CO Poisoning Question

[Duke Dive Medicine]

The passage you quoted is great and supports what I have read but it does not clearly discuss the mechanism of dissociating CO from the blood....

...My understanding is that each erythrocyte has 4 heme receptor sites that can bond with (in the context of this discussion) O2 or CO. The affinity of CO to heme is with regards to the chemical bond it makes compared to the chemical bond O2 makes. Is it correct that inundating the body with O2 at higher PP results in it being more likely that all 4 receptors of an available erythrocyte will be occupied by O2 thereby keeping CO from having a place to bond?

If the above notion is true, then is it a misnomer that CO "displaces" O2 in the blood? Or does the displacement something that is realized in erythrocytes that do not have all 4 sites bonded with O2? I know that CO on one site affects the propensity of the other sites to bond with molecules of CO and O2, but I just wanted to drill into the actual mechanism of how the CO is displaced from the red blood cells....I haven't found much info that delves into the chemical of physical properties of the transport/dissociation mechanism...lots of info out there about how CO2 is transported and disassociated/removed from the blood/body, but other than various sources repeating to one degree or another what you quoted, I can't seem to find much on the actual mechanism of what is happening at the molecular level/cellular level for CO.

Thanks for the feedback and clarifications you have provided.

-Z

Higher inspired pO2 means that there's a high diffusion gradient along the heme / blood / alveolar continuum. CO will follow that gradient.

Best regards,
DDM

 

[Akimbo]

Higher inspired pO2 means that there's a high diffusion gradient along the heme / blood / alveolar continuum. CO will follow that gradient.

Best regards,
DDM

Physics always trumps biology... even when we haven't figured out all the "why" parts yet. I can't tell if that fact gives me comfort or makes me feel stupid. Comfort in my own ignorance perhaps???

 

[Duke Dive Medicine]

Physics always trumps biology... even when we haven't figured out all the "why" parts yet. I can't tell if that fact gives me comfort or makes me feel stupid. Comfort in my own ignorance perhaps???

You and me both mate!

 

[DandyDon]

Built-in hard-wired CO detectors have been required since the 2009 building codes in the US, along with smoke detectors.

That may be true. I found H.R.1796 - Carbon Monoxide Poisoning Prevention Act, Latest Action: Senate - 08/05/2010 Read twice and referred to the Committee on Commerce, Science, and Transportation. I am not sure if one was ever passed. It's largely up the states and local jurisdictions I think, but then - you can pass all of the laws you want, but how many will be enforced? I have a little house on one of my farms that a couple rented from me a few years ago, and I never heard anything about such requirements. I recently gave them a new First Alert Smoke & CO alarm. I own the house that I live in and it's several decades old, so not covered. And these hardwired CO alarms - how long are they good for?

I see it more of the dweller's responsibility. I test all of my alarms on the first of each month (and remind my FB friends for all of the good that does, maybe some), I take all of my smoke alarms outside every fall and smoke test them, and I check the expiration date on all ever fall (reminding FB friends as well).

I have no argument as you are absolutely correct. I just purchased one and am typing this just after climbing back in the car to head home and install it....the store only had battery powered units....I will check some other stores this weekend and buy a couple more. For us, the battery powered ones may be preferrable as we could always pack and use them when we move back to the US.

I want to apologize for my outburst as that was rude of me. I''m glad to read that you are buying some. Battery powered are great as long as you keep extra batteries on hand and replace as needed. I've read too many sad stories of Smoke alarms being disabled when the battery was removed and forgotten. That low-battery beep is annoying.

I like plug-in models but only with battery backup. You need coverage in a power failure too.

My problem with CO detectors is calibration. Where do you get proper calibration gases? With an O2 detector, we always have access to 21% and often have access to 32%, 36%, 40% or higher. If you're gonna trust a CO detector only a couple years after you bought it, you hafta calibrate it against a gas with a known CO content. Preferably two gases, one below your min limit and one above your min limit. Where do you source those gases?

An uncalibrated sensor is worthless.

For homes, it's not critical as while their sensors will drift, it's not enough to matter much before end-of-life. For tanks it's more challenging. Analox made a good one that one could calibrate in the field, but the market was resistant to the price. You had a chance to get one then, but of course by now you'd need a new sensor.

 

[Zef]

That may be true. I found H.R.1796 - Carbon Monoxide Poisoning Prevention Act, Latest Action: Senate - 08/05/2010 Read twice and referred to the Committee on Commerce, Science, and Transportation. I am not sure if one was ever passed. It's largely up the states and local jurisdictions I think, but then - you can pass all of the laws you want, but how many will be enforced? I have a little house on one of my farms that a couple rented from me a few years ago, and I never heard anything about such requirements. I recently gave them a new First Alert Smoke & CO alarm. I own the house that I live in and it's several decades old, so not covered. And these hardwired CO alarms - how long are they good for?

