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BACKGROUND

Viscoelastic testing allows for the rapid assessment of the hemostatic properties of whole blood, measuring clot formation, strength, and breakdown.1 The most common forms of viscoelastic testing commercially available include rotational thromboelastometry (ROTEM) and thromboelastography (TEG). These tests both evaluate hemostasis in a similar fashion and with a similar graphical result, although they contain slightly different proprietary terminology. TEG has traditionally been performed by combining whole blood with reagents in an oscillating cup with a suspended pin and associated torsion wire. The new TEG 6s is a cartridge-based system with four channels, piezoelectric actuator, and paired optical detection system.2 This cartridge-based system improves ease of use and intradevice reliability.3,4 Studies have shown that TEG/ROTEM can detect hypercoagulability of pregnancy, effects of heparin, patients at risk of thrombosis, and guide transfusion in postpartum hemorrhage.5

Postpartum hemorrhage (PPH) is the leading cause of maternal mortality worldwide and the leading cause of preventable death in the United States.6 The rate of hemorrhage in the United States is 0.9% to 3.2%, and the rate of hemorrhage requiring transfusion is between 0.9% and 2.3%. Similar to transfusion in trauma, there has been an ongoing debate regarding the ideal ratio of blood product transfusion. Retrospective studies have shown a decrease in blood product usage, particularly fresh frozen plasma (FFP) and platelets, likelihood to be admitted to the intensive care unit, fewer hysterectomies, and shorter hospital length of stay in patients with severe PPH when the cases are managed with the use of viscoelastic testing.7 Another study found the use of viscoelastic testing led to reduced blood product usage and rates of transfusion-associated complications.8

The inherent advantage of viscoelastic testing likely stems from the relative importance of fibrinogen in obstetric hemorrhage. Prior studies have shown that a fibrinogen level <200 mg/dL is the only value to have a 100% positive predictive value for PPH progressing to severe hemorrhage requiring transfusion.9–11 A prior study has shown that fibrinogen measured by TEG is approximately 40 mg/dL greater than the traditional Clauss laboratory method.12 These findings are consistent with our current study showing TEG 6s functional fibrinogen level (FLEV) approximately 45 mg/dL higher and returning a result more than 30 minutes faster.13 Interestingly, recent work in TEG demonstrated that less than 15% of patients undergoing PPH had an increased rate of clot lysis.14 This and other prior work potentially point to the underlying mechanism in most PPH complicated by medical bleeding due to underutilization of fibrinogen and hemodilution rather than clot lysis.

GOALS

  • Identify coagulopathies that contribute to the progression of PPH (>1000 mL) to severe hemorrhage requiring transfusion.

  • Rapidly assess the potential contribution of medical bleeding with a point-of-care test that allows quick, actionable results, often in less than 30 minutes.

  • Manage hemorrhage with a goal-directed transfusion strategy that repletes the appropriate products while ...

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