POCUS Lung

Introduction to Dyspnea

Dyspnea is one of the most common symptoms in medicine.

It has been estimated that dyspnea is the presenting problem in one to 2.5% of all patients visiting a primary care doctor.

The prevalence is even higher in emergency departments.

3.7 million visits to the United States Emergency departments are related to dyspnea as a chief complaint each year.

Causes of Dyspnea and Focus on Pleural Effusions

Indeed, there are many respiratory diseases that can cause dyspnea.

COPD, pneumonia, lung cancer, and pleural effusion, especially pleural effusions are easy to detect with ultrasound.

It can be applied in a primary care setting, for example, with the help of a handheld device.

When it comes to pleural effusions, ultrasound is more sensitive and specific than the chest x-ray.

Even small amounts of fluid can quickly be detected.

This is important since early diagnosis and early treatment can save lives.

Lecture Overview

In the following lecture, professor Thomas Binda from the Medical University of Vienna Department of Cardiology will show you how to image the lungs and how to detect pleural effusions.

The pleura, the chest wall, and the lung play a very important role in the etiology of dyspnea.

If you put it all together, more than half of all patients, especially in the elderly population, will have a pulmonic cause of dyspnea.

Now, there are obviously many reasons why the lung can be involved.

The good thing is with primary care ultrasound, we're able to diagnose many of these pathologies.

We'll be focusing here now mostly on pleural effusion, but be aware that pleural effusion is common in conditions such as pulmonary embolism, chronic thromboembolic, pulmonary hypertension, pneumonia, and lung cancer.

So we'll be covering these topics as well.

Role of Physical Exam and Patient History

And what is the role of the physical exam and the patient history in the diagnosis of pleural effusions?

Well, here are some facts.

The physical exam is helpful to rule out, but not to rule in pleural effusions, you need at least 500 milliliters of fluid, so you can actually detect a pleural effusion on auscultation and the other means of physical exam.

Many patients with pleural effusions are actually asymptomatic and a physical exam cannot differentiate between an exuded and a transited.

Role of Chest X-Ray

And what is the role of chest x-ray?

Well, of course you can detect pple effusions there, but again, you need a lot of fluid.

You need at least 300 milliliters to be able to see a pleural effusion on the chest x-ray and don't forget to have the problem of radiation.

All this is not present with ultrasound.

So primary care ultrasound plays a pivotal role in the diagnosis of pleural effusions, as you will see in this lecture.

Advantages of Lung Ultrasound

So to summarize, lung ultrasound allows dynamic imaging.

It is highly portable, provides immediate results, and it is more sensitive than any other modality we have to diagnose.

Pleural effusions,

Anatomy for Lung Imaging

The lung is obviously located within the rib cage.

Now the ribs themselves are a barrier to ultrasound.

Nevertheless, we have the intercostal spaces from where we can nicely see the lung no matter if we image from the front, from the side or from the back.

In the middle of the chest is the heart.

This is the structure which borders the lung, both the right and the left lung.

And then we have the dia rag, which is the coddle border of the lung.

This dia rag moves during inspiration moves downwards.

Remember, underneath the left lung we have the spleen, and underneath the right lung we have the liver.

Observing the motion of the dia frag during the ultrasound examination will provide a lot of information and we will need this if you wanna detect pleural effusions.

The lung is covered by the pleura.

We have the visceral part which lies directly on the lung, and we have the parital part in between is the pleural space.

This is exactly where pleural effusions accumulate.

Depending on the poster of the patient, the location will be more prominent in the one or the other part.

If someone, for example stands, then you will have most of the fluid in the basal parts of the lung.

If he lies on his back, you'll see it more in the dorsal regions.

So consider this when you image patients with a pleural effusion.

It's best to investigate the patient in upright position.

Place the transducer so that you orient it in a longitudal direction with a marker pointing to the head.

So cran, start in the front in the meoc clavicular line, then move to the side to the auxiliary lines.

And if you want to also to the back to the scapulary lines, observe especially the basal parts of the lung, so the motion of the diaphragm.

This is where you most frequently will find pleural effusions

Imaging the Lung with Linear Probe

Imaging The lung is actually quite simple, especially if you're only looking for a pleural effusion.

You can image the patient both in a supine position or if he sits up even in a halfer client position, it's possible to look at the lungs.

