0:01

We just saw emphysematous cholecystitis

0:03

with a bit of portal venous air, the, uh,

0:05

blood vessels draining the gallbladder,

0:07

Obviously going to the liver. And if you

0:09

have air within the gallbladder wall,

0:10

you may get some portal venous air.

0:12

But let's go on a side quest.

0:14

Okay, this side quest: air in the liver.

0:17

What is different?

0:19

Two separate patients.

0:20

Take a look at this for a moment.

0:23

Who would you rather be?

0:24

I like to play

0:24

"would you rather"

0:25

all the time when I'm working,

0:26

uh, teeth for hair or hair for teeth.

0:28

But it's always a good way to think out whether

0:30

or not something is either normal or completely

0:34

abnormal because frequently, findings can

0:36

strangely be on that extreme of the spectrum.

0:39

So here on the right we have a patient who

0:41

has, um, a lot of air within the liver,

0:43

but notice that it's very central and that

0:45

it is paralleling the portal veins here.

0:48

This is pneumobilia; this is air within the bile system.

0:52

You can imagine that this patient has had a prior

0:53

sphincterotomy, or maybe passed a stone, or has a

0:56

Whipple, or some reason why that duodenal papilla

0:59

sphincter is no longer working, allowing air

1:01

from the GI tract to reflux into the liver.

1:05

I always think of this in a way to keep my mind

1:08

on why it's frequently central in location.

1:11

Remember that bile goes from the periphery

1:13

of the liver, and it drains very slowly.

1:16

I mean, bile is like low-key, right?

1:18

It's not moving too fast.

1:19

It's going slowly down the bile ducts.

1:21

Down to the common bile duct

1:23

and then into your GI tract.

1:24

So you can imagine that air refluxing up into that

1:28

slow system would be caught centrally within the liver.

1:32

As opposed to our patient here on the left who, um,

1:35

has a very dramatic appearance of portal venous air.

1:37

You can see the air is within

1:38

the periphery of the liver here.

1:40

There's always these little tiny branches throughout

1:42

the liver, and this is air moving in blood pool.

1:46

So this is air coming from

1:47

either air within the gallbladder, like

1:50

in our case, or air within the bowel.

1:52

Some reason that there is air that has gone from

1:55

the GI tract intraluminal into the wall of a viscus

1:59

that is drained by the portal system and is now

2:01

going into the liver and moving in blood pool quick.

2:04

This is a highway, right?

2:05

Blood flows quick and goes out

2:07

into the periphery of the liver.

2:10

So this is pneumobilia, and here is portal venous air.

2:14

Obviously, you would choose to have

2:15

pneumobilia over portal venous air, because

2:17

that's usually fairly catastrophic.

2:19

So pneumobilia on ultrasound will just

2:21

be little echogenic foci causing dirty

2:24

shadowing, and that's a typical appearance.

2:25

Frequently, it's going to be very central.

2:27

You're not going to see any movement

2:28

of those little foci frequently.

2:30

You can correlate it with a history of a sphincter-

2:32

otomy, or ask your clinicians if the patient's had

2:35

a sphincterotomy as opposed to portal venous air,

2:38

which is frequently in the periphery.

2:39

See in this left lobe of the liver on

2:41

ultrasound, you can see the branching

2:42

just in the very periphery of the liver.

2:45

This is actually a good indication of why bedside

2:48

ultrasound is so valuable in the ICUs, because you can

2:51

basically put an ultrasound probe on that left lobe

2:54

and see if there's anything echogenic and moving.

2:57

Here is a patient with pneumobilia. Again, by convention,

3:00

we have the portal vein back here.

3:01

Here's the hepatic artery, here's that common bile

3:04

duct with those echogenic foci as opposed to, um, this

3:07

patient with, uh, portal venous air where it moves.

3:11

And this is a cine clip just

3:12

showing those actual echogenic

3:14

air bubbles going into the portal vein.

3:17

I mean, this is as dramatic as you can get.

3:19

I do love drama whenever possible, so I

3:21

always try to bring these cases to my trainees.

3:24

And this is something where you may want to

3:25

just like run and hide if you see this.

3:28

Yeah.

3:28

Run the other direction.

3:30

This is a case of a patient with that pneumatosis

3:32

intestinalis where you have air within the wall

3:35

of the small bowel, which is outside of, you

3:37

know, the discussion of this case, but still fun.

3:39

And you can see that portal

3:40

venous air into the liver as well.

3:42

So when you see portal venous air, remember that it

3:45

is, uh, frequently from a GI tract, and you're looking

3:48

for, uh, signs of necrosis or whatnot in the bowel.

3:51

Um, in our patient, we had a necrotic, air-

3:55

distended emphysematous cholecystitis.