Comparison of activated clotting times measured using the Hemochron Jr. Signature and Medtronic ACT Plus during cardiopulmonary bypass with acute normovolemic haemodilution

Abstract

ObjectiveThis study compared the activated clotting time (ACT) measured using the Hemochron Jr. Signature (HACT) with the ACT measured using the Medtronic ACT Plus (MACT) during cardiopulmonary bypass (CPB) with acute normovolemic haemodilution (ANH) in patients undergoing cardiac surgery.MethodsThe ACT was checked at baseline with both devices after inducing anaesthesia, and 400 to 800 mL of whole blood was withdrawn to induce moderate ANH. Before initiating CPB, a 300-IU/kg bolus dose of heparin was administered to maintain the HACT at >400 s; protamine was later given to reverse the anticoagulation. The ACT was checked using both devices at baseline, during heparinisation, and after protamine administration.ResultsIn total, 106 pairs of samples from 29 patients were analysed. The ACT showed a good correlation between the two devices (r = 0.956). However, Bland–Altman analysis showed that the MACT was higher, particularly at baseline and during heparinisation. Multiple regression analysis showed that the blood glucose concentration significantly influenced the differences between the two ACT devices.ConclusionsThe HACT was lower than the MACT during CPB with ANH in patients undergoing cardiac surgery. Clinicians should be cautious when using each ACT device within generally accepted reference ACT values.

Will high-dose heparin affect blood loss and inflammatory response in patients undergoing cardiopulmonary bypass?

“…Assuming a statistical power of 80% to reach an alpha level of 5%, the needed sizing of each group would be 15 patients to discover a difference of 300 mL in blood loss between groups, considered to be a clinically significant difference. Previous studies 2,14 have shown that assuming a blood loss variability of 300 mL is reasonable. R (Version 3.5.…”

“…ACT was measured before and during CPB with high range ACT kaolin cartridges (Medtronic ACT Plus ® System). 14 Blood sampling was drawn from the patients’ arterial line or from the CPB circuit. After weaning of bypass and protamine reversal, a high-range heparinase test cartridge (Medtronic ACT Plus System) was used in addition to ACT to determine any residual heparin in the blood.…”

The Standard Point-of-Care Hemochron Jr. ACT+ Test in Monitoring Heparin Administration for Cardiopulmonary Bypass in Severe Factor XII Deficiency

“…Without aprotinin, baseline celite measurements before heparinization tend to be 10% higher than those of kaolin tests, while kaolin ACT values generally exceed those of celite-based tests during CPB (10). However, baseline ACT+ values are approximately 20% lower than those of standard celite ACT tests and this difference seems to persist during full heparinization for cardiac surgery in comparison with both kaolinand celite-activated tests (11)(12). This suggests that the combination of the three activators in the ACT+ test can initiate the intrinsic coagulation cascade more rapidly than celite or kaolin alone.…”

More Effective Anticoagulation During Non-Cardiac Arterial Procedures Using Activated Clotting Time Guided Heparin Administration

“…Because a significant variability in ACT values has been reported between different brands of ACT devices findings cannot be extrapolated on a 1:1 basis to institutions using different brands of ACT devices and different type of cartridges to perform the measurements. [25][26][27][28] For the current study we used the Hemostatis Management System Plus (HMS Plus, Medtronic Inc. ® , Minneapolis, MN, USA). Besides the ACT, the HMS Plus also estimates heparin dose and heparin dose response.…”