Thoracic POCUS + Lung Ultrasound Flashcards
a thoracic POCUS evaluates:
1) Pleural air
2) Pleural fluid
3) Pericardial fluid
4) Bedside echo
a lung ultrasound evaluates:
Dry lung (normal)
Wet lung (disease)
Consolidated lung
Nodules
a dry lung is a lung that is
full of air (normal)
What are the benefits of thoracic POCUS
-Done bedside
-Discriminating
-Inexpensive
-Radiation sparing
-Repeatable
What probe do you do thoracic POCUS with
curvilinear 5-10mHz
How do you do thoracic POCUS
-Probe perpendicular to ribs
-Notch towards head
-Depth varies
-Pause at each intercostal space: tells motion of the lungs
For thoracic POCUS, the probe should always be places
perpendicular to ribs
ribs give a landmark to tell where you are
For thoracic POCUS, the notch should always face
towards the patient’s head
What is the safest patient position for patient positioning
Sternal or standing -
most of lung volume is located dorsally
if flipped on back, gravity collapses lungs
What are the layers that you should know when doing thoracic POCUS
1) Ribs
2) Parietal pleura (doesnt move)
3) Layer of serous fluid
4) Visceral pleural (attached to lung)
5) Lubrication fluid
6) Lung
Pathology in the pleural space causes separation of the
Parietal pleura and viscera pleura
to see the gator sign, the probe needs to be positioned
perpendicular to the ribs
What is the gator sign
a sign that is seen when you position the probe perpendicular to the rubs
each eyeball is the rib head and you see a pleural line connecting the two eyes
as well as rib shadows
What is the glide sign
parietal pleura (attached to body wall) meets the viscera pleura (stuck to lung surface) slides past each other as the lung changes in shape in expiration and inspiration
With the glide sign, what should you be looking for
1) Two pleural surfaces are in contact with one another (no air or fluid between)
2) That you have lung underneath that is air filled
T/F: ultrasound waves can penetrate air
False
How does pneumothorax impact glide sign
it causes it to be absent
What are the 5 sites in thoracic POCUS
1) Caudo-dorsal site (Left & Right)
2) Middle (Left & Right)
3) Subxiphoid
What is the purpose of the caudodorsal site on thoracic POCUS
screen for pneumothorax
-air always rises
-if the patient has a glide sign then no pneumothorax (especially here)
T/F: if the patient is in lateral then the caudodorsal site is not the preferred site to screen for pneumothorax
False- thorax is dome shaped. this is still the place you should screen for pneumothorax
How do you get to the caudodorsal site for thoracic POCUS
palpate the xiphoid and go straight up
aiming for intersection of middle 1/3 and dorsal 1/3 of thorax
What does a pneumothorax look like on thoracic POCUS
there is no glide sign
the visceral pleura drops away from the parietal pleura
cant see the lung because ultrasound cant penetrate air
if you see the absense of a glide sign on ultrasound, what can you do to confirm
aspirate and if you get air then you get your diagnosis
if you lose your glide sign, how might you move the probe to confirm it
move it cranioventrally
this is because air moves upwards
How can you assess how serious a pneumothorax is
Lung line- assess where the glide sign is lost
if the lung line mid thorax = moderate
if lung line isnt seen until ventral then more severe
With SQ emphysema, what is seen on your thoracic POCUS
cant see gator sign (rib heads), because there is air in the subcutaneous tissue - just see air (grey)
need to push probe down to see gator sign and then you can evaluate for glide side (pneumothorax)
How do you evaluate for pneumothorax if there is SQ emphysema
need to push probe down to see gator sign and then you can evaluate for glide side (pneumothorax)
T/F: if you dont have air in the caudodorsal site, you dont have a pneumothorax
True- air always rises
What are you evaluating in the middle lung lobe site in thoracic POCUS
fluid -because it drops
(blood, pus, etc.)
