Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques

Carter, Andrew J.; Hicks, Karen A.; Heldman, Alan W.; Resar, Jon R.; Laird, John R.; Coombs, Vicki J.; Brinker, Jeffrey A.; Blumenthal, Roger S.

doi:10.1002/(sici)1097-0304(199609)39:1<97::aid-ccd22>3.0.co;2-k

Cited by 15 publications

(10 citation statements)

References 11 publications

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“…In these studies less heparin was used with lower target ACT values. 22 , 23 The differences may either be caused by the use of low range cuvettes or by the computation algorithm which is part of the Hemochron ® Jr systems.…”

Section: Discussionmentioning

confidence: 99%

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite

et al. 2021

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Introduction: The Activated Clotting Time (ACT) is commonly used to manage anticoagulation during cardiac surgery. The aim of this study was to compare the older manually operated Hemochron® Response and the automated Hemochron® Signature Elite. Methods: In this observational study the clinically relevant differences of both devices were investigated simultaneously, using duplicate measurements, in 29 patients who underwent a Coronary Artery Bypass Grafting (CABG) or Aortic Valve Replacement (AVR) in order to determine reliability, bias, and to detect which method has the lowest variation. Blood samples were obtained from the arterial line prior to surgery, after administration of 300 IU/kg heparin, 5 minutes after initiation of cardiopulmonary bypass and successively every 30 minutes, and after protamine administration. Results: A total of 202 measurements were performed. Of these 10 measurements were out of range in the Response and 9 in the Elite. About 27 single unstable magnet errors were seen in the Response versus no measurement errors in the Elite. No statistically significant differences between the Response (p = 0.22, Wilcoxon rank) and Elite (p = 0.064) duplicates were observed. The Response values were consistently higher during heparinization than the Elite measurements (p = 0.002, repeated measurements) with an average positive bias of around 56 seconds during heparinization (Bland-Altman). Overall, the coefficient of variation (CoV) increased during heparinization. Conclusion: The Elite was more reliable, but the variation was higher for the Elite than the Response. The observed positive bias in the Response compared to the Elite could affect heparin administration during surgery making the two systems not interchangeable.

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Section: Discussionmentioning

confidence: 99%

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite

et al. 2021

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“…The measured variable in a standard aPTT test is coagulation time, and no other information is evaluated. Currently there are different methods used to measure the aPTT time, and they include the following: (a) amperometric (electrochemical) measurement, (b) optical detection of mechanical motion, , and (c) optical readout of light scattering . The volumes of plasma required vary depending on whether the instrument is portable or not.…”

Section: Resultsmentioning

confidence: 99%

Microrheological Coagulation Assay Exploiting Micromechanical Resonators

2016

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Rheological measurements in biological liquids yield insights into homeostasis and provide information on important molecular processes that affect fluidity. We present a fully automated cantilever-based method for highly precise and sensitive measurements of microliter sample volumes of human blood plasma coagulation (0.009 cP for viscosity range 0.5-3 cP and 0.0012 g/cm for density range 0.9-1.1 g/cm). Microcantilever arrays are driven by a piezoelectric element, and resonance frequencies and quality factors of sensors that change over time are evaluated. A highly accurate approximation of the hydrodynamic function is introduced that correlates resonance frequency and quality factor of cantilever beams immersed in a fluid to the viscosity and density of that fluid. The theoretical model was validated using glycerol reference solutions. We present a surface functionalization protocol that allows minimization of unspecific protein adsorption onto cantilevers. Adsorption leads to measurement distortions and incorrect estimation of the fluid parameters (viscosity and density). Two hydrophilic terminated self-assembled monolayers (SAMs) sensor surfaces are compared to a hydrophobic terminated SAM coating. As expected, the hydrophobic modified surfaces induced the highest mass adsorption and could promote conformational changes of the proteins and subsequent abnormal biological activity. Finally, the activated partial thromboplastin time (aPTT) coagulation assay was performed, and the viscosity, density, and coagulation rate of human blood plasma were measured along with the standard coagulation time. The method could extend and improve current coagulation testing.

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“…The Hemochron Jr. Signature Microcoagulation apparatus (International Technidyne, Inc.) (11) was used with the ACT-LR cuvette. The initials LR designate Low Range and the assay is automatically terminated at 400 s.…”

Section: Evaluation Of Factor Viia Function By the Activated Clottingmentioning

confidence: 99%

Response of Factor VIII and IX-Deficient Blood to Wild Type and High Membrane Affinity Mutant Factor VIIa in an In Vitro Whole Blood Clotting Assay: Possible Correlation to Clinical Outcome

Henderson¹,

Key

Christie

et al. 2002

Thromb Haemost

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SummaryA modified form of the activated whole blood clotting time was used to evaluate response of blood from hemophilia patients to factor VIIa. Repeated assays of individuals over a one-year period showed consistency for each individual and significant difference between individuals. Four hemophilia patients with inhibitors gave low response to factor VIIa in the assay and were characterized as low or moderate clinical responders to factor VIIa therapy. Another four patients with moderate to good clinical responsiveness to factor VIIa therapy showed a strong response to factor VIIa in the assay. A factor VIIa mutant with enhanced membrane affinity showed 10 to 13-fold higher activity than wild type factor VIIa. The results may justify larger studies to determine the utility of this assay for evaluation of patient responsiveness and to set factor VIIa therapy levels.

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Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques

Cited by 15 publications

References 11 publications

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite

Microrheological Coagulation Assay Exploiting Micromechanical Resonators

Response of Factor VIII and IX-Deficient Blood to Wild Type and High Membrane Affinity Mutant Factor VIIa in an In Vitro Whole Blood Clotting Assay: Possible Correlation to Clinical Outcome

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Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques

Cited by 15 publications

References 11 publications

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron® Response and Hemochron® Signature Elite

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron® Response and Hemochron® Signature Elite

Microrheological Coagulation Assay Exploiting Micromechanical Resonators

Response of Factor VIII and IX-Deficient Blood to Wild Type and High Membrane Affinity Mutant Factor VIIa in an In Vitro Whole Blood Clotting Assay: Possible Correlation to Clinical Outcome

Contact Info

Product

Resources

About

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite

Clinical monitoring of activated clotting time during cardiothoracic surgery: comparing the Hemochron^® Response and Hemochron^® Signature Elite