Poison Center Pointers: Carbon monoxide ft. Dr. Mark Neavyn

NNEPC Medical Director Dr. Mark Neavyn joins our host, Chris, for a discussion of carbon monoxide. What makes this poisonous gas so dangerous? Where does carbon monoxide come from and why are CO poisonings more prevalent in winter? What should I do if my carbon monoxide alarm is going off? Dr. Neavyn addresses these questions and more in our February episode.


Karlee: Poison Center Pointers is brought to you by the Northern New England Poison Center. This podcast is not to replace timely advice or recommendations. If you have an actual poisoning emergency, scenario, or question, contact the Northern New England Poison Center by calling 1-800-222-1222, text the word POISON to 85511, or chat online at nnepc.org.

Chris: Welcome to Poison Center Pointers, a podcast presented to you by the Northern New England Poison Center.

Chris: Hello and welcome back to Poison Center Pointers. My name is Chris. Today, I am not joined by Karlee and Carolyn, but instead we have a special guest for you today. I’m joined by Dr. Mark J. Neavyn. Mark, thanks for being here.

Dr. Neavyn: Thanks for having me, Chris!

Chris: So, Mark is the medical director here at the Northern New England Poison Center. He is also an emergency physician, and we are very thankful and honored to have his time. We figured since we have his time, we would talk about one of the more important topics we encounter this time of year: carbon monoxide. Mark, do you have a lot of experience with carbon monoxide?

Dr. Neavyn: Uh, I do and I hate it so, so, so much. You have no idea. Carbon monoxide is the worst. It really is.

Chris: The worst. What’s your justification for that?

Dr. Neavyn: Well, you know it’s this thing that forms for who knows why? It’s something about combustion and, you know, it’s invisible. You can’t smell it. It’s not like gas from your stove where you smell something. You can’t smell it at all. You don’t know it’s there unless you have a working carbon monoxide detector and—

Chris: Oh, we’re going to hit on that pretty heavily today.

Dr. Neavyn: —I don’t know about you, but I’m paranoid about smoke detectors and carbon monoxide detectors and… I don’t know. Are they working? Are they not working? I feel like I have to constantly remind myself to change the batteries.

Chris: I am certain mine are working because I’ve changed every battery in every carbon monoxide detector in my house over the last year, and they always seem to go off at three in the morning. I don’t know if that happens to you, too? It turns into a nightmare.

Dr. Neavyn: Yep. Yeah that little reminder beep that happens every 6 1/2 minutes.

Chris: You have to convince yourself you didn’t actually hear it the first couple times?

Dr. Neavyn: Right. Yeah, oh, that must have been the house down the street. That couldn’t be our house.

Chris: Well, so, as Mark hinted at, what exactly is carbon monoxide? It is an odorless, colorless gas that is produced through combustion or burning things that contain carbon. What do we commonly encounter that contains carbon that we would be burning? Fuels.

Dr. Neavyn: Charcoal.

Chris: Natural gas. A lot of our heating systems, right? And carbon monoxide is produced when it’s in this sort of system, some sort of engine where active combustion is occurring, but it doesn’t have enough oxygen in it to create CO2 as a byproduct, otherwise known as carbon dioxide; instead we end up with carbon monoxide. And just a little brief overview as to what exactly it is, but why are we talking about it today?

Dr. Neavyn: Well, I mean, typically, Chris, winter time is the time for carbon monoxide cases to come to my attention. In particular, not only through working with the poison center, but also in my own clinical practice as an emergency physician. And some of the most tragic cases that I have involve carbon monoxide. Mostly because nobody means for that to happen. Nobody means to be sleeping and not realize that there’s carbon monoxide leaking from your generator or your furnace. And so it can be really tragic, and it can be really life threatening.

