Today we are talking about heart sounds. One of those finer points of
auscultation is knowing what I'm listening for, S1 S2 seemed like foreign
words; lub dub makes sense but where am I listening and for what reason. We're
gonna cover all that right after this.
Welcome back my name is Tammy and this is NurseMinder and on this channel we
do everything nursing so if you're new here consider subscribing below so that
you get the next video when it's released. So today we're talking about S1
and S2 those two the medical terms we use to describe what we're hearing when
the hearts atria contract and relax and when the ventricles contract and relax;
also known as lub dub. Before we can talk about where we're listening to them
and why that matters, we're going to do a quick review of the anatomy here. So as
blood is returning to the heart after it's been utilized and it's deoxygenated
it comes to the inferior vena cava which empties out about 80% of your body and
the superior vena cava. And the blood is gonna pool right here in the right
atrium - so let's just put an RA there
and the left atrium - we'll just label those here. While that is also happening
blood is coming back from the lungs that has already been oxygenated and it's
gonna empty into the left atrium. Now these two atriums, once they have the
certain volume in there, there's these stretch receptors that will signal the
brain to empty its contents, and these are going to open and the blood is going
to go down, after which time these flaps are going to close again. Now on
the right side you'll notice that there's three - we call it a tricuspid, and
the left one is called our mitral or bicuspid.
When the heart is moving blood through it, this is the first heart sound
you'll hear so this is known as our S1. So we're gonna put our tricuspid here
and bicuspid. Now an easy way to remember which one sits where is that it's always
right to try something and so we have the tricuspid, the three valves, on the
right side between the right atrium and the right ventricle. Now after the blood
has pooled into the ventricles it reaches a certain level and it pushes
those valves closed and so what that sounds like is you have that flow of
blood through it and we don't often hear the flow of blood through those chambers
but when we do that's called a murmur usually. But what's important to note is
that closing of the valves is what's making that S1 sound, the lub. This is
also known as the lub. Now the blood does need to then move out of the
ventricles to its designated area so from the right ventricle blood is going
through this first semilunar valve; now this one is taking blood through the
pulmonary system to the lungs to oxygenate, so this one is called the
pulmonic valve. And from the left ventricle,
blood is going to go then into the aorta to circulate through the body and this
is called the aortic valve. So if I bring those over here
it's our pulmonic and aortic valves that when they close they make S2, our
second heart sound and this is known as the dub.
So we have our lub in our mitral and tricuspid valves and we have our dub in
or pulmonic and aortic valves. Now this heart doesn't just neatly sink down
underneath that sternum, it actually is shifted and rotated such that the left
side of the heart is anterior and the right side is more posterior and this
changes where we're going to hear those sounds. So I have a mnemonic to help you
remember this I'm just gonna write it down here - I'll come to this side. Ape to
man. So we have a designated kind of a rotation that we use and the first spot is
going to be in my second intercostal space on the right side of the chest. So
right about here I'm going to put my stethoscope here I should hear my
aortic sounds louder and my aortic sounds are part of S2. So I should hear a
lub DUB, lub DUB, lub DUB. So my dub should be louder at this point. When you do
listen make sure you're telling your patients you're going to listen for
quite a while just to let them know that you're not listening because there's
something wrong but just because you want to focus on each sound at each
location to make sure you're hearing the right sound. So after we listen to the
aortic we're gonna move over to the pulmonic, and the pulmonic is best heard
on the left side in that second intercostal space. Now pulmonic is also
part of S2 so I again should be hearing the dub loudest. lub-DUB lub-DUB lub-DUB
Now there's a special point here called Erb's. Now Erb;s point is actually a
point where there is neutrality in the volume so they're equal in sound so you
should hear them coming up equal lub-dub lub-dub lub-dub; not one is higher or
louder than the other. That's my E and Ape. To Man. T stands for tricuspid and
that's still along that sternal border on the left side and that fourth
intercostal space. T stands for tricuspid - tricuspid is S1
S1 sounds like lub. It's my first heart sound so here is what it should be LUB
dub LUB dub LUB dub. Mitral we go to the fifth intercostal space but come more
midclavicular and again that's S1 LUB dub LUB dub LUB dub. So when you spend
some time listening at each of these points you'll want to focus first do you
hear S1 and S2 so listen for one sound, listen for the other, and then which one
is louder. That's going to tell you that you've got a healthy heart and that
there's no extra heart sounds. So we're looking for just to your S1 S2. We don't
want to hear any blood flow (whistle noise). We don't want to hear any the le-lub dub. Those are
extra heart sounds we will talk about in another video. So just to recap ape to man; aortic and
pulmonic at the second intercostal space; right and left,
those are my S2 sounds. Erbs point is a point of neutrality. Tricuspid and mitral
are going to help identify it S1. So what I have up here is just a door
closing just as an example as to what this looks like maybe in a visual. So if
you open the door and people go through it that's your blood flow going through
these valves. The doors open when the door closes - you know doors make sound -BAM -
That's the valves closing so if you have a series of doors and people continue to
go through that's kind of like your lub dub. So just a few more extra tips here.
If you're having a hard time hearing your patients heart sounds, roll them
onto their left side, that will bring the heart closer to the ribcage and give you
a better opportunity to hear those sounds crisply. Second if you want to
compare your S1 and S2 to the cardiac pulse it's actually S1 that coincides
with your cardiac pulse. So this you should be able to match up to the
patient's pulse if you're not sure if you're hearing S1 or S2, go ahead and
feel that pulse while you're auscultating and you'll know which one of those is S1
because the pulse matches it. And because it goes with the
pulse, coincidentally if you're looking at your ECG tracing, S1 also goes with
the R wave on your ECG tracing. Another thing to be listening for is the rate
and the rhythm. Now we know the normal rate is 60 to 100. When using your
stethoscope you'll want to make sure you first start using the diaphragm. Taking
your diaphragm and listening to all of those five heart sounds to make sure
what you're hearing is in fact the club and the dub- there's no extra heart sound
and noting its regularity and rhythm. Then you'll want to switch to listen
through the Bell you may find that you can hear extra heart sounds a little
better using the Bell. So again you start at your aortic, pulmonic, Erbs, tricuspid
and mitral just to make sure there's no extra heart sounds. So today we have
covered the tricuspid and mitral valve, try to the right, mitral to the left.
Our pulmonic and aortic also known as semilunar valves, and how they
work in tandem to create those sounds of lub and dub. So get your stethoscope out
start practicing and really starting to listen with those ears, sometimes close
your eyes so you can concentrate. It really does work and see if you can hear
the difference between all five points of auscultation. Until next time make it
a great day. :)