What is the preferred method for monitoring heparin therapy during cardiac surgery?

The preferred method for monitoring heparin therapy during cardiac surgery is the activated clotting time test (ACT). This test provides real-time assessment of heparin's anticoagulant effect, which is crucial during procedures where rapid anticoagulation and timely monitoring are required, such as during cardiopulmonary bypass in cardiac surgeries.

ACT measures the time it takes for a blood sample to clot after the addition of a specific activator. It allows for immediate adjustments to heparin dosing to ensure adequate anticoagulation while minimizing the risk of bleeding or thromboembolism. In the context of cardiac surgery, where precise control of anticoagulation is paramount, the ACT is particularly valued for its quick turnaround time and its ability to reflect the high levels of heparin that are administered during the procedure.

Other tests, such as APTT, PT, and TT, are less suitable for real-time monitoring during these high-stakes surgeries. APTT is often used in non-emergent situations to monitor heparin therapy but does not provide the immediate results necessary for the dynamic environment of cardiac surgery. PT primarily assesses the extrinsic pathway of coagulation and is more useful for monitoring warfarin therapy. TT evaluates the time taken for