Quote from nrs_angie
that helps alot.
but i have questions still about heparine drips and calculating them.
i don't know how much help i can be here, because we rely on a heparin drip protocol at our hospital, but i'll try. first, i've reorganized your questions to group them together by topic. i've included my website resources so you can investigate further.
(brace yourself for a mega-post.):chuckle
first, you need to realize that coumadin is associated with the pt/inr measurement, and heparin is associated with aptt measurement.
why do we use heparin? because you can get it into a patient's system fast, and because it can get out of the patient's system fast.
coumadin takes longer to act and is more difficult to control. coumadin is the long-term anticoagulation therapy, and until the pt/inr are therapeutic, you'll see the patient on heparin.
pt: prothrombin time
prothrombin time/international normalized ratio
this is soooo confusing to me.
first... i don't get when they say 2-2.5 x the normal value...
then i have also heard of a control number. where is that and how do i find it. they also say it is 1.5-2.5 x the control number or something like that.
i dont understand... are you supposed to multiply that number by 2.5 or what?
prothrombin time (pt)
[color=#003399]is the most common way to express the clotting time of blood. pt results are reported as the number of seconds the blood takes to clot when mixed with a thromboplastin reagent.
the international normalized ratio (inr)
was created by the world health organization because pt results can vary depending on the thromboplastin reagent used. the inr is a conversion unit that takes into account the different sensitivities of thromboplastins. the inr is widely accepted as the standard unit for reporting pt results.
*for oral anticoagulant monitoring following venous thromboembolism, myocardial infarction, atrial fibrillation or rheumatic heart disease: inr 2.0-3.0.
*for oral anticoagulant monitoring for those with mechanical heart valves: inr 2.5-3.5.
pt is performed to monitor oral anticoagulant therapy (coumadin) and to detect factor deficiencies of the extrinsic and common pathways.
the normal protime is determined by the laboratory each day by testing normal blood. any specimens that day are then compared to the "control" normal value. usually a normal control protime is about 11 seconds. when the protime is 22 seconds, it is said to be "twice control". generally a protime is considered to be prolonged if it is more than 1.2 times the control time.
Quote from nrs_angie
could someone tell me first... what are the normal values for each
the reference range
for prothrombin time is 7-10 seconds; the range for the inr is 0.8-1.2.
the ptt and aptt that you mention are the same test--
the aptt is used to monitor standard or unfractionated heparin but not low molecular weight heparin (lmwh) therapy.
because there are different pathways to form clots, there are different products and different tests to detect the effectiveness of anticoagulation products.
basically, coumadin's test is the pt/inr. heparin's is the aptt.
some of your confusion might lie with the fact that we test for several different clotting factors when a patient is on heparin therapy. the reason is obvious: if the patient's aptt is therapeutic, that's good. but while they're on heparin therapy, if their platelets are too low, the patient will bleed out. that's bad. even if the heparin is not the culprit.
Quote from nrs_angie
then with calculating the drip rates and raising it or lowering it.
can someone give me an example of how a drip rate is increased or lowered. please be specific... i am really confused.
thanks so much
at my hospital, we don't calculate. we follow a protocol sheet. every 6 hours, we have a ptt drawn. i can't recall offhand, but i think that if the aptt is between 50-75, it's therapeutic. higher, and we have to reduce the drip rate (with another nurse to witness the change and verify it) as well as hold the heparin for a certain period of time. if the aptt is too low, we might have to give a bolus, then increase the drip rate.
you're right. it is complicated, even with a protocol to follow. in addition, we have to have a daily pt/inr, cbc, and once the patient is therapeutic x2 aptts, we draw only a daily aptt.
also, with a patient on heparin, please make sure that the lab draws the sample from the other arm, not the one getting the heparin. it skews the results, i'm told.
i sure hope you could make sense of this, angie. if you have any more questions, feel free to ask. i might not know, but i can sure track down some interesting net resources to help you find out!