once you start CPR you want to really
make it count because patients are much
more likely to survive if you perform
high-quality CPR than if you perform
poor quality CPR and there are five
major determinants of CPR quality which
we're going to discuss in some detail
the first is the rate of compressions
100 to 120 is the rate that every
rescuer should be aiming for two is
adequate compression depth we want to go
about two to two and a half inches or
four to five centimeters
three is continuity you should be
performing CPR for a minimum of 60
percent of your total resuscitation time
if not more fourth is chest wall recoil
that's diastole in cardiac arrest and
that's what allows the heart to refill
so we want to make sure that we allow
the chest to recoil so the heart can
fill normally making each compression
count and last is hyperventilation hyper
inflating the lungs decreases cardiac
output and is another variable that
produces adverse outcomes in cardiac
arrest so let's start with compression
rate there's been a number of studies
looking at rate and this is one example
in this study they looked at the mean
rate of chest compressions among a large
sample of cardiac arrest patients and
they found that the patients who had
compressions at a rate of roughly a
hundred to 120 had the highest
probability of röszke which stands for
return of spontaneous circulation and
they also had the highest probability of
survival to hospital discharge or having
a longer term positive outcome so a
hundred to 120 is the rate you want to
go for and there's actual science
showing us that patients are more likely
to survive when we use that rate
compression depth we have a similar
study looking at depth as an isolated
variable again for patients getting
return of spontaneous circulation back
the optimal compression depth was just
under five centimeters
and same thing for survival to hospital
discharge the optimal compression depth
was just a little bit over five
centimeters and what they found in
general is that any compression death
depth over about four centimeters or 38
millimeters produced an odds ratio of
1.9 one of survival to hospital
discharge meaning that if you have
compressions of greater than 38
millimeters across the board you're
twice as likely to survive so it's a
really important variable and a really
easy one to optimize this graph is about
chest compression fraction so in this
study they looked at the percentage of
time in the overall cardiac arrest that
the patient had active chest
compressions being performed and they
stratified according to the percentage
so 0 to 20 20 to 40 40 to 60 etc and
they found not surprisingly a linear
increase in the likelihood of return of
spontaneous circulation as the chest
compression fraction increased so if you
spend more time during the code
performing CPR you're going to get a
better outcome and a higher probability
of survival this is the same data but
this is actually a survival curve rather
than the group stratified data and once
again chest compression fraction of
point eight point nine or 80 to 90
percent of the time produce the highest
likelihood of return of spontaneous
circulation in another study looking at
chest compression fraction the outcomes
were a little bit different in this
study they found that actually a 60 to
80% chest compression fraction produced
the highest odds ratio of survival to
hospital discharge and that's what the
current guideline recommends so you want
to be at a minimum of 60% ideally closer
to the 80% range for your chest
compression fraction the bottom line
though is you're clearly never going to
know numerically what your fraction is
during the course of a resuscitation you
just want to make sure that your CPR is
as continuous and uninterrupted as you
can possibly make it so chest will
recoil is a physiologically important
variable but there's actually no human
Studies on it that demonstrate improves
survival because it's kind of a
difficult phenomenon to study
but basically the idea is if you lean on
the chest in between compressions you're
going to increase the patient's inner
thoracic pressure right you're smashing
down on the chest so that's going to
raise the inner thoracic pressure well
we all know that positive pressure
ventilation also raises the inner
thoracic pressure so if you cram more
air into the lungs you're gonna raise
the thoracic pressure and the bottom
line what brings blood back into the
heart during diastole it's negative
inner thoracic pressure right it's that
negative pressure gradient that pulls
blood from the periphery back up to the
heart so if you raise the inner thoracic
pressure and make it not negative you're
gonna prevent the heart from filling and
you're going to decrease your cardiac
output by decreasing your stroke volume
the ultimate effect again is going to be
impaired cardiac output and that means
less blood flow to the heart itself less
blood flow to the brain and less
likelihood of spontaneous circulation so
bottom line high quality CPR is what you
need to do to optimize your chances of
survival and the determinants once again
are push hard four to five centimeters
push fast 100 to 120 compressions per
minute keep it going you want to make
sure your chest compression fraction is
a minimum of 60% if not more during the
course of the arrest and avoid
hyperventilation and chest wall leaning
if you do those five things you're going
to increase your patients odds of
survival so once you have really good
quality CPR going what's the next
question you need to answer you've
already decided your patient is
pulseless you've already initiated
