Pediatrics vs. Adult Fluid Differences (Nursing)

00:03 What are four of the main reasons that children less than two years of age have a greater need for fluids than adults? We've kind of hinted at that a little bit, because they have more total body water.

00:15 So they're going to need more fluid.

00:18 But compared to adults, kids less than two year olds have an increased metabolic rate.

00:24 You know, everybody's seen these crazy toddlers running around.

00:27 And it turns out that the inside of their bodies are running just as fast as the outside of their bodies.

00:33 So that metabolism is higher in a child that's less than two years old, than it isn't an adult.

00:41 They have an increased body surface area.

00:44 And that means, you know, if you remember back to the beginning of the presentation, we talked about the fact that fluid is needed for sweating.

00:53 If you have an increased body surface area, you're going to sweat a little bit more.

00:57 And so you can lose more fluid that way.

01:00 So children have increased body surface area.

01:03 They also have a higher respiratory rate.

01:06 It turns out, you really do lose a lot of fluid when you just breathe in and out normally.

01:12 And children breathe much more quickly than adults do.

01:16 So they're going to lose more fluid as they do this breathing in and out.

01:21 They also have as we talked about higher volumes of water proportionately compared to an adult.

01:28 So, if they lose that body of water, it's a higher percentage of their overall body in total.

01:35 And so, it really affects them more.

01:39 So again, children under two have a greater need for fluids.

01:45 The other thing that we need to know about is they have a more limited fluid reserve.

01:50 So when we are thinking about the term reserve, we want to think about the fact that for adults were going to hold on to our body water a little bit better.

02:01 Where as infants and children, they are not as able to hold on to body water.

02:08 So as they take it in, their bodies flush it out, and so they don't have this reserve of fluid.

02:15 There is also a greater amount of extracellular fluid exchanged or lost daily.

02:21 Again, that respiration can help with this process.

02:26 And it means that pediatric patients can become dehydrated much more quickly.

02:33 They also have functionally immature kidneys.

02:37 So it turns out when you're born, not everything works perfectly right away.

02:42 Some things need a little bit of growing time, and the kidneys are just such an organ.

02:46 So they are fairly small when the child is born.

02:50 Makes sense. You know, babies are small, their kidneys are small.

02:53 But it turns out that kidneys, the more surface area you have, the better they work.

02:57 So as you grow and your kidneys grow with you, they start to work a little bit better.

03:02 So those immature kidneys also mean that pediatric patients are at risk of losing some of that fluid.

03:10 Again, this is an illustration of the fact that when you think about a baby's kidney, they have little 5 centimeter length kidneys.

03:19 Where as an adult, that kidney is going to be much, much larger.

03:24 The other big difference between a smaller child and adult is that loop of Henle.

03:32 And if you remember back to your physiology courses, I know that was probably a long time ago.

03:39 But we talked about the loop of Henle.

03:41 And the fact that that helps us concentrate the urine.

03:44 And if the urine is concentrated, that means we're not losing as much water through our urine.

03:50 Now, if you have a smaller loop of Henle, you're not going to have quite the ability to concentrate.

03:56 So that means that kids are going to lose more water.

04:00 They're peeing out more water than an adult would.

04:03 Because the adults urine is going to be a little bit more concentrated.

04:08 So there are some additional critical differences in children when it comes to how much stuff is dissolved in their urine.

04:18 This first point here means that 550 mOsm just means the amount of stuff that's dissolved into the urine.

04:29 And you'll notice that there's 550 mOsm/l of urine for a preterm infant versus 700 mOsm/L in a term infant.

04:40 And that just means that there's less stuff in the urine of a preterm infant, versus what's in the urine of a term infant.

04:48 And then when you get to the adult, there may be up to 1200 mOsm/L of stuff.

04:55 And this stuff includes electrolytes and cells, and all of the things that we are getting rid of when we urinate.

05:03 So this can also be represented by these urine cups up here.

05:08 If you have really concentrated urine, it's gonna look dark.

05:12 and that means there's more stuff in there.

05:15 Versus if you have really light colored urine, there's more water in that urine.

05:20 There's less of these electrolytes and cells that were trying to pee out.

05:24 And so a neonate, or a preterm infant is going to have much lighter colored urine than an adult would have.

05:32 And that's one way to kind of check roughly check the concentration of urine.

05:39 Finally, what we want you to take away from this presentation is that everybody has water in their body.

05:47 There is proportions of where that water is located.

05:51 And there are small differences in pediatric patients that make managing fluid.

05:56 Sometimes a little more complicated, but it's something that if you understand that infants and children need a little more attention paid to their fluid status that you will be taking great care of all your pediatric patients.