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Thanks for having made it to the primer on severe brain injury at tbilaw.com. I'm Gordon
Johnson and I'm going to tell you a little bit about what our goals are on this primer
on severe brain injury.
We're first going to cover some basic definitions of things about the diagnosis that you probably
been given by the neurosurgeon. There are two really critical things for you to understand
when dealing with the questions of brain bleeds and hemorrhage. The first is that blood is
a toxic element to brain tissue if it's not inside a blood vessel. It's not where it's
supposed to be.
The second is anytime you have a brain bleed, or if even a significant hematoma or swelling,
what happens is that the brain becomes compressed by the additional amount of fluid that is
contained within the skull.
We have a model and this is something we use in the courtroom from time to time and I had
different, several different kinds, and I also have a foam rubber model of the brain.
To start in terms of understanding brain bleeds, hemorrhage and brain swelling, we should probably
take the top off of our model. This one is plastic. If we were talking more about specific
other issues, I'd probably use an actual human skull but showing but this is a plastic skull
and we can quite easily take the top off.
You can see inside of here is an actual representation of a human brain. What's different about this
brain that I contain here and the one I have in my hand is that this is a very firm, hard
object. You don't see any shimmer. In this brain, you do see the shimmer and that will
be more important when we talk about rotational injury and axonal injuries. But this brain
is actually much closer to the consistency of an actual human brain.
The key thing to understand when you're talking about bleeds, brain pressure events, is that
the skull has a certain amount of volume. It's, it's like a football or a basketball.
It can only take so much air, or perhaps even a car tire, can only take so much air. Ultimately
if you put too much air in the tire, it'll blow up. If you put too much blood inside
of the skull, if there's a bleed in the brain and the heart keeps pumping more and more
fluid into the brain but there's no release of that pressure, so there's no way to get
it out. There gets to be more and more pressure and ultimately that pressure is what causes
the most serious damage in most severe brain injuries. As there are more and more fluids,
more and more blood accumulates inside the skull, what happens is the smallest blood
vessels, the capillaries, get compressed. There may be enough power in the heart to
push blood through the major blood vessels, but the smaller the blood vessels are the
more (vulnerable to that loss of) pressure, that compression of the brain mass because
there's only so much movement inside the skull. The compression of that brain mass cuts off
the blood flow to those smallest vessels and when blood vessels and blood flow doesn't
get to those small blood vessels major areas of brain will begin to die.
The reason it dies is that it doesn't get fresh oxygen; it doesn't get fresh glucose
which is the brain's fuel and more significantly the toxic waste products that is created with
this chemical reaction - the little tiny fire that runs the brain - those fumes, those toxic
byproducts of the chemical reaction don't get removed and then the brain becomes a very
toxic environment and ultimately dies.