Chris: Yes, and as you’re kind of alluding to, it is kind of a common poisoning and a leading cause of toxicological death. I found some data that’s a little bit older, about a decade old, that suggested that CO exposure results in nearly 400 or so deaths yearly in the United States, up to 2,000 hospitalizations, and more than 20,000 emergency department visits. Now, some newer data from the CDC suggests that could be more like 40-50,000. You did kind of hint at some sources of exposure, and a lot of them are residential. Are there any kind of common sources of exposure that you’ve encountered so far in your practice?

Dr. Neavyn: I think the most common cases for me have either involved a furnace, a charcoal grill, a generator, or a blockage of an automobile exhaust. So, I can think of pretty tragic cases in all those scenarios, and often times it has to do with poor ventilation. In particular, in the winter months, what I really worry about is one, electricity going out and people using generators that are poorly ventilated, particularly if you’re putting the generator in your basement or in your garage and allowing that exhaust to seep into your home. The other situation that is particularly tragic is when somebody is trying to shovel out their car in these New England winters, and the snow bank has kind of blocked off their muffler. When that happens, the typical catalytic converter that all these cars have can’t kind of wash out your carbon monoxide, and so the carbon monoxide will back up into the cabin of the car and lead to really high levels of carbon monoxide for whoever might be waiting inside the car while the car warms up.

Chris: Some excellent points. Just to kind of list off a couple more common calls that we do receive here in poison center as to a potential source of exposure—and those are the major ones—again, he hit on heating systems, so whether it’s your home furnace, water boiler, as he said generator. Even fuel-powered space heaters can be a problem, as well. So, kerosene space heaters are a common one. House fires can be a source. It’s not really something that we’re going to touch on much today. Again, he brought up grills, even gas powered appliances, wood stoves, so even cooking appliances to some degree. Again, automobiles. And there are other odd exposures that are a little less common; those are the big heavy hitters.

Dr. Neavyn: And it’s not to say that winter is the only time you can get carbon monoxide poisoning. I’ve definitely seen it in the summer time, too. Either, like, you get a rainy day and you bring your charcoal grill into your garage so you can continue that grill-out, or one of the other common things with us being in lake country around here is boating. Boat, the motor boats can also off-gas carbon monoxide. So we have had some pretty bad cases in the news over the past couple of years of small children who are water skiing who are exposed to large amounts of carbon monoxide while they’re water skiing, which is not something that people would anticipate.

Chris: One of the things I love since having you come on as our medical director here is your ability to teach complex topics and simplify them in ways that I can understand them. And I thought it’d be great to kind of hear your thoughts on what exactly it is that carbon monoxide does inside the body. Why is it a concern? Why is it toxic?

Dr. Neavyn: Yeah. Well, thank you. I guess the reason why I like to simplify things is ’cause I’m a pretty simple person myself. *laughter* I don’t really like to clutter my brain with too much complicated information. But there is a lot of research on carbon monoxide, in particular in the way it poisons the brain and poisons the heart. But, basically, the way I think about carbon monoxide is it is taking up a space on your oxygen transportation. So, it prevents oxygen from getting transported to vital tissues. So, for example, somebody exposed to carbon monoxide may develop a heart attack, or they may develop stroke like symptoms. Those are in severe cases. The more difficult cases that I find are cases with lower level exposures over a long period of time who are developing these more vague symptoms like headache, nausea, vomiting. All of these things that really, if they didn’t know they were exposed to carbon monoxide, it would be hard for even an experienced ER doc to recognize those symptoms as being carbon monoxide poisoning.

Chris: I think you used the term “vagary” when you described it? I like that.

Dr. Neavyn: Yes, yes. The long list of vagary that happens with carbon monoxide, especially when kids are sleeping in the home—the carbon monoxide detectors have run out of juice and the child wakes up with a headache or wakes up with nausea. Your first instinct is to think, oh, that’s just a viral bug or something. It’s not really on our kind of—it’s not really at the top of our differential, so to speak, for what could be causing those symptoms. So around this time of year is when I start really reminding my trainees and emergency departments and in the poison center that, you know, if somebody is complaining of headache or nausea or some of these vague symptoms, it’s a good idea to just ask about whether they have carbon monoxide detectors and whether they have any risks.

