Created by Matthew McPheeters.
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- At7:20, why is the concentration of oxygen in room air stated to be 40%, when the truth is that it is only 21%? This is a glaring mistake that should be corrected. It also leads to another error, when at7:33, he incorrectly states that giving 100% oxygen results in "twice the amount of oxygen is reaching the alveoli..." when in reality 100% oxygen is nearly FIVE times the amount of oxygen found in room air.(12 votes)
- I think he may have gotten confused with 40 percent being the typical amount of oxygen a patient would get through certain high flow masks, but to get 100 percent a patient would have to use a non rebreather mask. That is the only way I could think he may have gotten the 40 percent number.(2 votes)
- at7:20why is the concentration of oxygen in air room stated 40%(1 vote)
In this video, we're going to be talking about how to treat bronchiolitis. But first, let us briefly review what bronchiolitis is, as that'll help us better understand the treatment. Remember, if you break down the word bronchiolitis, you can figure out what it is. It's inflammation of the bronchioles and that's shown over here in this diagram of the respiratory tract. This is zoomed in here and the orange is depicting the inflammation of these bronchioles. It's a very common respiratory tract infection in children under the age of two years old. It's caused by a virus known as RSV. Now, before I get into the specifics of how to treat bronchiolitis, I want to first mention a couple of points on how to prevent bronchiolitis infection in the first place. There are two general ways you can prevent RSV infection. The first category is to prevent exposure to the virus itself. Well, the easiest and most effective way to prevent bronchiolitis, is simply just hand washing. This is simple, but very effective because one of the most common ways RSV enters the respiratory tract is through our hands. The other way you can avoid exposure to RSV is have children avoid other children who are sick. The other category of ways to prevent RSV is by improving the body's ability to fight the virus when it is exposed to it. Since the children who tend to get bronchiolitis tend to be very young, one of these means of improving their ability to fight off infection, is by breastfeeding. This is because breast milk actually contains some antibodies from the mother and these antibodies can help boost the immune system of the child. Another thing you can do is to prevent smoke exposure. Secondhand smoke exposure causes an underlying low level of inflammation in the respiratory tract. So, children who are exposed to secondhand smoke are at an increased risk of developing an RSV infection if they are exposed to RSV because they already have some inflammation going on in their bronchioles. The last one I want to talk about here is a medication known as palivizumab. Palivizumab is a special medication and it's reserved only for children who are at very high risk of not only developing bronchiolitis, but developing really severe disease. The children who qualify for palivizumab are children who are born premature or children who have preexisting lung or heart disease that make them more likely to develop severe infection. What is palivizumab? It's an injection of preformed antibodies. These antibodies circulate in the blood and any time an RSV virus shows up in the blood, these antibodies immediately attack it and they bind up the virus and they allow the immune system to destroy the virus before it can even set up an infection. Once again, this medication is really only reserved for high risk children. Now that we know how to prevent bronchiolitis, let's move on to the treatment of bronchiolitis. The most important question you need to ask in the treatment of bronchiolitis is actually where are we going to treat the child? There are two factors to think about when the decision is made to go to the hospital or to stay at home. The first factor is the risk of developing severe disease. Some of the factors that would put a child at high risk for developing severe disease would be things like prematurity, age less than three months, or preexisting heart or lung disease. Any child that does not have any of these factors would be considered low risk. The second factor in the consideration of where to treat a child, is the severity of disease. The marker that is used for this is the oxygen saturation. Oxygen saturation is a marker of how well the lungs are able to put oxygen in the blood. It gives a provider an idea of how well the child's lungs are working. It's measured in a percent. Normal is 100 percent. So any child who has an oxygen saturation less than 92 percent, is considered to have severe disease. If their oxygen saturation is greater than 92 percent, they're considered to have less severe disease. Let's figure out where a child should be treated. Any child that is at low risk for developing severe disease and the severity of their bronchiolitis is less severe, those children are okay to be treated at home. Really, any child that has high risk regardless of the severity of their disease, or any child that has severe disease regardless of their risk level, should probably be treated at the hospital. Alright, so now we know where to treat the child, but what is the treatment going to consist of? It's important to note that the treatment of bronchiolitis is supportive. Now, what do I mean by this? Well, supportive therapy means that we're treating the child's symptoms and we're helping their body be as effective as it can be at