meeting you’re late you’re rushing but
you trip it’s a small trip but you’re on
the stairs so you fall first slowly then
faster then faster then bang you hit
your head you’re unconscious it’s a
medical emergency so what happens next
if you’re lucky you’re taken by an air
ambulance to a major trauma center
something like King’s College Hospital
isn’t mary’s hospital there the doctors
assess you and they determine you’ve got
a severe traumatic brain injury they
take you into the intensive care unit
they put your brain to sleep to try and
save it and then they wait and they wait
and they wait and see for five days for
10 days to see if you’re developing
what’s called secondary brain injury
basically there’s a 50/50 chance it’s a
toss of a coin do you wake up do you not
wake up do you i fine aid severe
disability do you live do you die a 1 a
0
I’m a bioengineer and what we do is try
and develop new technologies to try and
help us predict the one for 0 maybe even
to turn a 0 into a 1 when you’re in the
intensive care unit when we first went
into the intensive care unit we appeared
to be surrounded by data there were
screens behind us blinking
beeping but none of that data was
telling us how our brains actually were
how healthy the brains were and so
instead we had to try and develop
technologies to make this work ok
the intensive care staff here are in the
dark basically they are trying to care
for your brain that
they’re caring so intensively for these
patients and yet they have no data on
which to place their decisions so they
have to wait and see now that’s amazing
I mean if you take your phone out of
your pocket you know everything about
your friends you know what they are
wearing you know what they had for
dinner last night you’ve seen the
pictures so imagine that you could use
that technology as a way of finding out
moment by moment what’s happening inside
your brain and that’s what we’re going
to try and do so what data do the
clinicians actually have so here’s an
example of one sort of data this is an
x-ray section through somebody’s head
and this patient has been hit hard on
the head you can see there’s some
swelling inside there and critically
it’s pushed the black lines which are
the ventricles in the middle it’s pushed
them to one side and it’s squeezing the
brain against the skull that’s a bit of
information if you have a whole series
of stacks like this you can build
slightly a better picture so the data
has given us a better picture we can see
now for this patient they’ve been hit on
the forehead there the computer has told
us in red where there’s possibly blood
in blue where there’s some swelling in
the brain now with this we can tell
where the injury is but what we can’t
tell is what happens next and that’s the
vital piece of information if we want to
care for these patients so just imagine
that we could build tools that could
give us data that could tell us what’s
happening inside your brain moment by
moment to do that we need understand a
bit more about neuroscience so as we fly
into the brain we can see at the chanted
loom of connections between neurons each
spark is a thought an action a feeling
but each spark consumes considerable
amounts of energy and that’s provided to
your brain by blood flow rushing into
the brain bringing oxygen bringing
glucose to keep the cells alive now we
can’t normally see blood flow
this but there’s one special
circumstance when we can so that’s doing
your a surgery because they remove the
skull so you can see the brain this is
my great friend and colleague professor
Tony strong who’s a neurosurgeon
now sometimes during your surgery you
can actually see what’s going on and
this is a video from a cosmic colleague
you had a sack of it you sack of it and
your hands Wojcik in Germany and what
we’re seeing here at the bottom of so
the first thing that we see are the
curves of the brain right the folds of
the cortex but we then see this starting
from the bottom this angry hurricane and
is a hurricane of blood flow that’s
crawling out across the brain surface so
what’s underneath that underneath that
are neurons and they’re undergoing a
wave of depolarization where every
single neuro loses its energy it then
screened out for more blood flow to try
and bring it back to life now we can’t
normally see a picture like this but
maybe we could make some technology that
allows us to get that information here
is a strip electrode this is a metal
strip that’s placed onto the brain
surface at neurosurgery each contact
then looks downwards and listens to the
neurons underneath and it listens to
hear the electrical sounds of them
firing and you can see also the little
white tube is a probe that we’re
sticking into the brain to measure
something about the brain chemistry
what’s going on then so as that way the
depolarization moves up the strip we can
it hits the first electrode and we get
this signature of the depolarization
wave and we hits the electrode number
one then electrode number two then three
then four as the wave moves across the
brain now this spreading depolarization
wave as is called is really
extraordinarily destructive it’s in many
ways it’s a brain tsunami this is the
famous image of under the great wave of
Kanagawa
and the neurons rather like the poor men
in the boat here are sitting there
there’s an enormous wave of destruction
coming and we have to wait and see we
have to wait and see whether they live
or whether they die but to understand
that we need more data so the wave the
electrical information has told us that
the wave is coming but it doesn’t tell
us yet whether the brain survives for
that we need some chemical information
so what we do is we take a thing called
a micro dialysis probe and that’s the
white probe and that’s placed into the
brain tissue
we then pump liquid through it really
slowly so slowly that it would take an
hour to make a tear drop of that liquid
when the liquid comes out at the brain
we carry it in a tube and it’s a it’s a
stream of chemical data that goes into
our bedside analysis instrument inside
that we’ve got chemical sensors so each
one is a bit like a needle but the key
bit is at the tip the little electrodes
at the tip about the size of a human
hair
we can then coat them with a special gel
and inside that gel there are a reagents
so that that sensor records the
concentration of just one chemical be it
glucose or potassium or lactate so the
liquid comes out of the patient goes
into a specially designed microfluidic
chip and so it flows past the tip of
each sensor allowing each sensor to
taste what’s going on in the solution so
let’s now try and put this data together
this is data from a real human patient
and we see at the bottom that signature
of the brain tsunami coming past it hits
electrode one then two then three then
four but we can now add on to it the
chemical data and we’ll start at the top
start with the potassium potassium is
normally inside the neurons and what’s
happening as they depolarize they’re
spilling out all of their potassium and
that means the level goes up and we can
see that we can see the glucose the
glucose is what the brain is desperately
using to try and bring that cell back to
life and so the concentration of glucose
goes down lactate there’s not
of oxygen in the brain anymore and so
the lactic acid level goes up in the
brain so we have this little signature
of what’s happening to the brain in
response to that stimulus we also see
something else here which is that the
wave repeats and it repeats in these
patients again and again 30 times 50
times this wave of destruction hitting
the brain so what effect does that have
so when I am looking at the level of
glucose at the brain from normal going
down towards danger levels at the bottom
and the first spreading depolarization
when it hits the brain it takes the
brain glucose level down a bit but that
repeats and repeats and repeats and that
takes the brain glucose level down into
the danger level so we can now put this
complete picture together with our data
we’ve seen when there is a problem
that’s the electrical wave coming across
the surface but we’ve seen what it’s
done to the brain it’s taken the brain
glucose level from healthy down to a
danger level where that neuron can’t
survive and so he’s going to die and
that’s going to give us the secondary
brain injury we’ve completed the picture
and we’ve done that with data so we’ve
taken then we use data to take pieces of
this puzzle we’ve worked out what they
are weave out worked out how to put them
together to give us understanding and
maybe just maybe by doing that we can save lives thank