Tonicity of Solutions
In this session, we will give you a run-through of Solutions 101! This session will help you to better understand isotonic, hypertonic, and hypotonic solutions so you can better care for your patients!
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Hi Guys. Good morning everyone. Come on in.
I always want to know in these like super early morning sessions, like there’s anybody in my California or Alaska cause it’s 8:00 AM mountain time. Atlanta, New York City’s, you guys are east coast. You guys have been awake for a little while. We’re running guys. Alright. Hey, we got to California. Awesome. Cool guys. So we’re going to talk about tonicity today. City of solutions is a fancy schmancy word. Um, but basically what we’re talking about is the difference between hypotonic, hypertonic and isotonic solutions. So those are your three main types of solutions. So for those of you who don’t know me, my name is Nicole Weaver and the curriculum director for NRSNG. I have been a nurse for 10 years and an educator for five. And so I’ve done mostly critical care and emergency, which means I have given a ton of these different types of fluids. So hopefully I can help just kind of demystify it for you. The first thing I want to do that really quickly is review the difference between diffusion and Osmosis, because it’s going to play a huge role in understanding what’s happening in the body. Um, when it comes to our Phyllis. So if I’ve got a solution here, let’s say here’s my solution,
And on this side I’ve got, you know, 15 or 20 particles in this, I’ve got two, okay? And we’re talking diffusion. What is going to happen in diffusion in this side? What’s going to move? And which way is it gonna move? Let’s say this is side one and misses side too. What are we going to see happen with diffusion high to low? What is moving when you’re talking about diffusion, what moves high to low? Yeah, the particles. So when we’re talking to fusion that we’re talking about the movement of particles from high concentration to low. So you’re going to start seeing these particles shift over from side one to side two. Again, assuming this is a semipermeable membrane, if it’s a completely open, it’s all just going to blend. And if it’s completely closed, nothing’s moving, right? So semi-permeable means we’re going to see just the movement of particles until we even out the concentrations on both sides of the membrane.
Right? So that’s diffusion, diffusion, diffusion, really with the you guys, it’s too early. Diffusion is the movement of particles. Okay, so let’s see over here, let’s say we’re talking about as Moses, when we talk about us Moses and let’s just have real similar solutions over here. We’ll start with the same thing we started with before. So there’s no question. Okay, so that’s particles here. Not a whole lot of particles here. Osmosis though is the movement of what, when we talk about Osmosis, what are we talking about? The movement of, yeah, the solvent, the water, the fluid, whatever that, whatever that solvent is. So in this case, I’m just going to say fluid. Okay. So osmosis is actually technically movement of water to the movement of fluid. Okay. So what’s actually gonna happen here to even out these, if we’re just seeing Osmosis, what’s gonna Happen, but what? Which ways the water going to go one to two or two to one.
Yeah. The water itself is going to go from two to one. So you actually going to shift the water level up here, you’re going to lose some water level here and all of these particles are just going to kinda spread themselves out a little bit more. So you still have physically more particles over here, but because you have more fluid, it evens out that concentration. Okay? So we lose fluid on one side. We gained fluid on the other. So anytime you’re talking about just diffusion or Osmosis, whatever is moving moves from high to low. Okay? Not High concentration to low concentration, but if there’s more fluid on one side, it’s going to move away from that side. There’s less fluid on one side, it’s going to move towards where it’s less fluid. So the fluid moves from where fluid is high to where fluid is low.
Right. Does that make sense? So when you’re talking about tenicity and fluid solutions and hypotonic, hypertonic, isotonic, we’re looking at osmosis. Okay. We are 100% looking at osmosis. We’re looking at the movement of fluids. Okay? So what you don’t want to do is start getting really detailed into what’s the exact osmolarity and how many more particles are there. It doesn’t make a difference generally. Is there more fluid or less fluid? Because that’s going to tell you where the fluids is going to shift. Okay. Cause we’re talking fluid movement, not particle movement. Does that part make sense? Questions about that general overview. Y’all absolutely jump in and stop me if y’all have questions. Okay. All right, so now let’s talk tonicity. So anytime I’m giving fluids and I call it hypertonic, hypotonic or isotonic, hypo means less, right? Hyper means more. And ISO means the same. So what am I comparing it to? More than one. Less than what? Same as what? What am I comparing the fluids solution to?
