How effective are nasal cannulas?

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frcabot

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Has anyone tried nasal cannulas v. masks at altitude (obviously 18000ft or less -- cannulas are not approved for use about 18k ft) and have SpO2 levels to compare?

I used a nasal cannula a while back at 17k feet, and my SpO2 was somewhere around 85 or so. I don't think that's significantly better than without any oxygen at all. (I had a couple friends who experimented without O2, their SpO2 ranged from about 77-80).

I was using the oxysaver cannula, where the oxygen flow is adjusted based on altitude. I didn't use the mask to compare, but I imagine that the mask (partial rebreather) would have been much more effective.
 
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In the past I've found the same. 17000 is hard to keep levels up. 15000 or so was most comfortable. I never minded wearing to much, but passengers sure complain. Course you turn air down little for them and they go to sleep, so that helps. I think you maybe don't dry out as much with mask.
 
Those things feel like toothpicks up the nose! I just did 10 hours at 12-14k and was wondering if they make, or could I make a nose mask so the O2 would enter my nostrils but nothing would touch the insides!
I tested the O2 effect with my pulseox at those altitudes and if I pinched off the line, either one of us would go from mid 90s to low/mid 80s in a few breaths (then go right back up when unpinched) so we know they work at those altitudes.
 
I bet something like that could be made. When I had surgery years back that's how they administered the nitrous before putting me all the way under. It only went over my nose, but not in.
 
For reference....

Non Stop trip to OSH a couple of years ago... Late model 182T, N1175K..

Flew it @ 17,500 the whole way till past Volk and started the decent to Ripon.. 2 of us on board.. Bottle was full... The on /off valve on that Cessna was just that, it was either wide open or shut and not able to throttle the incoming O2..Cannulas for both of us.. O2 on gave us 92-95,so to make the bottle last we would alternate down to 85 or so and then go back on the bottle... The Cannulas were not uncomfortable at all... We landed with 150 psi left in the bottle after the 5.5 hour trip.

So, to answer the question... I considered the cannulas very effective.. IMHO.
 
So much for joining the 3 mile high club!
 
Art VanDelay said:
Aeromedix makes a cannula with a tiny re-breathe area. I haven't tried one yet but they claim they're better and make the O2 last longer because of the efficiency of the re-breathe chamber. Looks like a tampon on your face though but who's gonna see it anyway ?
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Dude. We make tampons on our faces look GOOD. :D
11418288_855750211127541_932803700_n.jpg
 
Art VanDelay said:
Aeromedix makes a cannula with a tiny re-breathe area. I haven't tried one yet but they claim they're better and make the O2 last longer because of the efficiency of the re-breathe chamber. Looks like a tampon on your face though but who's gonna see it anyway ?

http://www.aeromedix.com/oxygen-equipment/masks-and-cannulas/e-ox-oxymizer-mustache-cannula/
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This is what I use, I probably have a couple hundred hours of use on mine. Will probably continue to use it until I spring for a Mountain High System.

Planning on using it for another 20hrs or so of soaring in the next few weeks.

Brian
 
At a 6 LPM flow rate, a standard medical nasal cannula (at best) provides no more than 40% oxygen. A simple mask concentrates better...appx. 60% and a non-rebreather concentrates 90% or more if properly sealed. However, what you're looking at is a good target SpO2, which should be 92% or better. If you're not at that, then you shouldn't be flying at altitudes above 10,000 feet, and most especially at night. Around 10,000 feet, 40% oxygen by nasal cannula will give you about the same effective oxygen percentage you would have at sea level. Any higher and you're going to start experiencing deficits, perceived or not. This will be magnified if you have any cardio-pulmonary issues. One D-cylinder (appx. 300 liters would last 1 person a max of 50 minutes using a nasal cannula at 6 L/min.)
 
I have no problem keeping my oxygen levels above 96% up to 18k with a cannula. I hate wearing a mask, so I tend to stay below 18k.
 
SbestCFII said:
At a 6 LPM flow rate, a standard medical nasal cannula (at best) provides no more than 40% oxygen. A simple mask concentrates better...appx. 60% and a non-rebreather concentrates 90% or more if properly sealed. However, what you're looking at is a good target SpO2, which should be 92% or better. If you're not at that, then you shouldn't be flying at altitudes above 10,000 feet, and most especially at night. Around 10,000 feet, 40% oxygen by nasal cannula will give you about the same effective oxygen percentage you would have at sea level. Any higher and you're going to start experiencing deficits, perceived or not. This will be magnified if you have any cardio-pulmonary issues. One D-cylinder (appx. 300 liters would last 1 person a max of 50 minutes using a nasal cannula at 6 L/min.)
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I did the math many many years ago. Aviation use is in the 0.5 - 2.0 liter per minute range. This actually surprised me, in that we used 0-6 lpm in prehospital use, and in-hospital in some cases we use high flows (up to 25 lpm with specialized warmers/humidifiers) in our nasal cannulas...

If you get a medical grade pulse delivery regulator (able to give the equivalent of 6 lpm continuous flow), you can get MUCH higher instantaneous flows without the waste, and can dial it up higher than typical aviation usage would be for.
 
Doggtyred said:
I did the math many many years ago. Aviation use is in the 0.5 - 2.0 liter per minute range. This actually surprised me, in that we used 0-6 lpm in prehospital use, and in-hospital in some cases we use high flows (up to 25 lpm with specialized warmers/humidifiers) in our nasal cannulas...

If you get a medical grade pulse delivery regulator (able to give the equivalent of 6 lpm continuous flow), you can get MUCH higher instantaneous flows without the waste, and can dial it up higher than typical aviation usage would be for.
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You could do that (and reduce the fire hazard at the same time) There is a lot of wasted oxygen in a constant flow delivery system, though they do tend to be more expensive. I'm surprised by the low flow rate, since 2 LPM of oxygen would only give you about 24-25% oxygen at sea level. You'd have a sub-optimal SpO2 at way less than 10,000 ft. The SpO2 delivery target should be at least 92% at any altitude.
 
I did the math many many years ago. Aviation use is in the 0.5 - 2.0 liter per minute range. This actually surprised me
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That's what I was using (in my post above); about 1L/min...resulting in the noted mid-90's PO2.
My E bottle lasts many hours at that rate.
 
Depends what canula you are using. The simple medical canula can't deliver large amounts of oxygen, if you turn up the flow rate you just waste oxygen into the cabin without really doing much.

Above is a picture of one of the oximizers with the reservoirs that is a little better.

Another option is the special canuals that come with the demand regulators (either the Mountain High or Nelson/Precise). One tube in the canuala is used to detect inspiration. When that occurs the regulator opens and flows a lot of oxygen and then it shuts down when you stop breathing in (think SCUBA regulator if you're familiar with those). I've had good sats at 17000 with my Nelson setup.

I have a couple of NRB masks in the o2 kit as well, but we've never had to use them.
 
I find them effective to around 16,000' above that my stats start dropping.
 
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