Welcome to another MedCram lecture.
We're going to talk about emphysema today, otherwise known as C.O.P.D.
It seems as all these diseases have abbreviations in medicine.
This one is "chronic obstructive pulmonary disease."
What is C.O.P.D.?
It's a common preventable and treatable lung disease and the typical symptoms that you'll
see in patients with emphysema C.O.P.D.
is shortness of breath, and you'll also see cough, and if it's wet you'll have sputum
as well.
These are very nonspecific symptoms, but they're very typical of what you see in C.O.P.D.
How important of a disease is this?
Couple of statistics that you should know is it's the third most common cause of death
in the US; pretty significant.
There's a number 2 and there's a number 1 above it and that's heart disease and cancer
and sometimes these, depending on how you survey, will flip spots.
There's also number 4 and number 5.
The key here is that this is the only cause of death in the United States out of these
5 that have actually gone up from about 2007 to 2010 all the others have gone down in frequency
except for this one.
This is a pretty significant disease that we've got to be concerned about.
In addition to all of this, it's also the second leading cause of disability.
Okay, so the bottom line here is that this is a very important disease to know about.
In case of course, you're wondering how much of this costs the US healthcare system in
the United States every year, the answer is about 50 B with a billion; 50 billion with
a B. That's quite a lot of money As I mentioned, C.O.P.D or emphysema is a
disease that affects the lungs.
Specifically, if you were to take a look your lungs, you of course know that your lungs
have 2 sides and that there's a major airway call the trachea and it branches off into
the right and left main-stem bronchus.
From there it just goes down to smaller and smaller branches, without getting into too
much anatomy.
If we were to take these very small bronchioles or respiratory bronchioles they would eventually
end in a grape like cluster called a alveolus.
This essentially increases the surface area.
This is what a normal respiratory bronchioles would look like.
If you were to take all these alveoli in the entire lung and spread it out it would be
about the size of a tennis court.
It's pretty big.
These bronchioles of course allow the air that you breathe in to go down and cause gas
exchange.
Now C.O.P.D.
affects 2 main areas.
It affects this bronchus, the small bronchial and it also affects the alveolus in a bad
way.
What happens, is because the elastic fibers are destroyed, we'll get into that later,
is that that airway becomes very collapsible and essentially it becomes very small, and
that's where the obstruction in C.O.P.D. comes from.
Furthermore, you're also going to get destruction of the alveoli and you lose a lot of surface
area, so instead of having a nice tennis court you end up with maybe a badminton court or
even a table tennis court here that you're working with.
The surface area becomes much smaller and all these changes happen throughout the lung,
but mostly in the upper regions of the lung.
As a result of that it's hard to get the air out.
There's an obstruction, that's the key point there is that air cannot get out of the lungs.
That's why it's called chronic obstructive pulmonary disease.
In addition to that because these alveoli are all destroyed and become areas of large
balloons if you will, the long actually increases in size and as a result of that you get these
patients with large lungs but they're full of air and they can't get the air out and
that's basically C.O.P.D..
The way that we diagnose C.O.P.D.
is based on this obstruction.
We set them down in front of a spirometer, that's basically a machine where you breathe
into it and it measures how much you breathe out.
We asked them to basically breathe out after taking a deep breath in, breathe out as much
air as they possibly can and we measure it.
This represents how much air they can blow out given enough time to blow it out, so we
give them 6 to 10 seconds to blow it out enough time that they need to blow everything that
they possibly can out in the lung.
We call that, by the way, the forced vital capacity.
Otherwise known as the FVC.
That's how much air they can blow out completely.
We said that C.O.P.D.
is an obstructive lung disease so what we're really looking for is how fast can they get
that air out, because if there's an obstruction that's going to impede their ability to get
that air out as fast as they possibly can.
The next thing that we do is that we have them do the same maneuver, but we measure
how much comes out in 1 second, so there's kind of a timed proportion to this.
How much can you blown out given an infinite amount of time?
And how much can you blow out in just 1 second?
There's a little bit of a velocity factor involved there.
What we do is, we call that by the way, the forced expiratory volume in 1 second.
This is otherwise known as the FEV1.
Then we do a very simple calculation, we measure and we see.
We take this number, the forced expiratory volume and we divide it by the forced vital
capacity number and we come up with a fraction.
This is known as the FEV1 divided by the FVC ratio.
The definition that's come up in the literature is that .70, 0.70 is the cutoff.
If the FEV1 divided by the FVC ratio is less than .70 that means that you could get less
than 70% of the air that you could normally get out, given an infinite amount of time,
out in the first second.
That means you've got obstructive lung disease.
If you can get more than .7 out that means you don't have obstructive lung disease.
The question here is, can you get out at least 70% of the air that you could normally blowout
in the first second, and if the answer is yes then you don't have obstructive lung disease.
If the answer is no and it's less than .7, then you have obstructive lung disease.
Of course, the lower this number is, the FEV1, the worse your C.O.P.D.
is going to be.
Let's review.
C.O.P.D.
is 1) common, it costs a lot; 2) it's the third leading cause of death and is the only
1 of the 5 that are actually increasing in frequency; 3) causes difficulty with breathing
out, that's obstruction; 4) reduces the cross-sectional surface area, causes drops in oxygen; 5) you
diagnose it by spirometry, and then finally 6) the diagnosis is the FEV1 divided by the
FVC is less than .7 Thank you for joining us.