Posted by Colin on March 22, 2001 at 16:27:39:
In Reply to: i was wondering about CO2 loading but it just doesnt seem right posted by RaiderKarl on March 22, 2001 at 09:07:37:
[SNIP] “…it was a very relaxed descent. i was swimming slowly down a sand channel beside a rocky reef wall. i was using a ScubaPro S600 and Mark 20 regulator system, the best that money can buy. my equipment man had just tuned both to each other, so it was working perfectly. i never at any time felt tired. i wasnt doing any work. therefore i ask myself, how could it have been CO2 loading?” [SNIP]
RaiderKarl,
My assumption on this being possibly caused by CO2 is based on the depth and short time that you were there, as well as your experience at that depth. Any balanced regulator manufactured today, and maintained, would perform at the depth at which you were diving. I agree with you that your equipment was not an issue, but I do believe that your breathing may have been.
Granted you did state that you were relaxed, but any apprehension or excitement towards diving you “PR” may have lead to irregular breathing, to which you may or may not have been aware. CO2 buildup may be onset by not taking large enough breaths. It may also be onset by not breathing often enough. Either hypoventilation or an abnormal time between breaths allows CO2 buildup with an associated rise in blood levels.
My thought on your symptoms not being caused by oxygen toxicity was due to the level of your PO2 at that depth. And although narcosis may be the direct cause of unconsciousness in a diver at depths, the majority of cases of which I am aware, carbon dioxide has been determined to be the culprit.
Again, as I posted earlier, it may have been CO2… or it may not have been. Elevated CO2 levels do increase narcosis and the likelihood of CNS oxygen toxicity, so each one of these conditions may have lead to your experience. Perhaps I should have stated it as Kendall did, and replied, “Who knows.”
Also, as a side note… as varied are reports of the effects of narcosis and oxygen toxicity on different individuals, CO2 offers it’s own peculiarity with individuals that are declared to be “CO2 retainers”. These are individuals whose physiology prevents the lungs from efficiently ridding themselves from carbon dioxide, and therefore, should definitely be concerned with the issues of diving deep.