Inogen

[N201MKTurbo]

12 minutes ago, Marc_B said:

You'd be surprised.  We routinely check pulse ox on everyone from critical ill to standard vitals for a sprain in an otherwise healthy patient.

Skin pigmentation, fingernail polish, poor circulation, cold fingers...even healthy people have fingers that might not always read properly.  Most problematic I'd think would be use of fake nails/nail polish and vasoconstriction from just being cold in the winter or at altitude.  Some people also have hypersensitive vasoconstriction to cold (i.e. Raynaud's) and might not get a great reading at times.

This is why I think it's important to establish your baseline for what "seems right" for you and what seems like somethings "off".  Most of the decent portable pulse ox's that I've seen have a bar that beats up and down showing wave form.  If that's not correlating with your pulse, then it may not be accurate.  Some newer units have an OLED screen that actually show wave form.  Its a good idea to have a rough idea of where you "trend" at various altitudes as there are lots of variables in each of our "high altitude" physiologies.

I have been using a pulse ox for 20 years. I'm on my second one. The first was a very expensive medical grade that cost $600. The second was one I bought at the CVS that cost $45. They both seem to give the same readings. After a while using them, you get a feeling for it. I can usually call the reading before I see it. It is nice to have your feelings calibrated on a regular basis. If my pulse ox were to malfunction, I think I would know right away because it would be giving me a reading out of line with how I'm feeling.

[Hank]

49 minutes ago, N201MKTurbo said:

If my pulse ox were to malfunction, I think I would know right away because it would be giving me a reading out of line with how I'm feeling.

Unless your O2 saturation is low, as judgements is then first thing to fade away.

[Aaviationist]

As someone who skydived from 18k regularly, I’ve been hypoxic. 
 

the biggest danger of hypoxia is not knowing you have hypoxia. 
 

again, that’s why this is an important topic and you should not use devices in a way that specifically say you shouldn’t. 
 

there are plenty of examples on the internet of people clearly affected that don’t realize they’re being affected. To say you would recognize it is just wrong. Most likely, you won’t. 

Edited yesterday at 12:29 AM by Aaviationist

[Marc_B]

11 minutes ago, Aaviationist said:

there are plenty of examples on the internet of people clearly affected that don’t realize they’re being affected. To say you would recognize it is just wrong. Most likely, you won’t. 

This is greatly dependent on the altitude that you're flying (ultimate partial pressure) as well as the speed it drops.  i.e. 15,000 feet gradual decline to a low reading of 93%, vs 28,000 feet declining down to 69%.  Its also a good reason to routinely check your pulse ox anytime you're at altitude on oxygen (i.e. every 10-15 min) and with any question of symptoms or issue.

But you're correct in saying that often a SLOW change/decompression is probably more dangerous than a RAPID change as the rapid decompression demands attention.  It's also why I like the pulse demand delivery system as there is a more noticeable difference between flow and no flow.

The term that helps describe this is Time of Useful Consciousness/Effective Performance Time.  FAA Aeromedical Factors Ch 17.   AC 61-107B

I have 2 pulse oximeters that I fly with.  One stays hanging on the prop knob.  The other is in my flight bag in the back seat in a location that I can easily grab it.  If I'm in the FL's, I set a scheduled timer on the GTN for 10 min to say "check SPO2".  Makes it easy to keep honest.  Any question or by issue, by default, is an immediate request for descent to troubleshoot.  Flight level altitude isn't the time to "sort things out."  Yes, there are risks; yes there are mitigation tools and redundancy to make this safer.  But flight is a series of choosen risks and mitigation training/techniques.  You can't remove them all, and there are many risks that are way more likely to happen.

[Aaviationist]

4 minutes ago, Marc_B said:

This is greatly dependent on the altitude that you're flying (ultimate partial pressure) as well as the speed it drops.  i.e. 15,000 feet gradual decline to a low reading of 93%, vs 28,000 feet declining down to 69%.  Its also a good reason to routinely check your pulse ox anytime you're at altitude on oxygen (i.e. every 10-15 min) and with any question of symptoms or issue.

But you're correct in saying that often a SLOW change/decompression is probably more dangerous than a RAPID change as the rapid decompression demands attention.  It's also why I like the pulse demand delivery system as there is a more noticeable difference between flow and no flow.

The term that helps describe this is Time of Useful Consciousness/Effective Performance Time.  FAA Aeromedical Factors Ch 17.   AC 61-107B

I have 2 pulse oximeters that I fly with.  One stays hanging on the prop knob.  The other is in my flight bag in the back seat in a location that I can easily grab it.  If I'm in the FL's, I set a scheduled timer on the GTN for 10 min to say "check SPO2".  Makes it easy to keep honest.  Any question or by issue, by default, is an immediate request for descent to troubleshoot.  Flight level altitude isn't the time to "sort things out."  Yes, there are risks; yes there are mitigation tools and redundancy to make this safer.  But flight is a series of choosen risks and mitigation training/techniques.  You can't remove them all, and there are many risks that are way more likely to happen.

