 So our next speaker is Dr. Sarah Nicarvan. She's an anesthesiologist and intensivist from the University of Washington. She trained in anesthesiology at Washington University in St. Louis and completed a fellowship in critical care medicine and cardiothoracic anesthesiology at Stanford University where she subsequently served as faculty and directed the critical care ultrasound training program. She's the director of point of care ultrasound and associate program director of the residency program in the department of anesthesiology and pay medicine at the University of Washington. Dr. Nicarvan is a past president and chairperson for the Society of Critical Care Medicine ultrasound committee and critical care ultrasound course. She's a member of the national board of ecocardiography's exam writing committee and has lectured extensively both nationally and internationally over the last decade. Hi, my name is Dr. Sarah Nicarvan and I'm really, really excited to be sharing lung ultrasound in the ICU with you here today. I'm so sorry I can't be there kind of more live virtually but this is a really big, passionate area of mind and I hope that you'll walk away from this talk with a lot of information on how to apply lung ultrasound to your critically ill patients. Now, I have no disclosures to share with you and I'm hoping that we can talk a little bit about how lung ultrasound came to be. I'll try to introduce lung ultrasound to you and share an algorithm that I use in my practice and then we'll apply that algorithm to a number of different cases. Now, you know, it's been many years since lung ultrasound kind of was born in a way there was a consensus document that came out back in 2012, it was an international evidence-based kind of guideline and recommendations for the application of lung ultrasound for a certain pathologies in particular and then along the way other studies were done looking at, you know, how to apply lung ultrasound to patients with alveolar interstitial syndrome. This is another really nice piece to review lung ultrasound in the critically ill. If you get a chance, I would really recommend reading this by kind of the godfather of lung ultrasound, Dr. Daniel Lichtenstein and another really great review on lung ultrasound as primary survey for the acutely dysentic patient. So there are lots of studies that have been done and we're gonna share them along the way, but really what pathologies have, or which pathologies have been validated for the application of lung ultrasound assessments have been to kind of really rule out pneumothoracies, evaluations of consolidation, interstitial syndrome and pleural effusion. And so we're gonna try to focus on these things. This is a very broad category, which I'm trying to cover in 25 minutes. So just bear with me here as we move through it. You can use any probe to do lung ultrasound imaging. I will say that if I was stranded on a desert island and there was only one probe I could take with me to do lung ultrasound, it would be this curvilinear transducer because it provides enough axial resolution for visualization of the pleural line but also gives the appropriate amount of penetration for evaluations of consolidations and pleural effusions. The linear transducer is really great for seeing the pleural line, but unfortunately oftentimes it doesn't allow enough depth to catch those other pathologies that I just mentioned. Now anytime you scan, you have to have a scanning protocol. I predominantly practice in a cardiothoracic ICU and so my patients are usually plugged up and plugged into devices and different things and using this protocol that was validated back in 2005 in this bedside lung ultrasound in the assessment of alveolar interstitial syndrome paper is the one, this is the one that I use. So I take the chest and divide it into four quadrants using the parasternal line, the anterior axillary line and the posterior axillary line. I'll draw a line along about T5 or the nipple line and this will divide each section of the chest into four quadrants, this will be the right and then of course the left. Now make sure that when you're doing your imaging, you label your image because unlike cardiac imaging, lung ultrasound looks the same on both sides. So if you go back to look at it, you won't know whether you were on the right side or the left unless you labeled it appropriately. Now what is lung ultrasound? It's really an assessment of artifacts and I mentioned this because for cardiac imaging, oftentimes we have harmonics on to really kind of in a way diffuse out those artifacts and allow for better cavity imaging. But if you did that for lung ultrasound imaging, you'd get rid of the artifacts and wouldn't be able actually to do your evaluation. So if you don't have a lung ultrasound preset on your ultrasound probe and you're using an echo machine to do lung ultrasound, just make sure that your harmonics are turned off when you're doing your evaluation. We're looking at the difference in acoustic impedance between air and water because that generates ultrasound artifact and when there is underlying lung disease, that changes the pattern of those artifacts and