The Change of Activated Coagulation Time during Cardiac Surgery

Lee, Sang Chul; Chung, Ik Soo

Abstract

Since it's introduction by Hattersley in 1966, the acivated coagulation time(ACT) is widely used as a indicator of coagulation status of a patient during cardiac surgery. There have been many studies about the pre-heparin and post-heparin(post-protamine) ACT's, but the results vary. Comparisons of baseline ACT to postprotamine ACT revealed that there were studies which showed postprotamine ACT significantly above baseline ACT, while others were opposite. So we checked baseline ACT at three different point of time: 1) before anesthetic induction; 2) after anesthetic induction; 3) after sternotomy. We also checked postheparin and postprotamine ACT, and compared it with baseline ACTs. The postprotamine ACT showed significant increase compared with the preinduction and postinduction ACT and no significant differences between preheparin ACTs. We think that hemodilution and hypothermia might have influenced on the postprotamine ACT. It seems that baseline ACT can be measured anytime before the injection of heparin. But there are many factors which can influence the measurement of the ACT. Therefore, cares must be taken in the interpretating the result of ACT, considering the factors of ACT variability and clinical observations of blood coagulability.