Quote: (Originally Posted by
Janos)
I'm fairly sure I once heard [1] that high ppO2's reduced the initial symptoms of CO2 breakthough. So tunnel vision, dizzyness, etc. was less likely with a ppO2 of > 1.0 than witha ppO2 of 0.21.
Has anyone got any facts to support or disprove this?
Well, I did not know of anything so I asked Piantadosi. Here is his reply:
I am not sure what you mean by CO2 breakthrough--this is not a physiological term. There is CO2 breakpoint in breath-hold diving which O2 will help with some. For CO2 narcosis, I don't know of any data or any reason why O2 should help prevent that. A high PO2 and a high PCO2 is of course going to hasten the onset of CNS O2 toxicity, which contributes to the shortening of seizure latency in closed circuit O2 diving and 36%Nitrox diving.