7 ms·

Are you sure those cases are CO2 and not CO? Iirc CO is the truly fucked up one because it binds to hemoglobin much more readily than CO2 thus displacing both C

Are you sure those cases are CO2 and not CO? Iirc CO is the truly fucked up one because it binds to hemoglobin much more readily than CO2 thus displacing both CO2 and O2 in the blood.

agurk 4y ago
With CO the issue is that it binds to haemoglobin and stays bound to it permanently. Only a small proportion of CO2 in the blood is bound to haemoglobin (~10% [0]) so the real issue is that the O2 carrying capacity is reduced. As red blood cells are constantly being replaced limited exposure is not a long term issue, but this is a process that takes weeks. This means that someone with acute exposure cannot be helped with supplemental oxygen (or just being taken outside) unlike with CO2. CO2 in high concentrations causes issues through various mechanisms with a major one being that it impairs your ability to absorb O2 and other cellular disruption through increasing the pH of your blood [1]. This can cause unconsciousness in seconds at high concentrations and other potentially fatal impairments even at lower levels. So CO poisoning is worse as there's no (easy) therapy for it but it is still very possible to have fatal exposure to CO2 if you are not able to receive fresh air in a immediate time frame (minutes). There is also the general issue that confined spaces might be low on O2 as well, as described in this video on confined spaces in ships [2]. [0] https://www.ncbi.nlm.nih.gov/books/NBK532988/ https://www.ncbi.nlm.nih.gov/books/NBK532988/ [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/ [2] https://www.youtube.com/watch?v=uNVj_JpZia8 https://www.youtube.com/watch?v=uNVj_JpZia8
tialaramex 4y ago
With Carbon Monoxide there's a big risk of gradual poisoning. For example if you run a stove in a sealed compartment to keep warm, well, the Carbon Monoxide released can't escape and will gradually poison you over even several hours. If your body had a CO sensor, you'd realise there was a problem in plenty of time to flee, because it's so gradual, but it doesn't and so you might feel a little sleepy and that's it, you're probably never going to wake up. With Carbon Dioxide that gradual risk doesn't exist, you would realise there's a problem. You will probably even be woken if CO2 gradually rises, you'll become conscious, discover the air seems "stuffy" and go somewhere with fresh air. The problem in the drastic CO2 scenarios is it's too sudden. It's understandable (more so than with Carbon Monoxide) that we didn't evolve to cope with that. Prehistoric man did not use CO2 fire extinguishers.

Are you sure those cases are CO2 and not CO? Iirc CO is the truly fucked up one because it binds to hemoglobin much more readily than CO2 thus displacing both CO2 and O2 in the blood.

agurk 4y ago

With CO the issue is that it binds to haemoglobin and stays bound to it permanently. Only a small proportion of CO2 in the blood is bound to haemoglobin (~10% [0]) so the real issue is that the O2 carrying capacity is reduced. As red blood cells are constantly being replaced limited exposure is not a long term issue, but this is a process that takes weeks. This means that someone with acute exposure cannot be helped with supplemental oxygen (or just being taken outside) unlike with CO2. CO2 in high concentrations causes issues through various mechanisms with a major one being that it impairs your ability to absorb O2 and other cellular disruption through increasing the pH of your blood [1]. This can cause unconsciousness in seconds at high concentrations and other potentially fatal impairments even at lower levels. So CO poisoning is worse as there's no (easy) therapy for it but it is still very possible to have fatal exposure to CO2 if you are not able to receive fresh air in a immediate time frame (minutes). There is also the general issue that confined spaces might be low on O2 as well, as described in this video on confined spaces in ships [2]. [0] https://www.ncbi.nlm.nih.gov/books/NBK532988/ https://www.ncbi.nlm.nih.gov/books/NBK532988/ [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/ [2] https://www.youtube.com/watch?v=uNVj_JpZia8 https://www.youtube.com/watch?v=uNVj_JpZia8

tialaramex 4y ago

With Carbon Monoxide there's a big risk of gradual poisoning. For example if you run a stove in a sealed compartment to keep warm, well, the Carbon Monoxide released can't escape and will gradually poison you over even several hours. If your body had a CO sensor, you'd realise there was a problem in plenty of time to flee, because it's so gradual, but it doesn't and so you might feel a little sleepy and that's it, you're probably never going to wake up. With Carbon Dioxide that gradual risk doesn't exist, you would realise there's a problem. You will probably even be woken if CO2 gradually rises, you'll become conscious, discover the air seems "stuffy" and go somewhere with fresh air. The problem in the drastic CO2 scenarios is it's too sudden. It's understandable (more so than with Carbon Monoxide) that we didn't evolve to cope with that. Prehistoric man did not use CO2 fire extinguishers.