Some questions about heparin/coumadin, help!

Daytonite, BSN, RN · Jan 17, 2006

question #1

what lab value is monitored to determine the correct blood level for heparin? ptt for coumadin? pt/inr what is considered therapeutic? see web links

http://labtestsonline.org/understanding/analytes/aptt/glance.html

http://www.labtestsonline.org/understanding/analytes/pt/glance.html

question #2.

if someone on either of these requires surgery or begins to bleed, how would the effects be reversed?

for heparin:

http://www.drugs.com/pdr/heparin_sodium.html

for coumadin:

http://www.drugs.com/pdr/coumadin_tablets.html#o05

both sites are the information from the pdr and include what is to be done in case of overdosage.

question #3.

what is the stated advantage of the new low-molecular weight heparins ovet the older cheaper version? not sure

me, neither.

question #4.

heparin is given prophylactically to the post-postoperative patient. what does that mean? why is it given to this group of patients?

a prophylactic dose is one given to keep the coagulation factors at a level that will

prevent

the formation of blood clots, particularly in the lungs, although a blood clot can occur in any blood vessel of the body. post-op patients who are going to be on bed rest and not moving around very much are at a greater risk of forming blood clots due to less movement. you might want to review the effects of bed rest in the formation of blood clots.

questions #5.

heparin is given therapeutically to someone who has developed dvt or to someone who is suspected of having a pulmonary embolus. what is the difference between the prophylactic and therapeutic dosages and method of administration?

a prophylactic dose is given with the focus of

preventing

something from happening.

a therapeutic dose is given with the focus of

healing

something that has already occurred.

question #6.

what is the most common medication error related to administering heparin?

check out this web site:

http://www.ismp.org/

(institute for safe medicine practices)

just do a search on the site for heparin and you will get a return of articles or reports where heparin was involved in medication errors. you can compile a list of the errors related to administering heparin from that. i don't know that there is one particular common error that is listed anywhere. some of the incidents cited at this site, however are rather interesting. i saw one report of heparin being mistaken used as kcl and another of a pre-filled heparin syringe confused with a pre-filled syringe of phenytoin.

also, check out this thread which is currently active in this same forum:

https://allnurses.com/forums/f205/can-someone-explain-ptt-aptt-inr-138282.html

CrystalClear75, BSN, RN · Jan 17, 2006

question #1
what lab value is monitored to determine the correct blood level for heparin? ptt for coumadin? pt/inr what is considered therapeutic? see web links
http://labtestsonline.org/understanding/analytes/aptt/glance.html

http://www.labtestsonline.org/understanding/analytes/pt/glance.html

question #2.
if someone on either of these requires surgery or begins to bleed, how would the effects be reversed?
for heparin:
http://www.drugs.com/pdr/heparin_sodium.html

for coumadin:
http://www.drugs.com/pdr/coumadin_tablets.html#o05

both sites are the information from the pdr and include what is to be done in case of overdosage.

question #3.
what is the stated advantage of the new low-molecular weight heparins ovet the older cheaper version? not sure
me, neither.

question #4.
heparin is given prophylactically to the post-postoperative patient. what does that mean? why is it given to this group of patients?
a prophylactic dose is one given to keep the coagulation factors at a level that will
prevent
the formation of blood clots, particularly in the lungs, although a blood clot can occur in any blood vessel of the body. post-op patients who are going to be on bed rest and not moving around very much are at a greater risk of forming blood clots due to less movement. you might want to review the effects of bed rest in the formation of blood clots.

questions #5.
heparin is given therapeutically to someone who has developed dvt or to someone who is suspected of having a pulmonary embolus. what is the difference between the prophylactic and therapeutic dosages and method of administration?
a prophylactic dose is given with the focus of
preventing
something from happening.
a therapeutic dose is given with the focus of
healing
something that has already occurred.

question #6.
what is the most common medication error related to administering heparin?
check out this web site:
http://www.ismp.org/
(institute for safe medicine practices)
just do a search on the site for heparin and you will get a return of articles or reports where heparin was involved in medication errors. you can compile a list of the errors related to administering heparin from that. i don't know that there is one particular common error that is listed anywhere. some of the incidents cited at this site, however are rather interesting. i saw one report of heparin being mistaken used as kcl and another of a pre-filled heparin syringe confused with a pre-filled syringe of phenytoin.

also, check out this thread which is currently active in this same forum:
https://allnurses.com/forums/f205/can-someone-explain-ptt-aptt-inr-138282.html

wow!!!!!!:) :) :) thanks you sooooo much!

if anyone could also explain to me in easy terms what inr is, i would appeciate it. i keep reading it and reading it in my book and it says:

inr(international normalized ratio), has been developed to measure therapeutic levels of warfarin. the inr is determined by a mathmatical equation and reflects the patient's pt compared withthe standaridized pt value.

so i guess the standardized value is the "normal" value and the patients but it doesn't specify an equation but i guess it's not that important. i'm just a tad confused.

but again thank you so much(above poster) for getting back, you don't know how much that means!!!

i'm saving this under my favorites!!!