Chris: So I polled some colleagues in the poison center as to what are commonly encountered calls that we get, and I came up with a couple scenarios here. Figured we could kind of just run through them and think about what the next best steps are—what exactly is the concern here? How should we address it? ‘Cause I think these are questions that some people who are listening at home might have if they were ever to run into a situation like this, and obviously the most common one—my detector, my carbon monoxide detector, is going off in my house and I don’t know why. What should I do?

Dr. Neavyn: Yeah, I mean if a detector is going off in your house, you want to get out of the house. You don’t want to continue to be exposed to carbon monoxide if it’s in the house and these carbon monoxide detectors—I think we’ll get into it a little bit later, but they do have cutoffs of when they start to alert you to carbon monoxide, and if it’s going off, it means there could be an exposure and you want to stop that exposure as soon as possible.

Chris: Can’t ever assume that it’s not functioning, and we never want people to ignore a carbon monoxide alarm, so get the family together, children, pets. Leave the house and alert emergency services, right? The fire department has equipment exactly for this sort of scenario where they can ensure that the house is safe. They can determine what level of carbon monoxide is present in the house. So really, the best thing to do is to get out of the source of exposure.

Dr. Neavyn: Exactly, exactly.

Chris: This is one that sounds like you’ve probably encountered in the emergency department, as well, but we’ve had a variation of similar calls where the caller is concerned because their car or even their tractor, or they had what would normally be an outside grill running inside the garage. The garage is connected to the house and the caller is concerned because family is reporting that they feel a little bit lightheaded, maybe a little bit nauseous. Could carbon monoxide make its way into the house?

Dr. Neavyn: Absolutely. Oh. this is a classic one, especially with, like I said before, charcoal grills or generators running on fuel for this to happen, and people might not recognize that that’s an issue because they’re not going to, again, they’re not going to smell the carbon monoxide. They’re not going to see it, it’s not smoke. It’s not like you can see smoke coming into your house, right? It’s a gas, so it’s invisible. And it’s lighter than air actually, so it will dissipate through the house pretty easily. It’s not one of these other types of gases that is heavy and goes to the lowest ground point. This is lighter than air. Colorless, odorless, invisible to the eye and if people start developing symptoms, particularly, I would say if a group of people all have similar symptoms, that’s a concern to me that there’s multiple people getting exposed at the same time.

Chris: And I like to bring it up. Regrettably, I recently traded in cars and I no longer have a remote start on my car and when it’s, you know, negative 2 degrees in the morning before trying to get into work early. I know a lot of people like to start up their car, warm it up, right? I found a study that was done through Iowa State that found just warming up your vehicle for only two minutes with, you know, an overhead garage door open raised CO concentrations in the garage up to 500 parts per million. And what does that number mean? It’s enough that if you’re exposed to it, it’s going to produce symptoms and potential toxicity with prolonged exposure, so even just having the garage door open is not enough. We don’t want it in any sort of partially enclosed area. Another one I know I’ve got, another scenario I know I’ve got quite a few calls on—someone reporting that for the last couple weeks is every time they get in their car to drive to work or, you know, they have errands to run and they’re in the car for more than a couple of minutes, they start feeling dizzy and lightheaded. Do you have any thoughts on that? Is there ever really a potential for CO exposure in the car if it’s not a situation where, as you mentioned, the snow embankment clogs up the ventilation for the exhaust?

Dr. Neavyn: Typically, automobiles nowadays have really efficient catalytic converters that can kind of wash away your carbon monoxide that’s getting formed by your combustion engine. You know, it’s always possible that that system where air is flowing through can get blocked in some way, so if you’re starting to notice those types of symptoms while your car is running, it might be a good idea to get your car checked out to make sure that everything is functioning appropriately.

