Mountain High Cannula/Mask?

Tango Eight wrote on 10/1/2019 3:47 PM:
On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:
On Tuesday, October 1, 2019 at 6:45:06 AM UTC-4, John McLaughlin wrote:
Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

The legalitys are not so clear, but practically it is about remembering to
breathe only with your nose with the cannula. Something I felt i could do,
and so far have remembered. It is much easier to hydrate and communicate
with the cannula. Just don't forget...

RR

There are several reasons any given person might not breathe well on a cannula
at high altitude, mouth breathing is only one. Here's another: It is really
easy to hyperventilate on a cannula at 20+K. Trivially easy in fact.. If you
must use a cannula above 18K (which I recommend against), do not skimp on the
O2, don't use a dumb ass "oxy-miser" anything above 18K. Turn up the flow. If
in doubt, turn it up some more. Not a bad idea to monitor heart rate as well
as O2 saturation. Tachycardia is reliable indicator of breathing problems, and
it will catch hyperventilation (O2 saturation will not, key word alkalosis).

It's much easier to breathe well (and reliably) on a mask, provided the mask
fits and seals acceptably well. If you aren't breathing well, hydration and
communication are going to cease to matter.

Does it matter which face mask is used? The one that came with the Mountain High
EDS units I have is very basic, with a very small cavity, so I think it would not
increase the amount of CO2 you breathe. I'm assuming it's the CO2 content that's
the important factor - is that true?

They do have a mask with a rebreather bag, so perhaps that's the one you should use?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1