so someone’s had intracellular fluid, someone’s said body’s fluid. So it’s okay blood. So it’s actually the blood plasma that I’m comparing it to. So I’m not comparing it to intracellular fluid because that’s not where I’m putting it, right? When I put this fluid in, I put it in the veins, right? So I’m actually comparing it to blood plasma. All right, so not the cells. I’m not comparing it to cells. I’m not comparing it to intercellular fluid, interstitial fluid. I’m comparing it to the blood plasma. Yes, blood plasma is technically intracellular fluid in the blood, but specifically that fluid, okay? Cause think about it. It’s IB fluid, right? So it’s going into the veins. I’m comparing it to the blood plasma. So in my blood stream, I’ve got blood cells and I also have just other cells out in my tissues, right? So as the blood sits here, my normal blood plasma, is there any shifting of fluid happening, anything significant bloods here?
Am I shrinking myself and my swelling myself now? Right? It’s just normal. Whatever my blood plasma is, that’s what my body is used to. And so there’s no major shifts of fluid happening in my normal bloodstream, right? So if I put something in my bloodstream that changes that concentration, it’s going to cause fluid shifts. Okay? So anything other than what’s normally in my blood. So when I say I, so tonic, ISO means equal. That means when I put that fluid, that isotonic fluid into the bloodstream, it’s the same. So am I going to cause any kind of fluid to shift if I put something that’s the same into my bloodstream? No, exactly. So it’s the same. Normally as blood plasma sits there, there’s no fluid shifts. If I put something in that’s the same, there’s no fluid shifts. So what are two really common examples of ISO tonic IB solutions? There’s two really common ones, and s and LR. Yup. And as normal saline, which is 0.9% 0.9% normal saline, and then LR, which is lactated ringers. You’ll know what the difference is. What does LR have that NSF doesn’t?
Yeah. Electrolytes. It actually doesn’t have much sugar in it, like glucose, but it has electrolytes got uh, potassium, magnesium, um, lactate. So it actually has electrolytes in it. So one question people ask a lot is why, how would you decide between one and the other? And I will tell you most commonly we’ll see LR given in trauma and when people have lost a lot of blood. So if you’ve lost whole blood, that means you’ve lost fluid and electrolytes and cells. Right? So I’m going to replace you with LR because I can help you replace those electrolytes when I’ve lost a lot of fluid due to things like dehydration, vomiting, things that are just kind of fluid, not blood, then I’ll replace with NSX. Totally fine. So that’s usually when you start to see the difference. But know that LR has more electrolytes in it than normal saline. Almost alien just has sodium, sodium chloride more basically. All right, so those are isotonic. You put ice out of town. Again, all we’re doing is adding volumes. So sometimes you’ll see it called a volume expander, but basically all we’re doing is adding volume into the bloodstream. The cells should not be affected. Okay, so let’s Talk High Bo. Hypo means less. Okay. So when I say hypo tonic, do I mean that there’s less fluid or that there’s less particles compared to bloodstream?
Yeah, less particles. So I want you guys thinking conceptually. So hypo means there’s less particles than, is this fluid solution more dilute or more concentrated than my blend? Yeah, it’s more dilute. So there’s less particles, more fluid. It’s more dilute than the blood. So when I start putting it into the bloodstream, it’s actually going to dilute my bloodstream. So now let’s just do an example. Let’s say I had four particles out here and I had four particles out here. It were in here, and now we’ve made it more dilute. Now we’re more diluted. So which way is the fluid gonna want to go out of the bloodstream? If it’s more dilute, do I have more fluid or less fluid in the bloodstream? Okay.
Yeah, it’s going to want to go out of the vessels. There’s now because I’m more dilute, I have more fluid. And remember with Osmosis, fluid always moves high to low, where the fluid tie to where the fluid is low. So I’m actually going to go out of the bloodstream. So out of the vessels means out into the tissues. It means out into other cells. It means into red blood cells, basically anywhere other than here is fine. That’s what we’re going for. So when I dilute my blood stream because I have a hypo tonic solution, I’m going to cause fluid to shift into the cells. So what’s going to happen to my cells?
Yeah, they’re going to swell up. My sales are going to swell up. My favorite, a mnemonic I ever heard was actually one of you guys was when you think hippo or Hypo, hippo, like big fat hippo. So they swell up. So why would I want myself? Why would I give a fluid knowing it’s going to cause myself just, well, would I ever actually want myself to swell?
