 Everybody, Dr. Rowe here. Acid-based disorders are very important in healthcare, so it's very important that we cover them in detail. In this video, I'm going to do an introduction and talk about all four of them. And then I'm going to mine a little bit deeper in a following video. Let's just go ahead and look at our normal ranges first and then what constitutes acidosis or alkalosis. So the normal pH of your blood is 7.35 to 7.45. So if the pH drops below, excuse me, 7.35, you will have an acidosis condition. It's really acidemia, but the physiological condition is called acidosis. If the pH climbs above 7.45, you will have an alkalosis condition. The other key players are going to be your partial pressure of carbon dioxide, PCO2. Normally should be 35 to 45 millimeters of mercury, and then HCO3R bicarbonate should be normally 22 to 26. Now you might see different ranges, different numbers than that, but for now we're primarily going to be talking about a higher or a lower. The exact numbers won't matter, depends on who's measuring it and the lab values. So another thing real important, now there's a little bit of disagreement here, so I want you to know this is my opinion, and I think there's evidence to support this, that the most common acid-based disorder is respiratory acidosis. But if you look on Google, you do some different research, some people are going to say that it's metabolic acidosis. So here's what I would say. Respiratory acidosis is the most common, and you'll see why a long list of things can lead to respiratory acidosis, basically any chronic lung problems. And then any drug that lowers breathing rate, et cetera. But metabolic acidosis, I think that's the most common in the intensive care unit. The most common to be serious emergencies, and we'll look at those in a moment. So I just wanted to kind of pause and say that first. Let's start here with the first one then. So I gave you the reference ranges already, and you'll see even the numbers that I put on the screen are a little different than the numbers that are there in table 26.3. Like I said, there's going to be some variability, but we're going to be talking higher and lower here. So metabolic acidosis, you're going to see because it's an acidosis, the pH is going to drop. And then you're also going to see that your bicarbonate levels are going to drop. So primarily metabolic acidosis is an issue where you don't have enough bicarbonate. So the pH of drop and the bicarbonate has dropped. But notice that carbon dioxide is normal, and then it's CO2 starts to drop. That's because your lungs are now trying to compensate for the metabolic acidosis. So I don't want to make sure you're not confused by that. Metabolic acidosis, you primarily think bicarbonate. The carbon dioxide is a compensatory response. So for example, if someone has a metabolic acidosis, you see normally carbon dioxide levels should be 35 to 45. Their PCO2 would be below 35, but not because there's anything wrong with their lungs. It's because their lungs are trying to compensate for the metabolic problem. Very important to understand that. So metabolic acidosis, most common causes, diarrhea would lead to a direct loss of bicarbonate. So that would be one way to develop a metabolic acidosis. But the two that I think of primarily are lactic acidosis and diabetic ketoacidosis. So lactic acidosis would be the overproduction of lactic acid. You might be thinking exercise, and that can happen. Intense exercise for too long can put somebody in a state of metabolic acidosis. But the primary cause of lactic acidosis is sepsis. This is actually what killed my grandmother. She was a diabetic. She had a wound that wouldn't heal. It became septic. And then the overgrowth of microorganisms leads to a hypoxia, which leads to lactic acidosis, and it can definitely be fatal. So lactic acidosis would be a common cause of someone entering the ICU, for example. And then diabetic ketoacidosis, an uncontrolled diabetic, can have an issue where they produce way too many ketone bodies, way too many of these ketoacids, and their body can't deal with that. The pH change plus the dehydration that comes with that can also be fatal. So diarrhea, lactic acidosis, and diabetic ketoacidosis would be the three primarily causes of metabolic acidosis. The pH is still down, which is why it's a respiratory problem. Notice that carbon dioxide levels are too high, and hopefully this makes sense. Carbon dioxide, think carbonic acid. So there's too much CO2. It means there's too much carbonic acid. Too much acid, pH drops. Then normally, by carbonate, you see it's normal, and then it responds by raising. Nothing wrong with the metabolic half of things here. That is a compensation. So what causes respiratory acidosis? Anything that leads to hypoventilation or impaired movement of air. So this could be any of your chronic lung problems, COPD, emphysema, asthma, pneumonia, any lung problem, acute or chronic, congestive heart failure can be an issue here too. What else can cause hypoventilation, breathing too slowly, age, central nervous system disorders, and drugs, and other kind of medication as well. So anything that causes you to get rid of too little carbon dioxide would lead to a respiratory acidosis. Next, we have metabolic alkalosis, not near as common. Primary cause here, and hopefully understand why, acidosis conditions are way more common if not go back and watch the earlier videos. We're always teetering on the edge because we're always making acids. Metabolic alkalosis, the most common example would be vomiting. If you think about it, every time you vomit, you just got rid of a cup or however much of gastric juice, which is full of hydrochloric acid. Now your body has to use acids to generate more stomach acid. So every time you vomit, you're pouring acids out of your body. If you do that too often, you're getting rid of acid, so your pH will climb. So that's going to be metabolic alkalosis. Notice the normal issue is going to be bicarbonate, so you're going to have too much bicarbonate or not enough actual acid, and then your lungs will try to compensate, which is why it's normal and then would increase. And then lastly, we have respiratory alkalosis. This is primarily caused by hyperventilation. This is usually not a big emergency. If someone's hyperventilating, calm them down. Have them breathe into a bag, because notice their carbon dioxide levels are too low. If they breathe into a bag, they'll suck that CO2 back in. As the CO2 levels climb back up or they calm down and stop breathing so fast, their pH should return to normal and they should be fine. So hopefully understand how the compensation fits in there. I won't go into the exact values of what you'd see. We'll do a separate video on Rome when we cover that. All right, so that's kind of the short introduction. I know it's kind of a long video, but that's a short introduction. We're going to come back through and do a little bit more detail here as well. So that's going to be your four types of acid-based disorders. I hope this helps. Have a wonderful day. Be blessed.