating various types of coagulopathy, but early delivery of blood components (plasma, platelets, and packed red blood cells) in a high ratio has recently gained favor based upon data from the battlefield as well as large civilian trials.5 In addition, studies have shown that early administration of antifibrinolytic agents,6,7 and cryoprecipitate, can further improve the outcomes in severely injured patients.8

尽管在创伤照护方面取得了许多进展，但伤害是46岁以上美国人死亡的主要原因.1急性失血及其不良后果仍然是这些患者“可预防”死亡的主要病因。由于大多数因出血导致的死亡是早期的，因此迅速控制出血以及平衡复苏仍然是急性创伤照护的基石。在严重受伤的患者中发生创伤相关的凝血病通常是实现有效止血的主要障碍。正常的凝血系统取决于凝块形成和破裂之间的微妙平衡。受伤通常会使平衡倾斜，有利于在受伤部位形成凝块以止血。然而，主要的组织损伤，失血过多，组织灌注不足和创伤性脑损伤以及血脑屏障的破坏都被证明会扰乱正常的凝血稳态，从而导致凝血病的发展.2,3这表现为异常凝块形成和/或过度或快速凝块破坏（纤维蛋白溶解）。除非及时治疗，否则这种凝血病会导致进一步出血。这种恶性循环可导致凝血病，酸中毒和体温过低的“致死性三联征”的发展，这与死亡率极高有关。对创伤相关凝血病的分析表明，这是一个复杂的过程，有许多表型。例如，耗竭性凝血病导致传统凝血参数异常（国际标准化比率，部分促凝血酶原激酶时间）并预测死亡率，而纤维溶解性凝血病预测感染，终末器官衰竭和死亡率，而国际标准化比率没有可检测到的差异或关于治疗各种类型凝血病的最有效策略存在相当大的争议，但最近以高比率早期递送血液成分（血浆，血小板和包装的红细胞）最近得到了基于来自此外，研究表明早期使用抗纤维蛋白溶解剂^6,7和冷沉淀物可以进一步改善严重受伤患者的预后.8

Determining how, when, and in what doses to deliver all these products remain a challenge. Also,excessive and inappropriate delivery of these agents can be potentially harmful. Most trauma centers have developed Massive Transfusion Protocols (MTPs) to address these issues and to optimize the processes of care. However, there is considerable variability from center to center in the specifics of the MTPs. There is also no real consensus about how to adjust the doses of the different components (eg, red cells, clotting factors, plasma, platelets, antifibrinolytics) based upon the results of clotting studies that measure the various aspects of the hemostatic system. The conventional clotting studies are far from ideal, which has generated an interest in using viscoelastic tests to guide the therapy. These assays, such as thromboelastography (TEG), measure the entire life span of clot formation and lysis in real time,9 and can be performed as point-of-care tests. However, it remains unknown whether TEG-directed MTPs are actually superior to protocols that rely upon the conventional coagulation studies.

确定如何、何时以及以何种剂量提供所有这些产品仍然是一项挑战。此外，过量和不适当地递送这些制剂可能是有害的。大多数创伤中心已经制定了大规模输血协议（MTP）来解决这些问题并优化照护过程。但是，在中期计划的具体细节中，中心之间存在相当大的差异。基于测量止血系统的各个方面的凝血研究的结果，关于如何调整不同组分（例如，红细胞，凝血因子，血浆，血小板，抗纤维蛋白溶解剂）的剂量也没有真正的共识。传统的凝血研究远非理想，这引起了使用粘弹性测试来指导治疗的兴趣。这些测定，例如血栓弹性描记术（TEG），实时测量凝块形成和裂解的整个寿命⁹，并且可以作为即时检验进行。然而，仍然不知道TEG指导的MTP是否实际上优于依赖于传统凝血研究的方案。

This study by Gonzales et al is a very timely effort from a group that has been a leader in this field. Using a prospective randomized trial, they have shown that a massive transfusion protocol directed by TEG resulted in a survival benefit compared with guidance based on conventional coagulation assays. This survival benefit resulted from less hemorrhagic deaths and less early deaths. Interestingly, an MTP based on conventional tests led to a higher transfusion of plasma, platelets, and cryoprecipitate compared to TEG guidance. But, more blood product administration did not create a more robust hemostatic environment. Although the survival benefits were in the early (first 6 h) period, the survivors in the TEG-guided group had more ICU-free and ventilator-free days. In short, TEG-directed approach delivered less blood products while achieving better outcomes. This, clearly, is what we would like to see. But we must also look critically at the study protocol to determine whether the results can be generalized to a larger trauma population.

Gonzales等人的这项研究是一个非常及时的努力，来自这个领域的领导者。使用前瞻性随机试验，他们已经证明，与基于传统凝血试验的指导相比，TEG指导的大规模输血方案产生了生存益处。这种生存获益是由于出血性死亡较少和早期死亡较少。有趣的是，与TEG指导相比，基于常规测试的MTP导致更高的血浆，血小板和冷沉淀输血。但是，更多的血液制品使用并没有创造出更强大的止血环境。虽然生存益处是在早期（前6小时），但TEG指导组的幸存者有更多无ICU和无呼吸机的日子。简而言之，TEG指导的方法可以减少血液制品，同时实现更好的结果。显然，这是我们希望看到的。但我们还必须批判性地研究研究方案，以确定结果是否可以推广到更大的创伤人群。

Overall, this is a very well done study, in a very difficult patient population, that provides fairly compelling data in favor of using TEG to guide the early delivery of blood products. However, I am not entirely certain that their results can be easily reproduced in centers that do not routinely use the TEG technology. Just like any other test, best outcomes are obtained when the care providers use the test results to make appropriate decisions. The trauma community will have to be educated aboutthe proper use of TEG, and the technology will have to be widely available, to realize its full potential. Also, the development of computerized decision support algorithms that would enable the machine to interpret the results and suggest appropriate treatments would make it user friendly and decrease the chances of wrong treatments. Finally, the equipment has to be made small, portable, and cost-effective, to make it practical for small hospitals, emergency medical systems, and the military. The current machine is expensive, nonportable, difficult to maintain, and requires well-trained personnel to run. But like most technologies, as long as there is a market demand the equipment gets better and more cost-effective. In fact, a smaller point-of-care TEG machine (TEG 6 s) has just been introduced, and it is hoped that the technology will get even better in the future. In my opinion, this study should prompt all of us to review our institutional MTPs and incorporate the use of vasoelastic tests in our treatment algorithms.

总体而言，这是一项非常完善的研究，在非常困难的患者群体中，提供了相当引人注目的数据，有利于使用TEG来指导血液制品的早期使用。但是，我并不完全确定他们的结果可以在不经常使用TEG技术的中心轻松复制。就像任何其他测试一样，当照护提供者使用测试结果做出适当的决定时，可以获得最佳结果。必须对创伤社区进行有关正确使用TEG的教育，并且必须广泛提供该技术，以充分发挥其潜力。此外，开发计算机化的决策支持算法，使机器能够解释结果并建议适当的治疗，这将使用户友好，并减少错误治疗的机会。最后，必须使设备小巧，便携且具有成本效益，以使其适用于小型医院，紧急医疗系统和军队。目前的机器昂贵，不便携，难以维护，并且需要训练有素的人员来运行。但与大多数技术一样，只要有市场需求，设备就会变得更好，更具成本效益。事实上，刚刚推出了一款较小的照护点TEG机器（TEG 6），希望未来该技术能够更好。在我看来，这项研究应该促使我们所有人审查我们的机构MTP，并在我们的治疗算法中使用血管弹性测试。