I will first focus on the linear probe and show you what we see here, and then we'll use the sector probe, which is in my view, better to image a pleural effusion.

So for the linear probe, we'll need to set the scanner to the lung program, which I'll do right now.

Then I will image the patient in the third intercostal space.

On the right side, I will place the transducer in such a way that the marker is pointing upwards so towards the head in a longitudinal direction.

So this is the image that I get.

Now I will just optimize the brightness by increasing the gain a little bit.

So what do we see here? We see the rib, which is the black spot right here.

We see an echo free space behind this rib, so we do not see very much of the lung right here.

If I'm slide the transfuser a little bit downwards, I'm now right in between two ribs.

Here we can see the subcutaneous tissue muscle and fascia of the chest, and we see this very bright line here.

This is the visceral and parital pleura.

Note that there is this motion, this sliding motion.

This is the normal finding of pleural sliding for anatomical purposes.

If you would image the patient on the back and you would see an echo free space here, that would denote a pleural effusion.

Underneath we see the lung, you'll see these bright horizontal lines, which are actually the A lines.

This is a normal finding of the lung.

You can perform this examination on different parts of the lung.

I'll now move to the other side and here you will see that we see a pretty similar finding with the only exception that we actually have the heart underneath beating.

But again, we have these echo free spaces which represent the ribs, the pleural sliding and the A lines.

Imaging with Sector Probe

Next I will show you how to use the sector probe to look for a pleural effusion.

We'll be imaging from the right and from the left upper quadrant.

So I'll put some gel right here and then place the transducer with the pointer with the marker.

Looking towards the head cranial here, I would be looking for the spleen, which you can see very nicely right here.

I will just adjust the brightness by increasing the gain a little bit more that you can see it better.

Underneath you see the kidney and the very bright semicircular line here is the pleura.

You will note that as the patient breathes, the pleura moves up and down.

If the patient has a pleural effusion, you would see an koic space right here, which we do not.

Now, if the patient would have such a pleural effusion, you can continue and move the transducer up one intercostal space to see how far this PLE effusion actually reaches.

In other words, you can kind of look at the size of the effusion.

Once we've looked at the left side, we can move to the right side.

Here we do pretty much the same thing Again, the marker is pointing upwards towards the head and we place a transducer here.

Now we see the liver, which actually gives us sometimes a better window to the pleura than the spleen.

On the other side here we see the liver, and right here underneath the liver is the kidney similar to the left side, we're looking for an anticoag space, which is not present here.

Detecting Small Pleural Effusions

This is actually as difficult as it gets.

Next I would like to show you how you can even exclude a very small pleural effusion, an effusion which is located in the sinus.

Let's double check if our model here truly has no pleural effusion.

So again, I will be imaging in a longitudinal direction with the marker pointing upwards.

Here I will be imaging the area where I expect the DIA rag to be, which is right here.

Again, you can see the interface between the pleura and also the liver.

Now with inspiration, you see that the image turns dark, so lung tissue is moving into the field of view.

This again is a indicator that there is no pleural effusion.

Now, if I move the transducer up a little bit, you will see that all of a sudden I only see lung tissue.

I see the typical A lines.

So I'm quite sure that there is no fluid within the pleural space.

There's another way to look at it.

This is a tip that I would like to give you, which I find quite helpful.

I rotate the transducer in a more horizontal position, and here I would image the liver and then move up one intercostal space or just slightly.

As a matter of fact, I'm still within the same intercostal space and all of a sudden I see the lung tissue with the A lines.

So again, there is no fluid that I see here in between.

I also find the horizontal position quite helpful.

If I wanna see how large a pleural effusion is in this situation, I would move up until this pleural effusion vanish is.

Now I know how far the effusion reaches upwards.

So you see it's not very difficult to really detect even a small ple effusion.

Tips for Imaging Pleural Effusions

A few final tips, if you image a patient, do not forget that you have to increase the gain so that you do not mistake a dropout.

For a pleural effusion, look for the atli tactic lung tissue, which often swims within a pleural effusion.

And finally, if you do have a patient where you know he has a pleural effusion which had been diagnosed previously, take the opportunity and image the patient yourself because that will make you more confident when you maybe for the first time encounter.

A pleural effusion,

Prevalence and Causes of Pleural Effusions

Pleural effusions are quite common.

We find approximately 1.5 million pleural effusions per year in the us.