SCmomof3, RN · Jan 21, 2006

Great info! Just a quick way our instructor taught us to keep track of which test is for which drug - count on your fingers :)

CoumadinPT = 10 fingers

HeparinPTT = 10 fingers

Hope that makes sense.

NurseKitten, MSN, RN · Jul 27, 2009

Coumadin interferes with the extrinsic clotting pathway.

Heparin interferes with the intrinsic clotting pathway.

(And you thought you'd never use all that A&P! :) )

Heparin itself it a poor anticoagulant. The value of Heparin is that it drastically increases activity of antithrombin, making it 1,000 to 10,000 times more active when Heparin is bound to it. Antithrombin binds to and inactivates thrombin(factor IIa), preventing it from splitting fibrinogen (inactivated form) into fibrin (activated form). It also IXa, Xa, XIa, XIIa.

Coumadin interferes with Vitamin K metabolism in the liver, itself. It interferes with production of factors II, VII, IX and X.

As for why low molecular weight heparin is beneficial: it has to do with distribution of drug in the body. Drugs with a molecular weight higher than 1000 have a hard time diffusing across biologic membranes. Heparin's is ~12000. LMWH's is less than 1000.

Hope that helps.

NurseKatie08, MSN · Jul 30, 2009

Coumadin interferes with the extrinsic clotting pathway.
Heparin interferes with the intrinsic clotting pathway.
(And you thought you'd never use all that A&P! :) )
Heparin itself it a poor anticoagulant. The value of Heparin is that it drastically increases activity of antithrombin, making it 1,000 to 10,000 times more active when Heparin is bound to it. Antithrombin binds to and inactivates thrombin(factor IIa), preventing it from splitting fibrinogen (inactivated form) into fibrin (activated form). It also IXa, Xa, XIa, XIIa.
Coumadin interferes with Vitamin K metabolism in the liver, itself. It interferes with production of factors II, VII, IX and X.
As for why low molecular weight heparin is beneficial: it has to do with distribution of drug in the body. Drugs with a molecular weight higher than 1000 have a hard time diffusing across biologic membranes. Heparin's is ~12000. LMWH's is less than 1000.
Hope that helps.

Also regarding why LMWH is beneficial--in situations where LMWH or Heparin is being used for post-op prophylaxis, I'd say fewer needle sticks are a benefit. When I receive post op pts to rehab on heparin, they are typically on 5,000 units SC q8h. When I receive people on Lovenox, they are typically on 30mg or 40mg SC q24h.

celclt · Aug 1, 2009

INR target for coumadin is typically 2.0-3.0. Someone who has a-fib may have a target of 1.5-2.5. A normal person's INR really has no value- it is only a test for those on coumadin. A person who is on coumadin will take 2-3 times longer to clot than a person not on it. So a bolus of lovenox/heparin to stop the clot in it's tracks from spreading( the body will absorb the clot), the coumadin is started the next day but takes several days to kick in. Once the patient has been on coumadin and stabilized at a INR of 2.0, lovenox (qd vs.bid dosing) is d/c'd and pt remains on coumadin only. Protamine sulfate reverses heparin, vit K reverses coumadin. For big bad massive clots, they will get tPA.

A concern with heparin is HIT (heparin induced thrombocytopenia- so you need to know your pt's platelet count.

I could go on and on, I had a PE in Jan and just came off of coumadin- INR stabilization was tricky d/t diet- but it is easier to change the dose than the healthy diet! Leafy greens have vit K so INR will drop,increasing clot risk.

There are a TON of drug interactions that potentiate(increase) or negate (decrease) effects of coumadin. Patients may know it as "thicken or thin your blood" , it's not really " thin" just a greater or lessened ability to clot. Your drug book will be your best friend for q's like these-- Davis' and Mosby's will both list much of the info you asked--hth!

allnurses Guide · Aug 1, 2009

I have rarely seen INR target for AF be as low as 1.5. This paper suggests 2.5 max. Valve patients often have a higher target.

http://cme.medscape.com/viewarticle/493854

We have recently stopped using lovenox to bridge low INR as we have noted an increased incidence of intracranial hemorrhage with its use. We are bringing patients back inhouse and bridging with heparin infusion instead.

NurseKitten, MSN, RN · Aug 1, 2009

Yes ma'am, I have taken care of some Lovenox-induced (at least WE think so!) ICH's. Yay for y'all!

littlenursemom · Aug 1, 2009

Re: Question 2

if a pt is on coumadin/heparin theraphy and are expected to have surgery, typically these meds are held in advanced and labs are drawn to determine their risk for bleeding.

celclt · Aug 1, 2009

I have rarely seen INR target for AF be as low as 1.5. This paper suggests 2.5 max. Valve patients often have a higher target.
http://cme.medscape.com/viewarticle/493854
We have recently stopped using lovenox to bridge low INR as we have noted an increased incidence of intracranial hemorrhage with its use. We are bringing patients back inhouse and bridging with heparin infusion instead.

I had an initial shot of lovenox then Arixtra to bridge.

allnurses Guide · Aug 2, 2009

Yes, fondaparinux is a great and under-utilized drug.

Re surgery - drugs are held, INR and aPTT checked, and patients can receive Vit K or FFP if required to reverse high INR. Because heparin has a shorter duration of action, it doesn't usually require reversal.