So what’s your take on the Inogen for 2 people at 18k or 1 person at 21k then?

[Marc_B]

1) I think that in general (and for me) a nasal cannula is insufficient above 18000 ft.

2) I can’t say as I haven’t seen any data or personally used it.  Can an Inogen be us d with a facemask? How does it compare with me personally?

so besides just echoing manufacturer’s recommendations I couldn’t tell you. BUT, I think a solid plan would be to fly with a friend on a XC, one using Inogen and the other on built in oxygen and perform a flight test. Of course knowing that rest, hydration, fitness, etc all can make day to day result differences with same person.

However if a concentrator resulted in same or better oxygen saturations up to 18,000 ft I’d say that’s a positive result. Goal for me is > 96%.

personally wouldn’t use it in flight levels without better manufacturer guidelines and testing.

But zero apprehension of using a pulse demand oxygen concentrator below 14,000 ft. 

[Marc_B]

But if you’re asking how would this fare with a chronically oxygen dependent COPD patient passenger…completely different story and completely different risks.

probably ask if they’ve flown commercially and safely and if not, then no go. If so then fly <8000 ft MSL. 

[Aviationist]

18 minutes ago, Marc_B said:

1) I think that in general (and for me) a nasal cannula is insufficient above 18000 ft.

2) I can’t say as I haven’t seen any data or personally used it.  Can an Inogen be us d with a facemask? How does it compare with me personally?

so besides just echoing manufacturer’s recommendations I couldn’t tell you. BUT, I think a solid plan would be to fly with a friend on a XC, one using Inogen and the other on built in oxygen and perform a flight test. Of course knowing that rest, hydration, fitness, etc all can make day to day result differences with same person.

However if a concentrator resulted in same or better oxygen saturations up to 18,000 ft I’d say that’s a positive result. Goal for me is > 96%.

personally wouldn’t use it in flight levels without better manufacturer guidelines and testing.

But zero apprehension of using a pulse demand oxygen concentrator below 14,000 ft. 

Agreed.

For 2 people, unless you want to get 2 inogen units, the manufacturer guidance and logical, safe limitation is 14k ft.  Also, saying you were able to get (what was it, 91%? 93%?) on the inogen is NOT a good number, and is considered the beginning stages of hypoxia.  The guidance from the FAA is if you are at 90% you need more or better oxygen.

 

For 2 or more people, an oxygen tank is a much better choice.

 

With a home concentrator and compressor you can fill your own tanks and still have all the oxygen you would need for normal every day use.

 

Mike is going to do whatever the cheapest thing is regardless and circle talk around logic because someone on the internet with no qualifications told him it's ok.

Edited yesterday at 01:37 AM by Aviationist

[N201MKTurbo]

1 hour ago, Hank said:

Unless your O2 saturation is low, as judgements is then first thing to fade away.

Actually, I did the PROTE two years ago. I could still do math problems after 5 min at 25000. 
 

The operator finally said “put your mask on”. I said I was good. He said he wasn’t going to open it up until I put it on. So I did.

I just get very fatigued. I was breathing like Dr. Blue said about 20 years ago. I practice sometimes when I’m flying up high. It takes practice. When you are in the high teens, put on your pulse ox and take off your oxygen and practice breathing to see how high you can keep your SpO2. At 18000 I can usually keep it in the 90s. Just barely. If you start feeling stupid, put your oxygen back on.

The breathing is to inhale as deeply as possible, slowly, then hold it for a few seconds, then slowly exhale as deeply as possible. Pushing as much air out as you can. Then repeat of course. It takes practice. There is an urge to breathe fast and shallow. That is bad. With practice the urge goes away.

[N201MKTurbo]

With a cannula, you have to remember to breath in with your nose, as specified above, an exhale through your mouth. If you exhale through your nose, you blow out the bolus of oxygen in your sinuses.  If you inhale through your mouth you won’t get any oxygen.

Masks are for people who forget how to breath properly.

[N201MKTurbo]

In the old days, pilots just stuck an oxygen hose in their mouth and sucked on it. Watch the old movie Test Pilot and you will see it.

[Paul Thomas]

So much info. Thank you!

I always get a lower reading on my left index and than my right one. I'll have to check my pulse oximeter once I'm home to see what features I have.

[Hank]

2 hours ago, N201MKTurbo said:

In the old days, pilots just stuck an oxygen hose in their mouth and sucked on it. Watch the old movie Test Pilot and you will see it.