It’s okay. You can say you wouldn’t want that, right? We wouldn’t want to cause the cellular swelling, would we? But what f what if I have a little cell out here that super dehydrated, right? I have this out here. It’s super dehydrated and I need to force my body to give it fluid and let it get back to normal size. Okay. So this is why I don’t want you to be confused by when we talk about this, we say, oh, hypotonic fluids cause the cells to swell and then we go, why would we want to do that? Right? This is why. So the number one thing we give hypotonic fluids for is cellular dehydration. Um, what is a very, very common condition or two of them that cause cellular dehydration. There’s a couple of really common ones. Also just generally dehydration, lots of vomiting that causes dehydration, right? What condition can I have that cause as you want me direct can absolutely cause dehydration. What about, I’m going to surprise you guys at best. What about these two? Right,
right. Because that’s literally what they do. That hyper osmolarity causes the cells to get super dehydrated. They’re paying a lot, right? So DKA and HHS, because of that hyper osmolarity, they get very, very, very dehydrated in ourselves. So when we start giving them fluids, a lot of times we give them half an s, which is a hypotonic solution because it helps with this. We’ll usually start with just normal salian. We’ll start by just giving them fluids and kind of taking them back up. But a lot of times as we bring their sugar down, we need to give them a sugar solution. We’ll actually give them d five half ns because then we get sugar. But we also allow them to help fix that dehydration. So examples, best examples of um, hypo tonic solutions are like half Ns, d five w those are good examples. Hypo tonics.
Alright. Does that make sense? So hypo means that the bloods now more dilute the fluids going to shift out of the bloodstream and into the cells. The cells are going to swell. Now typically we don’t give this to make them swell. We give them to, we give it to bring them back to normal. But keep in mind, if you give too much too fast, you can actually swell in versus out. So we still have to be cautious. We still have to be careful, but know that this is typically the reason why we give it. That makes sense. Questions carry great questions. So curiosity is d five w change in the bag in the body. So what you’re referring to is some people will say, well, it’s isotonic in the bag and it’s Hypo hypo tonic in the body. So DFW is actually the best example of that because it’s two 52 in the bag, which normal osmolarity in the blood is like two 70.
So some people will say that that is isotonic purely because of the number. But what happens to that dextrose? The moment it gets into the body, what do we do with it? As soon as it gets in the body, what are we doing with that? Dextrose? It’s sugar, right? We’re using it. We’re using it. So we’re just taking it. So d five w a hundred percent acts as a hypotonic solution. It just, it does. So once the intake gets in the body, we’re using up some of that dextrose and that osmolarity is going to go way down cause we’re basically talking water, which has an osmolarity of zero. Right? And so absolutely. Um, it’s, it’s hypotonic in terms of how it acts in the body. That’s really the only one people argue about. Um, once you start seeing like d five, half ass, like the osmolarity changes a little, it’s actually still like a little bit lower. And so people don’t tend to, uh, don’t tend to argue about that one because the osmolarity is a little lower because d five w is so close to normal bloodstream, they start to say, well, it’s ISO tonic now that a type of tonic in the body. So that’s the one, that, good question. That is the one that people get weird about. Um, all right, any other questions about hypo before I move on to hyper and then I’ll open it for questions.
Awesome. All right. So remember, here’s our blood stream. We’ve got cells everywhere. So now let’s think we’re literally talking the opposite now, right? The opposite of Hypo is hyper. So hyper means it has more particles, right? So does it have more or less fluid than the bloodstream? Awesome. So if he is on this, so less fluid means it’s more concentrated. Okay. Less fluid, more concentrated. So which way is the fluid gonna want to shift? If I have less fluid in here than I did before into the vessels. Exactly. So into the vessels is where my fluid wants to shift. And that can come from interstitial, it can come from this cells, it can come from me cells. But either way, I want to shift the fluid into the vessel because my vessels all concentrated now, right? So what’s gonna Happen to my little cell, my poor little cell? You’ve taken away all its fluid. My poor little stale is going through. There’s my shrunken little cell. Okay, so same question. Would we ever really want to cause ourselves to shrink and shrivel? No. So what do we use hypertonic fluids for?