Chris: Another scenario I personally have had quite a few calls—someone calling after reporting that they’re running their space heater inside of the house. They’ll call and they’ll complain that they’re starting to feel weird—they have a headache, they’ve been nauseous, they actually vomited. Have you ever encountered any scenarios like that in the emergency department?

Dr. Neavyn: Yeah, yes, a lot of these space heaters run on kerosene and if there’s not adequate ventilation, you will get carbon monoxide building up, and I think the population at risk that I’ve seen tends to be construction workers where they potentially are working in a home that maybe has no electricity to it yet, or doesn’t have heating running quite yet, so they use these kerosene heaters to warm the home while they’re constructing it, and I’ve seen that a few times actually, so, that’s something to keep in mind that those kerosene heaters can really cause problems if you don’t have adequate ventilation.

Chris: Right. And even just keeping a couple windows and doors open might not be enough, as we had said, with keeping cars or tractors or grills in the garage. Last scenario I have here—we’ll just go with the classic. It’s something we’ve already mentioned a couple times here. I am working on having a generator installed and want to make sure we are safe from the exhaust that comes with the generator. How exactly do we go about this? I found online that, through some research, that the rule of thumb is to keep your generator 20 feet away from the house?

Dr. Neavyn: Yeah, I would definitely err on the side of caution with these things, and also, sounds obvious in retrospect, but close your windows. Oftentimes people will have a window open in one room when it’s getting warm in that particular room and they don’t realize that the fumes from whatever it is that’s causing the carbon monoxide is just kind of drifting right into that window.

Chris: Similar to having exhaust from your car blocked up—say it gets a little snowy, a little bit icy—we can have that issue with ventilation for generators, too, as well. So, the best way to go from here, considering that we have an emergency physician on the podcast, can you walk us through what management might be like in a situation where a patient has to come in to the hospital for evaluation?

Dr. Neavyn: Well, I think, first and foremost—so carbon monoxide poisoning is really a spectrum. So you can have mild symptoms, but you can also have pretty major symptoms—like symptoms of a heart attack, so you can develop chest pain, you can faint—if you have any of those serious symptoms you need to call 911 immediately because we do not want to delay getting you the care that you need. If you have mild symptoms and drive yourself in, I guess that’s appropriate in some cases, but if there’s any question of the symptoms being more severe, I would always say err on the side of calling 911 and getting to the emergency department as fast as possible. And actually, you know, the primary treatment for carbon monoxide is oxygen therapy, and so calling 911 gets you connected to oxygen as soon as that ambulance arrives at your home, which is super important.

Chris: And just to throw it in there, we’re always available as a resource. If you’re questioning whether or not you do require evaluation in the hospital, obviously emergency services is there, but so is the poison center—we’re all trained for this certain topic. So if there’s ever any sort of shadow of a doubt you can always give us a ring. I think probably the most important thing we can talk about today, much like a lot of the other podcasts here: helpful prevention tips. What can you do to make sure your family, your loved ones, even just yourself, that you’re healthy and you’re not exposed to CO?

Dr. Neavyn: Yeah, we’ve talked about it before, but carbon monoxide detectors are the single most important way to prevent carbon monoxide poisoning. ‘Cause there’s so many different ways carbon monoxide can build up in a home, and we will not know it unless we have a detector.

