POINT-OF-CARE
COURSE
ULTRASOUND
TITLE
ESSENTIALS
HANDBOOK
Teacher
name
Viveta
Lobo,
MD
Table of contents
Pocus 101
Understanding POCUS basics
4
Understanding the basic physics of ultrasound
5
Understanding the principles of scanning
7
Understanding knobology
9
Understanding artifacts
10
Efast
Understanding POCUS in trauma assessment
12
Viewing the right upper quadrant (RUQ)
13
Evaluating the left upper quadrant (LUQ)
14
Obtaining the subxiphoid view
15
Mastering the suprapubic view
16
Evaluating for pneumothorax
18
Echocardiography
Understanding when to use POCUS ECHO
19
Learning how to acquire the four basic ECHO views
21
Understanding contractility
23
Understanding pericardial effusion
24
Understanding chamber size
25
Inferior vena cava (IVC)
Knowing when to perform an IVC study
26
Getting and understanding the views
27
Lung ultrasound
Understanding when to image the lung
28
Acquiring the eight basic views
29
Identifying B-lines and pleural effusions
30
Abdominal aorta
Knowing when to scan the abdominal aorta
31
Obtaining the views
32
Evaluating for an abdominal aortic aneurysm
34
Hepatobiliary
Understanding when to scan the gallbladder
35
Obtaining the view of the gallbladder
36
Imaging the common bile duct
37
Evaluating for acute cholecystitis
38
Renal and bladder
Understanding when to perform a renal scan
40
Performing a renal study
41
Evaluating for hydronephrosis
43
How to measure bladder volume
45
First trimester pregnancy
Knowing when to scan in first trimester pregnancy
46
Performing a pelvic ultrasound study
47
Confirming a definitive intrauterine pregnancy
49
Evaluating for an ectopic pregnancy
50
Determining gestational age
51
Orbital
Knowing when to perform an orbital scan
52
Imaging the normal orbit
53
Evaluating for critical ocular pathology
55
Lower extremity study (deep venous thrombus)
Understanding when to perform a deep venous study
57
Evaluating the femoral region for an acute DVT
58
Evaluating the popliteal region for an acute DVT
59
Soft tissue
Knowing when to perform a soft tissue exam
60
Identifying normal versus abnormal
61
Ultrasound-guided procedures
Understanding the principles
63
Central venous access
64
Peripheral venous access (PIV)
66
Paracentesis
67
Thoracentesis
68
Lumbar puncture
Appendix
Reference list
72
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POCUS 101
Understanding POCUS basics
What is POCUS?
POCUS, or point of care ultrasound, is an ultrasound exam that is performed by a physician at the bedside,
while assessing or managing a patient. You may perform it to help with a diagnosis, plan a treatment or
intervention, or assess your treatment plan.
What is the “focused question”?
We are not radiologists who do “comprehensive”
assessments of organ systems, but instead we
approach the ultrasound scan with a specific
question that we want answered. For each
application, you must know what you are looking
for before performing the point of care exam.
Renal
SED
U
FOC
?
Is there hydronephrosis?
Gallbladder
Are there gallstones?
Abdominal aorta
Is there an abdominal aortic aneurysm?
Learning curve
Your acquisition and interpretation skills will improve, but will require practice and review.
4
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POCUS
POCUS 101
101
Understanding
Understanding
thethe
basic
principles
physicsofofscanning
ultrasound
How are
Probe
marker
images created on the screen?
Find the
Sound
ismarker
mechanical
on your
energy
probe
with
and
frequencies
the dot on up
thetoscreen.transferring
The dot on energy
the screen
to structures
corresponds
in their
to the
pathmarker
and on
20,000
your
probe.
Hz. Diagnostic
That means,
ultrasound
structures
is closest
pulsed sound
the probe marker,
causing
willmolecules
appear closest
in those
to the
structures
dot sidetoofvibrate.
the screen.
The
waves with frequencies of 2.5–10 MHz.
reflection of that sound (the echo) from a structure
back to the crystals in the transducer is what is
Like all sound waves, the ultrasound waves
seen on the screen. All probes display the returning
travel at a constant velocity through a medium,
echoes at a certain frame rate.
Reflected wave
Sender/receiver
Image orientation
Object
Original wave
distance (r)
Longitudinal
(Sagittal/long-axis view)
Transverse
(Short-axis view)
Coronal
What is density?
Depending on the density of the structure, the echo
returned will vary causing it to look different on the
screen. If an object reflects all waves back it will
be seen as a bright, or hyperechoic, structure (e.g.,
structures high in calcium, such as bones/stones).
If the ultrasound wave travels through the medium
it will appear as a black, or anechoic, structure on
the screen (e.g., fluid). Structures that allow some
ultrasound waves to travel through and some to
bounce back appear gray, and are called hypoechoic
(e.g., tissue/organs).
Black = fluid (e.g., blood, urine)
Gray = tissue/organ
White = high density tissue/organ (e.g., bone)
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What is frequency?
POCUS 101
Understanding the principles
visualize deepof
structures,
scanning
and a high frequency
Frequency is the rate at which a wave travels within
a material. Different probes use different frequencies
to facilitate the imaging of different structures: a
low frequency probe uses longer wavelengths to
probe uses shorter wavelengths to visualize
superficial structures.
Probe marker
Find the marker on your probe and the dot on the screen. The dot on the screen corresponds to the marker on
your probe. That means, structures
closest the probe marker, will appear closest to the dot side of the screen.
