Next, let's discuss the PA catheter
placement in relationship to the heart.
The PA catheter travels down the
superior vena cava into the right atrium,
and then crosses the tricuspid valve
and goes into the right ventricle.
It takes a bend upwards and
crosses the pulmonic valve
and then terminates in
the pulmonary artery.
It's important to take note of where the
ports are in relationship to the heart.
The infusion port sits in
the superior vena cava,
the CVP port sits in the right atrium
and gives us our central venous pressure.
And the PA port sits in a
branch of the pulmonary artery
and given us our pulmonary
We've discussed our arterial line
monitoring, our central venous monitoring,
and we've talked about the
pulmonary artery catheter.
Let's talk about the pulmonary artery
catheter values that we get from it.
The first one is our central
venous pressure monitoring,
our normal value is 2-8 mmHg.
This is normal and normal people with
normal size hearts and normal vasculature.
A lot of times we like our patients
to have a CVP more to 10-12,
depending on what's going
on with the patient.
Years ago, we used to think
that this was an absolute value,
meaning if the CVP is at
8 or if the CVP is at 10,
then our patient is normal bulimic and they
do not need any more fluid resuscitation.
We're now finding that this should
be treated as a relative value,
and that we should trend
it with the patient,
meaning every patient,
their heart needs maybe a different number
of millimeters of mercury with
our central venous pressure.
Maybe some do well with an 8,
maybe some need a pressure of 10 or 12,
depending on if there RV is
a little bit more dilated.
So your central venous
pressure can also be called
your right atrial
pressure or your preload.
It's your preload because it's the pressure
going into the right side of the heart.
This can be an indication
of your fluid volume status,
and your right
So wait, we think this could be also
RV function or fluid volume status.
How do I know the difference?
Well, it can be difficult.
That's why we don't use it
as an absolute value anymore,
but rather a trending value when
it comes to fluid volume status.
If you look up and your patient
has a fluid volume status
of a CVP of 10,
15 or even 20 mmHg
that doesn't automatically
mean they're hypervolemic.
It could mean that the RV (right
ventricle) is starting to fail,
and that blood is backing
up into the right atrium.
If this is the case,
we should probably talk to the provider,
maybe get an echocardiogram to see
how that right ventricle is doing.
Now central venous pressure can be
elevated in conditions of hypervolemia,
right ventricular failure,
cardiac tamponade, chronic LV
failure and pulmonary hypertension.
anything that prevents blood flow
from traveling through
the right ventricle
through the lungs and to the
left ventricle is going to backup
and elevate our central
Central venous pressure is decreased
in conditions of hypovolemia,
vasodilation and tachycardia.
Now, in hypovolemia,
both of those are reducing
the pressure going back
into the right side or
reducing that preload.
Hypovolemia by not having enough
fluid volume in the vasculature
and vasodilation by dilating
the vasculature too much
for it to be able to
create the pressure.
CVP is decreasing tachycardia,
because the right atrium
does not have enough time for it
to fill creating that pressure.
Moving on to pulmonary
Our normal pulmonary artery
pressures is about 20/8-30/15 mmHg.
When you think of
pulmonary artery pressure,
I want you to think about
the pressure that's inside
the pulmonary artery being
the blood pressure, right.
So on our left
side of our heart,
the blood pressure is
Well, that's the pressure
that's inside the aorta.
But in our pulmonary artery
pressure 20/8-30/15 mmHg,
that's the blood pressure that's
inside the pulmonary artery.
Our first number is our
pulmonary artery systolic number
that's created when
the RV contracts.
So with this number,
I want you to think of lungs.
Any reason that it's high is
typically because of lungs,
or things that
involve the lungs.
It's elevated in pulmonary
ARDS, which is acute
respiratory distress syndrome,
or pulmonary embolism.
All of those are preventing blood
flow from going through the lungs
when that RV contracts.
The bottom number is the
pulmonary artery diastolic
which is created when the
right ventricle is at rest.
It is also called the left
ventricular in diastolic pressure,
which is kind of weird
when you think about it.
When the RV is at rest the LV is
at rest and you're in diastole,
so why is it reading
the left ventricle?
Let me show you a diagram that can maybe
clear it up just a little bit for you.
This picture here dissects
the right side of the heart
and the left side of the heart.
We have a Swan-Ganz that's
sitting in the pulmonary artery,
and it shows the
heart in diastole.
So, in diastole, both pulmonic
and/or aortic valves are closed
in our tricuspid valve and
a mitral valve is open.
So in diastole, that Swan-Ganz is
read through the pulmonary artery,
through the lungs, into the pulmonary
vein, into the left atrium,
and since that
mitral valve is open,
it's reading that pressure
into the left ventricle.
So your pulmonary
is also your left ventricular
and diastolic pressure.
So it's reading that pressure
going into the left ventricle.
Think about CVP.
Your CVP is the pressure going
back into the right side.
Your PAD is a pressure going
back into the left side.
Your pulmonary artery
diastolic number is elevated
in conditions of left ventricular failure,
mitral valve disease, cardiac tamponade,
and pulmonary embolism.
So your CVP is elevated and
right ventricular failure.
It's the same way with your PAD,
it becomes elevated when the LV
fails and pressure is backing up.
Also, mitral valve disease,
mitral valve stenosis
prevents blood flow
from going through.
And cardiac tamponade,
everything is increasing because
there's pressure on everything
from fluid outside of the heart.
And then with pulmonary
hypertension and pulmonary embolism
that's preventing blood flow from going
through the lungs at a tremendous amount,
which is elevating all of our
numbers on the right side.
Our next value is our pulmonary
artery wedge pressure.
This can also be called our
pulmonary capillary wedge pressure,
or left ventricular filling
pressure or just our wedge pressure.
All of those terms
mean the same thing.
When you inflate the balloon,
what you're doing is effectively preventing
blood flow in that branch of the lungs,
in your reading the
pressure after the lungs.
This is called your pulmonary artery wedge
pressure because you're wedging the balloon
against the vasculature
preventing blood flow.
So really, you're you're
creating that static column
and you're seeing the pressure
going into the left ventricle.
This is very common to your
pulmonary artery diastolic pressure.
This indicates fluid status,
the fluid going into the the left
side of the heart and LV function.
So with CVP, it's your fluid status
going into the right side of the heart
and could be an
indication of refunction.
Your wedge pressure is an
indication of fluid status
for your left side of the
heart and LV function.
The wedge pressure can be
elevated and mitral valve disease,
left ventricular failure,
cardiac tamponade, pericarditis,
and fluid volume overload.
Everything that causes
the PAD to increase
would also cause your
wedge pressure to increase.
So, why do we use wedge versus your
pulmonary artery diastolic pressure?
Well, technically your
wedge will be about 3 mmHg
less than your pulmonary
artery diastolic number.
So a lot of times now, physicians don't
even want us to wedge the balloon.
We'll just use the PAD
number as our wedge pressure.
But there are some conditions
where your wedge pressure
will be different than
your diastolic of your PA.
And those conditions if you have
a right bundle branch block,
severe mitral valve disease,
left ventricular compliance issues and
aortic or pulmonic valve insufficiencies.
Any of those,
you'll need to wedge the balloon
to get an accurate left
ventricular end diastolic pressure.