I met a guy at my home drove in WV who set an early altitude record (~30,000msl) using a thermos to hold his oxygen. He passed out, and woke up on the way down before making a safe landing. 

My C doesn't like going that high, but I did grab a CFI and O2 bottle before flying to Yellowstone. We hit 15,000 msl on a hot August afternoon, and I later calculated DA of 18,800; my controls were mushy, and I was having to step climb. I'm thinking an Inogen or such would work for me, I generally cruise 10K or lower, but have been known to go to11K for mountain wave activity around Mt. Mitchell (the highest peak east of the Mississippi).

[Bug]

On 6/10/2025 at 9:18 PM, 201er said:

How can someone even misuse it? Breathe too much?

Clearly a gateway drug; first O2, then, before you know it...

[Hank]

5 hours ago, Bug said:

Clearly a gateway drug; first O2, then, before you know it...

I've been hit! Now I'm up to snorting almost 79% N2 . . . Pretty soon I'll be stealing it from the tire store.

[Pinecone]

21 hours ago, Aaviationist said:

Now I will give my opinion. 
 

if you want to rely and base your life, your family’s lives, and the lives of those that are underneath you on an oxygen source the manufacturer specifically says you should NOT rely on, then go for it. 
 

I think most people who will read this thread are smarter than that. 

What part of most of using a continuous monitoring of actual blood O2 levels can't you grasp???????
 

The regs are written based on NO monitoring of O2 saturation levels.  So they are conservative.

Like OSHA regulations that require a minimum of 16.5% oxygen in a space for entry.  That is a lot higher level that is needed at sea level, but is set for high altitude work, IIRC at over 7000 feet.  But instead of making things more complicated, they just set a level that works at all normal working altitudes.

And you are also not understanding that individual responses differ.  I have mentioned before that I was on a flight with a couple of pilot friends where we had to go to 13,500 for about 15 - 20 minutes to clear some clouds.  I was left seat giving the person in the right seat of CFII work with the third in the back.  I noticed that the right seat pilot's head was swaying and bobbing.  I was fine.  I checked the guy in the back and he was OUT.  Cleared the clouds, went down to 9,500 and head bobbing stopped and the guy in the back woke up.

So YOU may need more O2 delivered than I do.  But the suggested limits are based on the average person or even biased to someone needing more O2.

Again, with ANY O2 system these days, you should monitor your sats when flying.

And have you heard of ANY incidents using an oxygen concentrator in a GA aircraft?

[Pinecone]

10 hours ago, N201MKTurbo said:

With a cannula, you have to remember to breath in with your nose, as specified above, an exhale through your mouth. If you exhale through your nose, you blow out the bolus of oxygen in your sinuses.  If you inhale through your mouth you won’t get any oxygen.

Masks are for people who forget how to breath properly.

Inogen delivers O2 pulses when you breathe in, so no bolus waiting in your nasal cavity. 

The same with the Mountain High O2D2 for tank based systems.  The O2D2 also alarms if it does not detect an inhalation in a certain time period.  So if you start mouth breathing it will alarm as is not detecting the inhalations.

[Pinecone]

10 hours ago, N201MKTurbo said:

Actually, I did the PROTE two years ago. I could still do math problems after 5 min at 25000. 
 

The operator finally said “put your mask on”. I said I was good. He said he wasn’t going to open it up until I put it on. So I did.

That was how I was when I did the altitude chamber in USAF UPT.  They gave up waiting for me to become incapacitated.  I was woozy, but could still scrawl my name and do simple math problems.

[Fly Boomer]

6 hours ago, Bug said:

Clearly a gateway drug; first O2, then, before you know it...

Yep.  As they used to say "rots your brain, and leads to harder drugs."

[Pinecone]

11 hours ago, Aaviationist said:

As someone who skydived from 18k regularly, I’ve been hypoxic. 
 

the biggest danger of hypoxia is not knowing you have hypoxia. 
 

again, that’s why this is an important topic and you should not use devices in a way that specifically say you shouldn’t. 
 

there are plenty of examples on the internet of people clearly affected that don’t realize they’re being affected. To say you would recognize it is just wrong. Most likely, you won’t. 

No, what you need to do is a chamber ride or PROTE session to see what YOUR hypoxia symptoms are.

If we never used devices in a way that the manufacturer says we shouldn't, we would be running our engines just rich of peak and doing top overhauls every few hundred hours, much less running LOP.  Just ask those who bought Bravos new and followed the POH.

Also, remember that for any device sold these days, the owner's manual is more written by the legal department than the engineering department.

 

[Pinecone]

19 hours ago, Aaviationist said:

So again, you’re just making things up and saying I don’t have experience?  Of course I do. 
 