that's what we're looking for. You can see the bright plural line is really about typically half a millimeter below the ribs. You can see the chest wall here and I try to get this image with my orientation marker pointed towards the patient's head so that I can get some ribs in my field and get a sense of where I am. So you can see here that about half a millimeter below the ribs, you're seeing this bright plural line and it's sliding kind of to and fro. This is what we call lung sliding and you can see it almost like ants marching up and down as the visceral and parietal pleural slide against each other. Now, you can evaluate this with M mode by putting M mode across the pleural line and when you do as the visceral and parietal pleural rub against each other, they cause almost this smudge or this motion artifact which makes this image look like what we call a sandy beach sign. So you're standing on the sand here and you're looking at the water. This is static chest, chest wall. It's not moving really and that's why you see kind of almost like stasis or no motion but then once the pleura kind of slide against each other, you're able to see this motion artifact. This is a normal finding in normal lung sliding. Now, notice here how this patient has once again, normal lung sliding. You see these B lines which are reverberation artifacts that start from the pleural line and they go all the way down to the base of the image and you can see this to and fro motion but in this patient, you can see, here's that bright pleural line, half a millimeter below the rib and there's really no sliding and you don't really see any B lines and if you were to put M mode over this image which you would end up seeing is that stasis that you saw in the chest wall, you would see below the pleural line and this is what we call a barcode sign or stratosphere sign. So this is really pretty significant for a lack of lung sliding and something that you should do anytime that you're worried that there is not lung sliding. Now, if I say a lack of lung sliding, automatically people think of enuma thorax but I will say that lung ultrasound is not very specific when used for the evaluation of enuma thorax. It's very sensitive, you can easily rule it out. So if you put the probe on the chest and there's lung sliding the patient does not have enuma thorax but if there is no lung sliding then you have to employ a enuma thorax algorithm and look for other things. So if there is no lung sliding you then need to look to see if there are B lines. If a patient has intact visceral and pleural contact there will be B lines and this will not be a case of enuma thorax but if there are no B lines and that's once again concerning and you're now gonna move to look for a lung point which we're gonna talk about now. A lung point is really that inflection point where the visceral and pleural separate from each other. This is the margin of enuma thorax and it can be very specific if it's seen in the anterior lung fields in the presence of A lines but please be cautious in patients who have pulmonary blebs because they have been known to mimic enuma thorax by causing a lung point. So you need to know a little bit about the history of your patient. Now, this is a ultrasonic graphic finding of a lung point. You can see the pleural line here is gonna come up and slide makes contact and then it falls back as the patient kind of exhales. So you see lung sliding and then that lung sliding goes away. Here it is, there's the lung sliding here and then it's gonna fall back and then you won't see lung sliding here. Here's another really example, a good example with arrow markers to kind of delineate where that inflection point occurs. This is called a lung point and when it's seen in the anterior lung fields in the absence of pulmonary blebs it is really pathic mnemonic for a enuma thorax. Now, let's say you do your evaluation and you don't see a lung point. So you can't say that it's a mnemothorax. You don't see a lung point. So now you're gonna look for this thing called a lung pulse. And basically a lung pulse is the rhythmic motion of the pleura as it's adjacent to the heart. This typically is seen in patients who have poor aeration of their lung. So maybe the lung is consolidated or you're evaluating the left chest in a patient who has a right main stem intubation. So basically the visceral and parietal pleural have contact with each other but the lung is just not being ventilated well. It's not being aerated well. And so every time the heart beats it causes a small little pulsation of the pleural lines against each other, which you're seeing here. This is absent in a mnemothorax. So if you don't see clear lung sliding but you see a lung pulse this cannot be mnemothorax. Once again, notice how there are these almost like rhythmic motion of the pleural line with the cardiac beat. There is a lot of risk for false positives when using lung ultrasound for evaluation mnemothorax. So you can see an absent lung sliding in patients who have bad ARDS or bullish lung disease like we just mentioned. Pneumonia with poor lung aeration, fibrosis or patients who have had pleuro-DCs in the