You guys can take swollen cells. Yes. So here I am, I’ve got this huge swollen cell and I’m like, oh my goodness, there’s too much fluid in that cell. I’ve got to figure out a way to pull it out. I give a hypertonic solution. Best example, 3% sailing. Now, just to hint, you guys don’t call it 3% Ns. And as his normal saline, which is 0.9% right? So 3% saline to 3% saline. I’m a shove that in my vessels is going to get super concentrated and it’s going to pull all this fluid and I’m going to allow myself to kind of bring itself back down to normal size. Okay, so a, you guys gave great examples here. So fluid overload. We absolutely could give a hypertonic solution for just for spacing and fluid overload a lot. Most of the time we do it for cellular purposes because we can typically just give regular diuretics for fluid overload.
I’m assuming kidneys are functioning, but when we actually have a cellular issue, we need to be able to pull it out of a cells. Um, and usually quickly. And so Sophia gave the best example. This isn’t the only time, but the best example of what we use, uh, something like 3% salient for his cerebral edema. So we’ve got somebody, maybe they had a stroke, maybe it had a head injury. Um, maybe they had something metabolic happened and they now have cerebral edema. So their brain cells are swelling. That is an emergency. I can handle some third spacing for a little while, right? I can handle some swollen legs, some societies, um, even pulmonary edema. I can support that with a ventilator and I can support that with diuretics. Um, but as soon as I start to get those brain cells swelling, I’m in big trouble. I’m in big trouble. Um, and so this is the most common example of when we go this extreme and give somebody 3% is cerebral edema. And so we’ll give 3%. We might even get, might even give man a tall man. A tall is technically a hypertonic solution, um, but it’s, uh, because it’s an osmotic diuretic, that’s literally its job is to go in hyper, concentrate the bloodstream and pull all that fluid out. So,
Does that make sense? So, cerebral edema Breena is super, super swollen. We give 3% saline, we pull the fluid out of those swollen cells and help decrease the cerebral edema, decreases symptoms, decrease intracranial pressure,
and the brain. Does that make sense?
So big thing to know about 3%. How do we need to administer 3% saline when we’re giving it? [inaudible]
Can I give it in just like a regular peripheral id and just push it?
Nope. Central Line. Yup. Central Line. It is extremely caustic to the veins. You’ve got to have a central line. I have given 3% very slowly in a peripheral, in an emergency, but it’s super not recommended. Um, you could start by giving something like one and a half percent if you have a peripheral line and can’t get a central line just to start giving them something. But 3% really should be in a central venous catheter, peripheral, um, a pick line as well as appropriate a port. Anything that goes into that big vein in our heart is the best way that we want to do that. And relatively slowly that once you’re in a central line, this speed, the rate doesn’t matter as much. But again, just like I said, you know, we’re never actually trying to shrink and shrivel up ourselves, but if we give too much too fast, we will. So you still want to be cautious. You still want to be careful with your administration.
makes sense. So the, the um, memory device I heard here for this one is being hyper active and you think of somebody who like works out all the time and they get super skinny.
So hippo high, high hypo hippo, like a fat hippo, hyper hyperactive, someone works out all the time, gets deeper skin. But again, remembering, understanding how the movement of fluid happens and I was Moses and what we’re trying to accomplish, that really helps as well. You guys know, I like to teach you guys the path though so that you know that as well as memory devices. Right? Okay. What questions can I answer for you guys about fluids? Um, I’m about to post a couple of links for you while you guys ask questions. Um, one of them is a link to, um, our fluid lessons. So in our material into your question, two seconds in our fluid and electrolytes course, I’m going to post the links for the three types of IB solutions lessons. But there’s also lessons in there about, um, the fluid pressures and fluid shifts.
So make sure that you check those out. Okay? There is another cheat sheet that will talk you through the IB solutions and their osmolarity. So this is the one I was talking about right here. Three talked d five w it’s 252 milliosmoles per liter. So it’s considered isotonic in the bag, but I can tell you that actually is hypersonic anybody. So question was, what did I say about Mannitol? Mannitol is an Osmotic diuretic. It literally by what Osmotic diarrhetic does, is it hyper concentrates the button and pull fluid just like a hypertonic ivy solution would. It’s just not a Christus. I considered a crystal aid. It’s Mannitol, but it does the same thing. Um, so what IB fluid is used for DKA. So in DKA, we typically are going to start them with a normal [inaudible]. If you’re talking about that first bag, you hang normal saying, just get fluids in them, right?
