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When I was in the Marine Corps, I participated in a specialized form of swim qualification
called the Helo Dunker. This is a simulated helicopter crash inside of a swimming pool.
So, picture like this big metal tube... There are seats, there are windows,
and you are strapped to this seat, not in full gear but you are in boots,
camis, you have a Kevlar helmet, a rubber rifle, and most importantly, blackout goggles
because they want to make your life as difficult as possible because they will then submerge you
and then they will rotate the entire structure around in the pool to disorient you and your
job is to detach yourself from the harness in the seat, pop out a window and then swim out to
safety, hopefully not drowning in the process - it's pretty intense and while that may sound
enjoyable to many of you out there and I knew plenty of guys that was enjoyable, I hated it.
I did not like that at all and that's because on one particular submersion - thing did
not go my way and water just - I blindheld vast quantities of water
and when you have blackout goggles, you're strapped to a seat and you've been spun around,
that whole situation just induced a panic response in me. I was literally drowning in that moment.
And now obviously I made it that's because there are qualified swim instructors who are
observing everything and one of them recognized me
in the situation and took me out of there and I'm obviously here to tell the tale but I will never
forget that panic, that sensation is so unique, it's so scary, and that's what I want to talk
about today because as horrifying as it actually is, it's also very fascinating to understand.
So, we're going to use the cadavers to look at the lungs, breathing, see exactly what's going
on during the drowning process. It's going to be a fun one. Let's do this.
According to the World Health Organization, drowning is the process of experiencing
a respiratory impairment from a submersion or immersion in a liquid and that's probably
the most obvious thing in the world to you. I mean, we are talking about drowning after all,
but the thing to understand is, you can survive a drowning and still say that you drowned.
If you're rescued at any time, they term that a non-fatal drowning. Then, if you die as a result
of the drowning process, then we call that a fatal drowning. So, for me, I can actually say
that I drown when I was in the helodunker but I would say that I suffered a non-fatal drowning.
Let's quickly discuss some risk factors associated with drowning because some of them might actually
surprise you. So, the first one I want to talk about is age and the younger you are,
the more likely you are to drown. We find worldwide under the age of 15, a high
risk of drowning. Now, if you're a one year old, you're obviously going to have a higher
risk than say a 12 year old but still simply being under the age of 15, higher risk overall.
Males are going to be more like to drown and we find this is likely
because males tend to take bigger risks than females do on average.
Maybe he jumps off a cliff or something, maybe they're drinking around like say in a boat or
something along those lines. Again, it's not that females don't drown it's just that males
are more likely to drown than females. Not being able to swim - this one's probably
super obvious to you is a pretty big risk factor but what's interesting to me
is that most drownings tend to occur in fresh of water. So, that's lakes and rivers.
We do find drownings occur in swimming pools and in oceans but by far,
they actually happen in fresh bodies of water.
Epilepsy - Um, picture this - Uh you're in a bathtub and you have a seizure,
that's obviously a very, very dangerous situation.
Intoxication like I just already mentioned is a big factor but that can happen for males and
females but being intoxicated around water is never a good thing. I mean people have drowned
in bathtubs. They drown in potholes, they've drowned in toilet bowls, believe it or not.
So, I hope I'm not surprising anybody by by saying that drinking and being around bodies of water,
not the best combination and then the last one is actually exhaustion. This I mean,
you could be a very good swimmer but you're in a very bad scenario
and if you're too tired, you are going to go through this drowning process.
You are now looking at a right human lung and I want to quickly mention that this is
a healthy lung. I know a lot of people see this darkened color here and assume that maybe this
was a smoker's lungs or unhealthy lungs in general but these are healthy looking lungs.
This darkened color here, these are blood vessels and this is exactly what you would expect to see.
These lungs are pink, there's also some dark purple on the back side - again,
this is exactly what you'd want to see, so these are very healthy looking lungs,
but the lungs are going to be squishy. So, that's because it's made of elastic
tissue so it can expand so it feels very similar to a sponge. But then attached
to it is going to be this long tube here that we call the trachea or the windpipe.
Now, this is just a transport tube if I can get this into focus.
