Okay, now, unfractionated
heparin is a pretty old friend.
It's been around forever.
It's a really big polymer and
it has a negative charge.
It can't cross membranes and that's
why we have to give it SubQ or IV.
So, for this medication, make
sure you write, "No oral," right?
Can't be given orally.
It has to be given SubQ or IV.
Now, heparin suppresses coagulation
because it helps that antithrombin.
An antithrombin is against thrombin.
And antithrombin inactivates
thrombin and factor Xa.
Remember the lab work, one of the things that we
can do for heparin is aPTT and a factor Xa level.
So, this medication slows
down coagulation, right,
by assuring that it can help that antithrombin,
so that's a big helper.
So, heparin is a helper to antithrombin.
Now, factor Xa normally converts
prothrombin into thrombin, cool.
So, if this helps factor Xa, then we'll have
more prothrombin turned into thrombin.
Remember, thrombin is what
promotes that platelet activation.
It helps that clumping.
So factor Xa is really important
because it helps thrombin do its job.
Now, there's lots of words there after thrombin.
Stop, for just a moment, and make sure that's
very clear to you what thrombin does,
and rewrite that in your own words in your notes.
With heparin, the lab tests that we do, the
little a, the PTT monitoring, so the aPTT.
That's the test that's used for
unfractionated heparin, right?
It's an activated partial thromboplastin time.
Now, you remember that because you
think back, how does heparin work?
Remember, it suppresses coagulation
by assisting antithrombin,
that inactivates thrombin and factor Xa.
So, that would make sense that we would do
an activated partial thromboplastin time.
So that test should be easy for you to remember.
The normal value's up to 40 seconds.
It is important that you know the normal
values of all the important lab work, right?
So, the normal value --
Does anyone know the normal value for PT?
And when we put you on medications,
we want that to be elevated.
Same thing applies here for heparin.
If a normal value is 40, and we place you on
heparin, we want that value to be higher.
That's what we're looking for.
Usually, it's 1.5-2 times normal.
Now, I did the math for you because sometimes
when you're studying pharmacology,
it's just like, "Oh, do it for me."
So there you go.
The therapeutic target is 60-80 seconds.
Normal is 40, but if I have you on heparin,
I have you on heparin for a reason.
So I want it to be 1.5-2 times normal, roughly, so 60-80.
So let's walk through how that looks as a nurse.
If I have a patient on unfractionated heparin,
and I know that the healthcare provider
is shooting for 1.5-2 times normal.
When I get lab work back and
it's 73, how do I evaluate it?
Is it therapeutic?
Yes, it's within 1.5-2 times.
The healthcare provider has communicated
to me that's what they're shooting for.
Everything is good.
I can continue to give the heparin.
If the level is 45, what does that mean?
Is it therapeutic?
No, it's not.
We haven't reached that level.
So I would need to communicate with the
health care provider so they're aware.
They may want to change the dosage.
Now, what if the aPTT, the activated
partial thromboplastin time is 98?
Now, we've got a problem right?
Now they are too high, meaning
they're at risk for bleeding.
So, I'm going to stop the medication
or hold the medication,
contact the health care provider immediately
and they'll determine what the next best step is.
Okay, unfractionated heparin
is an older friend, right?
heparin is a newer discovery,
and it doesn't have as many problems,
but I want to go over a few of the
problems with unfractionated heparin.
Now, things that will affect the
bioavailabilit of heparin, that means,
how effective it is in the body, and how
much of there is, is a patient's age.
As they get older, this becomes more difficult.
If the patient is extremely overweight,
if the patient has some changes in
their heparin-binding proteins,
that's not going to be as obvious
to you as age or obesity.
But that's something that could
be an underlying problem.
If the patient has liver disease,
well, how would you know that?
It might be in their HMP, it might be in their
admission assessment when you assess them,
or you might see that in things
like their ALT lab results.
What about renal disease?
Again, it could be in any of those sources
that we talked about for liver disease.
You'll also review the patient's
BUN and creatinine lab work.
And the patient might just
have some heparin resistance.
You'll learn that as you see
that no matter what the dose is,
you have a difficult time getting
them to a therapeutic range.
Now, these are the things that might
alter the dose response to heparin.
This individual might have an increased
factor VII, or fibrinogen levels,
or they might have decreased
or they might be on some oral
Now, those are pretty specific.
And when it comes to what's going
to take up real estate in your brain,
I would focus more on underlining the words,
"aging, obesity, liver disease,
and kidney disease," okay?
Those are going to be very
common things that you see.
The next bullet point tells you about
some very specific and unusual cases.
They can affect it, but it's more of
a nice-to-know information for you.
Now, if someone already has
a prolonged aPTT, without heparin,
it's going to be real scary for them to get heparin.
This can happen in patients who have
lupus, which is an autoimmune disease,
or if somebody just has some
deficiency in these factors.
So, most important on this slide is remembering
people as they age, people that are overweight,
people that have liver
disease or kidney disease,
this is going to affect how much
heparin is available in their bodies.
Then I would look at the next
2 categories and just say,
"Hey, there's some very specialized diseases,
or some lack of factors in patients' bodies
that could also impact the use of heparin,"
but you're not going to be able to memorize
all those and keep it in the real estate.
I always like to think, think of the real
estate in your head as like high-dollar,
downtown Manhattan, New York kind of real estate,
and you have to selectively choose what's
most important to keep up there.
Now, finally, if PTT is already
heparin anti-Xa levels might be appropriate.
Okay, so this is when we talked about
that lab work, the heparin anti-Xa level.
This is another thing, another tool
that we can use to evaluate it.
If the aPPT is problematic, we can
just look at a heparin anti-Xa level.
You'll see this possibly in your practice.
Some places may be using it more than others,
but it might become more and more common.