Long wavelength
Low frequency
Short wavelength
High frequency
Image orientation
Low frequency probes
High frequency probes
1–5 MHz
10–15 MHz
Longitudinal
(Sagittal/long-axis view)
Transverse
(Short-axis view)
Coronal
Linear
Phased-array
Curvilinear
Visualize deep structures
Visualize superficial structures
6
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POCUS 101
Understanding the principles of scanning
Probe marker
Find the marker on your probe and the dot on the screen. The dot on the screen corresponds to the marker on
your probe. That means, structures closest the probe marker, will appear closest to the dot side of the screen.
Image orientation
Longitudinal
(Sagittal/long-axis view)
Transverse
(Short-axis view)
7
Coronal
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Gain
Make sure to have good contrast between structures.
Too much gain
Just right
Too little gain
Depth
Make sure what you are focusing on is in the center of the screen.
Too much depth
Just right
Too little depth
Scanning techniques
Sliding
Rotating
Holding the probe in the same orientation, move/
slide the probe up/down/left/right on the patient.
For example, if you are scanning the length of
someone’s abdominal aorta, you will start at the
top and then slide your probe all the way down their
abdomen to visualize it entirely.
Keeping probe in same spot, turn the probe clockwise
or counterclockwise. This technique is often used
when scanning an organ in two planes. For example,
if you are looking at the gallbladder in a long-axis
view (with the marker pointing to the patient‘s head)
and you now want to move to a short-axis view, you
will keep the probe in the same location but rotate
the head of the probe so that the marker points to
the patient’s right.
Fanning
Holding the probe in the same spot/location, tilt the
probe. This is a VERY IMPORTANT technique and
allows for the complete evaluation of a structure. In
ultrasound we are performing scans in 2D, but you
are looking at the 3D organs—fanning allows you
to scan the entire width of that organ, so you don’t
miss any critical findings.
8
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POCUS 101
Understanding knobology
Knobology: The functionality of controls on an instrument as relevant to their application.
M-mode
Doppler
M-mode is used when you want to know if a
particular structure is moving or not. In this mode,
you can also perform certain calculations based on
the rate of movement.
Doppler can reliably differentiate a vein from an
artery by highlighting the rate of flow (which is
reliably different in a vein and an artery). If you place
the Doppler calipers within a vessel, you will produce
a sound based on the flow within that vessel. A
pulsed flow will correspond to an artery, whereas a
steadier, passive, flow will be of a vein.
Color (Doppler)
2D
Color Doppler is great for identifying vascular
structures, or anything that has flow.
Pressing 2D will return your screen to scanning mode.
If you are ever lost and want to start again, hit 2D.
9
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POCUS 101
Understanding artifacts
An artifact is any structure in an ultrasound image that is not directly produced by an organ.
High attenuation
Low attenuation
When ultrasound beams encounter high attenuating
structures (such as this bright white structure), the
echoes are diminished posteriorly and an acoustic
shadow—which is this dark anechoic shadow seen
here—is formed.
When ultrasound beams encounter low attenuating
tissue, such as fluid, echoes are enhanced
posteriorly, causing something called posterior
acoustic enhancement. That is why structures that
are posterior to this bladder are very bright (just as
bright as if you increased your gain).
When I look for gallstones, I often
will look primarily for the black
shadows to confirm the presence
of a stone.
10
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Refraction
Gas scatter
At times you will notice, along the edges of a structure,
two dark lines coming off. This is edge artifact, and it
happens when ultrasound beams cross tissues that
are very different. For example, you will see edge
artifact at the edge of a vascular structure.
When the ultrasound beam encounters air, much of
the signal is lost to scatter, obstructing visualization
of any of the structures. Air will often become a
hindrance to you when scanning, and you will have
to develop trouble-shooting techniques to get rid of
air in your scanning field.
Reverberation
Mirror-image artifact
Reverberation artifact is caused when your
ultrasound beams encounter two highly reflected
parallel structures, like the pleural line. The sound
will bounce back and forth between these two
structures, tricking your ultrasound probe to thinking
that the length of the reflection back to the probe is
longer, as if you were visualizing deep structures.
When this happens multiple echoes are recorded
and displayed deeper than the actual structure.
If a structure, such as your liver, is located close to a
highly reflective interface (such as the diaphragm),
it is detected and displayed in its normal position.
However, the strong reflection coming off the
diaphragm will cause additional sound waves to
bend towards the neighboring anatomy, causing
the sound waves to have a longer travel time and
to fool your ultrasound machine to thinking there is
an additional anatomic structure. A duplicate of the
real image appears on the other side of the strong
reflector, causing the mirror-image artifact.
11
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EFAST
Understanding
Understanding POCUS
POCUS in
in trauma
trauma assessment
assessment
D
SE
CU
SED
U
FO
C
FO ?
?
Is
Is there
there free
free fluid
fluid in
in the
the peritoneum
peritoneum
or
pericardium?
or pericardium?
The focused assessment sonography in trauma (FAST) exam is part of the advanced trauma life support
The focused assessment sonography in trauma (FAST) exam is part of the advanced trauma life support
(ATLS) protocol, and should be performed after your primary survey, if indicated. If there is a concern for lung
(ATLS) protocol, and should be performed after your primary survey, if indicated. If there is a concern for lung
injury, specifically pneumothorax, the “extended-FAST” or EFAST exam should be performed.
injury, specifically pneumothorax, the “extended-FAST” or EFAST exam should be performed.
Your indications are:
Your indications are:
Trauma
Trauma
Unexplained shock
Unexplained shock
Low hemoglobin
Low hemoglobin
EFAST
EFAST has
has limitations:
limitations:
Screening
Screening tool
tool
>400
>400 mL
mL blood
blood
Peritoneal
Peritoneal blood
blood
Supine
Supine patient
patient
Does
Does not
not diagnose
diagnose source
source
12
Ruptured ectopic
Ruptured ectopic
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EFAST
Viewing the right upper quadrant (RUQ)
Right upper quadrant (RUQ) view
You should visualize three sections of the RUQ.
