![]() ![]() Before introducing a POC test these relevant parameters should be considered when patients are under high doses of heparin.Īnother main issue of POC devices is the lack of standardization which prevents comparison of results obtained in different laboratories or operating rooms employing different devices. Some studies have reported a large bias for hemostasis POC tests mainly during CPB. This analysis can reveal both the magnitude of the differences and the bias of the method, which can be systematic (to the same degree throughout the range of measurement) or proportional (to varying degrees throughout the range of measurement). In hemostasis POC testing it is important to examine the obtained values using difference plots or Bland-Altman analysis. Therefore, when a single ACT measurement does not seem to match the patient's clinical conditions, this test should be repeated. However, the mean differences in ACT values can be significant during heparinization. Most ACT devices do not assess duplicate patient samples due mainly to the use of a fresh blood microsample with cartridges, which avoid the handling of blood. The precision and the accuracy of ACT have been investigated by studies on duplicate samples which have demonstrated a good agreement on the average. Actually, the clinical safety of POC tests in hemostasis is based on achievement of accurate and reliable results to ensure safe and appropriate patient care. In particular, comparison studies between similar tests (celite-ACT vs kaolin-ACT or bedside ACT vs bench-top ACT) and precision studies (evaluation of between-instrument and within instrument coefficient of variation - CV -) have been poorly performed. On the contrary, some apparatuses initially built to determine PT and aPTT, have been updated with ACT tests and diverse ACT methods to dose heparin and protamine administrations.ĭespite the common use in cardiac surgery, few studies have evaluated the reliability – with the criteria of precision, accuracy and validity – of POC testing in clinical conditions. Moreover, most of the POC devices, initially assigned to perform ACT test, are now able to do multiple clotting test, depending on which test tube or cartridge is selected. Several kinds of instrumentation with different detection methods (test principle) are now available with diverse equipments (bedside machines and/or bench-top apparatus) and with specific handling of samples and assay performances. Indeed, POC testing in hemostasis – especially ACT test – has rapidly developed due to both clinical and technological advances. In the last years, different studies on clinical outcome through various hemostasis POC tests and devices have been consistently performed. Monitoring of anticoagulation and transfusion therapy guidance are the main targets in cardiac surgery. Basic Perspectives of POC Testing in Hemostasis in Cardiac Surgery The purpose of this overview of hemostasis POC devices was 1) to review the old and emerging techniques used in cardiac surgery to monitor the anticoagulation by heparin, and 2) to consider whether the new POC instrumentation which assesses platelet function may be easily used in the field of cardiac surgery to predict bleeding after cardiac surgery. ![]() Assessment of hemostasis POC testing for use in cardiac surgery requires information about the devices available: the ease of employment, the clinical impact of different types of ACT and the knowledge of the advantages and disadvantages of new technologies. Now, technological advances in hemostasis bedside instrumentation or point-of-care (POC) laboratory equipment, which can rapidly assess coagulation and platelet function, facilitate these objectives. Ĭritical care physicians and cardiac surgeons are engaged to improve the quality and outcomes of care. In particular, ACT has a widespread clinical use for CPB, interventional cardiology procedures and hemodialysis. Today, ACT is performed with different automated devices which measure clotting time of native whole blood samples after contact activation. ACT has been used for many years to monitor heparin treatment specially in those conditions in which high blood concentrations (over 1 IU/mL) cannot be accurately evaluated by aPTT. ACT test, which is a modification of the Lee and White whole blood clotting time, uses an activator, either kaolin or celite to accelerate coagulation by activation of the contact pathway. The activated clotting time (ACT), described by Hattersley in 1966, has been the first bedside system employed to assess coagulation during CPB. Thus, an important issue is to rapidly monitor the degree of heparin-induced anticoagulation and its reversal. During cardiopulmonary bypass (CPB) high dose heparin is needed to prevent thrombosis of circuits used during extracorporeal circulation (ECC). ![]()
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