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Carbon monoxide and freediving

Siku

Well-Known Member
Sep 23, 2010
248
28
68
UK
I've been looking at some old threads and have read that breathing air tainted with carbon monoxide (e.g. exhast fumes from the back of the boat) can cause poisoning leading to BO etc.

Can anyone explain to me how the carbon monoxide affects the diver, physiologically and/or chemically? Can a small amount on the surface (i.e. not enough to notice) can have a bigger affect once at depth?

For reference there is a description of carbon monoxide poisoning symptoms here:

[ame="http://en.wikipedia.org/wiki/Carbon_monoxide_poisoning"]Carbon monoxide poisoning - Wikipedia, the free encyclopedia[/ame]

Thanks
 

azapa

51% freediver 49% spearo
Jan 31, 2007
2,623
471
123
53
Central Coast, Chile
basically it blocks the uptake of O2 into the bloodstream.

It can be fatal, ie the typical "car left in garage with engine on" suicide or the gas powered heater with blocked exhaust flues.

The affected drifts into a blackout. I hate spearing off stinky outboard engined boats. Always remember to breathe up up-wind of them. I can really feel the difference when I get a mouthful before a dive.

Sorry, not technical enough I am sure, just my 5 pesos worth ;)
 
OP
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Siku

Well-Known Member
Sep 23, 2010
248
28
68
UK
So the headache symptom of CO poisoning is due to hypoxia?

Thanks for your input Azapa. Can you explain a little more about what differences you feel when exposed to CO?
 
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Siku

Well-Known Member
Sep 23, 2010
248
28
68
UK
Consider a diver with some CO in their lungs. As partial pressure of CO rises, the concentation of CO in the lungs rises proportionately.

According to wiki "Concentrations as low as 667 may cause up to 50% of the body's hemoglobin to convert to carboxyhemoglobin. A level of 50% carboxyhemoglobin may result in seizure, coma, and fatality".

A concentration of 66.7ppm at 1 atmos would be 667ppm at 10 atmos (90m). As symptoms (headache, nausea, etc) would take hours to come on at constant exposure of 66.7ppm, a single breath contaminated to 66.7ppm would go undetected.

On the other hand, 66.7ppm of a, say for ease, 10L lungful is only 0.67 millilitres of CO. Is that sufficient to bind 50% of the haemoglobin, even assuming it is all delivered to the blood?
 

azapa

51% freediver 49% spearo
Jan 31, 2007
2,623
471
123
53
Central Coast, Chile
Headache is a symptom, just as high CO2. Simply put, if I am at the wrong end of a stinky engine exhaust my apnea is reduced 50%. I just have an enormous urge to breath on otherwise simple dives. At this stage I question the mental association to be half the problem though, as I seem hyper-sensitive.
 

efattah

Well-Known Member
Mar 2, 2001
3,294
481
173
BC, Canada
www.fluidgoggles.com
I took one breath of exhaust from my car tailpipe as an experiment. Using my CO analyzer, my carboxyhemoglobin level rose dramatically to around 10-15% and it took 24 hours to return to normal.

I took my CO analyzer on a boat with blue exhaust outboard motor. The CO concentration was so high that the analyzer was destroyed.

Then, diving off the same boat, I felt rapid onset of hypoxia (fading vision) from extremely shallow dives.

The big danger is that if your blood is laced with carbon monoxide, blackout will come early and without warning. There is no way to tell.

All it takes is ONE BREATH of exhaust from any motor and you are screwed!
 
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