hello now I'm gonna talk about one of my
favorite topics which is basic life
support for cardiac arrest so let's
start off with a case scenario we have a
58 year old man he's running along in a
sporting event and he suddenly drops
becoming pulseless and APNIC what do you
want to do to save his life
we're gonna talk about the most
important interventions that you can
perform right there on the scene that
are most likely to improve his outcome
we're gonna talk about why this happened
physiologically what might be going on
with him and we're going to talk about
the supporting evidence that helps us
know what the most effective
interventions are so what is cardiac
arrest
the term cardiac arrest refers to the
abrupt cessation of effective
circulation basically it means the
hardest stopped it encompasses a lot of
different underlying diseases and
conditions but the final common pathway
in each case is that the heart is not
producing the effective circulation of
blood to the body so the primary cause
of cardiac arrest first and foremost is
coronary ischemia the whole world over
that is the number one cause but there
are other things that can lead to
cardiac arrest as well including
cardiomyopathies structural heart
lesions such as valvular disease
electrical conduction app conduction
abnormalities such as Brugada syndrome
or other channel appa these metabolic
disturbances particularly those in
electrolytes toxic ingestion 'z there
are a number of poisonings that can
produce cardiac arrest and there are
other non cardiac conditions that can
lead the heart to stop when we look at
the epidemiology of cardiac arrest in
the United States we have about half a
million arrests per year of those about
60% occur outside of the hospital and
four out of hospital arrest there's only
about a ten percent survival rate
although that number does go up to 30%
for cases which are witnessed by
bystanders and the victim receives rapid
CPR about 200,000 of these events are
about a little more than a third occur
inside of the hospital and in the
hospital we have
percent survival rate which is double
what we get outside of the hospital but
it's still really not great
obviously that survival is going to be
affected by the etiology of the arrest
the hospital itself how prepared it is
to deal with high acuity events and
believe it or not the time of day as far
as the epidemiology goes the incidence
of cardiac arrest increases linearly
with age so as you get older you have a
higher and higher risk of having an
arrest and 57% or almost two-thirds of
the patients are men when you look at
the cardiac or rhythm in patients with
cardiac arrest about 1/4 have either
ventricular fibrillation or ventricular
tachycardia which are known as the
shockable rhythms among those patients
you have about a 30% survival rate
the remaining rhythms which are
pulseless electrical activity and
asystole
only produce about a 10 percent survival
rate so there's a big difference in how
likely you are to survive based on what
type of rhythm your heart goes into at
the time of arrest overall shockable
rhythms represent a minority of arrests
only about 25% but three quarters of
patients who survived have shockable
rhythms so you are much much more likely
to survive a cardiac arrest if you have
ventricular fibrillation or ventricular
tachycardia rather than one of the other
to arrest rhythms when you see somebody
in cardiac arrest they are invariably
100% of the time unresponsive pulseless
and most commonly APNIC although a few
will have preserved
agonal respirations or gasping when
you're evaluating an unresponsive
patient you want to always get help
right away not every patient who's
unresponsive is in cardiac arrest but
you should assume the worst case
scenario assume that your patient is in
cardiac arrest and that you need
immediate backup and even if your
patient doesn't turn out to be in
cardiac arrest it's never a bad idea to
get help because the things that make
you unresponsive are never good
once you have help on the way the next
question you want to ask yourself is
does this patient have a pulse
this is why in cardiac arrest
we don't use the old ABC mnemonic that
we talked about in Prior lectures to
assess the patient we use CA B
circulation first because the first and
most important question is whether or
not your patient has a pulse we want to
check the pulse for a maximum of 10
seconds always in the carotid and if at
the end of that time there either is no
pulse or we have any question as to
whether or not there's a pulse we're
going to go ahead and initiate CPR only
after we've decided whether or not a
pulse is present are we going to worry
about airway and breathing so while
you're checking the pulse you can look
for clinical evidence of respiration
again sometimes you'll see agonal
breathing or gasping and rescuers often
mistake this for normal breathing but
you should never see normal rhythmic
breathing in a cardiac arrest if you do
you should rethink whether or not your
patient is really in cardiac arrest so
like I said your most important question
is whether a patient has a pulse
we're going to assess that by palpating
the carotid pulse the reason we go for
the carotid is in shock this is the last
pulse to go so patients who are
hypotensive but still do have
spontaneous circulation might lose their
radial or their femoral pulses but
they're always going to keep their
carotid pulse up until the last moments
before they cease to have circulation
once again you get a max of 10 seconds
if you don't clearly detect a pulse in
that timeframe start CPR you're never
gonna hurt a patient by performing
unnecessary CPR but you will absolutely
hurt people by withholding CPR when in
fact they don't have spontaneous
circulation