Respiratory Capacities (Nursing)

00:01 I want to take a moment here and walk you through what respiratory capacities are.

00:06 The first time I saw these, it was really confusing for me.

00:10 So we worked up a way that we can demonstrate this, we can illustrate it for you.

00:14 So you can see how they all relate to each other.

00:17 Now, fair warning, this is going to make sense as we walk through it of course, because we're together and we're talking through it.

00:23 But I'm going to encourage you to try to recreate a drawing that makes sense to you, you're welcome to recreate ours or you can make your own type of drawing.

00:31 But this is what it's going to take for you to really commit this concept to a high level of understanding and have it encoded well in your brain.

00:40 So you can make decisions based on it and have it accessible when you need it on your next exam.

00:45 So let's take a look at Jose as a young healthy guy, right? His total lung capacity is that first big box, and we're going to call that total lung capacity of 6.0 L.

00:57 So that big box represents 6.0 L.

01:00 We've already got that written in there for you.

01:02 So you see what we're working with.

01:04 Now, we're going to break the total lung capacity into two categories.

01:09 It's about a 50/50 split as you'll see.

01:12 So we have inspiratory capacity at about 3.0 L and functional residual capacity at 3.0 L.

01:19 So the first three concepts we're talking about Jose's total lung capacity, can be broken down to his inspiratory capacity and his functional residual capacity.

01:30 Now I want to talk about vital capacity.

01:33 Look at the components of vital capacity where we have that box.

01:37 So for vital capacity, it is all of the inspiratory capacity, plus a little bit of the functional residual capacity that gives us about 4.5 L.

01:50 Now we're going to add a lot to the right side of your screen.

01:54 First of all go all the way over to the right, the bottom line represents if there was no air in the lungs, the next line above that is the maximum expiration.

02:06 So look at that the line of maximum expiration, there's still air left in your lungs, that's what residual volume is.

02:14 The air that's left in your lungs after your maximum expiration.

02:19 Next line up is your resting volume.

02:23 And the very top line is your maximum inspiration.

02:27 Now remember, we divided those up between inspiratory capacity and functional residual capacity.

02:33 So let's start at the bottom.

02:35 So for functional residual capacity of an expiratory reserve volume of about 1.5 L and residual volume of 1.5 L, that's again, split 50/50.

02:47 Now ask yourself, how much of that remains in my lungs after maximum exploration? Right, 1.5 L your residual volume.

02:56 If everything is in a perfect world.

03:00 Now go back up to the top, the difference between the resting volume and the maximum inspiration.

03:06 That's your tidal volume of 0.5 L and inspiratory reserve volume of 2.5 L.

03:12 So I know you tracked with me because you're really sharp.

03:16 But please know that you're going to need to go back and spend some more time with his concept, just to make sure that it's encoded solidly in your mind.

03:25 So let's take a look at the respiratory capacities as far as a forced expiratory volume measurement.

03:31 Now look at what it is, right? If Jose is a young healthy fit man.

03:36 Now let's look at Jose as a older healthy fit gentleman, you'll see that his FEV1 is definitely less.

03:47 Now let's talk about peak expiratory flow rate.

03:51 Now you've got on the diagram, you can see the difference between the average for men and for women and we've told you about their body size there on the right.

03:58 These are the normal values for peak expiratory flow.

04:02 Now we often use this with asthmatic patients.

04:04 So the doctor can make decisions or the healthcare provider can make decisions on medication adjustments based on the patient's baseline PEFR.

04:14 And then what's going on, if they start to feel like they're having some trouble breathing or some difficulty.

04:19 So PEFR for men and for women, you see the normal values there.

04:25 And these would be for like a young Jose.

04:29 Now let's take a look at pulmonary function values.

04:32 Okay, I got to be honest.

04:34 When I see a chart like this, my brain kind of just glosses over.

04:37 So I want to show you how to chunk the information on this chart.

04:41 It's an easy strategy that you can use on everything.

04:44 Look at that second column, the shorter squattier one.

04:49 What are the options we have? I have an equal sign a downward arrow which means decreased or an upward arrow which means increased.

04:55 Alright, that's not rocket science.

04:57 So what I would do in my notes if I were you is I would write down the equal sign, which volumes are equal, whether you are older or younger, which volumes are relatively equal.

05:11 Ah, you see that there's one at the top, total lung capacity is usually equal.

05:19 Also we have Arterial pH and Arterial PaCO2.

05:23 Okay, so those are three measures that we see remain the same, relatively the same when you're growing older.

05:30 Now, which ones are decreased? Right, vital capacity, FEV1, PEFR and diffusing capacity, and the pulmonary arterial oxygen, the PaO2.

05:44 So the CO2 stays the same, but the PaO2 decreases.

05:50 Okay, that's the way you can chunk information.

05:53 Think through check, your comprehension.

05:55 Ask yourself, why do these stay this way? Why is this equally the same? Why would this go down? That's the best way for you to learn this content.

06:04 Just trying to memorize this chart is a horrible and ineffective way to study.

06:10 You have to do some mental gymnastics with the information so that you can keep it solid in your mind.

06:16 And one of those strategies is chunking.

06:18 Put all the equals together, put all the ups together, put all the downs together.

06:22 That's going to give you a much better way to hang on to that information and to let it stick.