For every argument of “it doesn’t say that” I posted the documentation to the contrary. Having the documentation itself in one place is useful. 
 

some people will do and believe what they want, grasping with all their might to the unscientific internet opinion when written facts and documentation is put in front of them. 
 

you can never change the minds of those people. You can only present the facts so when others click the thread everything needed for them to make an informed decision is in one place. 
 

“there’s no reg that says you need a mask above 18k”. There is and I posted it. 
 

“there’s nothing in the Inogen documentation that says not to use it above 14k for 2 passengers and 18k for a single user” there is, and I posted it

 

”there is no guidance on what the FAA says is a suplimental oxygen source” there is and I posted it. 

You probably believe that the FAA altitudes where O2 is required are based on actual physiological needs for O2.

 

[Aaviationist]

You’re doing a lot of rage posting while completely ignoring everything discussed on the last 2 pages. 
 

Good for you for not letting facts get in the way of your opinions. 

I bet the most vocal people in opposition to anything I’ve said have an average age of at least 67 and most definitely need more oxygen than their younger counterparts. 

Edited yesterday at 12:56 PM by Aaviationist

[N201MKTurbo]

25 minutes ago, Pinecone said:

Inogen delivers O2 pulses when you breathe in, so no bolus waiting in your nasal cavity. 

The same with the Mountain High O2D2 for tank based systems.  The O2D2 also alarms if it does not detect an inhalation in a certain time period.  So if you start mouth breathing it will alarm as is not detecting the inhalations.

I have a Precise Flight demand regulator. It only supplies oxygen when you inhale. Even though it doesn’t flow any oxygen when you stop inhaling, your nasal cavity still has oxygen rich air that didn’t make it to your lungs. If you exhale through your nose, you will blow that air out, still wasting some O2. Not as much as with a continuous flow system.

[Aaviationist]

1 hour ago, Pinecone said:

What part of most of using a continuous monitoring of actual blood O2 levels can't you grasp???????
 

What part about Pulse ox units (especially cheap ones) not reading properly at lower 02 percentages or with the presence of CO can’t you grasp?

 

Again, for you specifically, I’m willing to bet you are old and already have low 02, requiring you to have a higher oxygen need which the Inogen says it won’t supply (for 2 people above 14k and 1 person above 18k)

 

I get it, you’re going to do something stupid and ignore the advice of everyone around you. 
 

but for others reading this thread, at least they have all the information here to make an educated decision even though people like you are cluttering it with multiple rage posts. 
 

the Inogen says it does not provide sufficient service above 18k for 1 and 14k for 2 people. 
 

You need to spend at least 100$ to get a pulse ox unit that is accurate (the cheap 30$ units are not accurate at all outside of controlled environments)

 

there ARE regulations in part 23 that require a mask above 18k. 
 

these are facts. 

Edited yesterday at 01:23 PM by Aaviationist

[Pinecone]

Just now, Aaviationist said:

What part about Pulse ox units (especially cheap ones) not reading properly at lower 02 percentages or with the presence of CO can’t you grasp?

 

Again, for you specifically, I’m willing to bet you are old and already have low 02, requiring you to have a higher oxygen need which the Inogen says it won’t supply (for 2 people above 14k and 1 person above 18k)

 

I get it, you’re going to do something stupid and ignore the advice of everyone around you. 
 

but for others reading this thread, at least they have all the information here to make an educated decision even though people like you are cluttering it with multiple rage posts. 
 

the Inogen says it does not provide sufficient service above 18k for 1 and 14k for 2 people. 
 

You need to spend at least 100$ to get a pulse ox unit that is accurate (the cheap 30$ units are not accurate at all outside of controlled environments)

 

there ARE regulations in part 23 that require a mask above 18k. 

You don't know what I spent on my pulse oximeter.   And I base mine off of my resting sat at near sea level.  NOT on absolute numbers.

And I KNOW my hypoxia symptoms.

Again Imogen recommendations are for average people with a safety factor.  They want to make sure that most people are fine with their numbers.  Many people may be able to use different numbers based on their personal physiology.  You seem to think that one size fits all.  I did two 3+ hour flights this past weekend.  Out at 17,000 and back at 16,000.  I was on ships O2 with an O2D2 with my pax on the Imogen.  On the outbound trip, setting the O2D2 at D5, which automatically starts O2 at 5000 feet and adjusts for altitude, my sats were a bit low.  So I ended up at F2 setting to keep my sats up.  On the way home, I was fine at the D5 setting on the O2D2.  Good pulse ox numbers and no evidence of hypoxia.  So even using a built in oxygen system, just setting the numbers is NOT enough.

You keep saying I am doing something stupid.  Nope, I am using available information to use the equipment in a reasonable manner.

And since you seem to think that anyone who does not agree with you is "stupid" I am done with you.  I love the ignore setting.