Original subtitles

hi everyone today we're going to talk

about pulmonary oedema and before we

look at some radiographs I just want to

show you schematically what we're gonna

be talking about so this isn't exactly

anatomically correct but for the

purposes of this talk it's going to be

very useful so what we have here is a

cluster of alveoli and at the periphery

of this cluster avalue alveoli we have a

pulmonary capillary or venule okay and

in between the two is the pulmonary

interstitial so let's think for a second

about a patient with left ventricular

heart failure so a patient with LV

failure has increased pressure in the

left ventricle that gets transmitted to

the left atrium and that gets

transmitted to the pulmonary veins the

pulmonary veins will respond initially

by dilating and this is not yet

pulmonary edema

this is a redistribution of blood in the

lungs and usually what happens is in a

normal person the veins in the lower

lungs are larger than the veins in the

upper lungs well in a patient in the

early stages before pulmonary edema

there's a cephalization of the blood

flow in which the veins in the upper

lungs will dilate and they'll be about

equal or even greater in size to the

veins in the lower lungs and in this

stage this is called pulmonary vascular

congestion or cephalization of the

pulmonary vasculature but it's not yet

over

edema because the fluid is still in the

pulmonary vessels so as that pressure

continues to increase however then fluid

will start to leech out from the vessels

into the interstitial space okay and

that I'm going to demonstrate by this

blue line in the interstitial so this is

called interstitial pulmonary edema and

this is actual pulmonary edema because

fluid has now left the pulmonary veins

and capillaries as that fluid continues

to build up it spills out of the

interstitial space and goes into the

alveolar space

and this is the final stage of pulmonary

oedema and it's called alveolar

pulmonary edema or airspace edema when

you have an actual patient with

pulmonary edema you're gonna see a

little bit of pulmonary edema that's

airspace and some pulmonary edema that's

interstitial the appearance is usually

very heterogeneous so what I've tried to

do with this is give you an overview of

the pathophysiology of pulmonary edema

so just as a review we start out with

increased hydrostatic pressure which

causes pulmonary vascular congestion and

cephalization of the pulmonary vessels

and then fluid leaves the pulmonary

vessels and goes into the interstitial

space where we then have interstitial

pulmonary edema and then fluid then

spills into the alveolar space in which

point we get alveolar pulmonary edema

all right so let's look at some

real-life examples of pulmonary edema on

radiograph ok so let's take a look at

this example this is a patient with CHF

you can see that their heart is slightly

enlarged and when i zoom in on the

vessels when I'm trying to figure out if

they have pulmonary edema or not I take

the vessels in the upper lung and I

compare those vessels to an equidistant

point in the lower lung equidistant from

the hila and you can see that these

vessels in the lower lung this one is

behind the diaphragm here are slightly

larger than the vessels appear in the

upper lung which seem to be a little bit

smaller and thinner okay and this is a

patient who has no pulmonary edema okay

so let's take a look at this same

patient a couple days later when they

developed pulmonary edema so at this

time what you'll notice about the

vessels is that these vessels in the

upper lung are now equal in size to the

vessels in the lower lung and the other

thing is they appear to be crowded as

well right and that is because not only

are the vessels more enlarged but they

are not as well-defined as they were on

the prior study okay so let me just zoom

this in here

and we'll compare the exact spot so

notice how you could see and define the

borders of these vessels very well when

they have normal lungs but now the

borders of these vessels becomes very

fuzzy right and the other findings that

you'll see here are that you'll see

vessels all the way out in the lung

periphery and these are curly B lines or

inter lobular septal thickening okay so

this is a patient who has interstitial

pulmonary edema but remember that I told

you that most patients with pulmonary

edema will have some interstitial and

some alveolar edema well in this patient

there's also alveolar edema as well so

all of this stuff down here this stuff

down here represents alveolar edema okay

so in this patient we have interstitial

pulmonary edema with these curly B lines

and this indistinct pulmonary

vasculature and we have alveolar edema

okay how about a more subtle case so

here I have the same patient again as in

the earlier example and I just want to

zoom in into the right upper lobe and

what I want you to notice is that in the

right upper lobe here we have those same

three vessels 1 2 3 but in this example

those vessels are dilated but as opposed

to the other example you could still see

the borders of these vessels very well

so I would say that in this example we

don't have overt pulmonary edema but

instead we have cephalization of the

pulmonary vasculature or pulmonary

vascular congestion without over edema

in other words the vessels or the blood

has redistributed to the upper lungs but

the edema fluid has not leached out of

the blood vessels into the interstitial

space

the point that I'd like to make here is

that some radiologists use different

terms for pulmonary edema so I am using

the term pulmonary vascular congestion

to mean a redistribution of blood in the

lungs but without actual edema some

radiologists used the term pulmonary

vascular congestion to mean pulmonary

edema

okay so it's important at wherever

institution and you're working at to

understand the vocabulary that people

are using so that everybody can be on

the same page so let's take a look at

another example so in this case I'm

looking at the vessels and trying to

determine if there's pulmonary edema and

I think in this example that the vessels

are sharp the borders of the vessels are

very well demarcated and the vessels in

the upper lungs are smaller than the

vessels in the lower lungs so in this

case I would say that there's no

pulmonary edema this is normal well a

day later you could see that there's

been a big change first of all the

vessels in the upper lungs are a lot

more indistinct that means that the

edema fluid has moved from the vessel

the vessel to the interstitial space and

then another even better sign here is

that we have inter lobular septal

thickening and that is manifest by these

curly B lines which are short one

centimeter lines in the lung periphery

and this represents fluid in the

interstitial space so this is a patient

with interstitial pulmonary edema if we

go further even one day further we could

see that there has been an increase in

the amount of pulmonary edema and rather

than seeing just lines what we have here

are fluffy airspace opacities in both

lungs so in this case we have alveolar

edema but remember that in most cases

where you have alveolar edema you will

still have interstitial edema and if we

zoom in to the right lower lung

we have curly B lines here so we have

alveolar edema and interstitial edema

both

okay let's take a look at another

example so this is our baseline study

here and you can see at this point that

the patient has a swan-ganz catheter

they also have a big heart and they have

an AI CD in place so already I'm

thinking that I should be on high alert

for pulmonary edema so what I'm trying

to decide whether they have pulmonary

edema let's zoom this up and let's look

at the vessels so the vessels here in

the upper lungs I would say are very

sharp and they're normal in size the

vessels in the upper lungs are smaller

than the vessels in the lower lungs so

let's look at a follow-up study a couple

days later now the first thing you'll

notice when you look at this follow-up

chest x-ray is that the vessels in the

upper lungs and the lower lungs for that

matter have dilated in comparison to the

baseline study so that tells us that

there has been redistribution of

pulmonary blood and this is pulmonary

vascular congestion now the next

question of course is is this simply

pulmonary vascular congestion or is

there also interstitial pulmonary edema

and what I would say is that these

vessels while they are dilated they

still remain sharp I could still see the

borders of them very clearly therefore

the fluid remains in the pulmonary

vessels and has not yet leached out into

the interstitial so I would call this

pulmonary vascular congestion without

over edema so that was the last example

and I hope you all learned something

today about the radiographic appearance

of pulmonary edema if you have any

questions about this video or other

concepts that we've discussed feel free

to leave a comment below or you can

direct message me my contact information

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