Jugular Venous Pulse (JVP) – Waveforms & Evaluation for JVD


hi welcome to another MedCram lecture
we’re going to talk about the jugular venous pulse specifically we’re going to
talk about how to measure it but it’s good for and what the diagnostic
considerations are in terms of interpreting the waveforms so if you
take a look at the heart you’ve got the left side and the right side this is
primarily something we’re going to look at here on the right side where we put
in a central line into the internal jugular vein and down into the SVC which
is usually where the tip is now this is a hollow tube and so we’re able to
actually measure in a central line what’s going on in this vessel which is
a extension of the right atrium now you can also do this and we’ll talk about
this later you can also do something called a right heart catheter where we
actually float a right heart cath in here into the right atrium into the
right ventricle into the pulmonary artery and we wedge the catheter here
which as you recall after it goes to the lungs we’ll come back and actually
measure what’s going on in the left atrium so yes we are able to actually
measure what’s going on the left atrium but for right now let’s just talk about
the jugular venous pulse which is a measurement that we get in the internal
jugular vein the tip of which is in the SVC so again to review there’s two ways
that you can look at a jvp you can either look at the output from a central
line that you’ve placed or number two you can just look at the patient’s jvp
jugular venous pulse and that’s the internal jugular vein so that’s when
they’re lying down you can actually look at that area that’s just around the
sternocleidomastoid or the SCM and look at the waveform as it comes up the rest
of today’s discussion is going to be on specifically the central line wave
output cuz that that’s one way we can actually look at the waveform and see
what the waveform is doing and actually measure the waveform so we’ll talk about
that before we get to that I wanted to sort of clarify a little bit though when
we should measure the central venous pressure in a central line and that is
when someone is breathing spontaneously versus when sew-on is breathing
the ventilator so this is supposed to signify what the intrathoracic pressure
is and the intrathoracic pressure also affects the central venous pressure
because the veins are running in the thorax so when someone is breathing
spontaneously this is their intrathoracic pressure before they take
a breath in and then when they take a breath in the intrathoracic pressure
goes down and then when they breathe out it comes back up again well this is
exactly what’s going to happen to the central venous pressure and so when
you’re looking at the waveforms it’s going to be changing and so depending on
what point during the respiratory cycle you’re at you’re going to get a
different waveform and so the key point here is to always measure at the end of
exhalation this is the true point of measurements the same thing goes for
when you’re breathing on a ventilator except however when you’re breathing on
a ventilator instead of breathing in and having a negative pressure in your chest
the ventilator is pushing air into your chest and as a result of that the
intrathoracic pressure doesn’t go down but instead it goes up the same
principle applies you should always check the central venous pressure at the
end of exhalation as a result of that you’ll see here indifferently that when
you’re measuring it on someone who is breathing spontaneously without positive
pressure ventilation that measurements always going to be at the top of the
cycle on an exhalation when someone is breathing on a ventilator it’s always
going to be at the bottom but still and exhalation so I just want to make that
point for those of you who actually measure central venous pressure I think
I want to now switch to actually talking about the actual waveforms that we see
on the jugular venous waveform and the point that I want to bring up here again
is specifically we’re actually we’re measuring remember the central line is
going into the internal jugular vein and it’s resting just at the tip of the SVC
and where the right atrium is anywhere along this line and so think about the
things that are going to make the pressure here go up and think about the
things that are gonna make the pressure go down okay so let’s think about things
that would make the pressure go down and that’ll make sense later so things that
are gonna make the pressure go down it’s gonna be if we have the atria the
right atrium if it’s relaxing if the volume is getting bigger so atrial
relaxation is gonna make the pressure go down okay what else could make the
pressure go down well if the tricuspid valve opens and blood is allowed to
leave the right atrium and go into the right ventricle so tricuspid valve open
alright what would make the pressure go up in this area well we know that the
right atrium can contract and so when it does contract it’s going to squish that
blood into a smaller space that’s going to make the pressure go up so atrial
contraction it’s going to make it definitely go up and also the closure of
this valve so if the opening of the valve makes it go down the closure of
this valve so tricuspid closure what’s going to happen when this valve closes
remember that blood is always coming towards the heart and so as a result of
that if everything is in a closed system the pressure is always going to start to
rise if this valve is closed because this this chamber is continuously
filling up with blood so with that kind of knowledge that’s actually go over
what the waveform looks like so here’s a sample of what the waveform looks like
at first it looks kind of complicated but it actually is not and we’ve got
certain waves here and you’ll see that over and over again the first wave I
want to bring your attention to is the a wave okay that’s that first bump the
second is the C wave okay and then we have an X descent and then we have a V
wave and then finally we have the wide descent and it starts all over again
and so this area right here corresponds to this area right here and so this is
one cycle now based on what we said before remember where we’re measuring
this we’re measuring this and the superior vena cava so what is this a
wave here this a wave is simply atrial contraction and
as such you’re gonna see that when the atria contract you’re going to be going
through starting from about right here atrial systole this is where the right
atrium is actually contracting to about this point right here and then you’ve
got atrial diastole okay so when the atria when the actual muscle of the
atria contract you’re going to get this upswing in pressure at that point and
it’s right about here you’ll get closure of the tricuspid
valve this is because systole occurs ventricular systole occurs okay we’ll
put that up here ern tricular systole as a result of that when the right
ventricle contracts it’s going to close the tricuspid valve now there are some
people that believe that this bump right here is the tricuspid valve actually
closing some people also believe that the C stands for carotid artery because
the carotid artery runs right next to the jugular venous pulse and that
pulsation is also going to cause an increase in the pressure that is sensed
in the internal jugular vein whichever way you like to think about it
this see here is ventricular the beginning of ventricular contraction now
that the valve is closed however what occurs is the atria continues to relax
as it started here it continues to relax down because remember we’re measuring
pressure on the right side and so X specifically is atrial relaxation and
that’s important to remember now that the atria has relaxed and the X
wave has as we see here the X wave is causing a descent which means that the
pressure is going down in the right atrium there’s going to come a point
where the blood is continuing to come in to that right atrium and it’s going to
start to fill up again until it reaches a certain point here right about the top
here where the tricuspid valve opens and as a result of that the blood then
leaves the right atrium and goes into the right ventricle and you have the
by descent so what is the wide ascent is blood from the atria going down into the
ventricle so what is V V is specifically filling of the right atrium I like to
say V stands for veiling okay imagine a German saying filling filling there is
filling of the right atrium so again to review a is atrial contraction then you
have the C wave which is caused by right ventricular contraction after that you
have relaxation of the right atrium which causes the ex descent then the
tricuspid valve finally opens at the top of the V wave so you have relaxation and
then filling when the valve opens again the pressure drops again and you have
the right ventricle is now filling during the Y wave and then finally you
get back up to the top again and you’re back at another a wave so to review
again a is atrial contraction see is a ventricular contraction ex descent is
atrial relaxation V is atrial filling passively and then finally Y descent is
blood going from the atria down to the ventricle on the way back up to another
atrial contraction thank you for joining us look for the second in the series
where we talk about the pathology and how this waveform can actually help us
make diagnoses