compressions what do you need to know
now the answer is of course what is the
cardiac rhythm and specifically is it a
rhythm that we can treat with
electricity is it a shockable rhythm so
shockable rhythms like we said before
are more likely to survive patients who
can be shocked are more likely to live
through a cardiac arrest but
defibrillation is a very time sensitive
intervention meaning the faster you do
it the more likely it is that your
patients going to benefit from it
so for shockable rhythms we consider
to be more important than anything else
you can do more important than CPR more
important than ventilation more
important than drugs or IV access it is
the single most important thing that you
can do so if you have a shockable rhythm
you need to know early and you need to
treat it early here's one of our
shockable rhythms this is ventricular
fibrillation it's very easy to identify
it's randomly fluctuating it goes up and
down there's no pattern there's no rhyme
and reason there's no QRS complexes it's
just a disorganized squiggle the second
one is ventricular tachycardia now in
v-tach there actually is organization to
the QRS complexes but they're wide and
bizarre-looking so anytime you have a
fast rhythm with wide QRS complex
complex 'as you should suspect that to
be a ventricular tachycardia and by the
way these are the two rhythms that the
automated defibrillators that you see in
public places are looking for when they
determine whether or not a patient
should be shocked in cardiac arrest so
why do we only shock v-fib in v-tach
this frustrates a lot of students
because you see on TV
everybody in cardiac arrest gets shocked
and they all jump up and come right back
to life right well it doesn't work that
way in the real world because the whole
goal of using electricity is to
reorganize a rhythm that is disorganized
now when you are in a non shockable
rhythm like peña you have some major
problems on the table but electrical
disorganization is not one of them it's
not an issue for patients and non
shockable rhythms and at best if you go
and shock an on shockable rhythm nothing
will happen
at worst you could potentially hit the
patient at the wrong point in the
cardiac cycle cause an R on T phenomenon
and ultimately precipitate a dysrhythmia
like ventricular fibrillation so the
last thing you want to do in a cardiac
arrest is take somebody who has a normal
rhythm and turn it into v-fib that's
clearly not benefiting anybody so we
don't perform too
relation for any rhythm except our two
shockable rhythms v-fib and v-tach I
mentioned before that defibrillation is
a time sensitive intervention and this
graph clearly shows why so as you can
see the more time that elapses as we
move along the axis there the lower the
likelihood of survival for the patient
so for patients and shockable rhythms
who are getting shocked within the first
minute you can see 3540 percent of those
patients are surviving but by the time
we get out to 6 minutes it's less than
20% of the patients surviving so we
really want to make sure that as soon as
we're humanly able to do so we assess
the rhythm and we defibrillate if we
identify a shockable rhythm again short
time to defibrillation high likelihood
of survival and as we go down to 2 3 4 5
6 and more than 6 minutes you can see
that the odds ratio or the likelihood
that the patient is going to survive the
event goes down consistently with every
minute that passes it's really key to do
this quickly all right now once you've
gotten your high quality CPR going and
you've assessed your rhythm and
defibrillated if it's indicated what do
you want to do next well this is when
you can start thinking about respiratory
support for your patient so you can
initiate bag valve ventilation in order
to give your patients an oxygenation you
want to also coordinator chest
compressions with your breathing so
you're going to do 30 compressions
followed by two breaths 30 compressions
followed by two breaths you also if
you're in a hospital setting are going
to establish vascular access and you're
going to continue reassessing the rhythm
every 5 cycles or 2 minutes for the
duration of the resuscitation now a lot
of students ask me dr. young this is all
great but this is like basic basic stuff
right what about the cool stuff like
putting in Airways and pushing drugs
well unfortunately advanced
interventions in cardiac arrests don't
really make much of a difference this is
a study that came out of Scandinavia
that really showed whether
you're performing basic life support or
advanced life support your outcomes are
very similar so in these two cases you
can see the red line represents patients
who got no IV access no IV drugs and no
advanced airway interventions and the
green line represents patients that did
receive those interventions and you can
see how very similar the outcomes for
both groups were so bottom line is that
CPR and defibrillation is by far the
most important element of your
resuscitation and all the advanced stuff
really doesn't make as much of a
difference as we'd like so let's get
back to our case so we have our 58 year
old guy who collapsed at a sporting
event what are we gonna do for him well
like we already said one we're gonna
call for help as quickly as we can
- we're gonna think C a B so we're gonna
go to him and we're gonna decide whether
or not he's got a carotid pulse if he
doesn't we're gonna go ahead and
initiate chest compressions and then
once we can get access to a
defibrillator which hopefully at a
sporting event would be pretty quickly
we're gonna put it on assess the rhythm
and defibrillate if of course it's
indicated
you