Nitrox and gas narcosis

[munitor]

Apologies. I should have tweaked my searches and looked for oxygen+narcosis. Dr Deco section has looked at this and the guidance is that O2 is no where near as narcotic because so much of it is metabolized. It is narcotic at ultra high pressures that are well beyond what induce CNS seizure, but at sub-seizure pressures it apparently has little or no effect. link here

Interesting that both NAUI and PADI clearly state that EAN does not reduce narcosis.

 

[wedivebc]

Apologies. I should have tweaked my searches and looked for oxygen+narcosis. Dr Deco section has looked at this and the guidance is that O2 is no where near as narcotic because so much of it is metabolized. It is narcotic at ultra high pressures that are well beyond what induce CNS seizure, but at sub-seizure pressures it apparently has little or no effect. link here

Interesting that both NAUI and PADI clearly state that EAN does not reduce narcosis.

PADI is not really sure what their stand on this issue is since in the rebreather instructor manual is says care must be taken to prevent lowering of PPO2 during high workloads as it will cause an increase in nitrogen narcosis
I was surprised when I read that since I had also read what you posted above and that is a definate contradiction within their own teaching material.

 

[padiscubapro]

Apologies. I should have tweaked my searches and looked for oxygen+narcosis. Dr Deco section has looked at this and the guidance is that O2 is no where near as narcotic because so much of it is metabolized. It is narcotic at ultra high pressures that are well beyond what induce CNS seizure, but at sub-seizure pressures it apparently has little or no effect. link here

Interesting that both NAUI and PADI clearly state that EAN does not reduce narcosis.

ANDI's position has been from day 1 that increasing the oxygen and decreasing the nitrogen will reduce narcosis..

I also mirror dave's feelings.. Sometimes I dive with a setpoint around 1.1 or so, on a 45m(~150fsw) dive air diulent for those mathematically challenged that means I have 20% oxygen in the loop.. I feel a slight buzz at this point, if I bump the po2 up to a 1.3 - 1.4 (24-25% oxygen) its gone and if I let it drift back down I feel it comming back on...

an aside for those arguing for rediculous levels of helium, COMEX studies show that Helium STARTS acting narcotic (though still minor) at Exposures of about 6-7 Atas PHe (from saturation divers), Thats as shallow as 300fsw with a 60% Helium mix.