Using the phased-array probe in the coronal crosssection, with the indicator towards the patient’s
head, start on the lower rib spaces and then slide up
to see all three parts of the RUQ view.
A positive RUQ view will be first seen at the caudal
tip of the liver (most sensitive), then in the Morison’s
pouch and the liver-diaphragm views.
Marker
superior
3
2
1
1 Caudal tip of liver
2 Morison’s pouch
3 Liver-diaphragm
1
2
3
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EFAST
Evaluating the left upper quadrant (LUQ)
Left upper quadrant (LUQ) view
There are two parts of the LUQ view you want to
visualize for free fluid.
A positive LUQ view will be seen first at the spleendiaphragm view, and then in the spleen-renal view.
Using the phased-array probe in the coronal crosssection, with the indicator towards the patient’s
head, place the probe in the lower rib spaces and
slide down to view both parts of the LUQ view.
Marker
superior
1
2
1 Spleen-diaphragm
2 Spleen-renal
2
1
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EFAST
Obtaining the subxiphoid view
The subxiphoid view is useful to look for a traumatic
pericardial effusion.
Using the phased-array probe, place the probe under
the xiphoid process with the indicator towards the
patient’s right side, and aim up into the chest. You
should be able to visualize the entire heart, and
surrounding pericardium.
Normal
Marker
right
Subxiphoid
Abnormal (positive)
15
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EFAST
Mastering the suprapubic view
Using the phased-array probe in the suprapubic
area, low on the mid pelvis, aim down towards the
patient’s feet. The indicator should be towards the
patient’s right for a short-axis view, and towards
the patient’s head for a long-axis view.
Long axis:
Marker superior
Short axis:
Marker right
Suprapubic
Females vs. males
There is a difference in where free fluid is seen in females and males.
Cul de sac
Retrovesical space
Uterus
Bladder
Bladder
A positive suprapubic view in females is seen
behind the uterus (cul-de-sac) in both short- and
long-axis views.
A positive suprapubic view in males is seen behind
the bladder (retro-vesicular), in both short- and
long-axis views.
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Short-axis view, female
Short-axis view, male
Long-axis view, female
Long-axis view, male
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EFAST
Evaluating for pneumothorax
An “extended” FAST or EFAST exam is performed if
there is a suspicion for lung injury, specifically when
there is concern of a pneumothorax.
Marker
superior
Using a linear probe, with the indicator towards
the patient’s head, place the probe high under the
clavicle in the mid-clavicular space. Then slide the
probe down to subsequent rib spaces to evaluate
multiple regions.
The ultrasound image visualizes the pleural line, and
you look for the presence or absence of “sliding”.
Positive sliding is normal; its absence is concern for
a pneumothorax.
M-mode can be used to confirm the presence
of sliding. A normal lung with pleural line sliding
will produce the “sandy beach” tracing whereas a
pneumothorax will produce the “barcode” tracing.
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ECHOCARDIOGRAPHY
ECHOCARDIOGRAPHY
Understanding when to use POCUS ECHO
Understanding when to use POCUS ECHO
D
USE
FOCUSED
FOC ?
?
Is heart contractility normal?
Is there
heart a
contractility
Is
pericardial normal?
effusion?
Is
there
a
pericardial
Is the heart
chamber effusion?
size normal?
Is the heart chamber size normal?
Whenever the knowledge of contractility, pericardial effusion, or chamber size will help with patient
Whenever theperform
knowledge
of contractility,
pericardial effusion, or chamber size will help with patient
assessment
a POCUS
ECHO.
assessment perform a POCUS ECHO.
Contractility
Contractility
Pericardial effusion
Pericardial effusion
Chamber size
Chamber size
Views
Views
There are four views:
There are four views:
Parasternal long-axis view
Parasternal long-axis view
Parasternal short-axis view
Parasternal short-axis view
Apical view
Apical view
Subxiphoid view
Subxiphoid view
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Marker controversy
Cardiologists have traditionally placed the dot to the
left of the screen when performing ECHOs. However,
POCUS users leave it on the right of the screen. To
accommodate for this difference, the probe position
is changed 180 degrees when acquiring the images,
hence producing the same exact image orientation
on the screen.
Cardiology
POCUS
20
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ECHOCARDIOGRAPHY
Learning how to acquire the four basic ECHO views
The ECHO exam has four basic views. You need to acquire all four views to confirm or exclude your findings.
Parasternal long view
Parasternal short view
Using the phased-array probe, place the probe in
the 3rd–4th intercostal space, just left of the sternum,
with the indicator towards the patient’s left hip.
Using the phased-array probe, place the probe in
the 3rd–4th intercostal space, just left of the sternum,
with the indicator towards the patient’s right hip.
Marker
inferior left
Marker
inferior right
21
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Subxiphoid view
Apical 4-chamber view
Using the phased-array probe, place the probe under
the xiphoid process, with the indicator towards
the patient’s right side, and aim up into the chest.
You should be able to visualize the entire heart and
surrounding pericardium.
Using the phased-array probe, place the probe under
the left nipple (at the point of maximal impulse (PMI)),
with the indicator towards the patient’s right side, and
aim up into the chest. You should be able to visualize
the entire heart and surrounding pericardium.
Marker
right
Marker
right
22
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ECHOCARDIOGRAPHY
Understanding contractility
Contractility
You will characterize contractility as normal, hypodynamic, hyperdynamic, or absent.
