Abstract:

Objective To compare the effects of different ratios of protamine to heparin neutralizationcommonly used in cardiopulmonary bypass（CPB）on coagulation by using thromboelastography（TEG）on the basisof activated clotting time of whole blood（ACT）. Methods According to the dose ratio of protamine to initial heparin，patients were randomly divided into 0.6，0.8，1.0 and 1.3 group，with 25 cases in each group. ACT and TEG values，heparin residual rate，postoperative drainage，and protamine adverse reactions in each group were recorded andcompared. Results （1）There was no significant difference in postoperative drainage of the four groups.（2）TEGparameters of the 0.6 group showed a worsening trend after neutralization，which was statistically different fromthose of the 1.3 group.（3）The residual heparin was related to the proportion of protamine，and the residual rate inthe 0.6 group was the highest.（4）The drainage of patients with high residual heparin and that ofpatients withoutresidual in the same group indicated statistical difference. Conclusions When the ratio of protamine to heparinis ≤ 0.8，the residual rate of heparin is higher，and the bleeding risk increases accordingly.When the ratio is 1.0 or1.3，the residual rate of heparin is low，and there is no obvious damage to the coagulation function，and the risk ofbleeding is low.

Key words: TEG, protamine, heparin, coagulation