Chris: A couple helpful hints on maintenance and management of carbon monoxide detectors: generally recommended to check or replace batteries one to two times yearly—not always a good idea to wait till that annoying beep wakes you up at 3:00 in the morning, right? They say to replace the unit generally every five years or so. A couple key points I wanted to get into is placement of the car monoxide detector. As Mark previously pointed out, it’s lighter than air. It can diffuse throughout the house with ease, and it’s not going to stay down at ground level since it’s lighter than air. So generally we recommend having carbon monoxide detectors high on the wall. We want them on all levels of the home. Best not to put it next to any heating vents or have it covered by furniture or drapes. And we want it in all hallways where there’s people that are sleeping. Another key piece is making sure that you have a quality product. Generally they’ll run you somewhere in the 30 to 50 dollar range. We like to recommend products that have a UL mark on the back—that stands for Underwriters Laboratories. And that just means it was third-party tested to show that it meets the standards of what is recommended for the reliability of these products. For home use, look for a statement that says single station carbon monoxide alarm and make sure it’s battery powered, or if it’s electric, it has a battery backup in case of loss of power. Any other helpful hints that you have stored away for us there that we haven’t already mentioned?

Dr. Neavyn: Yeah, I think the big one is not ignoring that alarm and not assuming that if you open the windows, everything is going to be fine because that carbon monoxide detector is just detecting the carbon monoxide in its little area and you don’t know if the carbon monoxide levels where you’re sleeping might be higher and not only that, like you don’t know, if there’s children in the home, how much carbon monoxide exposure they’ve had. And I really worry about children because you know they’re still developing. Their brains are growing like crazy, and anything that might affect that brain development really needs to be treated appropriately. So I would say don’t blow off an alarm—if the alarm is going off, get your kids out of the house, get the family and dogs out of the house, and you know, make sure the fire department comes to your house and determines the carbon monoxide levels in your home and make sure that it’s safe to return. The other thing is, you know, if you have one of these mixed use detectors that detect smoke and carbon monoxide at the same time—I know my smoke detectors go off all the time because of my terrible cooking.

Chris: Yes.

Dr. Neavyn: And so, like, don’t be tempted, just don’t be tempted to take the battery out. You need to have that functioning carbon monoxide detector, even if occasionally you’re burning stuff on the stove.

Chris: That’s right. Couple other prevention tips: having your heating system and water heater serviced yearly; if you have a chimney, making sure that you have it cleaned and serviced every year ’cause that flue can get all gunked up, or the ventilation can have issues; as I previously mentioned, having a mechanic check the exhaust system in your car and truck yearly; big one is not to use your oven appliances as a heating source. Again, all the other recommendations we previously made: not bringing your generator inside, your space heater, grill—those are the heavy hitters that we can think of from calls that we receive here. I don’t know if you had any last pointers or important information you wanted to get across to our listeners regarding carbon monoxide?

Dr. Neavyn: Yeah, I think for me the key points that I want everybody to really recognize is that carbon monoxide is the silent killer, in the winter months particularly, but all year round. We don’t know it’s there unless you have a detector. And if you have symptoms like headache, dizziness, lightheadedness, nausea, vomiting—more significantly, if the rest of your family is having the same symptoms at the same time—that could be a sign that you’re having carbon monoxide issues. So if in doubt, call your local fire department to have your home assessed for carbon monoxide levels if you’re not sure if your carbon monoxide detector is working.

Chris: Definitely want to say thank you again for taking the time to chat with us. We appreciate you being here with us, Mark.

Dr. Neavyn: Yeah, thanks for having me, Chris. This was fun.

Chris: Hope to have you again soon. Maybe we’ll have a less scary topic next time because Mark is full of all sorts incredible factoids and stuff you would never know otherwise, so.

Dr. Neavyn: Well, poisonings are always scary, but, uh, hopefully I can help kind of explain stuff in in a less scary way next time.

Chris: Absolutely. Well, we want to say thanks again for all our listeners out there for checking in to this episode of Poison Center Pointers. You can like, share, and subscribe to us on Facebook and Twitter, and visit our website at nnepc.org. Remember, if you have an actual poisoning emergency, scenario, or even just a question, contact the Northern New England Poison Center by calling 1-800-222-1222; text the word POISON to 85511; or chat online at nnepc.org. Thanks again for listening.

Dr. Neavyn: Thanks, everybody!

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