Dr. Peter Antevy explains why intubating a severely obstructed asthmatic is dangerous: air-trapping raises intrathoracic pressure and blocks right-ventricle filling, while common asthma drugs lower diastolic blood pressure. Paralysis removes the patient's ability to generate negative pressure and can cause immediate cardiac arrest. Use IV fluids and pressors instead.
Chapters
Hey, this is Dr. Peter Hantevi. Welcome to another edition of the Hantevi Minute. I wanted to talk this week about asthma and why intubating a sick asthmatic is probably the last thing you want to do. There's some physiology we need to talk about and we'll talk about the medications after that. So I have here a schematic of the heart and the lungs around it. And I'm pointing out to you the right ventricle, and I'm pointing out here the aorta and then the coronaries. It's important to understand that asthma is an obstructive disease. That means that they have a hard time getting air out. That means you get air stacking and you have pressure on that heart from all sides. So the heart is kind of being smushed, if you will. That makes it hard for the right ventricle to actually fill. The asthmatic, on the other hand, tries to negate that by taking these big deep breaths. And then that negative pressure allows blood to rush into the heart. So that big breath in is helping the asthmatic fill the heart. And that's a very important concept. Now the heart is actually getting fed. It feeds itself using the coronary artery. Now that happens during diastole. So your diastolic blood pressure is very, very important because that's when your heart itself is actually getting blood supply. So we have two concepts to focus on the air stacking and then the blood pressure issues. For the air stacking, of course we're going to use typical asthma treatment, right? So that's your albuterol, your atrovent and so for forth. But also very importantly, because of the pressure on the heart, you want to give fluids. And I think fluids are very underestimated in asthma. But remember that when you're looking at asthmatic's heart on X ray, it's tiny, it's thin, and that's because of the air stacking. So asthma treatment and fluids. Let's talk about how those medications now will affect the blood pressure. And so let's talk about medications for a minute and how they relate to the diastolic blood pressure. Very important. The albuterol is a beta agonist. And what it's going to do to your diastolic blood pressure, it's going to lower it. Magnesium will also lower your diastolic blood pressure. So as you're treating your asthmatic patient, you're lowering the diastolic blood pressure. Remember, that's what feeds your coronaries. So you have a patient who is not filling and you're limiting their diastolic blood flow. That's a patient who is going to continue to get worse unless you consider the alternatives. The alternatives are using saline and that'll increase your blood pressure. But then don't Forget to use epinephrine 1-1000 IM push pressure epi or an epi drip also, or norepi drip because you do not want that diastolic blood pressure to go down. Here's what happens if your diastolic blood pressure goes down and then you decide to intubate the patient. All of a sudden. If you paralyze this patient, that negative pressure that they were using to fill their heart goes away. They have no diastolic blood pressure and that asthmatic patient will have a cardiac arrest right on the spot. So that's not something that you want to do. So focus the treatment. But what it does to your diastolic blood pressure. Look at the diastolic blood pressure, fix it and actually give treatment that will help increase your patients diastolic blood pressure. So we're looking at blood pressure at the same time as we're looking at air stacking. Those two things are very important to look at together. And do not intubate an asthmatic if you don't have to. So let's summarize. Asthma. It's not an oxygen problem, it's a CO2 problem. Right? Don't blast them with oxygen. They need help exhaling. Give fluid, normal saline. Watch their diastolic blood pressure, number one, because of the medications that you're giving. And then lastly, try to avoid intubation. And if, if you have to intubate, you should give them EPI m some sort of presser if you will. You can go to EPI IV or norepi. But remember that these are the important items to remember with asthma. Again, this has been Dr. Peter Antevi. Thank you so much. Happy holidays. Happy Thanksgiving to you and your family. Thank you.
