[Intro Theme] [Mike] A pericardial effusion can be visualized best from the subcostal window, looking through the liver. An effusion will look like an anechoic stripe surrounding the heart in this location. Here’s an example of a small pericardial effusion. In this particular effusion there’s no evidence of pericardial tamponade which is, of course, the thing we are most concerned about, and the reason for performing a pericardiocentesis. Pericardial tamponade can be visualized on ultrasound, but it’s not 100% sensitive, so if the patient has a good clinical presentation in the presence of an effusion you really have to worry about tamponade until proven otherwise. When we think about pericardial tamponade with ultrasound, there’s three things that we look for. The first, and probably the most important, is right ventricular collapse. This is an example of right ventricular collapse from a pericardial effusion causing tamponade. Here we see the free wall of the right ventricle is collapsing during diastole. The next thing we look for is the presence of a collapsed LV. So we think that if the patient has a reduction in forward flow because of collapsing of their right ventricle the LV is therefore not filling. This makes the LV hyper-dynamic, meaning that the walls touch during systole. So this patient, for example, has an ejection fraction of approximately 100% because the LV walls are touching during systole. Now this is because the LV’s not filling appropriately because of the lack of forward-flow coming from the right side of the heart. The last thing we’re looking for is a dilated IVC. If someone doesn’t have appropriate forward flow because of lack of filling of the right side of their heart, we can expect the blood to back up into the inferior vena cava. To look at this, we’re looking at a subcostal window, this is a subcostal long-axis window, and you see the effusion here, here we see the liver, and the IVC is nice, fat, dilated, and not collapsing at all with respiration, telling me that there is a significant reduction in forward-flow. To perform a pericardiocentesis with ultrasound you’re going to need a couple of things. The first and most important is obviously the ultrasound machine. And we can use either the curvilinear abdominal probe, if we’re performing a subcostal technique, or we can use the thoracic probe, or the cardiac probe, if we’re performing an apical technique or with the subcostal technique. Of course you’ll also want a pericardiocentesis tray. Now you don’t have to have one of these if you’re not placing a catheter, you can simply use a spinal needle and a large syringe. However, if you do want to place a catheter, I recommend you keep a pericardiocentesis tray in your emergency department. There’s two particular windows that we use when we perform a pericardiocentesis under ultrasound guidance. That’s the subcostal window, which is the more classic window, performed usually without ultrasound guidance, and then the apical window, which has gained a good bit of popularity since the use of ultrasound for guiding this procedure. Some people also use a parasternal technique, going in the third or fourth intercostal space, however I prefer not to use this due to the location of the left anterior descending artery. The concept of lacerating that artery just sort-of scares me. This is an example of performing an ultrasound-guided pericardiocentesis from the subcostal window. The steps that we mention here are pretty much the same steps that you would use for the apical window, the only difference being the orientation of the ultrasound probe. For this particular example we’re using a curvilinear abdominal probe, however you could also use the thoracic or phased-array probe for this image. Here we see we’re looking at a heart with a fairly significant diastolic collapse of the right ventricle and a fairly large effusion. We’re going to be coming through the liver here and we’re actually visualizing the pericardium through the liver here. I’m going to insert the needle just lateral to the probe, to the patient’s right side, that way I’ll be going through the liver and towards the patient’s pericardial sack. As I insert the needle and draw back I’ll get a flash of blood into the syringe. Once I’ve seen this blood I’m going to confirm that it appears my needle tip is in my pericardium. After I do that I’ll take the syringe off and I’ll place a wire through the needle into the pericardial sack, again confirming that the wire is in the pericardial sack and not the ventricle. I’ll use ultrasound for this confirmation. Then I’ll slide a dilator over the wire, and finally pass a catheter over the wire and remove the wire. At this point I can place the wire (correction: catheter) to down-drain, to drain the pericardial effusion. Here’s an example of a real-time performed pericardial effusion. Here we’re using the phased-array probe from a subcostal window and you can see the needle coming in just-about right here. And we see we’ve popped through the pericardium and once we’ve popped through the pericardium we’re going to start advancing our wire down. You can see the wire pushing down on the right ventricular free wall here as it goes into the pericardial sack. After the wire we’ll of course push the dilator over the wire, here we see the dilator coming in, and then finally the catheter will be placed over the wire, into the pericardial sack. Once the catheter is in place and it’s hooked up to down-drain you can actually see the pericardial effusion diminish in size. And here we can see that pericardial effusion getting much smaller. In addition to the subcostal window, you an also use the apical four-chamber window. For this particular window I’ll again place the needle just lateral to the probe, however this time I’m going to come from a medial orientation, directed towards the apex of the heart. I’ll again be able to see virtually the same thing that we saw with the last image, however we’ll of course use the phased-array probe in this instance because it’s much easier to visualize through the rib-spaces with the phased-array probe rather than with the curvilinear. A few tips and tricks: So agitated saline is a great technique for making sure that you’re actually in the pericardial sack as opposed to placing the needle or the wire into a ventricle. Here’s an example of injecting agitated saline into the pericardium once you have the needle in what you believe is the pericardium. You can see how the agitated saline lights-up and is extremely hyper-echoic in the pericardial sack here. If we were inside a ventricle, let’s say the left ventricle for example, we would see the left ventricle light-up as opposed to remaining dark here. Agitated saline can be a great way to confirm that you’re in the right location, especially if you’re trying to tap a small pericardial effusion, or if you’re just not very comfortable with placing a large dilator into a ventricle. Needle-in-plane technique: Some people talk about using the needle-out-of-plane technique, which would mean going with the needle through the center of the probe, however I prefer having the needle come in laterally so that we have the needle in-plane and in-view the entire time. This allows us to see the needle tip and really know where it is in space. So I’ll have the needle come in just lateral to the probe and then that way I know where to expect it on my screen. I would expect the needle to come in just here laterally, going towards the pericardial sack. Again, I’m going to have the needle actually come in right next to the probe marker, that way I know to expect the needle coming from the probe marker, as seen here. Go where the fluid is: It’s important to remember that with pericardiocentesis there are no… …margin for error as possible. So, wherever the pericardial effusion is the thickest is probably where you should go with your needle. If that happens to be parasternal, even though Mallin said, “don’t do it,” on his little podcast, go for it. Whatever you’re most comfortable with. So apical, subcostal, parasternal, wherever that effusion is the largest is probably going to give you the best chance of success without taking out a ventricle and placing a catheter in someone’s aorta.