This is just a transport tube and it's just transporting air to and from the lungs
and then up top, we have the larynx or the voice box. Now, if I can turn this around,
this is pretty cool and you can see this awesome cross section of the larynx.
Now, I did an entire video all about laryngial anatomy, so you should go check that out after
this video, but what I want to do right now just briefly discuss breathing and how it works. Now,
actually, Jonathan made an entire video on breathing itself that you should also go
check out after this video. So, this will be a real quick and easy version of it
but when you breathe in, I mean, obviously, it's going to go through the mouth and the throat.
It's going to then go through the larynx and it's going to go pass down the air,
the oxygen that is coming in and then it's going to go down - See if I can turn this around and you
can see the inside of the trachea. It's not all that exciting to look at 'cuz it's just a hollow
tube in there air is going to go down until it gets to the lungs and that's where the trachea,
as you can see, as we look at this medial surface here, the trachea begins to branch and it branches
a lot and this branching is just going to fill up the entirety of the lungs.
So it's just going to branch and branch and branch until it becomes microscopic.
These little tiny air sacs at the end of all the branching
are called alveoli, and alveoli are going to be surrounded by blood vessels, tiny little vessels
called capillaries and this is where you're going to have oxygen go into the bloodstream.
It's going to diffuse into the bloodstream attached to hemoglobin and then just - which
are on the red blood cells and then go out through the entire body. At the same time carbon dioxide
will then leave the bloodstream and go into that respiratory tract and then just do the exact
opposite trip that oxygen just took. It's going to then get exhaled going up and out.
But we - this is actually pretty important... We need discuss this real quick, the fact
that oxygen is used by cells to make energy. It's extremely important. At the same time,
cells produce carbon dioxide. That's a waste product. It is very important to
get carbon dioxide out of the body, out of the bloodstream and if you don't, there are
going to be some pretty intense consequences and that's exactly what we're about to see.
Now, the whole drowning process can be said to occur in four stages. Now,
you could subdivide those stages even - to even more stages but I think four is be just enough
but it's important to understand that all four of those stages typically happen within just
seconds to minutes. It's a very quick process.
Now, it can be much more prolonged. Let's say you're swimming and drowning in very,
very, very cold water and then you begin to suffer from hypothermia. In that instance,
blood is going to start draining from your appendages, like your arms and your legs
in order to keep your core and your brain warm and give them oxygen.
That means you are going to consume overall less oxygen, because not a lot is going to your
muscles. So that can actually prolong the drowning experience, but I think it's probably best for us
to assume that this entire process is going to be happening within just a few minutes at most.
In the first stage of drowning, there is going to be a voluntary breath hold and you
are going to hold that breath for as long as you possibly can until the urge to breathe completely
overwhelms you. I mean, this one's probably going to make a lot of sense, right? It's like,
you're swimming, you're swimming, you're drowning, you're trying to figure out the situation,
you're doing whatever you can but eventually that breath is going to start to go away, right?
The oxygen is going to get burned through and as that happens,
you're going to become more desperate. Now, to understand why you're so desperate,
there's a few terms we need to talk about first. The first one is called hypoxia. Hypoxia is when
you have low levels of oxygen inside of your blood even though you have enough blood flow to an area,
right? So, it's not like there's a tourniquet or something around there.
Now, next one is called anoxia. Anoxia is where there's a complete absence of oxygen
to the organ or tissue. That can be very, very bad because if there's no oxygen, cells can die very
quickly and you can have an irreversible permanent injury. That's going to be important coming up.
The next thing is called hypercapnia. Hypercapnia is when you have too much
or elevated levels of carbon dioxide inside of your bloodstream. Remember,
carbon dioxide is that waste product that you're supposed to be breathing out, but here you are
holding your breath so it's just accumulating inside of your blood and that can actually
have an effect on the PH level, right? Though it lowers the PH level of your bloodstream turning
it acidic. We call that respiratory acidosis. So, your blood just starts to become acidic.
But your body is not just going to let you do that, right? Say like if you were just holding
your breath at home right now which hopefully don't - you're not holding it too long, but if
you held your breath like eventually you're going to get to this point where your body's "Look,
I'm not just going to let our blood turn to acid". So what it causes is an inhalation reflex, right?
