title: The effect of dilution on plasma coagulation kinetics determined by thrombelastography is dependent on antithrombin activity and mode of activation.
abstract: Hemodilution-associated hypercoagulability has been the focus of several investigations because significant morbidity and mortality have been associated with perioperative thrombophilia. Because most investigations implicate imbalances in procoagulant/anticoagulant activity as the etiology of hemodilution-associated hypercoagulability, we determined the effects of dilution on coagulation kinetics and clot strength with thrombelastography (TEG(R)). Control plasma (+/-celite activation) and antithrombin (AT)-deficient (<10% activity) plasma were diluted 0%, 10%, 20%, and 30% with saline. TEG(R) variables measured included time to clot initiation (reaction time, R), speed of clot propagation (angle, alpha), and clot strength (amplitude, A; or shear elastic modulus, G). Dilution of control plasma (10%-30%) resulted in a significant (P < 0.05) 16% decrease in R values, no change in alpha values, and decrease in A and G values. AT-deficient plasma had significantly smaller R values compared with control, and dilution did not change R values in AT-deficient plasma. Celite activation eliminated dilution-associated changes in R values in control plasma but resulted in linear decreases (R(2) = 0.88-0.96, P < 0.0001) in alpha, A, and G in response to dilution. Thus, our data indirectly support the concept that decreases in AT activity cause dilution-mediated hypercoagulability in plasma. Finally, celite activation permits quantification of dilution with TEG.
authors.affiliation: Department of Anesthesiology, The University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Vance G
authors.initials: VG
authors.lastname: Nielsen
authors.forename: Ralph T
authors.initials: RT
authors.lastname: Lyerly
authors.forename: William Q
authors.initials: WQ
authors.lastname: Gurley
mesh_terms: D000991:Antithrombins / Q000502:physiology*; D001777:Blood Coagulation / Q000502:physiology*; D001793:Blood Preservation; D002951:Citrates / Q000494:pharmacology; D007692:Diatomaceous Earth / Q000494:pharmacology; D004548:Elasticity; D006438:Hemodilution / Q000009:adverse effects*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010949:Plasma / Q000502:physiology; D015842:Serine Proteinase Inhibitors / Q000502:physiology*; D013916:Thrombelastography
chemical_list: D000991:Antithrombins; D002951:Citrates; D015842:Serine Proteinase Inhibitors; D007692:Diatomaceous Earth