00:01
The other item that we need to think about
with both compliance and surface tension
is how this affects the
overall work of breathing.
00:08
So this is how much energy it
takes for a person to breathe.
00:13
To do this, we have to know that the
lungs themselves want to collapse.
00:19
So to actually breathe,
you’re going to have to
overcome the elastic force
necessary for there to be a
collapsing of the lungs.
00:29
We can use a diagram such as this
in which we have the amount of pressure
on the X-axis and volume on the Y.
00:38
We’re going to have a number of
different denotations on this graph
just to help you orient what
part we’re talking about.
00:46
So if you’re trying to
overcome elastic forces,
that is the force between A, B,
C, D, and 0, then back to A.
00:58
So that’s all of that portion that
is shaded in that kind of gray-blue.
01:06
To overcome the
non-elastic forces,
that is this particular graph
where we go from A, E, C, F, A.
01:15
So it forms that kind of nice
elliptical circle there.
01:20
The inhalation component
goes from A, E, C, B, A
where that part that’s just
on the right hand side.
01:34
Or during exhalation,
it’s A, B, C, F, A.
01:42
Why this becomes important.
01:44
If someone has a
restrictive lung disorder,
it’s harder for them to fully inflate their
lungs because of resistance in inflation.
01:55
Therefore, that person is
going to need to generate
a greater negative pressure
to fully fill the lungs.
02:02
So they are going to take more
energy to fill the lungs.
02:06
Therefore, when they
go from A, E, C, F, A,
it requires a greater pressure change
and therefore, they have to exert a lot
more effort to get in the particular air.
02:22
Obstructive disorders also have a
problem with work of breathing.
02:26
But you’ll notice for this, it really
just inflates this particular graph
because they have a problem
getting a lot of their air out.
02:34
And so they’re overcoming
a lot of resistance
so they have to push
air out of the lungs.
02:41
And that can be seen in this diagram
where you have A, E, C, D, F,
back to 0 and then A.
02:52
Where work of breathing comes in
together with the rate of breathing,
is that we’re trying to overcome
both non-elastic and elastic work.
03:02
And this creates a
total work component.
03:06
Most people’s respiratory rate is at the
area of the lowest amount of total work.
03:13
It can be seen here.
03:16
In a pathophysiological state, such as someone
that has a restrictive lung disorder,
it creates a lot
of work for them.
03:26
So if it’s hard to inflate your lungs
and taking a lot of effort to do so,
how do you avoid doing that?
Maybe just breathe
more frequently.
03:35
So someone with a
restrictive lung disorder,
oftentimes has a very
high respiratory rate,
simply because they’re trying not to work
as hard to totally inflate their lungs.