I see it more of the dweller's responsibility. I test all of my alarms on the first of each month (and remind my FB friends for all of the good that does, maybe some), I take all of my smoke alarms outside every fall and smoke test them, and I check the expiration date on all ever fall (reminding FB friends as well).


I want to apologize for my outburst as that was rude of me. I''m glad to read that you are buying some. Battery powered are great as long as you keep extra batteries on hand and replace as needed. I've read too many sad stories of Smoke alarms being disabled when the battery was removed and forgotten. That low-battery beep is annoying.

I like plug-in models but only with battery backup. You need coverage in a power failure too.


For homes, it's not critical as while their sensors will drift, it's not enough to matter much before end-of-life. For tanks it's more challenging. Analox made a good one that one could calibrate in the field, but the market was resistant to the price. You had a chance to get one then, but of course by now you'd need a new sensor.

@DandyDon , no offense taken.

The CO detector I purchased today has a battery power indicator on the LCD display, along with other visual indications of full/low battery such as led lights and the alarm chirping when power is low. The plan is to keep an eye on the unit to ensure things are copacetic with regards to CO levels in the house, especially in winter when we are burning oil at a higher rate, right now we are only burning oil for hot water, so the use/demand is a lot lower, but it does not take much if there is an issue with boiler or chimney so I am glad I got one.

The packaging states the unit is good for 7 years. This is similar to smoke detectors which I replaced throughout the house with units that are supposedly good for 10 years. At @ 34 euros for a CO detector I could amortize the cost more conservatively and replace it at 5 years for an affordable cost of 6.80 euros per year compared to 4.86 per year over 7 years...6.80 is ridiculously cheap for the peace of mind and potential life saving protection the CO monitor offers....I feel foolish for not having purchased one when we first moved in.

This has been a great discussion...I hope @Akimbo is not offended that his thread got sidetracked with a discussion about household CO monitors.

@Duke Dive Medicine I find it interesting that CO supposedly has 210 times the affinity to bond with heme than O2 (it would be interesting to understand how that figure is derived) yet it will give up the covalent bond based on the diffusion gradient caused by high concentration of O2....it still has me wondering if there is something else going on that causes the CO to more freely disassociate from the heme such as increased alkalinity of the blood due to the greater amount and higher PPO2 during treatment. It is difficult for me to accept that it is simply due to the gradient between the two. This just tells me I need to do more reading/research.

-Z

 

[Akimbo]

I hope @Akimbo is not offended that his thread got sidetracked with a discussion about household CO monitors.

Not in the least. It would be rather small to take offense at a hijack that could save people's lives.

 

[Akimbo]

I am not sure if one was ever passed. It's largely up the states and local jurisdictions I think,...

US Related: I understood (perhaps incorrectly) that a unified building code was accepted in 2009 that became the basis for all building departments. This was based on the IBC (International Building Code) but local building jurisdictions had leeway to adjust for local conditions. It helped simplify a lot of conflicting and confusing insurance and mortgage requirements in addition to limiting building department legal and political liability.

 

[DandyDon]

At @ 34 euros for a CO detector I could amortize the cost more conservatively and replace it at 5 years for an affordable cost of 6.80 euros per year compared to 4.86 per year over 7 years...6.80 is ridiculously cheap for the peace of mind and potential life saving protection the CO monitor offers....I feel foolish for not having purchased one when we first moved in.

Well, that's a little higher than many other name brand models cost. I got the last few on Ebay, altho I did run into some fakes there (and got my money back) and I don't know about shipping to your country. I'm glad you're happy enough.

 

[Zef]

Well, that's a little higher than many other name brand models cost. I got the last few on Ebay, altho I did run into some fakes there (and got my money back) and I don't know about shipping to your country. I'm glad you're happy enough.

This one has a LCD display that shows peak CO level recorded, the current level, the peak during the last 24 hours and the average level during the past 24 hours, It also came packaged with a separate smoke detector which sells for 12-15 euros separately...I don't need the smoke detector but the same CO detector packaged separately was 29 Euros....I am sure I can find a place to install an extra smoke detector or know someone who could use it.

-Z

 

[Bob DBF]

It helped simplify a lot of conflicting and confusing insurance and mortgage requirements in addition to limiting building department legal and political liability.

CA, for one, requires CO detectors in new construction, at time of sale, and in rentals.

I am sure I can find a place to install an extra smoke detector or know someone who could use it.

I had an extra so I put it near the floor in the garage. The gas hot water heater is there and it doubles as my shop. Also the dogs have a door to the outside, and I figure they would rather go out in the heat rather than listen to it.