Review of PaO₂ (Nursing)

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.