![]() ![]() Burgos, Michelle Moore Lim, Hyunsoo Huynh, Monique Velis, Evelio Arocha, Marino Tirotta, Christopher F. The Journal of Extra-corporeal Technology. "Urban Myths and the ACT: What is Not True and What Really Matters When it Comesto Monitoring Anticoagulation". This page was last modified on March 30, 2010 ^ a b c > ACT This article was last reviewed on March 20, 2008.For patients on anticoagulants, the time is increased. A common reference range is between 70 and 120 seconds. For example, systems that do not pre-warm the vial or sample may see increased time to clotting because clotting times increase with temperature. Results can vary based on the equipment and methodology used. The coagulation end point can be determined by the optical (e.g., increased opacity detected by optical sensor) or mechanical properties (e.g., increased rigidity detected by the displacement of material in the vial) of the clotting blood. The sample is maintained at a specified temperature, often 37 degrees Celsius. Typically a sample of blood is put in a vial or cartridge along with coagulation activators. While the glass tube surface activated coagulation, the clotting time could be decreased with the use of other activators like celite and kaolin. It fell out of favor to monitor heparin dosing during cardiac surgery because of the dedicated time required. Previously, to monitor coagulation effects, blood was placed in a glass tube, kept at 37 degrees Celsius, and manually manipulated until the blood was no longer fluid. The ACT was first introduced by Hattersley in 1966. Clotting time measurements can be affected by drugs such as warfarin, aprotinin, and GpIIb/IIIa inhibitors, and physiologic disturbances such as hypothermia, hypervolemia, and hypovolemia. Prolongation of the ACT may indicate a deficiency in coagulation factors, thrombocytopenia, or platelet dysfunction. It is usually ordered in situations where the partial thromboplastin time (PTT) test may take an excessive amount of time to process or is not clinically useful. The clotting time is based on a relative scale and requires a baseline value for comparison due to inconsistencies between the source and formulation of the activator being used. It measures the seconds needed for whole blood to clot upon activation of the intrinsic pathway by the addition of factor XII activators. The ACT test can be used to monitor anticoagulation effects, such as from high-dose heparin before, during, and shortly after procedures that require intense anticoagulant administration, such as cardiac bypass, interventional cardiology, thrombolysis, extra-corporeal membrane oxygenation (ECMO), and continuous dialysis. Activated clotting time ( ACT), also known as activated coagulation time, is a test of coagulation. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |