Hemmorrhage

- Hello, my name is Phil Perera
and I'm the emergency ultrasound coordinator
at the New York Presbyterian Hospital in New York City,
and welcome to SoundBytes Cases!
In this SoundBytes module entitled
Part 2 of bedside ultrasound of the aorta,
we'll go further on our discussion
of bedside ultrasonography of the aorta,
and detection of abdominal aortic aneurysms.
We'll begin with a review of the definitions
and the anatomy of the types of
abdominal aortic aneurysms that you
may encounter in the emergency department.
We'll look at a number of ultrasound images
demonstrating triple-A's, and we'll
conclude with a discussion of the
potential pitfalls of bedside imaging
of an abdominal aortic aneurysm.
This illustration shows the types
of abdominal aortic aneurysms that
may be encountered in clinical practice.
The more common type of abdominal aortic aneurysm
is defined as Fusiform, or diffuse dilatation
of the abdominal abdominal aorta.
Remember that a triple-A is defined
as an aortic diameter greater than three centimeters.
Let's start by looking at the picture to the far left.
What we see here is a diffuse dilatation
of the aorta beginning at the level below the renals,
and ending just above bifurcation into the iliac arteries.
Notice the picture towards the middle;
some of these fusiform aneurysms
can extend from the abdominal aorta
all the way down into the iliac artery.
Now the less common type of abdominal aortic aneurysm
is known as Saccular, as shown
in the picture to the far right,
where you have a localized out-pouching
of the abdominal wall.
This next illustration makes the point
that choosing the correct probe orientation
is very important in terms of getting a
correct measurement of the aorta,
due to the cylinder effect.
Let's look at the two long axis views
of the probes along the aorta, as shown
towards the left of the image here.
Beginning in probe position 1,
we see a side slice, in which the probe
is positioned towards the side of the aorta,
and underestimating the true diameter of the aortic lumen.
We can see that positioning the probe
towards the middle of the image,
as shown here in probe position 2,
we'll get a correct diameter, but this can be
difficult to ascertain using the long axis orientation.
A better orientation is to position the probe
in the short axis configuration,
as shown in probe position 3,
one can then get a sense in terms of the true lumen,
and get the best measurements
of the abdominal aortic aneurysm.
In the last illustration we made the point
that it's important to image the
abdominal aortic aneurysm for an accurate dimension
in the short axis configuration.
But it's also very important to include
outer-wall to outer-wall in the measurements
of the abdominal aortic aneurysm.
Here we can see a measurement
of a triple A only including the inner lumen,
and notice that we could vastly underestimate
the true diameter of this very large triple-A.
Here's the correct dimensions
of the abdominal aortic aneurysm,
and notice here, that we're measuring
anterior, posterior, and laterally,
including the thrombus that coats the outer walls
of this abdominal aortic aneurysm,
in addition to the true lumen,
and we get an outstanding number of
eight by eight centimeters on this triple-A.
Here's a short axis view of a
very large abdominal aortic aneurysm
in a patient who presented to the emergency department
with abdominal and back pain,
and with a small indicator arrow
I'm showing in the B mode image towards the left,
the large triple-A, and there's the spine,
which is our landmark for determination of the aorta.
Now we can see the Color Power Doppler image
towards the right, showing pulsations of blood
within this very large triple-A.
Next we're going to measure this
abdominal aortic aneurysm, and notice
we have a short axis configuration
including outer-wall to outer-wall,
that includes the inner lumen, and the outer thrombus,
and we have a measurement of 4.8 by 4.9 centimeters,
making a criteria of a triple-A
greater than three centimeters.
This video clip is another short axis
orientation of a very large triple-A
in a patient who presented the the ED with abdominal pain.
We mark the spine as our landmark,
and anterior to the spine we see a very large triple-A.
Notice the true lumen, and the accumulation of thrombus
that's seen substantially anterior to the true lumen.
Next, we'll measure this triple-A,
and here we've placed our calipers
from outer-wall to outer-wall
in a short axis configuration,
and we come up with an aneurysm
of 6.3 by 5.8 centimeters, again making
the criteria of a very large triple-A
greater than three centimeters.
This video clip shows a very interesting triple-A,
with multiple onion-skin layers of thrombus
surrounding a very small lumen
towards the middle of the triple-A.
And notice again that we could vastly underestimate
the true dimensions of this triple-A,
if all we included was the lumen.
We see here a very large burden of clot
surrounding the lumen circumferentially
in a short axis orientation.
Next, we're going to position the probe
in a long axis orientation, and I'd like
to categorize this as the Subway sandwich sign,
and what we see here is the lumen,
making up the filling of our Subway sandwich,
and notice the anterior and posterior
burden of clot making up the loaves of the bread,
circumferentially surrounding the lumen.
So a very large triple-A and long axis configuration.
Next we're going to measure this triple-A,
and here we're putting the calipers
from anterior, posterior, and laterally,
trying to add that lumen and the
thrombus to our measurements,
and I came up with a measurement
that was 6.3 by 6.16 centimeters,
again making the definition of a triple-A.
This image is a short axis configuration
showing an extremely large triple-A,
in a patient who presented to the ED
with abdominal pain, during a snowstorm
in New York City in January.
Notice the very large triple-A
and the chaotic flow of blood inside.
You can almost see the thrombus deposition
from the swirls of blood in this very large triple-A.
Here's a long axis configuration
of the same triple-A, and again we can
almost take the patient's heartbeat, or pulse,
by measuring the movements of the swirls of blood
within this chaotic flow of blood within the large triple-A,
and we can see the deposition of the thrombus
both on the anterior and posterior walls
of this very large triple-A.
Here we're putting color Power Doppler down,
to again show that this is a vascular structure,
and what's interesting is again we
can see the chaotic flow of blood,
round and round within this triple-A,
that contributes to the substantial burden
of clot formation that occurs on a triple-A.
In the next image, we're going to measure
this gigantic abdominal aortic aneurysm
in the short axis orientation,
and we measure from outer-wall to outer-wall,
we get a measurement of 8.8 by 8.6 centimeters.
So this patient went directly to the operating room,
and had successful placement of a stent.
This is a rare video clip showing a saccular
abdominal aortic aneurysm, in a patient
who presented to the ED with epigastric abdominal pain.
We have the probe positioned in a long axis configuration,
superior to the left, and we see the aorta
running from left to right, and
we see an outpouching of the aorta coming anteriorly there.
That's a saccular aneurysm, and as we measure it,
we come up with a measurement of 4.45 centimeters.
As the patient was symptomatic
with epigastric abdominal pain over this aneurysm,
she went directly to the operating room
for operative repair.
Let's go over some pitfalls and
useful hints for imaging of the abdominal aorta.
At times, the aorta may be difficult to see,
secondary to excess bowel gas.
We may press the transducer more
firmly towards the spine to displace the bowel gas
and get a look at that aorta.
If the patient has a high body mass index,
we can use a lower frequency to
increase penetration, and to get
a better look at the abdominal aorta.
Using Color Doppler can help us to identify vessels,
and be careful because there are times
when the spine may look like a triple-A,
but again close attention to the spine,
and the location of vascular structures anteriorly
will clear that up.
This video clip shows an example
where the spine could be mistaken
as a large abdominal aortic aneurysm.
Notice that it has the appearance
of a dark structure within the abdomen,
and at first glance it could look like
an abdominal aortic aneurysm, however,
we note that there's positile structures
anterior to the spine, we see the aorta to the left,
and the IVC towards the patient's right side.
We could also use color Power Doppler
to differentiate the vascular structures
of the aorta and IVC versus the spine.
This ultrasound image shows another interesting pitfall.
At first glance, we see a very large, dark structure
towards the top of the picture here,
that could be mistaken as a
very large abdominal aortic aneurysm.
But again, close attention to the location
of the spine posteriorly will help us out.
Notice we see the bone table of the spine,
notice just anterior to the spine
we actually can see here the aorta.
This very large structure is actually
a very large mesenteric cyst,
and it failed to have pulsations with power color doppler.
In conclusion, thanks for joining me
for this SoundBytes module going over
Part 2 of bedside ultrasound of the aorta.
Hopefully through this module you
now understand the definition of
and anatomy found on bedside ultrasound imaging
of an abdominal aortic aneurysm,
and now you can use bedside sonography
as a rapid diagnostic tool for picking up a triple-A.
Remember, that if a patient has unstable hemodynamics,
and a large triple-A is seen on bedside sonography,
that patient must be assumed to have a rupturing triple-A.
Using bedside sonography, we can facilitate
timely operative management of these patients
and possibly save a life.
So I hope to see you back in the future,
as SoundBytes continues.

Brightcove ID

5508128547001

https://youtube.com/watch?v=WKnFD6KeO4c

How to: Abdominal Aorta Measurements

Read more about How to: Abdominal Aorta Measurements

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Learn to measure the abdominal aorta with ultrasound.

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- Once we've done the survey,
we wanna go back and take measurements
of the aorta in a transverse view in three levels.
One level is proximal above the level of the renal arteries,
the second is just at the level of the renal arteries
and the third is at the level of the bifurcation.
We're gonna go back to the epigastric area
and look for our landmarks again.
In the middle of the screen we have the aorta pulsating
to the right of the aorta the IVC
and anterior to the aorta we have
the superior mesenteric artery.
I'm going to freeze the image here
and perform two measurements.
Measuring from the outside wall to outside wall,
so I measure the entire size of the aorta
and just the residual lumen of an aneurysm.
I will perform two measurements, anterior to posterior,
and a transverse measurement.
From there I'm gonna move a little bit more inferior
optimizing the image so I can see
the wall of the aorta clearly.
I will freeze the image.
Perform my measurements, the same two views again.
From the outside wall
to the outside wall,
that's the AP measurement and the same for the transverse.
The measurement is displayed on
the bottom left of the screen and
in this case our measurement is 1.36 centimeters
by 1.69 centimeters.
So we're looking for a value of over three centimeters
to be considered aneurysmal.
I'll keep moving down in a transverse view
towards the bifurcation.
Here we see the aorta divide.
So right before it divides, I want to
perform my measurement at that point.
So I will freeze and perform the
same two measurements again.
Anterior
and transverse.
From outside wall to outside wall.
And that is the completion of the measurements
you need to do for the abdominal aortic exam.

Brightcove ID

5745409357001

https://youtube.com/watch?v=SHhKyEaW1NM

How to: Abdominal Aorta

Read more about How to: Abdominal Aorta

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Learn to examine the abdominal aorta with ultrasound.

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- So what I'd like to do now
is walk you through the abdominal aortic exam.
We do this exam when we're looking for
abdominal aortic aneurysm.
We're gonna use a phased array transducer.
This is a good all-purpose transducer
for the emergency department,
so you can use this for fast exam or abdominal aortic exam.
We're gonna start in the transverse view.
I'm going to put some gel on the patient,
from the epigastric area to the area of the umbilicus,
in a straight line.
I'm going to orient the transducer
so the marker is to the patient's right.
And i'm gonna place it straight up and down
in the epigastric area.
The first thing that you're gonna see
on the ultrasound image
is a round, pulsating structure in the middle of the image,
and this will be the aorta.
Immediately posterior to this round, pulsating area
will be the shadow of the spine.
So we just see the anterior surface of the spine
as the white, bright line,
and then behind this, we see a shadow.
That is what we call the spine shadow,
and you can use that as your landmark
to identify the aorta all the way down the body.
So we're gonna start in the epigastric area,
assessing the size of the aorta.
The first landmarks that we want to see,
to know that we are superior enough
above the renal arteries, is the SMA.
This is going to appear as a smaller anechoic circle
just anterior to the aorta.
So just be careful you don't mistake this
actually for the aorta 'cause it is possible
there could be an aneurysm
in the superior mesenteric artery as well.
Immediately anterior to this is the pancreas,
and then, to the right of the patient,
on the left of the screen, we see the IVC
as this hypoechoic structure.
So from this point, we're gonna move down
we're looking for the left renal vein to cross over
as our landmark for the renal level,
and we're gonna continue moving inferiorly.
If you see bowel gas like this,
just wiggle the transducer a little bit
to try to push it out of the way and work around it.
And I'm gonna decrease my depth as I move inferior
because the aorta is gonna move anterior in the body.
So I can decrease my depth to get it into better view.
'Kay, and we're dealing with some bowel gas here.
I just push it away with the transducer,
and here's the aorta, pulsating,
just sitting anterior to the spine,
with the IVC to the right.
I'm going to continue down to the level of the umbilicus,
pushing away the bowel gas,
and here, I see the aorta divide
into right and left iliac arteries.
So now we see two round circles instead of one.
Once we finish the transverse sweep,
we're gonna turn the transducer so the orientation marker
is facing the patient's head.
We'll place it again starting at the epigastric level.
I'm gonna increase the depth here a little bit,
find the aorta, and, at this point,
because I'm in a sagittal view,
it should appear as a long, black tube
moving from the left to the right of the image.
We can see here in the image,
I'm in the very proximal portion of the aorta.
We see the liver anterior to the aorta.
I move up a little bit, I can see the heart beating
just above the diaphragm.
So I know I'm at the very proximal level,
and I'm just gonna start to survey down the aorta.
The branch that I'm seeing here, coming at a shallow angle,
is the superior mesenteric artery.
So I know I'm above the level of the renal arteries
when I see that landmark.
I'm gonna continue down,
following it in a longitudinal view,
and again, I see the shadow of the spine
directly posterior to the aorta.
I keep moving down, working around the bowel gas,
looking for the long, black tube
immediately anterior to the spine.
And again, I do this all the way down
to the level of the umbilicus.
And I will see a left iliac artery
and a right iliac artery.
And again, I can decrease the depth to optimize my image
because it is so anterior
by the time you get to the umbilicus.

Brightcove ID

5745320579001

https://youtube.com/watch?v=AqAHzGijNIo

Edge: Aorta Sagital

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3D How To: Abdominal Aorta Exam

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3D animation demonstrating an Aorta ultrasound exam.

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- [Voiceover] A curved or phased array transducer
with an abdomen exam type is used to perform
an aorta ultrasound exam.
The entire length of the aorta from
the level of the diaphragm
to the bifurcation of the iliac arteries
must be evaluated in two planes.
The examination begins with the transducer
placed transversely in the epigastric mid line,
with the marker directed to the patient's right.
The aorta is seen as a round, pulsatile structure,
anterior to the bright reflection of the vertebrae.
The vena cava is an oval structure
immediately to the left of the aorta on the screen,
which changes in caliber with compression
or deep inspiration.
The abdominal aorta will course gradually,
becoming more superficial as it progresses distally.
The transducer is slowly moved distally
to identify the celiac trunk,
renal arteries,
superior mesenteric artery,
and bifurcation to the iliac arteries.
Note the location of any change in size
of the aorta or iliac arteries,
and measure in long and short axis views
from outer wall to outer wall
to determine the true diameter.
The transducer is returned to the epigastric area
and rotated 90 degrees clockwise,
with the orientation marker to the patient's head.
The transducer is swept side to side
to identify the maximal diameter of the aorta.
The abdominal aorta will have proximal to distal taper.
The transducer is moved distally
to evaluate the walls of the aorta
for any change in the shape or size.
If the aorta is difficult to visualize
due to overlying bowel, gentle downward transducer pressure
may encourage peristalsis of the overlying bowel.
Alternatively, consider moving the patient
into a left lateral decubitus position
to re-position the bowel away from the field of view.

Brightcove ID

5508114778001

https://youtube.com/watch?v=NI-tU5w-gzg