 Welcome to the UCVM BCDS video podcast making veterinary education free open access worldwide. I'm Serge and I'm Cern and Thank you for joining us. We're gonna keep talking about veterinary focused ultrasound techniques. What do we have today Cern? What's on the books? So today we're gonna talk about the glide sign This is something a lot of people have trouble with we realize this when we do a lot of our lecturing People have trouble finding the plural line and knowing what to look for the glide sign So we're gonna keep it simple. We need to for me, right? Yeah, that's important What are we gonna be talking about specifically glide sign? What are we what are we looking at? So what we want to do is we want to look for the key Atomic landmarks that will allow us to identify the plural line and then with that plural line We're gonna talk about the glide sign and what that means, but we're also gonna throw in some tricks of the trade All right, let's get going. So I have a pro. I'm gonna put it on the chest How do I how do I start that so I'm gonna say as you get good with ultrasound? Yeah, doesn't matter what your orientation the probe is pair enough and I switch it up all the time Okay, if you're a novice, yeah, put the probe perpendicular to the ribs. All right, so we got it perpendicular Here's two ribs. I'm putting the probe perpendicular to the ribs And when you put the probe perpendicular to the ribs It allows you to identify structures and the anatomy that will help you pick out where that plural line is Which is where we look for the glide sign perfect So sir, I did that and now we have this image that we have here All I see there right now is a bunch of lines, right? There's line there line there line there sir. How can we put that into some kind of reference? We want to find the key structures that find the plural line. We're up here in Canada So we're gonna talk about the bath sign. Okay. It's also known as the gator sign gator sign We have gators we have gators in Canada That would be a no so you have a bat. You're kind of picturing it, right? How does that help us, sir? What are we what are we picturing here? I? Guess I guess that's a bat what we want to do is we want to identify the body So in this image here about we see the body on the underside This is the big red line that curves all those red lines there Okay, and we see these two small red lines that curve down those are the wings of the bat So we want to imagine the body and the wings of the bat and what we're gonna try to do that superimpose These structures that we have in the schematic on to our ultrasound image from what I see the wings are like Cupping the rib heads. Is that kind of correct? Yeah, so the wings of the bat represent the rib heads Yeah, and because ultrasound doesn't go through the ribs below those you get rib shadows So what then sir and what are we looking for? There's a lot of lines here The first white line below the rib heads that joins essentially the rib shadowing that is your plural line And that's key. Okay, you got to find your plural line This is why that bat sign is important or the gators and I got it now It orientates you to where that plural line is going to be. Yeah, so this bright white line What does it really mean? Okay? So this is the thing that we most people struggle with where's the plural line? What's the glide sign? So let's break this down in a schematic, okay? So imagine schematically You can separate the inside lining of the thorax the perietal lining from the outside lining of the lung the visceral Plural okay, so we have the parietal and visceral pleura right exactly now in reality We don't see a gap there, but for the sake of this argument Let's pretend you can see a gap and when a patient breathes It is normal for the perietal and the visceral purra to move Unfortunately for us, they move at a different rate. So if you look at the schematic here, we can see oh, that's my dog Cyprus Yes, and she's breathing nice and slowly for us and we can see on inspiration versus expiration the two pleura move throughout the respiratory cycle Unfortunately, like Cern said that gap is in there, but the key thing we were just talking about is they're moving at different speeds So that creates a bit of a shimmer, isn't that correct? Correct. So here on this image You can see Cyprus breathing that same image we had before but then you have the shimmer telling us we have a glide sign That is correct. What does it look like on an ultrasound image then? Let's go one step further So again on the left here, we have the schematic we look here on the right We can see again that we have the rib heads. We have the rib shadow. Here's that pleural line You're just looking for shimmering along that pleural line And the other thing to keep in mind there's lots of movement the intercostal muscles Contracting the lungs moving the ribs are moving but the big thing you want to look at you want to ignore all That movement you just want to look at the pleural line And you don't want to say does the problem go up or down you want to look for movement along back and forth that That's the key concept to the glide sign But it can be really hard sometimes I put that probe on there and I'm looking all I see a bright white line What are some tricks we can use? Yeah, it's easy to identify the pleural line It's not so easy to identify the glide sign right so we want to make the pleural line more grainy so the shimmer It's more obvious one thing we can do here You see you got the probes perpendicular to the ribs very perpendicular and sometimes the pleural line Chills up really white because the ultrasound beam hits it so directly We could try to change the angle which the ultrasound beam strikes the pleural line So if we found the probe and then freeze will often shift our pleural line from bright white to more grainy So the shimmer is more obvious. Yeah, and sometimes you don't even have to change the angle that much another trick that I really like a lot is to take that probe and Instead of being between the two ribs or sitting on top of the two ribs You can move that probe over one rib and that gives us the effect of seeing the glide on Either side of that rib, especially at the edges of the image We get a much nicer glide sign because it becomes more grainy Yeah So often I sort of the abdomen and then I move to look if you are going from the abdomen to the thorax Do keep in mind that you want to change your machine settings Hmm We want to decrease the gain as we come off the abdomen We'll drop that down so that the pleural line becomes more grainy and as you drop your gain It becomes more evident that you can detect the movement or the glide sign Do keep in mind you want to go back up when you look for other lung pathology that we'll talk about another podcast But specifically when it comes to the glide sign Yeah So playing the game is going to be very important Especially when you're moving from one cavity to the other the other thing is coming off the abdomen Where are you out when you in the abdomen usually usually deeper, right? Especially those bigger dogs your depth is easily 10 12 sometimes centimeters in but when it comes to Looking at the lung in that glide sign you want to be maybe four to six centimeters Let's kind of give you some other pros and considerations sir. The animal needs to breathe. You have your two pleura together Mm-hmm. It's not until they move at a different rate that you see the glide sign So only look for the glide sign when the patient breathes. What about this sir? When you think about the glide sign and a motion of the pleura a deep breath You'll get a long glide sign in one direction and then it comes back the other way So you'll have a nice long slow consistent glide sign if you're breathing very shallow and rapidly then the distance that you get to Actually watch for that to develop you're short and it makes it harder to see so if you can manage to slow down your patient's respiratory rate and Increase the depth of breathing it often makes it easier to slide them with options a nation a little a little You need a pain medication may improve respiratory rates Another trick is don't move that probe too much, right? So if you're moving your hand a lot while you're looking for that glide sign You're actually gonna kind of create an artificial glide same thing told true that your patient's moving again It will create a false slide sign and it's not that black and white We've talked about keeping that probe perpendicular to the ribs as we'll see another podcast It's actually gonna help a lot if you once you get used to things You can move that probe into a parallel position between those ribs and not actually tends to oblique the angle with the probe Which it hits along it might be quite bright in the middle But it'll turn more grainy towards the edges Yeah, and you got a larger lung surface area to assess without fighting with the ribs interfering with your image And yeah, that brings to an end our glide sign podcast. Thank you for joining us Merci beaucoup, and we'll see you next time on our UCVM open access a bientôt au revoir