- [Instructor] When we think about breathing problems
at night we can think about
the problem coming from three key areas.
The first one being a problem arising from the brain
and the brain being a key central organ that controls
the respiratory centers that help regulate the lungs.
So, the brain is really important here.
And the second one being a problem with upper airways.
So if there is any obstruction to the airways
from the mouth and the noise to the lungs
that can cause a problem.
And last but not least,
we can also have a problem with
the lungs themselves or the chest wall.
Anything that stops the lungs from being able to expand out.
So, let us take each one of these things as step by step.
And let us start by looking at the airways.
So, the main issue with the airways is that obstruction
to the airways causes a significant problem
in terms of breathing at night.
And if we consider the air that goes in through our nose
and in through our mouth reaches our lungs,
we have points at which the soft tissues around our neck
may potentially relax at night
and they may potentially block this airflow intermittently.
They may potentially cause an obstruction to this airflow.
And when they cause an obstruction to this airflow
you may notice some snoring or gasping.
And this suggests that the airflow is being stopped.
That term is,
for a lack of airflow,
it's called an apnea.
And all that apnea really means
is that there is an absence of airflow.
So, if the airways are obstructed
we can have something called
Obstructive
Sleep
Apnea.
And this condition,
Obstructive Sleep Apnea,
is actually very common.
It gets worse as people get older.
These soft tissues block this airflow that we have
and this condition actually results in a variety
of daytime and night-time symptoms.
So, we actually mentioned some
of the night-time symptoms, right?
We mentioned this kind of snoring, gasping for air,
and these kind of apneas,
these kind of pauses,
breaks in the breathing where there's a lack of airflow.
This condition also poses problems during the daytime
because during the daytime
people can feel very tired and sleepy.
And they may particularly comment
that their sleep is never refreshing,
so they wake up feeling unrefreshed.
So, that's a little bit about this Obstructive Sleep Apnea.
And the way that we diagnose it,
we do a sleep study
or a polysomnography.
And what we're looking for is
15 or more of these apneas
that not only have pauses in the breathing
but you can also demonstrate evidence of the person's
having obstruction in the airways per hour.
And that's done on the sleep study,
on the polysomnography.
So, that's a little bit about Obstructive Sleep Apnea.
That's a very important cause
of Breathing Related Sleep Disorders.
Alrighty.
So, we've got obstructed sleep apnea
but what happens if there's something that is wrong
with the actual brain?
Now, the brain is part of the central nervous system, right?
So this is actually termed something different.
This is termed Central Sleep Apnea.
So, the way that we can thing about it,
again, we have this apnea,
which is this lack of...
Complete stop in airflow.
We have sleep cause it's going to happen at night,
the breathing's going to be effected at night,
and we have central because the brain
is part of the central nervous system,
and that's where there's a malfunction
of the centers that help control breathing.
And what we're looking for here
is the presence of these apneas
but there is no obstruction.
Again, on the polysomnography
we're only looking for five or more.
These are kind of the arbitrary criteria that are used.
We're looking for five or more of these apneas per hour
to be happening during sleep.
And really when we think about the apneas
we believe that the Central Sleep Apnea,
that there's a problem with the brain's control system
for ventilation.
So basically, the parts of the brain
that help control the breathing,
they are malfunctioning.
Now, I'm just going to talk to you about a particular type
of breathing malfunction that happens
in the Central Sleep Apnea.
And I'm just going to spend a second on that.
If we consider our normal breathing to be in and out;
inhale, exhale, inhale, exhale on this graph
there's a particular type of breathing that we see sometimes
in Central Sleep Apnea and it looks something like this.
It's a crescendo-decrescendo apnea type displace.
So, let me show you.
So, we have the crescendo
decrescendo
then we have an apnea.
No breathing.
And then again it starts.
Crescendo, decrescendo,
apnea.
And it carries on like that.
And this is actually something that's called
Cheyne-Stokes Breathing.
And with this Cheyne-Stokes Breathing we believe
that this is particularly related to Central Sleep Apnea
that's as a result of heart failure,
strokes, and renal disease.
Renal failure, I should say.
Okay.
So, we talked a little bit about the brain being
a site of malfunctioning
and we talked a little bit about the airways being
a site of obstruction.
Now, finally the lungs.
The lungs need to inflate and deflate
when we breath in and out.
So, any process that stops the lungs from inflating
or deflating appropriately is going to cause us a problem.
So, when we think about the lungs we can actually have
something called Hypoventilation Disorders.
Disorders of sleep associated hypoventilation.
And when we say hypoventilation
normally when we breath in and out
we get rid of carbon dioxide
but unfortunately when we don't breath
in and out enough,
when we don't ventilate our lungs enough,
we can get a build up of carbon dioxide.
And in some cases we can also not have enough oxygen.
Now, these kind of hypoventilation problems
with our breathing can occur because there's a problem
with the lungs,
the chest wall,
if we're using some medications
that depress our respiratory function.
Like narcotic painkillers for example.
If somebody is very obese
and just the sheer amount of obesity reduces their ability
to breath in and out and ventilate their lungs.
And the problem here is that this chronically elevated
carbon dioxide poses a problem because it can actually
result in right sided heart failure.
And never mind our low oxygen
because one of the things that we know
is that our brain,
our heart,
pretty much all the organs in our body
need oxygen to function.
So, if we have a low oxygen
we're going to have problems with our brain over time,
especially chronically,
we could have a degree of cognitive impairment.
We may have problems with our heart.
Some people may develop arrhythmias,
abnormal heart rhythms.
Again, over time.
And also our blood as well.
So, we can develop polycythemia which is a very elevated
amount of red blood cells in our blood.
And this can also be a problem.
That can cause it's own huge range of complications.
So, as we can see here,
Breathing Related Sleep Disorders,
we can really break them down
into these three big categories.
Are they related to the airways?
Obstructive Sleep Apnea.
Are they related to the brain?
Central Sleep Apnea.
Or are they related to the chest wall,
the lungs,
this kind of sleep associated hypoventilation
conditions or disorders?