– Hello, my name is Phil Perera, and I’m the Emergency Ultrasound Coordinator at the New York Presbyterian Hospital in New York City. And welcome to SoundBytes Cases. In this module we’re going to look specifically at Ultrasound of the Lung to Evaluate for Pneumothorax. Interestingly enough, a classical belief was that the lung was not optimal for ultrasound imaging. However newer findings have shown that actually ultrasound is an excellent modality for viewing the pleura and for detecting pnemothoraces. There’s been a lot of research looking at this and what’s interesting is that ultrasound has been found now to be more sensitive than chest X-ray in the diagnosis of pneumothorax especially in the supine trauma patient. And now we’re going to add on views of the lungs looking for pneumothorax as part of our Extended FAST Exam, or the E-FAST exam that we’ll be performing in trauma patients.
Position:64% We can also detect pneumothoraces as well in our medical patients. Now let’s learn how to perform the ultrasound examination for the pneumothorax detection. Here we have the high frequency linear type array probe positioned on the anterior chest wall at about the midclavicular line looking in to about intercostal space three. Now in most cases of pneumothorax with the patient supine the air would be predominantly seen in this area. Note we’re looking in a long axis configuration between the ribs with the marker dot oriented superiorly towards the patient’s head.
Once we’ve identified both the ribs and the pleura we can swivel the probe into the short axis configuration to further look at the pleura and to detect pneumothorax. Here we have the probe oriented in a transverse or short axis orientation between the ribs looking directly down at the pleura. Notice in this case the marker dot is located towards the lateral aspect of the patient. Using both long and short axis configurations will allow you to detect a pneumothorax with a high degree of accuracy. If no lung is seen on the anterior chest wall one can size out a pneumothorax by looking in the lateral positions as shown here. Notice the probe on the lateral chest wall in the short axis configuration between the ribs. If lung is seen here laterally but not anteriorly, this would tell you it was an incomplete pneumothorax. We can complement the short axis view by locating the probe into the long axis configuration with the marker dot towards the patient’s axilla to further examine into these lateral areas of the chest wall.
Here’s a nice pictorial showing the normal findings of a lung in a long axis type configuration. Superior rib to the left, inferior rib to the right. Notice that the ribs cast shadows posteriorly due to the inability of the soundwaves to permeate the hard calcifications of the rib. We see the chest wall anteriorly, and note here the two layers of the pleura. And we see here the outer parietal pleura, and the inner visceral pleura. Now while I’ve depicted these as two separate layers, in reality on ultrasound examination they’re seen as a single shimmering white line that moves back and forth as the patient breathes. And as the patient breathes we can see white comet tails, or linear lines, vertical lines, coming off the pleura down deep into the lung. So that will be the normal finding of a lung on long axis configuration. Here’s a nice ultrasound image showing a normal lung and what we see here, we’re in the long axis configuration, so the superior rib is to the left, inferior rib to the right.
Chest wall anteriorly, and we see here the lung sliding which is the opposition of the outer parietal and the inner visceral pleura. And we see the vertical comet tails coming off the back of the pleura. Thus this is a completely normal exam. No pneumothorax. But note the location of the pleura deep to the ribs, and that classic shimmering line back and forth as the patient takes a breath. Here we see more dramatic comet tails coming off the shimmering parietal and visceral pleura. In this patient we see the comet tails shooting off the back, telling us that this lung is up and there’s no pneumothorax. So vertical lines coming off the back of the pleura always mean that the lung is up and are always a good sign on lung ultrasound sonography. As we mentioned we should also swivel the probe into the short axis configuration to further examine the lung, and what we see here is a normal lung in short axis configuration. Note here we’re looking in between the ribs so all we see is the dome of the lung and notice that it slides back and forth as the patient breathes, and we see the vertical comet tails coming off the back.