Normal
Evaluate by looking at the walls of the left ventricle
(they should approach each other very closely in
systole), and the anterior leaflet of the mitral valve
(in parasternal long-axis view they should lift up
towards the septum very closely in diastole).
Hypodynamic
Notice how the walls of the left ventricle are far apart
during systole, and the anterior leaflet of the mitral
valve does not come close to the septum when it’s
open at its widest during diastole.
Hyperdynamic
Notice how the walls of the left ventricle touch
each other during systole, and the anterior leaflet of
the mitral valve comes up very close/touches the
septum above as it opens.
Absent
There will not be organized movement of the
ventricles or atria.
23
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ECHOCARDIOGRAPHY
Understanding pericardial effusion
Pericardial effusion
Evaluate for a pericardial effusion and, if present, assess for cardiac tamponade.
Pericardial effusion
Dark or anechoic fluid that surrounds the heart,
circumfrencially.
Cardiac tamponade
Defined on ultrasound as right ventricular collapse
during diastole.
Systole
Diastole
Pericardial effusion
Pleural effusion
Pericardial effusion vs. left pleural effusion
At times it is difficult to distinguish a pericardial
effusion from a pleural effusion. To easily tell the
difference, view the heart in the parasternal longaxis view.
A pericardial effusion will ascend over the
descending aorta (DA).
A pleural effusion will track below the
descending aorta (DA).
24
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ECHOCARDIOGRAPHY
Understanding chamber size
Chamber size
The right ventricle should be about 2/3 the size of
the left ventricle.
Chamber size
In the parasternal long-axis view, the right ventricle,
the aortic outflow track, and the left atria, should all
be about equal size.
Acute right ventricular strain, as seen in the setting
of acute massive pulmonary embolism, is best
appreciated in the parasternal short-axis view. In this
view you see a bowing of the septum into the left
ventricle, causing the left ventricle to acquire the shape
of the letter “D”. This is also known as the “D Sign”.
25
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INFERIOR VENA CAVA (IVC)
Knowing when to perform an IVC study
The inferior vena cava (IVC) is a good indicator of current volume status. It can have many clinical applications
especially in the setting of sepsis, or during resuscitation.
Normal IVC
Hypervolemic
We expect to see a slight decrease in the diameter of
the IVC during a normal respiratory cycle. Clinically
this translates into a “fluid tolerant” state.
If there is no, or very little, variation in the diameter
of the IVC with respirations, the patient is likely in a
hypervolemic or “fluid intolerant” state.
Before inspiration
Before inspiration
After inspiration
After inspiration
26
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INFERIOR VENA CAVA (IVC)
Getting and understanding the views
Similar to the subxiphoid view of the heart, the
phased-array probe is placed under the patient’s
xiphoid process and aimed upwards into the chest,
with the indicator towards the patient’s head.
Marker
superior
Hypervolemia
M-mode
Normally you should appreciate some variation in
the diameter of the IVC with normal respiration.
If there is no, or very little, change, you would be
concerned about hypervolemia.
M-mode can be used to evaluate the maximum and
minimal diameter change of the IVC during a respiratory
cycle. By placing the M-mode line 2 cm distal to
the inlet of the right atrium, or just distal to the
hepatic vein as it enters the IVC, you can measure the
maximum and minimum width. Little or no change
would be consistent with hypervolemia; a collapse
of greater than 50% is suggestive of hypovolemia.
27
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LUNG ULTRASOUND
Understanding when to image the lung
Lung ultrasound is a newer field and is most useful in the critically ill patient.
While the list is expanding, there are currently a number of diagnoses that lung ultrasound can help confirm:
•
•
•
•
•
•
pnemonia
pulmonary infarction
pneumothorax
pleural effusion
pulmonary edema
interstial lung disease
28
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LUNG ULTRASOUND
Acquiring the eight basic views
Using the phased-array probe, with the indicator to
your patient’s head, place the probe in each of the
four zones, bilaterally.
You should always have your depth set to a minimum
of 16. First, identify the bright white pleural line; a
normal lung ultrasound will likely have horizontal
A-lines that are reflections of the pleural line below.
Marker
superior
1
2
3
4
Zone 4
Zone 4 evaluates for pleural effusion, and is a different
view from the rest of the zones. Place the phasedarray probe with the indicator to the patient’s head,
in the coronal cross section (similar to RUQ or LUQ
of the FAST view). You are evaluating for a pleural
effusion, or fluid above the diaphragm.
A normal Zone 4 scan will show the bright white
diaphragm as it courses under the liver (or spleen
on the LUQ) and the spine shadow as it meets the
diaphragm. You should not see the spine past the
point where it meets the diaphragm.
Marker
superior
29
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LUNG ULTRASOUND
Identifying B-lines and pleural effusions
B-lines
B-lines are an indication of fluid in the lung. They
look like large bright lung “rockets” or “search lights”
coming off the pleural line, extending down to a
depth of at least 16 cm.
Two or more B-lines per zone (1–3) is
considered a positive lung field for fluid.
Two or more positive lung fields bilaterally
is indicative of pulmonary edema.
Pleural effusions
In a normal ultrasound image of zone 4, the spine
shadow cannot be seen beyond the diaphragm.
While you are looking for B-lines in zones 1–3 (to
identify fluid in the lung), in zone 4 you will look for
the spine sign as an indication of a pleural effusion.
Spine sign
The spine sign is the visualization of the spine shadow
beyond the diaphragm in the lung zone 4 (RUQ or
LUQ) and signifies the presence of a pleural effusion.