past. If the patient has an acute asthma exacerbations and the lungs are just over-inflated that can cause poor lung sliding. The patients have chest tubes or if you're evaluating the apices in particular in patients on mechanical ventilation with high mechanical ventilatory support, high peeps where you know the apices just stay inflated throughout the respiratory cycle. Now, if you wanna use lung ultrasound for the evaluation of consolidation what you're basically looking for is a tissue-like quality to the lung. We call this hepatization. So the lung will look almost instead of that gray kind of very ambiguous appearance. It'll look like a solid organ. Oftentimes these patients have lung pulse because the lung is not well aerated like we just mentioned. Sometimes you can see air bronchograms both static and dynamic which we'll cover. And you see this non-homogenous distribution of B-lines. This can be visualized in anyone who has a consolidated process so maybe it's adolescences, pulmonary infarction, lung contusion and pneumonia, cancer, you name it. So here's a patient of mine in the ICU. This looks a little funny because I use the curvilinear probe. This is directed towards the patient's head but this patient was actually prone which is why this looks so bizarre. Here is a big, poorly fusion which is a hypoechoic area of fluid surrounding this consolidated lung that looks really kind of squished down and has what we call this starry sky appearance that looks like all these little bright points. So these are static air bronchograms often seen in consolidated lung but if you look really carefully here in just a second you're gonna see these bubbles kind of come up and down in the airway and this is what we call a dynamic air bronchogram. Think of it like mucus bubbling up in the bronchi. This is a common finding in patients who have a consolidation secondary to pneumonia. Let me show you a better example of that here. Now here's the liver. Notice how the right lower lobe of the lung looks really kind of hepatized. It looks like the liver and consolidated. And if you look here you see these bubbles kind of moving up and down the airways. This is a dynamic air bronchogram in a patient with a pneumonia. So really interesting finding. Now interstitial syndrome is an umbrella and this umbrella really encompasses anything that can cause interstitial pathology in the lung. So this could be pulmonary edema, this could be interstitial pneumonia or pneumonitis, diffuse Prink-Mole lung disease like pulmonary fibrosis or ARDS. This topic is a giant topic and we could spend like an hour just on this topic alone. So we're gonna just be very superficial about this and I'm always happy to get messages from you later if you have more questions. Now, this is an example of B-lines. You see these comet tail rocket-like artifacts, reverberation artifacts. They start from the pleural line, they go from the pleural line all the way to the bottom of the screen, usually at least 12 centimeters in depth. They're laser-like and they obliterate A-lines which are reverberation artifacts of the actual pleural line that are typically seen equidistant from the pleural line. You don't really see them here because there are so many B-lines that they obliterate the A-lines. And you see that they're moving with the lung sliding. When you see more than two of this in a field and a field is between two rib spaces, then this is an abnormal finding and very commonly seen in patients with pulmonary edema. Now, how did we even get to do this? Well, B-lines were first seen to correlate with extravascular lung water and dialysis patients. So basically they used ultrasound to have assessed the lungs of patients who had insadrenal disease and they did the scans before the patients were dialized and noticed a higher amount of B-lines. And then they did the scans again after fluid was removed or the patients got diuretics and they saw that the number of B-lines reduced in both of these patient populations. So this is how kind of our understanding of using B-lines for the assessment of pulmonary edema kind of came to be. Now, here's an example of like diffuse B-line. So you have this relatively crisp looking pleural line. You see these bright comet tail artifacts and they're kind of everywhere. There's their homogenous in appearance. There's no area of the lung that really looks spared. This is very classic for pulmonary edema. But patients who have perincomal lung disease can also have B-lines but their distribution is different. So, there was this study that was done correlating B-lines to CT findings of fibrosis. And what they found was that patients who have fibrosis end up having pleural line abnormalities oftentimes have sub-pleural abnormalities and have this very non-homogenous distribution of their B-lines. And if you can look here, you can see these anterior sub-pleural consolidation. The pleural line does not look normal. It looks very kind of chewed up and irregular. And the patients have oftentimes these spared areas of normal lung. So, you know, there's these patchy disease process where this lung area looks pretty whiteed out. This white lung