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Myabe, but I am just further dropping the nitrogen with the helium and thus "making up" for the oxygen . However, these are almost always deco or deco travelling mixes where we have backgas on our backs . To dive, we would drop the ppo2 down considerably to beat this as well. Esat Atikkan wrote: > > Trey, > > The issue is the narcotic potency of O2 & if O2 > narcosis is possible. > > Despite its high MO partition, most have discounted O2 > narcosis as it is 'metabolized'. > I thnk otherwise: as not all O2 that partitions in > tissues are metabolized thus accumulation is possible, > albeit @ a slower rate. > > Given that, how does using 30% He ameliorate potential > O2 narcosis unless the mix is hypoxic? > > Thnx > Safe bubbles > Esat Atikkan > > --- Trey <trey@ne*.co*> wrote: > > Esat, we just overcome that by starting our helium > > at 30% minimum. IE, > > no matter what the calculation, the least helium we > > use is 30%, and we > > use helium in all bottom gasses regardless of depth. > > > > > > This is because we have found impairment with all > > air and nitrox mixes > > at all depths, and suspect damage at all depths > > unless helium is in the > > mix. > > > > Very unscientific, but very, very effective. > > > > > > Esat Atikkan wrote: > > > > > > Obviously O2 is metabolized. However not all O2 > > > partitioned in the body is metabolized - this > > becomes > > > particularly true when the ppO2 exceeds the O2 > > > required for metabolism - a situation wh/ is bound > > to > > > occur as ppO2 increases - say w/ depth. > > > > > > Thus, except for that threshold effect, O2 should > > B > > > treated as a narcotic component of respired gas & > > > inluded in END calculations - "how" may B the more > > > difficult issue. > > > > > > Safe bubbles > > > Esat Atikkan > > > > > > --- "Michael J. Black" <mjblackmd@ya*.co*> > > wrote: > > > > According to the Meyer-Overton hypothesis, > > narcotic > > > > potency of gases > > > > correlates with lipid solubility, and O2 has a > > lipid > > > > solubility of > > > > 0.11 (about the same as Argon, 0.14). Helium, > > in > > > > comparison, has a > > > > lipid solubility of 0.015. You all know how > > > > narcotic Argon is (very), > > > > and how non-narcotic Helium is. O2 is predicted > > to > > > > be about as > > > > narcotic as Argon by this hypothesis, except > > that O2 > > > > is not inert, > > > > and is readily metabolized. I believe that is > > why > > > > there is no > > > > listing of relative narcotic potency for O2 in > > the > > > > textbooks (I am > > > > looking at Bennett's chapter on Inert Gas > > Narcosis > > > > and HPNS, in Bove > > > > and Davis' Diving Medicine, 2nd ed.). It is > > listed > > > > as blank because > > > > the comparison is not valid. Mike Black > > > > > > __________________________________________________ > > > > Do You Yahoo!? > > > > Talk to your friends online with Yahoo! > > Messenger. > > > > http://im.yahoo.com > > > > -- > > > > Send mail for the `techdiver' mailing list to > > > > `techdiver@aquanaut.com'. > > > > Send subscribe/unsubscribe requests to > > > > `techdiver-request@aquanaut.com'. > > > > > > > __________________________________________________ > > > Do You Yahoo!? > > > Talk to your friends online with Yahoo! Messenger. > > > http://im.yahoo.com > > > -- > > > Send mail for the `techdiver' mailing list to > > `techdiver@aquanaut.com'. > > > Send subscribe/unsubscribe requests to > > `techdiver-request@aquanaut.com'. > > > __________________________________________________ > Do You Yahoo!? > Talk to your friends online with Yahoo! Messenger. > http://im.yahoo.com -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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