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ABDOMINAL AORTA
Knowing when to scan the abdominal aorta
D
USE
FOC
?
Is there an abdominal aortic aneurysm?
If a patient presents with hypotension and back pain,
you would want to rule out a ruptured abdominal
aortic aneurysm (AAA).
The standard of care for assessing an abdominal
aneurysm is with ultrasound.
A POCUS scan would provide the results quickly.
An AAA found during a POCUS
exam should be considered
ruptured until proven otherwise.
31
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ABDOMINAL AORTA
Obtaining the views
Using a low frequency probe (phased-array or curvilinear). Start at the patient’s xiphoid process,
perpendicular to the abdomen. Orient the indicator to the patient’s right for a short-axis view and to the head
for a long-axis view.
Short-axis view
Long-axis view
Identify the spine shadow; the aorta will be above it
to the right, and the IVC to the left.
Once you’ve identified the aorta in short-axis turn 90
degrees to see the aorta in long-axis.
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Familiarize yourself with the normal anatomy of the abdominal aorta and it’s branches so you correlate with
your ultrasound findings. Scan from the celiac trunk through the bifurcation into the iliac arteries.
Phrenic artery
Celiac trunk
Suprarenal
Gastric artery
Common hepatic artery
Spleen
Spelnic artery
L renal artery
R renal artery
Gonadal
SMA
Aorta
IMA
R common iliac artery
L internal iliac artey
R external iliac artery
Remember most aneurysms are
infrarenal so make sure to scan
the entire length.
33
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ABDOMINAL
AORTA
ABDOMINAL AORTA
Evaluating for an abdominal aortic aneurysm
Evaluating for an abdominal aortic aneurysm
There are two types of aneurysm: fusiform and saccular. Fusiform is more common.
There are two types of aneurysm: fusiform and saccular. Fusiform is more common.
Fusiform
Fusiform
Saccular
Saccular
When measuring the aorta, place calipers from the
When wall
measuring
the aorta,
outer
to the outer
wall. place calipers from the
outer wall to the outer wall.
Abdominal aortic aneurysm
Abdominal
aortic
=
dilation of the
aortaaneurysm
over 2 cm
= dilation of the aorta over 2 cm
Iliac aneurysm
Iliac
aneurysm
=
dilation
of the iliac artery over 1.5 cm
= dilation of the iliac artery over 1.5 cm
Remember, the aorta lies in the
Remember, the space
aorta lies
the
retroperitoneal
so ainruptured
retroperitoneal
space
so a ruptured
AAA
will not give
a positive
FAST
AAA will
not give
a positive
FAST
exam
(a FAST
exam
identifies
free
examor(ablood
FASTin
exam
identifies free
fluid
the peritoneal
space).
fluid or blood in the peritoneal space).
34
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HEPATOBILIARY
Understanding when to scan the gallbladder
D
USE
FOC
?
Are there gallstones?
There are many potential disease processes that cause pain in the right upper quadrant (RUQ) of the abdomen.
Subphrenic abscess
Cirrhosis
Bud-Chiari syndrome
Primary or
metastatic
carcinoma
Amebic abscess
Hepatitis
Gallbladder hydrops
or Courvoisier
gallbladder
Hodgkin disease
Common duct stone
Carcinoma of
the colon
Pancreatic pseudocyst
Polycystic kidney
Pancreatic carcinoma
Hypernephroma
Obstructive uropathy
Using ultrasound to evaluate the gallbladder and rule out pathology is a safe and efficient tool to consider
when formulating your work-up plan.
35
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HEPATOBILIARY
Obtaining the view of the gallbladder
There are three possible methods to acquire the images: coronal cross-section, subcostal X-7, or subcostal X-12.
Coronal cross-section
Subcostal X-7
Subcostal X-12
Place probe between the lower rib
spaces and fan.
Starting at the xiphoid process,
slide the probe under the costal
margin 7 cm to the right side.
Starting at the xiphoid process,
slide the probe under the costal
margin 12 cm to the right side.
X
X
Using a low frequency probe, place the probe in on of the three positions. Hold the indicator to the patient’s
right for a short-axis view and to the patient’s head for a long-axis view.
Gallbladder, short-axis view
Gallbladder, long-axis view
36
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HEPATOBILIARY
Imaging the common bile duct
Stomach
Gallbladder
Common bile duct
Pancreas
Duodenum
When finding the common bile duct, look for the
portal triad, specifically the portal vein (it will be
a bright-white walled, vascular structure). The
common bile duct should be right above it. A normal
common bile duct diameter is less than 0.6 cm until
the age 60. After that, you are allowed an increase
of 0.1 cm for each decade. For example, at age 70, a
normal width is less than 0.7 cm.
Gall bladder
MLF
(main lobar
fissure)
Portal
vein
Portal triad
Portal triad
37
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HEPATOBILIARY
Evaluating for acute cholecystitis
Acute cholecystitis is most often caused by gallstones:
bright, white, hyperechoic structures within the
gallbladder, that will cast an anechoic shadow.
Signs of cholecystitis
Sonographic Murphy sign
With your probe over the gallbladder, push on it; if
it causes the most pain over the abdomen, this is
positive sonographic Murphy sign.
38
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Pericholecystic fluid
This is (often subtle) inflammatory fluid around
the gallbladder.
Pericholecystic fluid, short-axis view
Pericholecystic fluid, long-axis view
Anterior wall thickening
An anterior gallbladder wall thickness of less than
4 mm is normal.
Anterior gallbladder wall, acute cholecystitis
WES sign
The wall echo shadow (WES) sign indicates acute
cholecystitis. Here, the gallbladder is full of stones,
such that all you see is a large anechoic shadow.
