P
Peter
Guest
On 11/11/2022 2:39 PM, Peter wrote:
I should have added that in some diving scenarios, rebreathers actually
are charged with 100% oxygen.
On 11/11/2022 9:36 AM, NY wrote:
\"Peter\" <HapilyRetired@fakeaddress.com> wrote in message
news:tkllon$1plh$1@gioia.aioe.org...
On 11/11/2022 8:43 AM, NY wrote:
It\'s why pure O2 (or O2+N2 with no CO2) in scuba breathing apparatus
is a bad thing: the body needs *some* CO2 to stimulate breathing.
Speaking as someone who in the early 1980s became a fully qualified
Navy open water deep sea diver and Navy diving medical officer who
trained on multiple devices using multiple gas mixtures, CO2 was
never part of any of the gas mixtures. I\'m talking about normal scuba
(compressed air) as well as special diving mixes that combine various
ratios of pure oxygen and/or pure nitrogen and/or pure helium.
Normal metabolism combined with the physiologic stress of diving plus
the work of breathing gases under pressures greater than 1 atmosphere
produces all the CO2 the brain needs to stimulate the breathing reflex.
If the exhaled air is re-breathed (combined with new air from the
cylinders) then I can imagine that the amount of CO2 that the body
produces is sufficient. The danger comes if all the exhaled air is
\"lost\" and not blended with the tank air: then you need to make sure
that the tank air has CO2 in it - which atmospheric air will do but a
mixture from oxygen and nitrogen tanks will not.
Absolutely wrong. I wouldn\'t be alive to write this if what you say
were true. The major health risk to a diver using a rebreather is a
failure of the CO2 scrubber, resulting in excessive CO2 in the
rebreathed air, toxicity, and a fatality if the diver can\'t surface.
Almost all rebreathers use \"nitrox\", a mixture of pure oxygen and pure
nitrogen. I know. I\'ve used these devices.
I should have added that in some diving scenarios, rebreathers actually
are charged with 100% oxygen.