– 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. Today’s module is going to look at the use of bedside ultrasound for placement of central venous catheters, specifically the internal jugular vein in the neck. So the question is, why use ultrasound for central venous access and why not just use the traditional landmark technique? Well, interestingly, multiple research studies now show a decreased number of puncture attempts are needed using ultrasound guidance and there’s also a lower complication rate such as lowering the risk of pneumothorax and hematoma. The US Agency for Health Care Research, the AHRQ, recommends ultrasound guidance for central lines right up there in the top 10 patient safety practices. Ultrasound will allow precise determination of the anatomy of the vascular structures in the neck prior to a puncture attempt.
Here’s the middle triangle of the neck that serves as the standard approach for cannulation of the internal jugular vein. We see here the branches of the sternomastoid muscle, the sternal head medially, and the clavicular head laterally. Here we’re putting our finger into the triangle of the neck and this indentation between the muscle heads would be the standard approach for placement of the needle. We see here that the clavicle forms the inferior boundary of the middle triangle of the neck. Within the middle triangle of the neck run two very important vascular structures and as per the textbook orientation of the carotid artery to the internal jugular vein, we see in the image here that the carotid artery should run medial to the internal jugular vein which lies lateral to the artery. However, unfortunately, there’s great variability in human anatomy and many times the internal jugular vein can overlap the carotid artery as shown in the drawing here. Notice the variation in location of the internal jugular vein to the carotid artery and many times the internal jugular vein is located on top of the carotid artery, making it difficult to cannulate.
Thus, it’s important to look with ultrasound before cannulation attempts to avoid puncture to the carotid artery. Here’s the high-frequency linear type array probe that we’ll be using to best map out the internal jugular vein before puncture attempts. Notice the probe marker there to the side of the probe. Here are the orientations that we can place the high-frequency probe in relation to the internal jugular vein for vascular line placement. Here to the left, we see the short axis configuration with the probe perpendicular to the vessel and notice that the vessel will appear on the ultrasound screen as a circle, as the vessel will be cut end on. To the right, we see the long axis configuration and note the probe placed along the long axis course of the vessel.
The vessel therefore on the screen will appear as a tubular structure as shown here in the image to the right. Here’s the high-frequency linear type array probe placed over the middle triangle of the neck over the internal jugular vein and carotid artery. Now, I like to have the probe positioned in a side-to-side orientation, with the marker dot oriented towards my left as I stand at the head of the bed. The reason for that is then the orientation of the probe marker will line up to the orientation of the screen indicator dot, which we see here is orientated towards the left on the ultrasound screen. Thus the left side of the probe will orient directly to the left side of the screen, and this will allow us to orient ourselves as we place the needle underneath the patient’s neck and cannulate the vein. Here’s a typical appearance of the internal jugular vein and carotid artery in a short axis configuration, taken with a B mode or gray scale image.
Note lateral here towards the left and medial to the right. Here we notice the internal jugular vein in a location more lateral and superficial to the carotid artery, which lies deeper and medial to the vein. We can see the depth markers to the side and we note the internal jugular vein at about centimeters depth. Now we can apply Doppler sonography to further differentiate the two structures and here again we notice the internal jugular vein lying lateral and superficial to the carotid artery. We note the Doppler sonography steady pulsations of the internal jugular vein that vary with respiratory pattern and we can also see the carotid artery with the pulsations with each heart beat differentiating the two structures. We can also press down with the probe to differentiate the two structures. The internal jugular vein should compress completely, while the more muscular outer walls of the carotid artery should keep it open with compression of the probe. Here’s another video clip showing the internal jugular vein and carotid artery in a short axis configuration. Notice here that this internal jugular vein is much more distended than in the last patient.
Here we see that the internal jugular vein is located more superficially at about centimeters and that it overlaps the carotid artery medially. Highlighting the fact that there’s great variability in the course of the internal jugular vein in relation to the carotid artery, even within the same patient, we’re running the probe from a position high within the neck in which the internal jugular vein is seen more laterally, to a position more inferiorly in which the internal jugular vein comes to rest more medially on top of the carotid artery.
Here’s a different patient in which the internal jugular vein is seen smack on top of the carotid artery. Notice here, we’ll place Doppler flow to confirm the carotid artery shown here deeper to the more superficial internal jugular vein. In this patient, it would be extremely difficult to cannulate the internal jugular vein without puncturing the carotid artery. Best to attempt cannulation in another area of the body. One pearl that can be used to further distend the internal jugular vein and make it a better target for a cannulation attempt is to have the patient Valsalva or hum. Notice here in the image to the left, the patient is bearing down and notice that the internal jugular vein becomes much bigger as the patient pushes down. In the image to the right, note the relatively small caliber of the internal jugular vein. Notice that it’s almost as big here as the carotid artery, but that it becomes much more distended as the patient bears down.
Using the Valsalva technique can make it a much better target for placement of the large cannulation needle. Here’s the high-frequency probe placed in a longitudinal or long axis manner on the patient’s neck. Notice here that it’s running along the course of the internal jugular vein as it runs up and down the patient’s neck. By convention here, I like to have the probe marker towards the patient’s head. Therefore, I know where it lines up on the ultrasound screen. Notice here as a screen indicator dot is towards the left that superior on the internal jugular vein will be located towards the left of the screen and inferior will be located towards the right of the screen. Here’s a long axis view of an internal jugular vein. I have the probe marker going more distally or superior within the neck so to the left is distal and to the right is proximal. Notice the internal jugular vein that appears like a tubular structure on the ultrasound screen and we see the blood flowing here from left to right. Here’s a video clip, again a long axis configuration in a different patient and here we see a much more distended internal jugular vein that’s lying on top of the carotid artery.
Notice the swirls of blood in the internal jugular vein showing the course of the blood flow from high within the neck to the left, low within the neck here to the right. In conclusion, thanks for tuning in for part one of Ultrasound Guided Central Venous Access. I hope I’ve been able to score the point that ultrasound is very helpful in determining the relative anatomy of the internal jugular vein and carotid artery prior to an invasive procedure as a textbook anatomy of the vein to artery is often incorrect and it’s best to use a combination of short and long axis views prior to a puncture attempt to best define the anatomy. So I hope to see you back in the future as SonoAccess continues and we return in central venous access part two..