appearance is really a more consistent with a patient who has some sort of underlying interstitial lung disease. And then they have these spared areas. This were findings that they saw in a patient with acute respiratory distress syndrome. Now, what about these studies that were done looking at lung ultrasound and CT and chest x-ray imaging? So, this is an example. You see a relatively crisp pleural line, pretty diffused homogenous B-lines everywhere, chest x-ray that correlates with pulmonary edema. So, this is a patient with pulmonary edema but what about this one? You can see that the lung is diseased. There is interstitial process going on. The pleural line does not look normal. There are areas of spared kind of lung here with a non-homogenous distribution of B-line. So, this was a patient with diffused interstitial pneumonia. What about this patient here who's some chest disease clearly abnormal, very abnormal looking pleural line here. You have these areas of spared lung very non-homogenous distribution of B-lines. This was a patient with idiopathic pulmonary fibrosis. Now, pleural effusions are very well assessed with lung ultrasound. Actually, lung ultrasound is exquisitely sensitive and specific for diagnosing pleural effusions much more so than even chest x-ray imaging. So, here you have a patient with an interposition of fluid, this hypo-coic fluid between the parietal pleura and the lung. And oftentimes you see the lung kind of consolidated flopping around like a jellyfish in air quotes within that pleural effusion. And you may be able to see this thing called a spine sign which means that there's some pathologic process going on in the chest which allows the ultrasound beam to get propagated forward so that you can actually see posteriorly and see the spine. In a normal chest and thorax that's filled with a lung that's filled with air, that doesn't allow the ultrasound beam to propagate. And oftentimes you cannot see the spine in a patient who has normal lung aeration that only really pops up once they have a pleural effusion or if they have a really bad consolidated lung that is hepatized and allows for the ultrasound beam to propagate forward. Now, what is this algorithm that I'm telling you about? This isn't validated. This is an algorithm that I use but I take care of patients in the CVIC or the CTICU. So when they're coming in hypoxic and dysphonic the first question I ask myself is, is their echo normal or not? If it is normal, then that's when I really move to evaluate the lung to see if there's lung sliding and what are the characteristics of the B-lines? Is are they patchy? Are they homogenous? Is there a pleural effusion? Can I see consolidation with static and dynamic air bronchograms or not? So let's apply this to a number of cases. So here I had a case. This was in the high time of COVID. I'm in Seattle. We had a lot of patients who were very sick. I had a patient who was 35 year old male. He was on VV FMO for COVID pneumonia and he had been on it for months. He was now tolerating intermittent sweep weins, and physical therapy. And he suddenly overnight at 2 a.m. has an acute drop in his circuit flows, becomes hypotensive, increased work of breathing despite the support of the VV FMO circuit. Fluids are initiated and baser pressures are started and we're attempting to increase the circuit flow but it's not working. And the circuit is alarming. We can't flow. So this causes a very broad differential diagnosis, right? This patient has pulmonary support to a certain extent but of course is young and has a high demand but he doesn't have cardiac support. And I'll tell you that I did an echo and that echo was normal as the first portion of that algorithm. So then I moved to evaluate the plural line. And you can see here R2 means I was in the right two zone. You can see his plural line on the right side has a subplural consolidations. This was very classic of patients with COVID. The plural line is not normal. He's got some V lines that you see here but the lung is moving and sliding. Now compare that over here. So here's a rib we're about half a millimeter below the rib. Here's the plural line. And not only do I not see lung sliding, I see A lines which tells me that my imaging plane is appropriate. I don't see any B lines that are coming down to obliterate these A lines. So if we think about this, do I see lung sliding? No, I don't. Do I see B lines? No, I don't. And I'll tell you that I scanned his whole left chest up and down and I did not find a lung point. And if you look at this, does this look like a lung pulse where it's rhythmic with the heartbeat? A patient who's tachycardic here, does he have a rhythmic motion? No, we do not see lung pulse here either. So I was convinced that this was a pneumothorax. I was getting ready to needle decompress the chest when they rolled in with the X-ray tech rolled in. And I said, well, what the heck? You might as well get the X-ray because no one's gonna believe me anyway. And look at what we found on chest X-ray imaging. So now to make my point, I needle decompress the chest. His hemodynamics did get better. Remember what this looked like, that it