WES sign, acute cholecystitis
39
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RENAL AND BLADDER
Understanding when to perform a renal scan
Consider getting renal ultrasound instead of a CT scan for patients with high clinical suspicion
for renal colic. If hydronephrosis is present, the current recommendation is to provide pain
medication and nausea medication for a trial period, and allow time for the renal stone to pass.
D
USE
FOC
?
Is there
hydronephrosis?
40
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RENAL AND BLADDER
Performing a renal study
Using a low frequency probe, placed in a coronal cross section in the lower rib spaces, examine the kidneys.
Orient the indicator to the patient’s head for a long-axis view, and rotate the probe 90 degrees, with the
indicator pointing towards the ceiling, for a short-axis view.
Renal, long-axis view
Renal, short-axis view
Marker
to ceiling
Marker
superior
41
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Using a low frequency probe, placed low over the suprapubic region and pointed down towards the patient’s
feet, examine the bladder. Orient the indicator to the patient’s right for a short-axis view, and towards the
patient’s head for a long-axis view.
Bladder, short-axis view
Bladder, long-axis view
Marker
right
Marker
superior
42
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RENAL AND BLADDER
Evaluating for hydronephrosis
Renal cortex
Renal pyramids
Renal artery
Renal pelvis
Renal vein
Ureter
Hydronephrosis is always seen in
the renal pelvis first due to a back
up from the ureter.
There are multiple grades of hydronephrosis: mild, moderate, and severe.
Mild
Moderate
43
Severe
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Mild
Moderate
The dilation is contained to the renal pelvis only.
The dilation has spread from the renal pelvis into
the calcyes.
Severe
The dilation has spread to the cortex, and you will
often lose the shape of the kidney.
44
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RENAL AND BLADDER
How to measure bladder volume
Using a linear probe, start by obtaining long- and short-axis views of the bladder.
Bladder, short-axis view
Bladder, long-axis view
Marker
right
Marker
superior
Measure the length and width in the short-axis view. Measure the depth in the long-axis view. Multiply the
length X width X depth X 0.7 to find the bladder volume.
45
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FIRST TRIMESTER PREGNANCY
Knowing when to scan in first trimester pregnancy
D
USE
FOC
?
Is there an ectopic
pregnancy?
While ruling out ectopic pregnancy is the main focus for a pregnancy scan, other evaluations
such as gestational age, ovarian cyst, and ovarian torsion, can also be performed.
46
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FIRST TRIMESTER PREGNANCY
Performing a pelvic ultrasound study
Isthmus
Fallopian tube
Fundus
Ampullary
Body
Cervix
Uterus
Ovary
For a pelvic ultrasound study you would use a transabdominal or endocavitory probe depending on
gestational age.
Gestation
Later (> 8 weeks)
Earlier
Bladder
Full
Empty
Scanning field
Wide
Narrow
Resolution
Less
Increased
47
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Transabdominal short-axis view
Transabdominal long-axis view
Endocavitory short-axis view
Endocavitory long-axis view
48
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FIRST TRIMESTER PREGNANCY
FIRST
TRIMESTER PREGNANCY
Confirming a definitive intrauterine pregnancy
Confirming a definitive intrauterine pregnancy
To confirm a definiteive intrauterine pregnancy on an
ultrasound, you need to find a gestational sac and a
To confirm
a definiteive
intrauterine pregnancy on an
yolk
sac within
the uterus.
ultrasound, you need to find a gestational sac and a
yolk sac within the uterus.
Gestational age
Gestational
age age, you can expect different findings on ultrasound.
Depending
on gestational
4.5–5on
weeks
weeks different findings5.5–6
weeks
Depending
gestational age, you 5–5.5
can expect
on ultrasound.
6 weeks
4.5–5 weeks
5–5.5 weeks
5.5–6 weeks
6 weeks
Gestational sac
Gestational sac
+ yolk sac
Gestational sac
+ yolk sac
Gestational sac
+ yolk sac
Gestational
+
fetal pole sac
+ yolk sac
+ fetal pole
Gestational sac
+ yolk sac
Gestational
+
fetal pole sac
yolk sac
+ heart
beat
+ fetal pole
+ heart beat
Gestational sac
With a transabdominal probe you can expect to see things about one
week later than when using an endovaginal probe. For example, you
With a first
transabdominal
probe you
expectweeks
to see(not
things
about weeks).
one
would
see the gestational
saccan
at 5.5–6
at 4.5–5
week later than when using an endovaginal probe. For example, you
would first see the gestational sac at 5.5–6 weeks (not at 4.5–5 weeks).
Fetal heart rate
Fetal
rate to calculate the fetal heart rate
You canheart
use M-mode
(normal is 120–160 bpm).
You can use M-mode to calculate the fetal heart rate
(normal is 120–160 bpm).
49
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FIRST TRIMESTER PREGNANCY
Evaluating for an ectopic pregnancy
Given the right clnical setting, the absence of a definitive intrauterine pregnancy visualized on ultrasound,
should be considered an indicator of ectopic pregnancy, until proven otherwise.
Free fluid
Free fluid is often visualized around the uterus, and/or in the right upper quadrant, in a ruptured ectopic pregnancy.
50
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FIRST TRIMESTER PREGNANCY
Determining gestational age
There are various techniques for confirming gestational age, based on the estimated gestational age per last
menstrual period.
Crown-rump length
Skull biparietal diameter
Femur length
Crown-rump length
Biparietal diameter
Measure the longest length from the crown (head) to
the rump (buttocks).
Measure the outer wall to inner wall of the skull at
the level of symmetric ventricles (level of thalamus).
