title: Adaptive force sonorheometry for assessment of whole blood coagulation.
abstract: BACKGROUND
  Viscoelastic diagnostics that monitor the hemostatic function of whole blood (WB), such as thromboelastography, have been developed with demonstrated clinical utility. By measuring the cumulative effects of all components of hemostasis, viscoelastic diagnostics have circumvented many of the challenges associated with more common tests of blood coagulation.
  
  
  METHODS
  We describe a new technology, called sonorheometry, that adaptively applies acoustic radiation force to assess coagulation function in WB. The repeatability (precision) of coagulation parameters was assessed using citrated WB samples. A reference range of coagulation parameters, along with corresponding measurements from prothrombin time (PT) and partial thromboplastin time (PTT), were obtained from WB samples of 20 healthy volunteers. In another study, sonorheometry monitored anticoagulation with heparin (0-5 IU/ml) and reversal from varied dosages of protamine (0-10 IU/ml) in heparinized WB (2 IU/ml).
  
  
  RESULTS
  Sonorheometry exhibited low CVs for parameters: clot initiation time (TC1), <7%; clot stabilization time (TC2), <6.5%; and clotting angle (theta), <3.5%. Good correlation was observed between clotting times, TC1 and TC2, and PTT (r=0.65 and 0.74 respectively; n=18). Linearity to heparin dosage was observed with average linearity r>0.98 for all coagulation parameters. We observed maximum reversal of heparin anticoagulation at protamine to heparin ratios of 1.4:1 from TC1 (P=0.6) and 1.2:1 from theta (P=0.55).
  
  
  CONCLUSIONS
  Sonorheometry is a non-contact method for precise assessment of WB coagulation.
authors.affiliation: Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: F William
authors.initials: FW
authors.lastname: Mauldin
authors.forename: Francesco
authors.initials: F
authors.lastname: Viola
authors.forename: Theresa C
authors.initials: TC
authors.lastname: Hamer
authors.forename: Eman M
authors.initials: EM
authors.lastname: Ahmed
authors.forename: Shawna B
authors.initials: SB
authors.lastname: Crawford
authors.forename: Doris M
authors.initials: DM
authors.lastname: Haverstick
authors.forename: Michael B
authors.initials: MB
authors.lastname: Lawrence
authors.forename: William F
authors.initials: WF
authors.lastname: Walker
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D008297:Male; D010314:Partial Thromboplastin Time; D011479:Protamines / Q000494:pharmacology; D011517:Prothrombin Time; D012212:Rheology / Q000295:instrumentation / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D014159:Transducers; D014465:Ultrasonics; D055682:Viscoelastic Substances / Q000737:chemistry; D014914:Whole Blood Coagulation Time; D055815:Young Adult
chemical_list: D011479:Protamines; D055682:Viscoelastic Substances; D006493:Heparin