This amounts to approximately 320 cases per a hundred thousand people.

So if you see patients, you will see pleural effusions.

Pleural effusions occur because there is an imbalance between the production of fluid and the removal.

Normally you have approximately 20 mls of fluid within the pleural space.

This is actually important so that the visceral and the peritol pleura can actually move.

If fluid accumulates, you will have separation of these two parts of the pleura and you'll see a space in between.

Under normal conditions, you will only have a separation of a few micro millimeters, so you will not see it in ultrasound.

So as soon as you see a separation, you can assume that a pleural effusion is present.

Here are some of the most frequent causes of a pleural effusion.

Congestive heart failure, specifically if there is right heart failure, infection, malignancy, kidney failure, pulmonary embolism and trauma.

Most frequently you will see pleural effusions.

However, in the setting of a cardiac disease, infection, pneumonia, and malignancies, especially if either lung is involved or if you have metastasis of the lung,

Pathophysiology of Pleural Effusions: Transudates vs. Exudates

to better understand the composition of the fluid which is in the pleural space.

Lemme go back a little bit to the pathophysiology.

Now, under normal circumstances, you have an equilibrium between the so-called hydrostatic pressure, which is the pressure within the vessels of the and the OID osmotic pressure caused by the plasma proteins which are in the vessel.

So almost no fluid will leak into the pleural space.

However, if you have high pressure within these vessels, for example, because there is congestion, this will cause an imbalance and fluid would leak into the pleural space.

Now, under these conditions, the fluid will be rather clear because no proteins are within the pleural space.

If you have a decrease in the OID osmotic pressure, in other words, if you do not have much protein in hyperemia, for example, in the pleural vessels, then two, there will be an imbalance and you will see leakage of blood into the pleural space.

So what you will see here is you will see transited if you have a defect of the vessel, leakage of the vessel wall.

In other words, an increased inter endothelial spaces here and proteins can actually move outta the vessel.

They will drag water with them.

Under these circumstances, you will have fluid accumulation, and at the same time, this fluid will be rich in proteins.

This is what we call an exited.

So the bottom line is if you have a transited, the fluid is clear.

You will not have many echoes within this fluid and an ultrasound, it will appear completely black.

If you have an ex exuded, you have proteins, maybe even fibrin, and the fluid will be dark and you will have echogenic pleural effusions.

We'll see examples of that later.

Now, when will you see an exuded and when will you see a transited?

Basically in the setting of infection and malignancy, expect an exuded and if you have congestion or cirrhosis with hypomania, you will have a clear fluid, a transited.

Imaging Examples of Pleural Effusions

Now it's time to take a look at some images and to look at how a pleural effusion can present.

Here on the left hand side, you have a phase array transducer, where we see an echo free space cranial to the diaphragm.

This is consolidated lung. This patient had pneumonia.

On the right hand side, you see a patient that does not have a pleural effusion.

How does a pleural effusion look if you use a linear transducer?

This is an example of a pleural fusion right here, this black echo free space, and you see the lung coming into the field of view right here.

This is the soft tissue which overlays the chest.

On the right hand side, you again see the lung here, but you do not see an echo free space.

What you see moving here is the pleura.

This is what we call pleural sliding.

Right here is a shadow. This shadow is caused by the rib.

Now let's take a look at one and the same patient and see how the pleural fusion looks if you use phase array transducer and a linear transducer.

Again, here we have the pleural effusion as an echo free space, and here we see the pleura as it moves.

This is the echo free space.

While the patient inhales, we see that in this region the pleura is kind of pressed towards the chest wall, but during the respiratory phase, we see this echo free space, which depicts a pleural effusion.

Of course, the size and the separation depends on where you are actually imaging.

The pleural the size of a pleural effusion can be looked at both with a phase array and also with a linear transducer.

With a linear transducer.

You will see a large separation right here while only a very small gap is seen in this patient here.

Just an example to demonstrate this once more, A patient who had pneumonia and pancreas carcinoma, we have a pleural effusion right here and the Alec lung tissue right underneath.

This is definitely a pleural effusion.

I guess you'll all agree that there is a pleural effusion, but if you look closely, you will see that even below the pleura there's an echo free space.

This is Aus, so remember sometimes you can catch both a pleural effusion and aus at the same time.

Of course, you can also measure the size of a pleural effusion.

To do that, he will look at the extent from a cranial to cowal position.