What happens is we’ll give them really normal sailing. We’ll start them on an insulin drip and we start to see their sugar come down. But with DKA especially, we have to keep giving them insulin until we fix the acidosis, right? So their sugar might come way down, but we still need to give them insulin. So then we start giving them a dextrose solution for their IB fluids instead of just regular normal saline so that we can kind of balance this, keep their sugars normal, but still give them insulin to fix the acidosis problem. So when we do that, we’d have, typically we’ll shift to a d five happiness.
So it’s a hypo tonic solution. Typically there are some people who will give that first bag or two of boluses will be normal saline and then their, their maintenance fluids will be half an ass also for that reason. Pilot. Okay. Making sure I didn’t miss any other questions.
What other questions can I answer for you guys? Oh, and I want to let you all know, actually just saw a video video on demand is coming. The recordings of these tutoring sessions is coming. I don’t have a date for you. Um, but it is coming. But I can tell you that I just recorded all of this in a podcast. So if you go to, um, the NRSNG radio app, which is our podcast app, or you have a subscription to the NRSNG podcast, this exact lesson, it’s about 12 minutes long, is there. So if you need to just hear it again and hear me talk through it again. There is now a podcast that you can just let, it literally just got released a couple of days ago so you guys can review that if you want to.
So I apologize. I still, I’m telling you man, these video recordings are coming. Our, our engineering team is working so hard. It’s pretty awesome.
Alright. As always,
Samuel said this is literally better than every single lecture we had them as at my school. I’m sad for you, but I’m glad. I’m glad that was helpful. It makes me as an educator that kind of makes me upset, but I’m glad I could help
Donna. So DKA. Yes, I can tell you about questions. I’m waiting. Ask Your question while Dan is asking her question. You guys, I’m going to post the survey. So if you guys have suggestions on other topics or anything you want to see, but also just tell us how we’re doing so we can always make it better for you. Okay.
Dexterous means out if to keep the sugar normal. Why do we give d five half ass? When I say dexterous moves out, it’s because the body is using it. The body needs to have the sugar to use to use the sugar. And so we give it insulin and dextrose at the same time. It doesn’t a hundred percent move out. Right? We don’t give dextrose and every single milligram of it is out like that. Right. The body uses it as it needs it, as it needs it, it’ll use it. Um, where’s the podcast? So you can look up, um, NRSNG on really any podcast app. I know iTunes for sure. I have it on. What do I have it on? I want to say Google music. I think I have it on, but there’s also an app. If you go to your app store, your play store or your, um, whatever the apple, what you guys, I’m not an apple person.
I’m an android person. Um, you can look for NRSNG radio. It’s an app that we have that is literally all of our podcasts. And so the NRSNG radio app has always updated with our new podcast and it’s on there as well. So done. Did that makes sense that when we give the dextrose it doesn’t all move out. It just gets used as we need it. So we’ll continue replacing it kind of as we need. And we watched their sugars. I mean if somebody is on an insulin drip, we’re watching sugars at least every hour anyways. So we’re always gonna keep that balancing act. The question hypo hippo. You guys can honestly, I don’t remember who it was. It was either fia or it wasn’t Sophia. She’s on here. She would have told me it was one of you guys gave me that one. The hypo hippo one. So I’m glad that that worked for you guys.
That’s what, that’s why I love our little cohort cause you guys are always helping each other.
Cool. All right guys. Fill out that form for us so that we know. So Donna, for this specific podcast I talked about defeating Osmosis. I talked about hyper or Hypo. Um, remember it’s just audio so I couldn’t draw pictures or anything, but I basically explained the difference. Talk about the different types of fluids that we use and why we use them. Kind of pretty general. Um, this most recent podcast, let me see if I can find it. I think it’s actually called the, what’s the difference between hypertonic and Hy-Ko? Tonic I think is what it’s actually called an, it should be one of the most recent ones. Trying to see if I can, but yeah, it should be it in fact it is. It’s the very, it’s the most recent one that was released to be able to find it. Um, in terms of the podcast name, it’s NRSNG, I think overall. All right.
Okay. Yeah, yeah. It’s harder to do teaching when you’re just on a podcast, but hopefully at least if you just need to hear the information again and then you can hear my voice in your head later. All right guys. Well we love you guys. Make sure you fill out that survey. Let us know what we can do and yes, I got going. I was like, one of these days, somebody is going to tell me happy nursing and it’s going to be awesome. Thanks. Alright guys. Have a fabulous day. I go out and be your best selves and as always, happy nursing.