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Abstract

Background: Measurement of the activated clotting time (ACT) represents a standard method for coagulatory assessments. The test employs specific agents to trigger the coagulation process. The present study aimed to compare kaolin (Hemotec®) versus a combination of silica, kaolin and phospholipid (Hemochron® Jr) ACTs.

Methods: Hemotec® and Hemochron® Jr ACT monitors were compared by simultaneous measurement of paired arterial blood samples (n-114) with respect to precision and bias during clinical conditions of cardio-pulmonary bypass (CPB). The influence of haemodilution on the ACT was tested in an ex-vivo model.

Results: The precision of Hemotec® and Hemochron®Jr ACT measurements attained 21±2.6 s versus 27.0±2.6 s(p= 0.126) during CPB and 2.5±2.2 s versus 9.4±6.9 s (p= 0.000) after protamine administration, respectively. The Hemochron® Jr monitor was associated with a bias of −102±13.7 s compared to the Hemotec® ACT monitor (p= 0.000) during CPB and −6.9±2.9 s after protamine (p= 0.025). Linear regression analysis of ACT readings between monitors reached r- 0.526 (p= 0.000). Hemochron® Jr ACT values correlated with the erythrocyte volume fraction r- 0.379 (p= 0.000). Ex-vivo data indicated that the Hemotec® ACT monitor was associated with relatively higher ACT readings after haemodilution.

Conclusion: The ACT is not a standardized measure. Test results are strongly associated with the specific compounds used to initiate the coagulation process.

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References

Shore Lesserson L , Gravlee GP. Anticoagulation for cardiopulmonary bypass. In Gravlee G , Davis R , Kurusz M , Utley JR eds. Cardiopulmonay bypass: principles and practice. Philadelphia, PA: Lippincott Williams & Wilkins , 2000: 435-472.

Hattersley PG. Activated coagulation time of whole blood . JAMA 1966; 196: 436-440 .

Bull BS , Huse WM , Brauer FS et al. Heparin therapy during extracorporeal circulation. II. The use of a dose - response curve to individualize heparin and protamine dosage . J Thorac Cardiovasc Surg 1975; 69: 685-689 .

Bull BS , Korpman RA , Huse WM et al. Heparin therapy during extracorporeal circulation. I. Problems inherent in existing heparin protocols . J Thorac Cardiovasc Surg 1975; 69: 674-684 .

Niinikoski J , Laato M , Laaksonen V et al. Use of activated clotting time to monitor anticoagulation during cardiac surgery . Scand J Thorac Cardiovasc Surg 1984; 18: 57-61 .

Reich DL , Zahl K , Perucho MH et al. An evaluation of two activated clotting time monitors during cardiac surgery . J Clin Monit 1992; 8: 33-36 .

Aylsworth CL , Stefan F , Woitas K et al. New technology, old standards: disparate activated clotting time measurements by the Hemochron Jr compared with the standard Hemochron . Ann Thorac Surg 2004; 77: 973-976 .

Carter AJ , Hicks K , Heldman AW et al. Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques . Cathet Cardiovasc Diagn 1996; 39: 97-102 .

Pan C-M , Jobes D , Van Riper D et al. Modified microsample ACT test for heparin monitoring . J Extra Corp Technol 1996; 28: 16-20 .

10.

Bland JM , Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement . Lancet 1986; 1: 307-310 .

11.

Hattersley PG. A semiautomated instrument for the activated coagulation time (ACT) . Am J Clin Pathol 1980; 73: 293-293 .

12.

Culliford AT , Gitel SN , Starr N et al. Lack of correlation between activated clotting time and plasma heparin during cardiopulmonary bypass . Ann Surg 1981; 193: 105-111 .

13.

Hug MI , Di Bernardo S , Berger F et al. Measurement of activated clotting time in children - comparison of the Celite i-STAT ACT with the Medtronic ACT II . Acta Anaesthesiol Scand 2004; 48: 211-217 .

14.

Wendel HP , Heller W , Gallimore MJ et al. The prolonged activated clotting time (ACT) with aprotinin depends on the type of activator used for measurement . Blood Coagul Fibrinolysis 1993; 4: 41-45 .

15.

Kmiecik SA , Liu JL , Vaadia TS et al. Quantitative evaluation of hypothermia, hyperthermia, and hemo-dilution on coagulation . J Extra Corpor Technol 2001; 33: 100-105 .

16.

Moorehead MT , Westengard JC , Bull BS. Platelet involvement in the activated coagulation time of heparinized blood . Anesth Analg 1984; 63: 394-398 .

17.

Koster A , Despotis G , Gruendel M et al. The plasma supplemented modified activated clotting time for monitoring of heparinization during cardiopulmonary bypass: a pilot investigation . Anesth Analg 2002; 95: 26-30 .

18.

Ottesen S , Frøysaker T. Use of Haemonetics Cell Saver for autotransfusion in cardiovascular surgery . Scand J Thorac Cardiovasc Surg 1982; 16: 263-268 .

19.

Ammar T , Scudder LE , Coller BS. In vitro effects of the platelet glycoprotein IIb/IIIa receptor antagonist c7E3 Fab on the activated clotting time . Circulation 1997; 95: 614-617 .

20.

Welsby IJ , McDonnell E , El-Moalem H 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 2002; 17: 287-292 .

Measurement of the activated clotting time during cardiopulmonary bypass: differences between Hemotec® ACT and Hemochron® Jr apparatus

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