fighting the infection, but we're not going to give any medications that specifically target the infection. If the child is treated at home, this is going to include things like making sure the child remains adequately hydrated and is feeding well. In addition, whoever is taking care of the child should monitor them to make sure that they don't develop any severe symptoms. Some of these severe symptoms would be difficulty breathing, an increased heart rate, or if they seem to get really tired or sleepy. If a child has to be treated in the hospital, the treatment is still going to be supportive. We're still going to focus on hydration and nutrition of the child, but the child is also going to be treated to improve their breathing. This can be done through a variety of medications. Let's talk about some of these medications. So, to describe how some of these medications improve breathing, let me bring in a diagram of a bronchial. So, let me describe what's going on here. In orange here, we have the inflammation of the bronchial. You can see this inflammation is taking up a lot of space which is narrowing the airway in the middle, but there're a couple of other things here I want to point out. These pink structures on the outside that are wrapping around the bronchioles, these are muscles. These muscles when they tighten, they actually will constrict the bronchial. This yellow part right here in the middle, that is a mucus plug. When you have infection of the bronchioles, there can be a lot of secretions that get into the airways and these secretions can plug up the bronchioles. I mention all these things because we have specific medications that treat each one of them. I want to remind you that I mentioned earlier, if a child is being treated in the hospital, the goal is to improve oxygenation. So, what are the medications that can be given to improve oxygenation in bronchiolitis. There are two groups of medications that can be used. The first group directly improves oxygenation and the second group of medication indirectly improves oxygenation. Our medication that directly improves oxygenation, is actually pretty straight forward. It's oxygen. Room air contains 40 percent oxygen. When we give oxygen, we can give up to 100 percent oxygen. So, if you think about it this way, every time the alveoli fills up with air twice the amount of oxygen is reaching the alveoli to be able to be exchanged into the blood. So, that is definitely going to improve oxygenation. The next class of medications is beta-agonists. What beta-agonists do is that they inhibit the muscles lining the bronchioles. When these muscles are inhibited, they're no longer able to constrict, and so instead, they dilate. So, more air will be able to travel through there to reach the alveoli. If more air is able to reach the alveoli then the body is going to improve its oxygenation. The next medication is something called hypertonic saline. Hypertonic saline is pretty much just a salt solution that's inhaled and this inhaled salt solution draws water out of the inflamed tissue and into the bronchial lumen. This will break up mucus plugs and allow them to be coughed up and out of the airways, and this improves the passage of air through the bronchial to then improve oxygenation. The next class of medications is corticosteroids. Corticosteroids actually target the cells that cause the inflammation in the bronchioles. So, when cortisteroids are given the inflammation kind of goes away. When that inflammation decreases, the airway dilates allowing more air to reach the alveoli and thus improving oxygenation. So, the last type of medication that can be given is epinephrine. I put epinephrine in the same color as the beta-agonist, because it has the same mechanism. It inhibits these muscles that normally constrict the bronchioles and so it results in dilation of the bronchioles which increases the airflow to the alveoli, and when you increase the airflow to the alveoli, you're going to subsequently increase oxygenation. So, now we've talked about all the different types of medications that can be given for bronchiolitis, but which ones do we actually give on a regular basis. The most important one to remember is oxygen, because in studies, oxygen is shown to be the most effective treatment of bronchiolitis. In regards to the indirect medications, both beta-agonists and hypertonic saline are considered second line. The reason they're second line is because the research doesn't really support their use. There's not a whole lot of clinical utility. Children who get beta-agonists and hypertonic saline, don't necessarily do better than children who don't. This being said, it's definitely okay for a provider to give a trial of beta-agonists or hypertonic saline and see if it improves the child's symptoms. If it does improve the child's symptoms, it's not going to hurt and you can continue giving it. Now, corticosteroids and epinephrine are third line medications. They are not routinely given to children who are admitted to the hospital for bronchiolitis. They're really reserved for children who have other underlying diseases that may make the bronchiolitis worse such as asthma. Let's briefly recap the treatment of bronchiolitis. Remember, that the most important question to ask is where the child needs to be treated based on their risks and severity of disease you'll decide whether or not the child needs to go to the hospital or can be treated with supportive therapy at home. If the child needs to go to the hospital, remember that the goal of therapy is to improve oxygenation and supplemental oxygen is the first line treatment.