So a completely normal examination in the short axis plane. Here’s another ultrasound image taken from the short axis configuration. Note here we see very prominent comet tails coming off the back of the lung as it slides back and forth. Again it’s that opposition of the parietal and visceral layers of the pleura that allow the lung shimmering, but notice here all the comet tails coming off the back. In this case this patient had some pulmonary edema associated with the lung and these comet tails are more pronounced due to the presence of water within the pleura. But notice all these vertical lines coming off the back telling us this lung is up. A way to document that the lung is up to print out for the chart is to put M-Mode, and generally what we do is locate it so the M-Mode cursor is down right at the pleura.
And what we see is the classic seashore sign, or waves on the beach. If we look anteriorly we’ll see the classic waves, or no motion of the chest wall, and below that, deep to the pleura we’ll see the positive motion of the lung making up the beach. So waves on the beach, or the seashore sign, and M-Mode documentation that the lung is up and that there’s no pneumothorax. Now that we understand what a normal lung looks like on bedside examination, let’s take a look at a pictorial showing a pneumothorax in a long axis view. We see here that the parietal pleura is now split from the visceral pleura, which is attached to the lung by a layer of air shown by the yellow color.
It’s the splitting of the parietal and visceral pleura that now causes a lack of lung sliding. And instead of the opposed visceral and parietal pleura sliding back and forth as the patient breathes, all we see is a single line, the parietal pleura, with a lack of vertical comet tails coming off the back. Here’s an ultrasound image taken from a patient who was stabbed to the left chest and who had shortness of breath. What we see here is a long axis view of a pneumothorax. Let’s take a look at the chest wall anteriorly, and right below that we see the parietal pleura, the single white line located directly inferior to the ribs. But notice the classic lack of the lung sliding. All we see here is a single white line that fails to slide back and forth as the patient breathes. Notice also the absence of the vertical comet tails. Here’s another image of a pneumothorax in a long axis configuration, and we see here the chest wall anteriorly, and the single white line which is the parietal pleura. Now this patient was acutely dyspneic, so notice that there is some motion of the chest wall and that the parietal pleura moves up and down, but notice the failure of horizontal sliding.
Notice also the absence of any vertical comet tails coming off the back of the pleura. Now let’s inspect a pneumothorax from the short axis view. We see the chest wall anteriorly, the parietal pleura as shown as a single, non-mobile white line in the middle of the image. Note the failure of movement back and forth, the lack of vertical comet tails, and what we see here is repeating horizontal air lines from the pneumothorax. To document the absence of lung sliding and the presence of a pneumothorax, we’ll again turn to M-Mode. If we put the M-Mode cursor down on the pleura, what we’ll see is a set of linear repeating lines. This documents no motion of both the chest wall and of the lung, making up a finding known as the bar code sign.
Here’s a pictorial showing interesting finding. The signature of an incomplete pneumothorax, known as lead point. And what we see is an incomplete pneumothorax with air collecting to the superior aspect of the image to the left. Thus splitting the parietal from the visceral layers and causing an absence of lung sliding superiorly. However, as the lung is coming up against the chest wall to the right or inferiorly, that’s where we’ll see the presence of horizontal lung sliding, and the presence of the vertical comet tails. Here’s an ultrasound image showing the lead point, and what we see here is the lung sliding to the right, the area where the lung touches up against the chest wall, and to the left the area of absence of lung sliding telling you there that air has collected between the visceral and parietal layers. So the ultrasound equivalent of the image that we just looked at telling you that this is an incomplete pneumothorax.
But here we see that lead point, or transition point, very well on bedside sonography. In conclusion I’m glad I could share with you this ultrasound module going over ultrasound of the lung to evaluate for pneumothorax. This is an excellent tool for viewing the pleura and making the diagnosis of pneumothorax, and there’s been some research showing that it may be more sensitive than chest X-ray in the diagnosis of pneumothorax, allowing rapid diagnosis of pneumo in both your trauma and medical patient, thus facilitating more timely management of these most critical patients. So I hope to see you back as SoundBytes continues.
As found on Youtube