Where do you place the probe for the middle lung lobe site
on the heart’s maximum intensity
then move cranially and caudally
What do you see on the middle lung lobe site if there is fluid
instead of gliding, you have separation of pleura
you will see through the fluid and see atelectic lung
What do A-lines mean
not much aside from air filled alveoli.
just visceral pleura reflections reflecting back at different times which gives it different depths
What fluids might be of pleural effusion
Blood
Pus
Neoplasia
Chyle
Transudate (CHF)
ultrasound cant help you discriminate
When doing thoracic POCUS of middle lung, what way do you move the probe
caudo-dorsally and mark the point in which you can see the glide sign
Moderate = mid
Dorsal = severe
What is significant of the cardiac view when doing thoracic POCUS
Left side CHF
-Left atrium might be big then it is CHF
What are the two cardiac views you can do when doing a thoracic POCUS
1) Short Axis plane
2) 4 chamber view
What should you see on the R short axis view of heart
Mushroom view - left ventricle with papillar views and then a sliver of right ventricle above
gets bigger in diastole and smaller in systole
What should you see on R short axis view of the heart and the probe is angled towards the heart base
Mitral valve leaflets - and fish leaflets
if you keep fanning more then you can get the Ao:LA ratio
What should the aorta to left atrium ratio be?
about 1 : 1-1.6
How do you quickly rule out left side CHF
look at Ao: LA ratio on the right short axis, fanned up to the base of the heart
T/F: you can assess for arrhymthias on ultrasound POCUS
true
How can you assess for pericardial effusion on ultrasound
probe in middle lung lobe site
see bright white snowglobe (pericardium) with anechoic fluid and heart in the middle
How might a dog get pericardial effusion
-Neoplasia (HSA)
-Idiopathic
-Coagulopathy
-Trauma (penetrating)
-Right CHF
-Infection
How might a cat get pericardial effusion
-CHF (left or right)
-FIP
-Neoplasia (LSA)
-Chyle
-Vasculitis (uremia)
a medical condition where fluid accumulates in a closed space, putting pressure on surrounding structures. In the context of the heart, cardiac tamponade occurs when fluid builds up in the pericardial sac, the thin layer surrounding the heart.
tamponade
What side of the heart is at most risk for tamponade
the right heart (less pressure) - collapses the right heart, which leads to no venous return and no cardiac output
Cardiac tamponade leads to
1) Collapsed R heart
2) Little to no venous return to heart
3) Little to no cardiac poutput
Why do we do a pericardiocentesis from the right side?
because you dont want to lacerate the Left coronary artery
Always do a pericardiocentesis on what side
RIGHT
(the left has a massive coronary artery you do not want to lacerate)
What sign does the normal thorax have
glide sign
What are kinds of pleural pathology you might see on thoracic POCUS
Fluid
Air
Masses (neoplasia, granuloma, lymphnodes)
Organs
What are the benefits of lung ultrasound
Bedside
Sensitive
Inexpensive
Radiation Sparing
Repeatable
What are the technical details when doing lung ultrasound
-Curvilinear 5-10mHz probe
-Perpendicular to ribs
-Notch toward head
-Depth 4-6 cm
-Pause at each IC space
When doing lung ultrasound, what is the order you go in
1) Caudo-dorsal
2) Peri-hilar
3) Middle
4) Cranial
5) Subxiphoid
For lung ultrasound, where is the caudodorsal lung site
around intercostal space 7-9
What is the curtain sign
a sign at the transition zone
-as breathes in, lungs slide over, as breathes out, they slide back
-this reveals the liver as lungs slide over
How do you minimize seeing abdominal contents in the transitional zone so you dont get it confused for lung pathology
just move ~3 intercostal spaces cranially so you are not within that transitional zone
How do you evaluate the caudo-dorsal lung field
go 3 intercostal spaces cranial from the transitional zone
then evaluate for wet/dry lung both 1 intercostal space cranially and caudally
How do you get to the perihilar lung space
about cranio-ventral from the caudo-dorsal view (about 5 or 6 intercostal space)
just look one intercostal space cranial and caudally
How do you get othe middle lung lobe site
about intercostal space 3-5 just feel for beat at highest intensity
if all you see is heart then move probe a little more dorsally
then look one intercostal space cranial and caudally
Where do you assess for the cranial lung site
put hand under armpit and hook in just cranial to first rib and then move into 3 intercostal spaces caudally
How do you get to the subxiphoid view
just caudal to the xiphoid, move probe cranially through the liver into the thorax cavity
How many sites should you look for dry / wet lung at each lung site
3 different places at each lung view x 2 (on each side)
1 time in the subxiphoid
What creates a B-line
interstitial fluid if cuffed by air filled alveoli (air) -doesnt say what causes it
B-lines drop directly from the pleural line because you are only seeing the fluid in the periphery of the lung tissue
What are the characteristics of a B-line *
1) Hyperechoic
2) Start from pleural line
2) Swing to and from (moves with respirations)
3) Unfading
4) Obliterate A lines
What are some causes of B-lines
anything that causes interstitial fluid to be cuffed by air
1) Cardiogenic edema
2) Non-cardiogenic edema
3) Hemorrhage
4) Contusions
5) Inflammatory cells/fluid
What will you see as interstitial edema gets worse
More B-lines (more fluid is cuffing air)
What will increase as the severity of edema increases
1) The number of B lines per site
2) Number of positive sites per hemithorax
this correlates with the severity of interstitial edema
What are the different ways you quantify B-lines
0
1
2
3
>3
Coalescing (infinite)
Why is the subxiphoid such a good place to look for lung pathology
because it goes through the liver
When might you see a coalescing B line
severe interstitial edema with alveolar filling: fluid cuffed by small volumes of air
Do normal lungs have lung rockets?