So you get to this point where you're just completely done and then it's desperately
you're going to inhale, but that's going to be pretty big problem and that's going
to lead to our second stage of drowning in a second, but just understand that as these
carbon dioxide levels are rising and rising, that's going to lead to panic and seizures.
This is that point where it's like you're realizing what's happening,
the carbon dioxide is rising, panic and seizures are coming in and so out of desperation,
the inhalation reflex kicks in and you are now the second stage of drowning.
So, you probably see what's going to happen here, right? So, as you do that and you're in water,
that water is now going to go into your respiratory tract. So, let's take a look
at the lung here. We'll go back to this larynx, get that in focus and as we turn it around, so
what you're going to see here is this little flap. This is called the epilotus and this is supposed
to block off the airways so water does not go into or food doesn't go into your respiratory tract.
But as you have that inhalation reflex it's going to open and the water is going to get
down into that larynx, but that's a problem because it doesn't want to do that. I mean,
I did an entire video actually of substances going down the wrong tube or the wrong pipe,
so you should go check that out after this video, but I'm sure you've been there.
If you've ever had water go into your respiratory tract, it immediately initiates cough reflex. So,
you're going to [Cough] to get it out but that's another problem. Here you are in the water
just [Cough] and more water is going to flood in. So, in 10% or so, around 10% of drowning victims,
they do find that they underwent what's called a laryngospasm. That is where and it's going
to be hard to tell but I'm touching with my fingers right now, the vocal cords.
The vocal cords are going to be on either side and what's going to happen is they're
going to slam shut. Again, this is about 10% or so of drowning victims.
They slam shut in an attempt to prevent more water from going down into respiratory tract.
At the same time, there could also be, I'll grab the section here again,
we'll open this up. You see those branching tubes right here? These branching tubes are
part of the bronchial tree. Those can also spasm in what's called a bronchospasm.
So, those can also slam shut in a desperate attempt
to seal off and prevent water from going down into the respiratory tract
and this is because your respiratory tract is not capable of digesting and absorbing water. So,
this is all just this pathway exist to just get it out but here you are
fully immersed in water, this is not good and this is going to lead us to the third stage.
And it's at this third stage that you've pretty much burned through
all the oxygen that was available to you and so you're no longer
in a hypoxic state. You're now moving into an annoxic state and that means
trouble. It just spells trouble for pretty much every structure and organ and tissue
in your body but it's especially troublesome for this organ right here called the brain.
Now, you're looking at a human cerebrum here. It's really awesome and amazing to look at but what I
want you to understand is that this organ which is around threeish pounds or around 1.4 kilograms,
this three-ish-pound organ consumes 20% of your daily calories. That's enormous. That's because
there are around 86 billion neurons inside of this thing all consuming oxygen to work but here
you are, you've deprived it for an extended period of time now of oxygen and now what's happening is
those 86 billion neurons are beginning to die and when they die, you're not going to get them back.
This is - at this point, you are - you are at an irreversible injury; consciousness is lost
and things are starting to shut down. The inhalation reflex completely ceases which
leads you to our fourth stage and it's at this point too much. Far too many of the neurons have
died and at this point, the brain just dies. You suffer brain death and it's completely
irreversible and at this point, we can say the individual has suffered a fatal drowning.
But remember, if you're rescued anywhere between that first and third stage, that means you
experienced a non-fatal drowning but that does not mean that you come away unscathed because
if you got to an annoxic state and depending on how long you spent in that annoxic state, that
means you're going to have suffered brain damage and that obviously can be very variable, right?
There's little brain damage and there's a lot of brain damage that you can still survive from.
So, depending on how long you're in that state, that means a lot. So,
while we can definitely say that I experienced a non-fatal drowning, I obviously didn't get
anywhere near that anorxic state. I mean, I definitely got to that second stage where I
had the cough reflex, the inhalation reflex, I definitely had aspirated water but luckily,
that swim instructor was able to get me out in time, removed the water, and I didn't suffer any
cerebral injuries. So, for that, I will forever be thankful to that swim instructor wherever you are.
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Thanks for watching everybody and I'll see you in the next video.