Thermoregulation in Neonates: the importance of keeping babies at the perfect temperature

Hello and welcome to Tala Talks NICU where we break down medical concepts and make them really easy so that you will understand them and hopefully retain them forever. This week we're going to be talking about thermoregulation or temperature control in neonates and why it's so important. So before we continue please remember to like this video and to subscribe to the channel if you're interested and to leave us a comment about what you would like us to cover next. So today we're going to go over 1. What is thermoregulation in infants? 2. Why do we care about it so much? 3. How do babies lose heat? and 4. How can we prevent this heat loss? So let's start with point number one. What is thermoregulation? Thermoregulation is literally temperature regulation or temperature control of the Newborns or neonates especially premature babies are really bad at maintaining their temperatures so it's really up to us or external sources to make sure that their bodies are always at an ideal temperature. And what is a normal temperature for a baby? The normal skin temperature is 36 to 36.5 degrees celsius and the normal skin temperature in fahrenheit is 96.8 to 97.7. The normal core temperature or the temperature inside our bodies is going to be a little bit higher than this and normally we measure this with a rectal thermometer so the normal core temperature is 36.5 to 37.5 degrees celsius and 97.7 to 99.5 degrees fahrenheit. What we try to do in the unit is to provide the infant with a neutral thermal environment which means that we provide exactly the right temperature for the infant so that it's metabolic demands and oxygen demands and energy demands at an absolute minimum. Or another way of saying this is that we give the ideal temperature to babies so that they don't have to put any energy into staying warm or even cooling themselves off so that they can use all their energy to heal and to grow. Number two. Why do we care so much about temperature control and neonates? The issue is that when babies get cold lots of really bad things can happen and a lot of those bad things can happen because the baby is using a lot of its energy stores to try to get warm and when they're using increased energy they're also using increased oxygen. So cold babies are more likely to get hypoxemic so have a lower oxygen level in their blood as well as obviously eventually this will lead to acidosis. They're also more likely to become apneic. They're more likely to have hypoglycemia because they use all their glycogen stores or their energy stores to try to stay warm and then obviously if they're using all their energy to stay warm then over a longer period of time they're going to have decreased growth. So always remember this practically. Say you have a baby that you've just given a bath to whether they're in the NICU or in the newborn nursery and all of a sudden the baby sat in the 80s and the baby's sugar is in the 30s. One of the first things that you should do is check the baby's temperature. They might just be cold right after the bath. If a baby gets really cold and stays there for a longer period of time and literally runs out of energy to try to bring itself back up so it's kind of an uncompensated amount of hypothermia, then that's when really bad things can happen. When really premature babies get cold they're at increased risk of IVH or intraventricular hemorrhage. All babies are at increased risk of DIC or developing just really bad clotting issues so that they can bleed really easily. Also they have an increased risk of developing sinus bradycardia where their heart beats just a lot slower. So logically they have a higher risk of developing hypertension and then shock. Remember that when we purposely cool babies, so when we're doing therapeutic hypothermia for babies with HIE, these are all some of the side effects that can happen when we do cool these babies. Most importantly, numerous studies for really decades have shown that infants getting very cold after birth, full-term babies as well as pre-term babies, greatly increases the mortality. In fact, being hypothermic after birth increases the chance of the baby dying by two to three times. This really is a global issue. It's not just in developed countries or in highly specialized NICUs. All babies, whether they're born at home or in a hospital or outside a building, are at greatly increased risk of dying if they get cold. We'll go over this in a video in the short future but a lot of units have a golden hour which is all these parameters that we try to get done within the first hour of a premature infant's life. One of the most important things that we follow and check is that initial temperature of the baby because we know that if that baby has good temperature they have a higher chance of survival. Number three, how do babies lose heat? So babies are really bad at good temperature control because they lose heat at a much higher rate than older kids or adults. In fact, relatively they lose heat at about four times the rate of older kids and adults. There are four main mechanisms of heat loss in a neonate and I'm going to go over them now. The first one is radiation. So this is heat loss from a warm object, or in this case the infant, to a cooler object nearby which isn't in direct contact with the object. So for example, this could be a baby and being placed in a cold isolette. So the baby will radiate heat to the walls, to the cooler walls of the isolette. Two, conduction. Conduction is heat loss from the warm object or the infant to something that it's in direct contact with. So for example, it could be a blanket, a cold blanket that the baby is lying on. The baby will directly lose heat to that cooler blanket. C, convection. This is heat loss to the surrounding air and then remember that hot air always rises. So the windier it is, the higher the heat loss will be. This is why you are always cooler or colder on a windier day. And the fourth one is evaporation. This is heat loss as the water evaporates off the baby. So obviously this is kind of most important immediately after the delivery