Skip to main content
Journal cover image

Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass.

Publication ,  Journal Article
Welsby, IJ; McDonnell, E; El-Moalem, H; Stafford-Smith, M; Toffaletti, JG
Published in: J Clin Monit Comput
July 2002

OBJECTIVE: Our aim was to test the hypothesis that new activated clotting time (ACT) technology, with modifications to instruments and reagents designed to detect earlier clot formation, would be associated with more precise but lower results. A secondary objective was to evaluate the potential impact of any change in ACT measurement on heparin requirements during cardiopulmonary bypass (CPB). METHODS: We compared the precision of two newer ACT systems: Actalyke, Helena Laboratories, Beaumont, TX and Hemochron Response, International Technidyne Corporation, Edison, NJ and assessed their bias with reference to a standard ACT system (Hemochron 801, International Technidyne Corporation, Edison, NJ). Bland-Altman analysis was applied to 81 duplicate samples from 22 patients undergoing CPB or percutaneous coronary interventions (PCI), covering the full clinical range of ACT values. We also estimated the change in heparin dose required to use the Actalyke rather than the Hemochron 801 results, to achieve our target ACT for CPB (480 seconds), and used a mixed model to test for significance. RESULTS: The precision of the Actalyke was superior to the Hemochron Response (mean difference of duplicates +/- 0.1% versus +/- 4.2%). There was no significant bias (p = 0.93) between the results from the standard analyzers (Hemochron 801 and Response), but the results from the modified system (Actalyke) were on average 18% lower than the Hemochron 801 (p < 0.0001). Estimated heparin requirements established that fifty percent of CPB patients would have required additional heparin (5000 to 17500 units), an average increase of 1060 units per patient (p = 0.05), if the Actalyke values were used to guide anticoagulation during CPB. CONCLUSIONS: Our results support the hypothesis that the modified technology (Actalyke) is associated with more precise but lower ACT results. We estimated these lower values would lead to increased heparin dosing during CPB. The impact of this increase on bleeding after cardiac surgery with CPB is controversial and requires further study.

Duke Scholars

Published In

J Clin Monit Comput

DOI

ISSN

1387-1307

Publication Date

July 2002

Volume

17

Issue

5

Start / End Page

287 / 292

Location

Netherlands

Related Subject Headings

  • Whole Blood Coagulation Time
  • Reproducibility of Results
  • Monitoring, Physiologic
  • Humans
  • Heparin
  • Cardiopulmonary Bypass
  • Blood Coagulation Tests
  • Anticoagulants
  • Anesthesiology
  • Adult
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Welsby, I. J., McDonnell, E., El-Moalem, H., Stafford-Smith, M., & Toffaletti, J. G. (2002). Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass. J Clin Monit Comput, 17(5), 287–292. https://doi.org/10.1023/a:1021298103264
Welsby, Ian J., Elizabeth McDonnell, Habib El-Moalem, Mark Stafford-Smith, and John G. Toffaletti. “Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass.J Clin Monit Comput 17, no. 5 (July 2002): 287–92. https://doi.org/10.1023/a:1021298103264.
Welsby IJ, McDonnell E, El-Moalem H, Stafford-Smith M, Toffaletti JG. Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass. J Clin Monit Comput. 2002 Jul;17(5):287–92.
Welsby, Ian J., et al. “Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass.J Clin Monit Comput, vol. 17, no. 5, July 2002, pp. 287–92. Pubmed, doi:10.1023/a:1021298103264.
Welsby IJ, McDonnell E, El-Moalem H, Stafford-Smith M, Toffaletti JG. Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass. J Clin Monit Comput. 2002 Jul;17(5):287–292.
Journal cover image

Published In

J Clin Monit Comput

DOI

ISSN

1387-1307

Publication Date

July 2002

Volume

17

Issue

5

Start / End Page

287 / 292

Location

Netherlands

Related Subject Headings

  • Whole Blood Coagulation Time
  • Reproducibility of Results
  • Monitoring, Physiologic
  • Humans
  • Heparin
  • Cardiopulmonary Bypass
  • Blood Coagulation Tests
  • Anticoagulants
  • Anesthesiology
  • Adult