2015肝素抗凝治疗的临床监测.ppt

And this is what you will typically see (in an ex vivo study using patient’s on UFH)... Each red dot is a patient. Again the heparin anti-Xa results are on the X axis. The PTT time in seconds are on the Y axis. ? The blue line is the linear regression line or the line of best fit. This is not an ideal assay. They do not correlate very well for reasons weve already established. ? (Speaker’s note – the reason for the ‘bad’ correlation…the patient differences in their absorption of heparin) (Speakers note - you need to know that this is called the Brill-Edwards method and is from the paper Establishing a Therapeutic Range for Heparin Therapy. Ann Intern Med 1993;119:104-109) ? * According to the CHEST guidelines, the PTT therapeutic range is determined by correlating PTT values with an unfractionated heparin level of 0.3 to 0.7 (IU/mL). ? (To find the APTT that corresponds to those heparin concentrations)…..At 0.3, draw a line up to the linear regression line and the PTT that correlates to that is 55 seconds (in this example). ? On the upper end at 0.7, draw a line up to the linear regression line and across, you will see the PTT time in seconds that corresponds to 0.7 is 85 seconds. You have now successfully established the PTT therapeutic range of 55 - 85 seconds (in this example). (Speaker’s notes – pharmacy will base their UFH dosing nomogram on this therapeutic range) * However, according to the CHEST guidelines, the Anti-Xa therapeutic range for VTE is 0.3-0.7. (Speaker’s note – that is the vertical area shaded in purple(ish) ? ? ? ? ? ? ? * Now lets look at a few patient results (begin from Left to Right): The 1st patient circled on left has a PTT of approximately 75 seconds. This patients PTT result is therapeutic. Remember, in this example, the PTT therapeutic range is 55-85 seconds. However the Anti-Xa level is 0.2 which means the patient is actually subtherapeutic. Based on the PTT, no change is required to the heparin dosing. However this p