This article explores the application of viscoelastic tests (VETs) in trauma-induced coagulopathy and trauma resuscitation. We describe the advantages of VETs over conventional coagulation tests in the trauma setting and refer to previous disciplines in which VET use has reduced blood product utilization, guided prohemostatic agents, and improved clinical outcomes such as the mortality of critically bleeding patients. We describe different VETs and provide guidance for blood component therapy and prohemostatic therapy based on specific VET parameters. Because the two most commonly used VET systems, rotational thromboelastometry and thromboelastography, use different activators and have different terminologies, this practical narrative review will directly compare and contrast these two VETs to help the clinician easily interpret either and use the interpretation to determine hemostatic integrity in the bleeding trauma patient. Finally, we anticipate the future of new viscoelastic technologies that can be used in this setting.

Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG® 5000) and rotational thromboelastometry (ROTEM® delta), have been supplanted not only by cartridge systems (TEG® 6S and ROTEM® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot®, Quantra®, and ClotPro®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.

In preclinical studies of fructose-induced NAFLD, endotoxin appears to play an important role. We retrospectively examined samples from three pediatric cohorts (1) to investigate whether endotoxemia is associated with the presence of hepatic steatosis; (2) to evaluate postprandial endotoxin levels in response to fructose beverage in an acute 24-hour feeding challenge, and (3) to determine the change of fasting endotoxin amounts in a 4-week randomized controlled trial comparing fructose to glucose beverages in NAFLD. We found that adolescents with hepatic steatosis had elevated endotoxin levels compared to obese controls and that the endotoxin level correlated with insulin resistance and several inflammatory cytokines. In a 24-hour feeding study, endotoxin levels in NAFLD adolescents increased after fructose beverages (consumed with meals) as compared to healthy children. Similarly, endotoxin was significantly increased after adolescents consumed fructose beverages for 2 weeks and remained high although not significantly at 4 weeks. In conclusion, these data provide support for the concept of low level endotoxemia contributing to pediatric NAFLD and the possible role of fructose in this process. Further studies are needed to determine if manipulation of the microbiome or other methods of endotoxin reduction would be useful as a therapy for pediatric NAFLD.

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