Which Product Is Ideal for You?

Summary

Con Argument (Dr. Sappenfield)

Fixed-ratio resuscitation: a combination of red blood cells (RBCs; usually, packed RBCs), platelets, plasma (fresh frozen or liquid plasma), and adjuncts; many hospitals now use whole blood resuscitation; platelets are obtained by apheresis or pooled from blood donation; adjuncts include calcium, cryoprecipitate, factor concentrate, and tranexamic acid; fixed-ratio resuscitation aims to avoid the coagulopathy associated with administering crystalloids during resuscitation after trauma

Other uses: treatment of other coagulopathies (eg, endotheliopathy); volume resuscitation to prevent adverse outcomes of hemorrhagic shock; stabilization prior to trauma surgery — usually administered in a 1:1:1 or 2:1:1 ratio, as in the PROPPR trial; the 1:1:1 ratio provides ≈29% hematocrit, 65% coagulation factor activity, 75 to 100 mg/dL of fibrinogen, and 80,000 platelets

Limitations of viscoelastic-guided resuscitation: ITACTIC trial — compared viscoelastic resuscitation using point-of-care testing vs standard resuscitation; reported no significant difference in any measurable outcome; mortality benefit of viscoelastic resuscitation — observed in only one, low-quality meta-analysis of predominantly elective cardiac cases; delays — results may be irrelevant by the time they are received; antiplatelet or anticoagulant medication — despite their effects on bleeding, patients taking these agents may have normal viscoelastic test results; conclusions — limitations include unproven efficacy and outcomes, clinically significant delays in results, high cost, and difficulty defining meaningful thresholds for transfusion

Pro Argument (Dr. Blaine)

Viscoelastic hemostatic assays: manufacturers claim equivalence among models (controversial); measure the “stickiness” of a clot over time; as a clot forms, the wobble of the pin produces a viscoelastogram tracing that resembles a wineglass (however, cup and pin models are outdated and no longer represent the standard of care; newer models [eg, cartridge-based] provide usable data at bedside in ≤20 min); most protocols match the different aspects of the clotting cascade with segments of the wineglass shape; the stem of wineglass correlates with the time needed for thrombin generation (a long stem indicates need for replacement of plasma or clotting factors); the degree to which the lines separate indicate fibrin polymerization (small separations indicate need for more fibrin); the maximum width of the wineglass theoretically correlates with platelet count, but 20% to 30% of this represents fibrin level; as the clot dissolves, lysis is indicated by the degree to which the lines come together

Bleeding after trauma: can be related to heparinization, depletion of factor V or other clotting factors, fibrin, decreased platelets, increased fibrinolysis, degradation of the glycocalyx in traumatic endotheliopathy, hypocalcemia (seen in 85% of trauma patients), metabolic derangements, and the injury itself; one approach to correction of bleeding is use of the 1:1:1 ratio of resuscitation to approximate whole blood

Adverse effects of adopting 1:1:1 resuscitation: there is a risk of overtransfusion and overtreatment when the patients who do not require transfusion and are not coagulopathic are given blood products; since the implementation of these protocols, the amount of plasma being used has increased dramatically across the world; data from the group that suggested the 1:1:1 paradigm show increased administration of plasma has led to higher rates of, eg, transfusion-related acute lung injury (TRALI), immune issues; at the time of the study, on the basis of retrospective data, these risks were believed to be outweighed by a survival benefit; however, prospective data have not confirmed the superiority of 1:1:1 resuscitation (ie, the speaker contends that equipoise exists); a 2018 meta-analysis showing no difference in outcomes between resuscitation approaches was of low quality

Utility of viscoelastography: helpful only when there is uncertainty about the correct course of action; the greatest benefit of using this technology is reduction in the use of blood products (however, in trauma resuscitation, it is associated with greater use of platelets and cryoprecipitate); thromboelastography (TEG) has been found to be more sensitive to factors VIII and IX than to other clotting factors; among parameters provided by TEG and thromboelastometry (ROTEM), maximum amplitude (MA; from TEG) and maximum clot firmness (MCF; from ROTEM) are most useful (roughly correlate with the quantitative platelet measurement); in trauma, factor V is the most important clotting factor to monitor (drops most quickly and dramatically); bleeding occurs when the level of factor V activity falls below 30%; real-world data from trauma cases show that, with standard coagulation tests, only ≈50% of clotting time can be attributed to clotting factor levels

Analysis of data from the PROPPR trial: the speaker attempted to determine the accuracy of different coagulation tests and the cutoff value at which bleeding begins for each; international normalized ratio shows an accuracy of 64%, with a cutoff of 1.4 (however, this cutoff results in a high rate of false-positive results); activated clotting test (ACT) was among the best-performing tests, but the cutoff was within the normal range; no test has been developed for factor V; the data suggest that fibrinogen can predict coagulopathy in two-thirds of patients, with a cutoff of 121 mg/dL (plausible, because fibrinogen levels <150 mg/dL are observed to be associated with onset of bleeding)

Best applications of viscoelastography: multiple studies suggest that monitoring levels of fibrinogen and platelets is most important in trauma resuscitation; therefore, viscoelastography is optimally used to identify hypofibrinogenemia and thrombocytopenia; actual levels remain the gold standard but may not be available in a timely manner; rapid, meaningful results require use of a specialized fibrinogen assay (ie, the functional fibrinogen test with TEG, FIBTEM with ROTEM); functional fibrinogen and FIBTEM are somewhat insensitive to mild hypofibrinogenemia, but this is acceptable because more severe cases (ie, those of interest) are detected; use of these tests is the fastest way to obtain the MA or MCF (if low, platelet count is likely low as well)

Final recommendations: the speaker advocates use of viscoelastic hemostatic assays for all trauma cases, with particular attention to the MA or MCF, and addition of a fibrinogen assay to guide fibrinogen dosing