PT/INR/PTT info?coumadin/heparin-

xtxrn, ASN, RN · Jul 25, 2011

OK- this is based on personal experience....my memory of all of the stuff from school is a bit foggy :).

Coumadin therapy requires PT/INR to adjust dose to get the INR into the therapeutic range for the best anticoagulation... PTs tell part of the story, but the INR (International Normalization Ratio) is usually what they use to determine if the dose is adequate. A 'high' PT/INR is different for people without Coumadin...therapeutic levels are higher than 'normal', since that's how the clotting is prevented- well, one way - it works on fibrinogen (aspirin works on platelets, Pradaxa works on thrombin, etc). A low INR means more Coumadin is needed. If the INR is over 3.0 (usually- some places use a different cut off, depending on the reason for the Coumadin), then the dose needs to be lowered (unless barely over 3.0- sometimes they watch it, and check it in another week).

How often PT/INR testing is done depends on how stable they have been, new problems (acute infections- many antibiotics make the INR go crazy high), and what the person eats (vit K rich foods decrease the INR because of the coagulating effects of vit K). It gets nutty- and is a pain in the butt to have to get labwork done all the time, and especially when it's 6 degrees outside.

The dietary issues are also a pain, since it requires consistent intake of the vit K foods, to keep things even. A LOT of medications effect the INR- if you've got a patient on a boatload of meds, the chances for interactions are virtually 100%- some increase the INR, others decrease it. Vitamin K is the antidote for very high INRs to prevent spontaneous internal bleeding (or nosebleeds, a lot of bleeding after lab or accucheks, etc).

Heparin requires PTTs to determine therapeutic doses. I used to think about P-T-T as the "pt time" or patient in the hospital, since it's seldom given outside of the hospital.... a low PTT requires more heparin, a high PTT requires lowering the dose, or if really high, protamine sulfate.

With both, people are advised to use caution when shaving, report any unusual signs of bleeding (tea colored urine, overt hematuria, any sx of GI bleed, nosebleeds, bleeding with BMs- preventing constipation is good :), weird bruising, petechiae, etc. If someone is in an accident or fall of any kind, they need to notify their MD and possibly get scanned to r/o bleeding.

There are some good new meds that help with things that Coumadin was the gold-standard for. I had to switch to Pradaxa because my INRs were horrible, while on this chemo, and even with 20mg of Coumadin per DAY, I still had an INR close to that of someone on nothing- not good (I'm on anticoags because of a hypercoagulopathy that caused multiple PEs in my R lung, to the point of putting pressure on the apex of my heart- showing cardiac ischemia; when the PEs were dealt with and my lung congestion went down, my heart went back to normal).

Low INR= need more Coumadin

High INR = need less Coumadin

Low PTT = need more heparin

High PTT= need less heparin

I hope this helps some :)

angell883RN · Jul 25, 2011

So- if one has a High ptt inr pt- then ones prone to clots? etc, potential stroke, etc? IF Im understanding at all!

To low-then bleeding potential is increased? (hence the no razors, vit K foods etc?)

xtxrn, ASN, RN · Jul 25, 2011

No- high test = higher chance to bleed

And the tests are usually done together only for baseline, or if the patient is on both heparin AND Coumadin (during transition from heparin to Coumadin, to go home)

High test = need less med

Low test = need more med :)

L8RRN · Jul 25, 2011

A "normal" INR is around 1 (if you check someone who is NOT taking any warfarin/Coumadin), so anyone on Coumadin will be considered "high". You want to maintain them within a therapeutic range which is usually maintained between 2-3 or 2.5-3.5 depending on the condition they take the med for.

Let's say a person comes in for an INR check and are at a 5. This is considered above therapeutic range. They are more likely to having bleeding complications, bruising, etc. If they are at 1.5, they are still "higher" than a "normal" INR but they are subtherapeutic because they are below their desired range of 2-3 or 2.5-3.5. Being subtherapeutic will make them more likely to develop a clot.

Hope that helps with Coumadin.

angell883RN · Jul 25, 2011

Sorry if this is a dumb question:uhoh3:- but it just doesnt seem to "click"-Yet! Lol--Ok- So thats why my pt with the INR of 1,7 was sent back from Endo-no procedure done?

1.7 is low correct? so would he have potential to clot or bleed? this is where Im getting confused- you give the coumadin to thin the blood- BUT- yet I was told to HOLD it-why? His blood is already "to" thin? he will do the endo procedure at a later date-

xtxrn, ASN, RN · Jul 25, 2011

If the person is not on Coumadin, 1.7 is high. If he's on Coumadin, 1.7 is not high enough.

But, some docs won't do tests on anyone with a higher than normal INR because the increased risk for bleeding is still there. But a 1.7 isn't that big a deal; some docs just use extra caution. They'll probably write orders to hold Coumadin before doing the test again.

:)

angell883RN · Jul 25, 2011

OK-- :yeah: THANK YOU & L8RRN for your input!! Its greatly appreciated!

Any goodies involving cardiac enzymes to share? highs/lows simply what they mean? :nurse:

xtxrn, ASN, RN · Jul 25, 2011

Cardiac enzymes aren't my thing :) There are a bunch of them, and they can get a bit complicated. Some just indicate muscle damage of things besides the heart. Others are very specific. I hated cardiac !! I'm sure someone will know :)

Esme12, ASN, BSN, RN · Jul 25, 2011

Cardiac enzymes are proteins from heart muscle cells that are released into the bloodstream when heart muscle is damaged. By measuring blood levels of cardiac enzymes, doctors can tell whether heart muscle damage has recently occurred. Therefore, measuring cardiac enzymes is often an important step in diagnosing MIs.

Current clinical practice is to measure two different cardiac enzymes when an MI is suspected: creatine kinase (CK), and troponin (T). CK is released into the bloodstream 4 to 6 hours after heart cell damage occurs, and peak blood levels of CK are seen after 24 hours. Elevated CK levels usually, but not always, indicate heart muscle damage. CK levels sometimes can be increased with damage to other kinds of cells as well. T is released into the bloodstream 2 to 6 hours after heart cell damage, and blood levels peak in 12 to 26 hours. Elevated levels of T are regarded as a more reliable indicator of heart muscle damage than elevated CK levels. Because T is an "earlier" marker of cardiac cell damage than CK, and because it is somewhat more accurate at indicating heart cell damage than CK, T is the preferred marker today for diagnosing MI.

Although not usualy quoting wikipedia this was an accurate and simple explanation of cardiac enzymes

et al http://en.wikipedia.org/wiki/Cardiac_marker

I hope this helps....

xtxrn, ASN, RN · Jul 25, 2011

But aren't some levels of CK indicative of other types of muscle damage? When I've had them done, I had some elevation in a couple of the cardiac enzymes, and my heart was fine..... :)

Lab handbooks are great for this kind of stuff :)

Altra, BSN, RN · Jul 25, 2011

What resources have you used to learn these concepts in the past - e.g., when you were studying for your med-surg certification test? Or throughout your six years of med-surg, emergency, ortho and oncology experience?