Now, treatment, all depends. I mean, this
could be all over the place. If your patient
is suffering from issue such as asthma or
COPD, then maybe you’re thinking about steroids.
But, if it’s pneumonia that’s resulting
in chronic type of issues, maybe it’s antibiotics
and with acute respiratory distress syndrome,
here once again, well, ventilatory
support, which is a highly hot topic for you
on the boards. Becomes important for
at least, introduce a few ventilatory
support assisted control type of modes of
respiration. You’ll see. Continue.
Options include the following. Oxygen, it’s
not really ventilatory support, so you want
to be careful here. With oxygen, remember,
if your patient is already accustomed to low
oxygen and is breathing normally, and then
all of a sudden, you introduce more oxygen,
that could be a problem. Be very careful.
Non-invasive. We’ll talk about in great
detail. These include your BiPAP or non-invasive
type of ventilator. NIV, it’s non-invasive
ventilation here. And intubation, of course,
will be your mode, we’ve talked about that
child who had respiratory muscles that then
became tired and fatigued and therefore, resulted
in retention of carbon dioxide and perhaps
the death of the child. So, we’ll talk about
endotracheal ventilation, but mechanical ventilation
Okay. Now, what are the indications for ventilatory
support? What are they? Hypoxia. PO2 of what? A 60.
Oxygen. Next, hyperbaric or hypercarbic
ventilatory support, when PCO2 is greater than 50
with the decreased pH. This means it’s
more of an acute nature. You wanna be careful
with that carbon dioxide being elevated. Not
a good thing. So this is indications for various
types of ventilatory support that we shall
walk through. Shock, major trauma, always
ventilatory support. Airway protection and
much more important than any cut-off is your
clinical impression of the patient. But, that’s
more about practice. Let’s make sure that
you are completely clear about what kind of
gas values are the cut-off point for you to
seriously start thinking about next step of management.
Now, what about these non-invasive ventilations
that you wanna be familiar with? We’ll walk
through here a few and then, we'll take a
little break from some of our modes and then
when we get into our next topic, what we’ll
do is we’re gonna hit that hard. We’ll
hit the modes especially, we’ll talk about
the terminology and what it means. But, here,
let’s first begin by laying down the foundation.
So, CPAP is something that you wanna be extremely
familiar with. It’s continuous positive
airway pressure. A positive on purpose,
because here, physiologically it’s important
for you to understand. Why? For the following
reasons. Normal breathing mechanics. Tell
me quickly, what happens to diaphragm upon
contraction when you wanna inhale? Contract,
moves downwards. Good. What’s your next
step? The pleural pressure, which is how
much? To begin with, you are at FRC. Oh, boy.
Pleural pressure was negative, approximately
negative 5. With the diaphragm contracting
and then now, the pleural pressure becomes
more negative. The more that your pleural
pressure becomes negative, what happens to
your lung? It expands. Is that clear? In the
meantime, there are a couple of things that
this then causes. So, upon let’s say
from -5 to -8, your pleural
pressure becomes negative. Do you remember
that from physio? Bring that here. Next, as
it does so, then what happens to alveoli?
Its pressure becomes negative. You’re gonna
suck in the air, like a straw. Clear?
Clear. In the meantime, what about that recoil
force? The recoil force has to then equal
that increased negative pleural pressure.
That’s just simple lung mechanics. Think
of it as being a straw sucking in all the
different things that has to occur in order
for that to happen. That’s a negative pressure
that’s doing what to alveoli? Expanding.
And that’s my point.
In physio, you know that you have to cause
a negative pressure, right, in order for your
alveoli to expand. Let’s say that the lungs
cannot. Say there is some kind of indication,
maybe it’s the PCO2 being above 50, the
PO2 being less than 60 mmHg. Maybe there’s
an indication or maybe your patient has obstructive
sleep apnoea. And at this point, you
have to get ventilatory support. This is going
to come in the way of continuous positive
airway pressure. Keep that in mind. You understand
the significance now and how different this
is than physio. You will see the consequences
Used acutely more for hypoxic failure, CHF
especially. Commonly used chronically to
stent open upper airway obstruction, especially
sleep apnea. Think of obstructive sleep apnoea,
but the only way that you can keep it open is literally
introducing positive pressure.
We’ll talk a little bit more. BiPAP is bi-level
positive airway pressure. Used acutely for
hypoxic and hypercarbic failure, very effective
in COPD. This would be the next step of management
in terms of really being able to control the
breathing of your patient.
Good evidence of support its use and how common
is immunosuppressed patient? Quite common.
So, immunocompromised, immunosuppressed patients,
let it be something like HIV, or, of course,
on immunosuppressive therapy. And you see
more and more and more of these patients,
so this becomes incredibly important for you.
This is known as BiPAP. Bi-level positive