(Femur length is not used until later in pregnancy.)
51
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ORBITAL
Knowing when to perform an orbital scan
D
USE
FOC
?
General assessment
of the eye to look
for common ocular
emergencies as well
as normal findings.
An orbital scan can be used for patients presenting with many concerns:
•
•
•
•
•
•
visual loss
visual defect
eye pain
orbital trauma
foreign body
headache/increased
intracranial pressure
52
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ORBITAL
Imaging the normal orbit
Sclera
Choroid
Retina
Cornea
Fova
Pupil
Lens
Iris
Optic nerve
Ciliar body
Using a high-frequency linear probe, and lots of gel,
place the probe gently over the eyelid. Place the
indicator to the patient’s right for a short-axis view,
and to their head for a long-axis view.
53
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General anatomical assessment
Optic nerve sheath diameter
On your image, identify the following structures:
anterior chamber, pupil, lens, and retina.
You should also measure the optic nerve sheath
diameter (B), which can be easily measured from the
posterior orbital wall. A normal measurement is
< 0.5 cm (B) when measured 0.3 cm posterior to wall (A).
Pupillary constriction
You can evaluate for pupillary constriction on an
ultrasound, in a similar manner to how you would in
a physical exam: keeping the scanned eye closed,
shine a flashlight into the open eye.
54
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ORBITAL
Evaluating for critical ocular pathology
Retinal detachment
Vitreous hemorrhage
Retinal detachment is seen best with reduced gain.
It appears as a ribbon-like structure, attached to the
posterior wall, within the vitreous chamber.
Vitreous hemorrhage is seen best with increased
gain and during a kinetic exam (moving eye). It
appears as detached hyperechoic particles floating
within the vitreous chamber.
Posterior vitreous hemorrhage
Globe rupture
A posterior vitreous hemorrhage has a hyperechoic
free-floating seaweed-like appearance, best seen
with increased gain and during a kinetic exam.
A globe rupture of the orbit is the loss of the normal
round shape. If this is noted, remove the probe and
do not put any further pressure on eye.
55
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Foreign body
Lens dislocation
A foreign body appears as hyperechoic material with
a shadow (often in the form of a ring-down artifact)
within the orbit.
Lens dislocation is indicated with the presence of a
hyperehoic lens within the vitreous chamber.
Retrobulbar hematoma
Retrobulbar hematoma appears as anechoic fluid
posterior to the orbit, in a traumatic patient.
56
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LOWER EXTREMITY STUDY
(DEEP VENOUS THROMBUS)
Understanding when to perform a deep venous study
If a patient presents with unilateral leg swelling or edema, this is a concern for deep venous thrombus (DVT).
D
USE
FOC
?
Is there an acute
lower extremity DVT?
POCUS has been shown to be effective in ruling out
acute DVT easily.
A DVT study is performed by attempting full
compression of lower extremity veins by the ultrasound
probe, at two points: the femoral region and the
popliteal region.
57
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LOWER EXTREMITY STUDY
(DEEP VENOUS THROMBUS)
Evaluating the femoral region for an acute DVT
Using the linear probe, placed high in the inguinal
region, evaluate the proximal femoral vein. Scan
distally for 5 cm, with graded compression every
1 cm, to evaluate for vein collapsibility.
Lateral
Marker
lateral
Medial
Superficial
femoral artery
Saphenous
vein
Deep femoral
artery
Common
femoral vein
Compression test
With the probe over the vein, push down on the leg
and see that the vein completely collapses (winks
at you!). If it does not compress, or only partially
compresses, with pressure, this is a positive study
for an acute DVT.
Normal
58
Abnormal
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LOWER EXTREMITY STUDY
(DEEP VENOUS THROMBUS)
Evaluating the popliteal region for an acute DVT
The patient should be placed in the prone
position, preferably.
Using the linear probe, placed high in popliteal fossa,
evaluate for the trifurcation of veins (anterior tibial,
posterior tibial, peroneal). From that point, scan
proximally for 5 cm, with compression every 1 cm.
Lateral
Marker
lateral
Popliteal
vein
Popliteal
artery
Medial
Compression test
With the probe over the vein, push down on the leg
and see that the vein completely collapses (winks
at you!). If it does not compress, or only partially
compresses, with pressure, this is a positive study
for an acute DVT.
Normal
59
Abnormal
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SOFT TISSUE
Knowing when to perform a soft tissue exam
D
USE
FOC
?
Is there cellulitis or a
fluid collection, or is
it normal tissue?
Performing a POCUS soft tissue exam can help you easily differentiate between
normal tissue, cellulitis, and an abscess.
60
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SOFT
TISSUE
SOFT TISSUE
Identifying normal versus abnormal
Identifying normal versus abnormal
Using a linear probe, placed over area of interest, assess the anatomy of the tissue.
Using a linear probe, placed over area of interest, assess the anatomy of the tissue.
Normal tissue
Normal tissue
In normal tissues, you can easily identify various
In normal
tissues,
can easily identify various
fascial
planes
and you
layers.
fascial planes and layers.
Abscess
Abscess
An abscess in indicated as anechoic fluid filled area
An abscess
in indicated
as(pus)
anechoic
fluid
filled area
with
hyperechoic
material
within
it. Pushing
with
hyperechoic
material
(pus)will
within
it. the
Pushing
on
the
abscess with
the probe
cause
pus to
on thearound,
abscess
with the
will cause
the pus to
swirl
causing
theprobe
“pustalsis”
effect.
swirl around, causing the “pustalsis” effect.
61
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Cellulitis
In tissue with cellulitis, there is a loss of fascial
layers and/or a cobblestone effect.