This is such an effusion.

Again, the alytic lung tissue, and here would be the measurement which is performed.

But basically, first it's important to make the diagnosis.

Of course, the size matters because it would depend on whether or not you can actually tap this pleural effusion.

That's why we're measuring this.

For example, I want to come back to the issue of whether or not a pleural effusion is an exuded or a transited.

Here on the left, you see a patient who had massive bacterial infection, a pneumonia.

In this case, you will see lots of fiber strands.

You can even see that this pleural effusion is chambered.

This is in sharp contrast to the effusion you see here.

The space here is completely black.

Right here again, you would see the etli tactic lung tissue within the pleural effusion.

Another example, fibro strands, a chambered pleural effusion and exited the same patient image.

Now with a linear transducer, pleural effusion and fibrous structures within this pleural effusion exited right here.

You would see massive organized, partially organized pleural fusion already.

Here's some other images that we took with another machine.

Look how bizarre these pleural fusions at times can look.

This is an exuded. Here.

You would have a esent effusion.

This is a transited. Here. You would have an exited.

This would be a more organized pleural effusion already.

And this image is just to show you that we could even image a pleural effusion if we perform a four chamber view because it is located lateral to the heart.

Remember, the position of the heart is in close proximity to the pleura.

Clinical Cases

Let's put all of this into a clinical context and let's take a look at some cases.

A 43-year-old man, he comes with fever and cough.

You put the transducer on the back on the lung, and you see this here, a pleural effusion.

As soon as you see this in combination with the symptoms that the patient has, you probably already know what he has.

He has a pneumonia. You can see that there's consolidated lung tissue.

Here. You have echo free space seen in this image and in this image, you can also perform an echocardiogram and confirm that he has normal cardiac function that is dyspnea, and his cough is not related to the heart, but rather to the lungs.

And here we have a 71-year-old male who has a carpal tunnel syndrome.

He does also report of dyspnea and loss of exercise capacity.

This case also shows you that it is often important to combine lung ultrasound with echocardiography.

So remember to also watch this module.

Now you perform an echocardiogram on him and you find this rather spectacular finding.

First of all, we see that the heart is rather small, but that there is massive left hypertrophy.

But even more important, left ventricular function is a catastrophe.

Very poor LVF.

This can also be appreciated here in the four chamber view.

But in addition, we see that there's an echo free space behind the ventricle.

This is a pericardial fusion, but this is not all.

When we looked at the lung, we found a pleural effusion.

Again, this is a diaphragm at lactic lung tissue.

And the same can be seen here with a linear probe.

There's an echo free space.

So the patient not only has poor left ventricular function, but also a pericardial and a pleural effusion.

What does the patient have?

Well, he has amyloid heart disease.

Now, amyloid heart disease is not such a rare entity, and as a matter of fact, it's associated with a carpal tunnel syndrome.

So here you've made a very important diagnosis.

A 26-year-old male comes to the office.

He reports that he has dyspnea, tachycardia, and is in New York.

Cardio class three to four, you perform an echocardiogram and you see this here.

This is extremely poor left ventricle function.

As you probably all now know, we see in the short axis view hypokinesia globally reduced left ventricle function.

In addition, we see that in the four chamber view, the ventricle is dilated and also the walls are not moving very much.

So this is very poor left ventricle function.

Now we'll turn to lung ultrasound.

What we see here is a small pleural effusion.

This is not a large effusion as we saw in some of the previous examples, but we can detect it with ultrasound.

Now, in the light of the findings that we have with echocardiography, we know that this is most likely associated with heart failure.

This patient has dilated cardiomyopathy.

As a matter of fact, very severe form. What do we learn?

We can use both lung and heart ultrasound together to establish diagnosis and to pick up findings which are otherwise sometimes not so easy to see, at least not in a primary care setting.

Conclusion

So to put all this together, a pleural effusion is not only an important cause of dyspnea, but it's very common.

You'll definitely encounter pleural effusions in your clinical practice.

With the help of primary care ultrasound, it's quite easy to detect the pleural effusion with ultrasound.

We can also differentiate whether or not the cause is a transited or an exuded, at least in many patients.

And if you combine primary care ultrasound of the lung with ultrasound of the heart, we can even detect whether or not a pleural effusion is caused because the patient has a cardiac condition.

So use ultrasound, make a difference for your patients.