was a poor kind of no lung sliding, no B lines were visible. There was no lung pulse. I couldn't find a lung point. Then we decompress the chest here. This is in the left two zone. And now suddenly you see plural irregularity, plural sliding and visceral and parietal, plural contact here. So this was kind of a very interesting case. And the next case I have is that of a 32 year old woman. She was 32 weeks pregnant. She'd presented with premature rupture of membrane and contractions, had early fetal decelerations and we were called by the OB team because she was really hypoxic. And she was hypoxic. She was on five liters face mask. She was setting 91%. She was relatively hypotensive. She was definitely tachycardic and she was febrile. So they had already started her on antibiotics and started giving her fluids. So as part of this algorithm, the first question I had was, what's her heart doing? What's her heart look like? So we did an echo. And as you can see here, her cardiac function is definitely not normal. She's got five in tricular, severe cardiac dysfunction. And if you think about these patients, you know, who are in heart failure, you're very familiar with the Frank Starling curve and how once they're kind of on the upper edge of the curve, increasing their preload really doesn't do much to increase their cardiac output. Now, if we can put the Merrick Lemson curve on top of the Frank Starling curve, you'll also see that in patients who are septic, their extravascular lung water kind of curve shifts upward. And for that same area of this Frank Starling curve where maybe they may have had some improvement in their cardiac output, maybe not a lot. They have a lot of extravascular lung water that causes a large increase in extravascular lung water. And when they're septic, that goes up even higher. So now we're looking at a point here. So whenever I have patients who are septic and then have cardiac dysfunction, I'm really concerned, we also have information, you know, from echocardiography that's longstanding that you can use diastolic assessments to kind of get a sense of what the cardiac filling pressures are. And we have patients who if they're E to E prime is really greater than 14, we see a very nice correlation between that relationship and pulmonary capillary wedge pressure. But, you know, oftentimes we have patients in this kind of gray zone that we don't really know what to do with. And this is when lung ultrasound imaging becomes really helpful. So in this patient, you can see her mitral inflow pattern is that a restrictive diastolic dysfunction. But her E to E prime doesn't necessarily fit into the bill of, you know, being greater than 14 elevated left ventricular and diastolic pressure or left atrial pressure. So, huh, so what do we do in this patient? So now we're looking at her and we know that her echo is abnormal and that clues you in to really start looking to see, does she have B lines and could this be pulmonary edema? So then I did a lung ultrasound on her and you can see a very crisp looking pleural line diffuse B lines everywhere. There's no area of sparing. They're almost homogenous and really kind of coalesced. So she had significant pulmonary edema. And after this, we really kind of knew that we needed to get aggressive about supporting her cardiac function. So really know what pathologies are best for evaluating lung ultrasound. Plural effusions, this is what lung ultrasound was made for, super sensitive, super specific for catching pleural effusions. For pneumothorax lung ultrasound is very sensitive so we can rule it out easily, but it's harder to rule it in if you don't see lung sliding, make sure you go through the entire pneumothorax algorithm. For interstitial syndrome, it's relatively sensitive. You really have to compare the B line morphologies to understand what might be the disease process. And for consolidation, it's kind of sometimes can be a little bit hit or miss because the consolidated process really has to reach the pleura in order for it to be visible but it can be helpful when it is visible. Always have a scanning protocol and use an algorithm to help work through your differential diagnosis. At the end of the day, ultrasound is just a supplement to your clinical judgment. We're all still doctors and practice providers so please use your clinical judgment, that is key. I wanna thank you so much for your time. Here's a patient who had COVID pneumonia. Look at how terribly jagged the pleural line is, these sub pleural consolidations diffuse B lines everywhere with some areas of sparing but really kind of a white lung. This is pathologic interstitial disease, not just pulmonary edema but underlying interstitial pathology. So thank you so much for your time. Feel free to reach out to me with any questions you might have and I hope you have a great rest of your conference. That's excellent, thanks Dr. Nick Revan. So I think many of you use lung ultrasound in order to assess issues with oxygenation both in ICU, maybe emergency cases in the OR. It's very interesting to see some of the correlation across modalities though. So I'm looking forward to hearing more in the Q and A.