Are you seeing this? Let's continue.
Other important patterns that you want to
keep in mind. You will like this. Watch. The
first one is called fixed obstruction. What
does this mean? Well, this could mean that
first and foremost, let’s begin the same
The loop spirometry, different pathologic
patterns that you are responsible for understanding.
We will begin with residual volume. Okay.
Does this-Does this even look normal? No,
it doesn’t. Actually, the both, the
bottom half and the top half look like they
are kind of sandwiched, isn’t it? It looks
like a-a burger, doesn’t it? Looks like
buns. That’s what it looks like. And that
black line in the middle, that is your piece
of bacon. I don’t know, whatever. So, the
point is they are compressed. What happened
here? There is difficulty with inspiration,
hence flattened and there is also difficulty
with expiration. What the heck kind of disease
is going to give you a fixed obstruction?
A ENT tumour. In other words, you have
perhaps dangerous, a head and neck type of
cancer. When there is a head and neck type of tumour,
cancer, this is then causing a fixed large
obstruction of both inspiration which is the
bottom half of the curve and the top half.
That is fixed. Let's move on to another
Now, first and foremost, dissect the curve,
interpret this. Where is my problem, please?
Inspiration? Exhalation? Good. Inspiration
only. You see that there is only a problem
with inspiration. Wow! What the heck kind
of problem or disease of pathology has given
me a problem with inspiration only? The problem
is extra thoracic pathology. Meaning, maybe
with the vocal cords. So, with the vocal cord
type of dysfunction or maybe perhaps fibrosis
or an upper airway mass, this is the most
tested, well, please understand, that you
are going to have a hard time inspiring. Is
that clear? So, therefore, the bottom half
of the curve has not been affected. But, you
do not have problems at getting the air out.
This is not, I repeat, anything to do
with obstructive in terms of the pulmonary
issue. Obstructive here, I wouldn’t even
use this word. I would just think of this
as being inspiratory issues.
Now, we do think about obstructive. I want
you to keep the theme of obstructive and inside
the lung. First and foremost, interpret the
curve for me. Where is my problem? Good. The
top half. What does that top half represent?
Exhalation. Interesting! Earlier discussion,
I just showed you obstructive lung disease
with scalloped type of second half of exhalation
with a left shift, meaning to say, an increase
in TLC. That was obstructive. Here, please
understand, when you have such a obstructive
pattern, that you will see at some point in
time, that this is a problem inside my lung
and this will be something like obstructive
disease, or but also, intrathoracic tumour
whereas the tumour in the first one, fixed.
Where was it? Oh, ENT. Ear, Nose, Throat.
Clear? Blocking, fixed. What was the one with
extrathoracic? That was vocal cord, problem
with inspiration only. More common than you
think, especially in health care workers.
Vocal cords often times, often times damaged.
Now, under the three main categories, take
a look at lung volumes. TLC, residual volume,
and once again, the Gold standard here
for measuring lung volume will be a body box,
plethysmography. Lung volumes used in measuring
residual volume, we talked about that spirometry
cannot, report’s out, your TLC and vital
capacity will be two big ones. Then reduced
TLC seen in what kind of disease, please?
Good. Restrictive. Elevated TLC and residual
volume will be seen in what kind of disease,
please? Good. Obstructive. We will call this