1978 Volume 9 Issue 2 Pages 219-223
Heparin is widely used as anticoagulant for prophylaxis of thromboembolism, in extracorporeal circulation, angiography etc. Since the measurement of heparin concentration in whole blood is difficult and it's effect depends on individuals, determination of appropriate heparin dose during cardiopulmonary bypass is not easy. For solution of these problems, we introduced activated coagulation time (ACT) which is reported by Hattersley in 1966. ACT is measured after mixing diatomite with whole blood. ACT is obtained more rapidly than Lee-White coagulation time. In this study, Hemochron 800, an automated instrument for detecting blood coagulation, was used. ACT obtained by Hemochron 800 is called Hemochron Time.
The study group consists of 24 patients who underwent open-hert surgery or recieved heparin therapy. Hemochron Time of non-heparinized blood ranged from 107 to 134 seconds and those of the heparinized blood with 3mg per kg ranged from 257 to 321 seconds. Before cardiopulmonary bypass, 3mg per kilogram body weight of heparin was administered intravenously, and 10mg per 200ml of ACD stored blood or 500ml of plasma expander was added in bypass circuit. Heparin was administered so as to control Hemochron Time between 300 and 400 seconds. At the end of bypass, Hemochron Time was also ued as indicator for determining protamine dose.
After introduction of this method, the amount of heparin and protamine used were decreaced. We found Hemochron time to be helpful for the management of heparinization, and protamin administration. This method has further use for clinical applications.