when the baby is wet or for example if the baby just had a bath. Premature infants are especially at risk for losing heat and that really is for several reasons. The first one is, is that they have much less subcutaneous fat. So they really just don't have as much padding on them. The second one is that they have high surface area to body weight ratio. So we talked about this earlier in the nine basic facts on fluids and electrolytes. So it's such an important concept for you to understand. If you don't get it, go back and look at that video. But the concept is, is that relatively there's just a lot more skin where heat and water can get out from compared to an older adult. And premature babies as well as all neonates have much lower brown fat storage as well as glycogen storage. Which are both energy sources used in older kids and adults to actually generate heat. So number four, how can we prevent heat loss? Logically we need to prevent all those four different mechanisms of heat loss and we really try to stop every single one of them. So let's go through them one by one. So the first one is how do we prevent the baby radiating heat? So how do we prevent heat loss from radiation? So one good way to do this is to make sure that the entire room and everything that the baby is surrounded by is at an increased temperature. In the delivery room or the operating room, the NRP recommends that the ambient temperature in those rooms is kept at between 23 to 25 degrees Celsius or 74 to 77 degrees Fahrenheit. I'm sure everybody who's watching this has had the same arguments with the OBs who are like under multiple layers and doing the operating. So that's always a bit of a battle in any hospital. Then again in the delivery room or if the baby is undergoing a procedure, very often we'll use the radiant warmer. So there's normally a warmer on the bed that you're drying the baby in and resuscitating the baby on that will directly radiate heat to the baby rather than obviously the baby radiating heat outwards. When the babies are in the unit then generally the incubators that they're placed in are constantly measuring the baby's temperature and then providing a heat source to keep the baby at that ideal temperature. Again like we said earlier we wouldn't want those incubators or that isolettes to be right next to a really cold wall or a drafty window because again if those walls are cold especially if they're single walls rather than double walls then the baby is more likely to radiate heat to the incubator itself. Number two, conduction. How do we prevent the baby from losing heat to conduction? So logically we need to warm up everything that the baby is directly in contact with. So that is why we heat up the blankets, we heat up the hat before wrapping the baby in these things. In micro preemies we also use something called warming pads. So these are kind of plastic bags they're used in sports medicine as well. They're plastic bags specially made they're filled with chemicals and when you kind of break the seal and squish it all up it starts becoming really warm because all of the chemical mixture. So we can put these warming pads directly underneath the babies so that really minimizes any conductive heat loss. In fact the babies should actually be getting heat from these pads. Number three, how do we stop convection heat loss from convection? So here the important thing is to try to stop air currents from moving above the baby. So obviously when we're in the unit babies are either in the isolette so they're pretty much completely blocked off from the air currents or they're in kind of more high walled cribs. Exactly also kind of preventing the air currents from affecting the babies. Even when we go to examine the babies very rarely do we open up the entire incubator. Normally we just kind of open up the little portholes and just kind of do our exam without opening the whole lid up towards air currents. Sometimes in the delivery room especially if it's kind of difficult to keep the sides of the of the warmer up which would obviously decrease the air currents but if everybody's trying to get in there then keeping the walls up would get in the way. So sometimes what we do is we kind of roll blankets up and then make a little nest so that the baby is buried in the nest and that in itself can prevent any convective air currents. And then four, how do we prevent heat loss from evaporation? This is probably the most obvious. In the delivery room or if a baby just had a bath then we have to dry them to make sure that that water isn't coming off their skin and taking the heat with it. Sometimes in the micropremies even before drying them we'll just put over a plastic wrap over their entire body and that will also prevent any evaporation of the fluid under the wrap and on top of their skin. And then for these tiny babies that we really continue to worry about the evaporation we'll put them in the incubators with humidities. So these humidities can start at 40 to 50 percent and it goes all the way up to 80-90 percent. I mean sometimes you put your hands in there and it kind of feels like a sauna. And just as a reminder increasing the humidity in the incubators for these tiny babies if it's deemed necessary can decrease the heat loss from evaporation and it can also decrease the fluid loss, the insensible fluid losses through the skin. So humidity in the incubator can kind of really help you with two different things. But remember that you are much more likely to feel at a cooler body temperature when it is a very dry environment as compared to when you're in a humid environment. I mean if you're at the same temperature in somewhere like Arizona versus somewhere like New Orleans and it's exactly the same temperature you're probably going to feel a lot cooler in Arizona which is really dry versus in New Orleans or Houston or whatever. Okay I hope that you learned something today. If you've reached this far and you've decided to send us a comment please include where you are based, which part of the world and which NICU you work in. It has been so lovely for us learning about all these different places. Anyway thank you so much for being here.