00:01
Hi, welcome to our video series
on impaired oxygenation.
00:06
Now, I titled this one, not all PaO2
are created equal,
because everyone
who's in nursing
needs to have an understanding
of the PaO2/FiO2 ratio. Ready?
This is gonna be really fun.
00:21
By the time
we're done with this,
I promise you,
you'll be able to apply this
in the clinical setting.
00:26
Now first, let's talk about
what PaO2 is?
I know you've probably heard
this name before,
but I want to make sure
you're really clear on what it is.
00:35
Now, I can't even talk about this
till you look at this
beautiful graphic
that I've got there for you.
00:41
You're looking at
one of the alveoli.
00:44
So we're looking at alveolus.
00:45
You see that oxygen is coming
in down from the top, right.
00:49
You'll notice that the alveoli has
direct contact with the capillary.
00:54
Now you've got some basement
membranes in there,
but that's where the magic happens.
00:59
That's where
the gas exchange happens.
01:02
So we're talking about a
normal range for a PaO2
is 80 to 100.
01:08
Now that's really important.
01:11
Okay, so make sure that one is one
that you keep revisiting,
because you'll need to know
the a normal range is 80 to 100.
01:19
But I'm going to show you
in the rest of the video
again, not all PaO2
are the same.
01:24
In fact, you can have
a normal PaO2
and really be in significant
respiratory problems.
01:31
So PaO2
actually stands for
Partial pressure of oxygen
in the...
01:38
you got it
alveoli.
01:40
Which is why we took some time
to talk about that picture
before we've been looked at this.
01:44
So we know normal level
is 80 to 100.
01:47
PaO2 means Partial pressure
of oxygen in the alveoli.
01:51
Because the pressure of oxygen
dissolved in the arterial blood
is the same thing as the number
reference we use for PaO2.
02:00
It's actually a measurement
of how well oxygen is moving
from the lungs to the blood.
02:05
Okay, so that means the alveoli.
02:09
So PaO2 gets a
pretty good example
of what's going on
in these little alveoli,
or like you see a single one here.
02:17
So it's a measurement, gives us an
actual number that we can quantify
that tells me how well
oxygen is moving
from the alveoli
into the bloodstream.
02:28
Now, these are
normal ABG values.
02:30
You know, the disclaimer
I used before all lab values.
02:34
Each and every individual lab
might have a little different
normal value.
02:39
For us, we're going to use
these values pH 7.35 to 7.45.
02:44
CO2 35 to 45.
02:47
PaO2, 80 to 100
is pretty standard.
02:51
Bicarb 22 to 26
and the Sat 95 to 100.
02:56
Whoa...
02:57
Okay, so, first thing
I want you to keep in mind,
PaO2 is partial pressure of
oxygen in the blood, right?
That's an arterial measurement.
03:07
We're talking about a pulse ox.
03:09
That's something that you either put
a clip on someone's finger,
maybe even on their nose,
on their ear,
depending on what you have.
03:16
And that reads a saturation.
03:19
This is not nearly as accurate
as a PaO2.
03:23
So if I'm a nurse
in a clinical setting,
I want you to know
the most accurate
is if you've drawn an appropriate
arterial blood gas sample
the PaO2 is a more accurate, clear,
concise, objective measurement
of what's going on in your patient's
lungs and bloodstream.
03:40
All right, when I see
a formula like this,
I get a little verklempt
because it looks
real complicated.
03:46
Here's the good news.
03:48
We don't have to do this.
03:50
Highly trained, educated people
in the lab, run this for us.
03:54
But I want you to understand
how complicated this is,
and how amazing it is
that we can measure this.
04:02
So PaO2, the partial pressure
of oxygen in the arterial blood
takes the barometric pressure.
04:09
It's represented here
by the letters PB.
04:12
Now they subtract
the water vapor pressure.
04:14
Usually it's about 47 mm Hg.
04:18
Next, we've got the fractional
concentration of inspired oxygen.
04:23
That's what you here referred to
as FiO2.
04:28
What's the next part of it?
Well, we look at the
gas exchange ratio.
04:33
None of that you need to know.
04:35
But what you do need to know
is that
we do some pretty amazing things
in our lab.
04:41
Those are highly educated,
bright people.
04:44
So when you interact with them
as a colleague,
please remember that
be kind,
respect what they do,
and you're going to get
a lot better results
for your patient.