It is time for us to put everything together.
Up until this point, we have clearly elucidated
the various modes of techniques and tests.
There will be few more, as we walk through,
but we are now getting into the heart of respiratory
Respiratory failure, in general, what is it?
You're focusing upon oxygen and the lack of
your body being able to properly ventilate.
Now, we have done this prior and the way that
we’ll continue with timeline becomes very
important for us. If it’s acute, well, this
is occurring within hours, which means that
you are not able to properly ventilate your
lung and nor can you properly get oxygen into
your arterial side. And by definition, when
we have respiratory failure, as I said, your
focus should be the inability to properly
oxygenate your arterial blood.
If it’s chronic, occurs over months to years.
You’re thinking about chronic diseases and
ultimately, please understand that your bicarb
will also very much be affected. By that,
we mean the following. If you have chronic
issues, then at some point, understand that
the body might actually become accustomed.
Remember from physiology. To increase levels
of carbon dioxide in a chronic time
frame. And so, therefore, clinically, at times,
what you’ll do is to then figure out that
your patient might have a chronic disease
by looking at an increase in serum bicarb
because the carbon dioxide is elevated chronically
for long periods of time. Hence, you know
that one of the things that you avoid doing
in a patient who has now become accustomed
to low oxygen tension and if you were to measure
this and then give the patient oxygen, then
please understand that the patient is going
to then further depress respiration. And so,
therefore, this then brings us to a physiological
phenomenon that you should be extremely familiar
with, known as the hypoxic drive.
Now, let’s go on and take a look at the definition
of respiratory failure. This is on the arterial
side. We’ll keep it relatively simple in
terms of its name and we'll go ahead and abbreviate.
This is PO2, but this referring to little
“a”, and that’s something that I assume
at this point you know, especially with the
suffix –emia. This will be less than 60,
compared to what is normal, which is approximately
95 to 100.
Now, there will be two different types of
respiratory failure. Type I and type II. Please
know that type I is a lot more common than
type II. If at some point, you do go into
type II respiratory failure, understand not
only is the oxygen depressed on the arterial
side, but also on the arterial side, you find
that the carbon dioxide, now, in order for
you to truly understand the significance of
45, that’s the carbon dioxide on your arterial
side is 40. So, for it to be above 45, you
know for a fact your patient has hypercapnea
or hypercarbia or it could be mixed between