Not really but 11% of radiographically normal dogs had 1 lung rocket at 1 location
What do the lungs look like when there is no air to cuff
(Tissue) because there is no air filled in the lungs
Ultrasound is able to penetrate
Nonaerated regions of lungs look like what
hypoechoic
(in contrast, interstitial fluid cuffed by air look hyperechoic)
If the lung is really consolidated, then there is a less risk of _______ when aspirating a lung nodule
pneumothorax
Nodules and consolidated lung look like what on ultrasound
hypoechoic structure
harder to see deeper nodules because of air
What is the limitation of ultrasound to see lung masses
if the mass is deeper than 1cm then you cant see it because of the air
eventually you can get lucky if its close to diaphragm and you can see it with a subxiphoid view
In a distressed cat, how do you rule out left sided CHF
Do an ultrasound
Dry lungs rules out L CHF (then move onto pneumonia)
can also look at Left atrium, pericardial or pleural effusion
What ultrasound findings are consistent with L sided CHF in cats
1) Wet lung
2) Greater number of positive sites
3) Greater number of B lines per site
get that cat on furosemide
For a dog with vehicular trauma, what are your top 2 differentials that you can evaluate on lung ultrasound
1) Pulmonary contusions
or
2) Pneumothorax
wet lung rules out pneumothorax
you see a dog with contusions
b-lines (this rules out pneumothorax)
What do you see in dog with ocntusions and pneumothorax
just lack of glide sign and A lines
(the air of the pneumothorax make it impossible to see the contusions)
T/F: if a dog has a hemothorax, you cant see the lung contusions until you drain the thorax
true - allows the lungs to fully expand
Lung ultrasound can rule out
1) L sided congestive heart failure
2) Pneumothorax post trauma
What are the limitations of lung ultrasound
1) Cannot characterize types of interstitial fluid
2) Cannot evaluate pathology deeper than 2-3 mm
3) Cannot evaluate parenchyma in the presence of effusion or air
4) Replace thoracic radiographs or CT
lung ultrasound cannot evaluate pathology deeper than
2-3mm
T/F: lung ultrasound cannot evaluate parenchyma in the presence of effusion or airs
True
What volume of fluid is present in the pleural space of a labrador
2-5ml of fluid
The motion of the lung surface you see just deep to the ribs on TPOCUS is called
Glide Sign
Why do you always face your ultrasound probe perpendicular with notch towards the head
notch is always on the left of the screen (towards the head)
Where in the lungs would it sound dull with pleural effusion
cranioventral portion
On TPOCUS how does pleural effusion appear
fluid around the lungs, so then the fluid is hypoechoic around the lungs
What monitoring is very important when doing pericardiocentesis
EKG
When performing TPOCUS, hold ultrasound probe _____ to the ribs
perpendicular
On TPOCUS, B lines indicate
interstitial fluid cuffed by air
hyperechoic line when fluid is cuffed by air
*can only see very surface of the lung
What are the characteristics of B lines
1) Always start from lung surface
2) Hyperechoic
3) Unfading
4) Obliterate A lines
5) Swing to and fro (with expiration and inspiraiton)
Are B lines hyperechoic, hypoechoic, or anechoic
Hyperechoic
What type of interstitial fluid can lead to B lines on TPOCUS
any fluid
-cardiogenic edema
-non cardiogenic edema
-Hemorrhage
-Contusion
-inflammatory cells / fluid
maybe tell based on location but otherwise you need to tap that
T/F: you can track progress of patient by the number of B lines
True
What is your top differential for B lines at right middle lung lobe but fine everywhere else
Aspiration pneumonia
Dog has B lines in caudodorsal site, do they have a pneumothorax
No- lung surface is in contact with the wall
if there was a pneumothorax, you would never see the B lines below
What is the difference between consolidateds vs atelectasis
consolidated - stuff in the lung while atelectasis is normal lung that is collapsed down