Loss of layers
Cobblestone effect
62
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Understanding the principles
Ultrasound guidance for needle-related procedures was
among the earliest uses for point of care ultrasound.
Use the linear probe (because you are usually
viewing superficial structures) in long- or short-axis
to find the target and visualize the tip of the needle.
You can use the static approach or the dynamic
Short axis/out-of-plane
approach. In the static approach you visualize the
area and assess for the best location, mark the skin
and then put the probe down before performing the
procedure; in the dynamic approach you visualize
the area and perform the procedure simultaneously,
under ultrasound guidance.
Long axis/in-plane
Make sure you are always aware
of where the needle tip is while
advancing your needle.
63
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Central venous access
Central access has multiple indications and
ultrasound guidance can be helpful in many cases:
•
•
•
difficult vascular access
central venous pressure monitoring
multiple ports
However, ultrasound guidance is most commonly
used for securing internal jugular access.
Using the linear probe in short or long axis, visualize the
venous vessel (often larger) that will easily compress.
Short-axis approach
Long-axis approach
64
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Note the distance from the skin to the vessel. Enter
the skin, at a 45-degree angle, at the same distance
away from the needle as the vessel is under the skin.
This ensures that when you are about to puncture
the vessel your needle tip will be directly visualized
under the probe. Remember to visualize your needle
tip at all times.
Skin
Skin
Target vein
65
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Peripheral venous access (PIV)
Ultrasound guidance is great for accessing difficult peripheral veins for intravenous placement. Review the
anatomy in the upper extremity where you would consider placing an IV and note the location of the large
superficial compressible veins.
Axillary
Cephalic
Brachial
Median cephalic
Basilic
Median cubital
Accessory caphalic
Median basilic
Median antebrachial
Palmar digitalis
Using the linear probe, make sure you are in good
position to visualize the screen while puncturing the
skin, and that you have your all supplies for placing
the IV in proximity.
And remember to take note of the
depth of the vessel and move the
needle tip back the same distance
before inserting.
66
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Paracentesis
Use a lower frequency probe to evaluate the area and mark for a static approach. If you choose to perform
the procedure dynamically, switch to a linear probe for better visualization of the needle.
Epigastric
vessels
You can place your probe in one of three locations
for performing a paracentesis. The preferred location
is either in the right lower quadrant (RLQ) or left lower
quadrant (LLQ). The midline approach is associated
with an increased risk of iatrogenic injury.
1
3
Bladder
Ensure at least 2 cm of fluid, without any structures
or vessels, for a safe procedure.
If performing midline, ensure that the
bladder has been emptied to minimize
the risk of bladder puncture.
67
Epigastric
vessels
2
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Thoracentesis
Use a lower frequency probe to evaluate the area and mark for a static approach. If you choose to perform
the procedure dynamically, switch to a linear probe for better visualization of the needle.
You can place your probe in one of two locations for
performing a thoracentesis: zone 4 of the right or
left lung.
You can perform the procedure with the patient
supine or with the patient sitting up.
It is important to visualize the diaphragm and assess
how large the effusion is, then choose a safe entry
point above the diaphragm that is within the effusion.
Scapula
Diaphragm
Once you select your entry point, make note of the chest
wall depth (as well as where the lung tissue is) so
that you know how deep to go to safely aspirate fluid.
Remember to enter with the needle right
above the rib, to avoid the neurovascular
bundle that sits beneath.
68
Diaphragm
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ULTRASOUND GUIDED
ULTRASOUND-GUIDED
PROCEDURES
Lumbar Puncture
Ultrasound guidance for lumbar puncture is helpful in patients where this procedure may be difficult due to
the patient’s habitus or a known variation of anatomy (e.g., scoliosis).
Traditionally the lumbar puncture is attempted at level of L4–L5.
L1
Conus medullaris
L2
Suprasinal ligament
Cauda equina
L3
L4
L5
S1
Cortical rim
Body
Cancellous
Transverse
process
Pedicle
Superior
articular
process
Vertebral foramen
Lamina
Spinous process
69
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Using a linear probe oriented for a short-axis view,
evaluate for midline by looking for a spinous process
at the level of L4. Mark the skin above and below the
probe, and connect the marks to draw a vertical line
Then, with the linear probe held over vertical line you
have just drawn, and oriented for a long-axis view,
evaluate for the interspinous space between the L4
and L5 spinous processes. Mark the probe on either
side, and connect the marks to draw a horizontal line.
Where the lines intersect is the point of entry for the
lumbar puncture.
70
APPENDIX
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Reference list
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Costantino, TG, Bruno, EC, Handly, N, et al. 2005. Accuracy of emergency medicine ultrasound in the evaluation of abdominal aortic aneurysm. J Emerg Med. 29: 455–460.
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Jalli, R, Sefidbakht, S and Jafari, SH. 2013. Value of ultrasound in diagnosis of pneumothorax: a prospective
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Kendall, JL and Shimp, RJ. 2001. Performance and interpretation of focused right upper quadrant ultrasound
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Lichtenstein, DA and Menu, Y. 1995. A bedside ultrasound sign ruling out pneumothorax in the critically ill.
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Lichtenstein, D, Mezière, G, Biderman, P, et al. 1999. The comet-tail artifact: an ultrasound sign ruling out
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PMID: 10342512
Lichtenstein, DA, Mezière, GA, Lagoueyte, J-F, et al. 2009. A-lines and B-lines: lung ultrasound as a bedside
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Mayo, PH, Goltz, HR, Tafreshi, M, et al. 2004. Safety of ultrasound-guided thoracentesis in patients receiving
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