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  #41  
Old 09-29-2011, 08:13 AM
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grantcarruthers grantcarruthers is offline
 
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Originally Posted by billnaz View Post
Altitude should have no effect on the function of the pulse ox. Take it with you to your doctors office and compare it to theirs. if it's close there it should be good. Some pulse ox trivia is they are fooled by carbon monoxide, so don't expect the sat reading to go down if you're being poisoned by an exhaust leak.
Good idea, however there are reasons to do this test at altitude IF you have the opportunity. Because the oxyhemoglobin dissociation curve is somewhat linear up around 97-100%, comparing readings at this end of the scale could be misleading and give false confidence in the cheapo unit. The changes in SaO2 are both more critical and dramatic around the 90% SaO2 area on the scale. This is where I want to compare the cheapo unit performance to something medical grade.

At 12k recently, I popped on the cheapo unit, 84%. Felt okay but if I really thought about it might be able to point to a few symptoms of mild hypoxia. Stayed at that altitude as I was only going to be there 30 minutes and it was a CAVU day so little challenge or deep thought needed. Did some deep breathing, pursed lip breathing, and some extreme tidal volume holds. Could get SaO2 into the 90-96% range but saw pretty significant swings back to the 80's, back to the 90's etc. The question is, is the cheap unit not quality enough to read well in this "critical" range or is the SaO2 just that volatile because of the non-linear nature of the oxyhemoglobin dissociation curve. This is why I'd prefer to do a side by side at altitude and really challenge the unit in the environment it will need to perform in.
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  #42  
Old 09-29-2011, 10:21 AM
prporter prporter is offline
 
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Originally Posted by N15JB View Post
Aerhed,

People living in Leadville do have somewhat higher pulse and respiratory rates, but the primary mechanism is an increase in the number of red blood cells. This turns out to be a mixed blessing though, as it causes thicker blood(think heavy weight oil). Many Leadville residents eventually develop pulmonary hypertension after years of pumping thickened blood, and by middle age may have to move to lower elevations.



Jim Berry
RV-10
Does the increased hemoglobin in any way increase O2 saturation? Does the increase, affect, either neg or pos, the ability to function at higher alt?
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  #43  
Old 09-29-2011, 10:53 AM
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Originally Posted by scsmith View Post
Anyone else have a similar experience to what I mentioned in post #14?

If my particular meter, or brand, was bad, and its not a general trend, then I may consider buying a new one.

I became pretty convinced its indications at altitude were meaningless when I turned the O2 on in my glider and my SaO2 only went from 86 to 88.
Its also pretty strange to be out hiking in the mountains, feeling great, and the stupid meter says 86.

Just curious if anyone else has had a meter that seemed to be affected by altitude.
Steve,

Its possible your meter was suspect. I noted you pitched it, and are considering another. I've had mine show a rise from 88 to 96 after going on O2. Given your fitness level and hi altitude activities, I would think you'd see the same or better. You're welcome to test mine next time you come up here to soar or climb. I'll look for the brand when I'm out at the hangar, but it was a low-mid priced unit from the net ($69). Good tool, IMHO.

Cheers,
Bob

Question for Jim Berry: Do the same effects/side effects seen in our Leadvillian friends occur in those of us living at, oh, say 4500' MSL? Just wunderin', as I stare out the window at the mountains!
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  #44  
Old 09-29-2011, 11:08 AM
N15JB N15JB is offline
 
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Originally Posted by prporter View Post
Does the increased hemoglobin in any way increase O2 saturation? Does the increase, affect, either neg or pos, the ability to function at higher alt?
The increased number of red blood cells and corresponding increase in hemoglobin does increase O2 saturation. That does translate to better performance at altitude. Athletes have capitalized on this by training at higher elevations. People living at Denver elevations have hemoglobin and hematocrit levels about 6% higher than those living at sea level. Leadvillians have levels higher yet.

Several posters have commented that they have flown at 10-15,000 ft. and did not feel impaired. The fact that you did not feel it doesn't mean you were not impaired. Early hypoxia symptoms are very subtle. Most people who take altitude chamber flights are very surprised at the deterioration in their hand writing, math and verbal skills. Most of us who feel we are superhuman(immune to hypoxia) are deluding ourselves.

Jim Berry
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  #45  
Old 09-29-2011, 11:17 AM
N15JB N15JB is offline
 
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Originally Posted by rvmills View Post
Steve,


Question for Jim Berry: Do the same effects/side effects seen in our Leadvillian friends occur in those of us living at, oh, say 4500' MSL? Just wunderin', as I stare out the window at the mountains!
Bob,

Not sure which effects you are referring to, but an increase in red blood cells and hemoglobin does occur at 4500 ft. An increased risk of pulmonary hypertension does not become clinically significant until approximately 8'000 ASL.

Jim Berry
RV-10
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  #46  
Old 09-29-2011, 02:10 PM
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Originally Posted by N15JB View Post
The increased number of red blood cells and corresponding increase in hemoglobin does increase O2 saturation. That does translate to better performance at altitude. Athletes have capitalized on this by training at higher elevations. People living at Denver elevations have hemoglobin and hematocrit levels about 6% higher than those living at sea level. Leadvillians have levels higher yet.

Several posters have commented that they have flown at 10-15,000 ft. and did not feel impaired. The fact that you did not feel it doesn't mean you were not impaired. Early hypoxia symptoms are very subtle. Most people who take altitude chamber flights are very surprised at the deterioration in their hand writing, math and verbal skills. Most of us who feel we are superhuman(immune to hypoxia) are deluding ourselves.

Jim Berry
RV-10
When I was competing, I was training at 7500ft., so I can attest to that. Hey Rosie, hope you are reading this- we may be ahead of the curve a bit with all of our cycling after all...!

Last edited by prporter : 09-29-2011 at 02:24 PM.
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  #47  
Old 09-29-2011, 04:22 PM
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Originally Posted by N15JB View Post
Bob,

Not sure which effects you are referring to, but an increase in red blood cells and hemoglobin does occur at 4500 ft. An increased risk of pulmonary hypertension does not become clinically significant until approximately 8'000 ASL.

Jim Berry
RV-10
Jim,

Thanks, you hit on the one side-effect I was talking about. Some history of hypertension in my family of sea level dwellers, and now I'm in Reno. Sounds like I may be in the middle ground where there is some benefit to living at higher elevations, but little of the downside (thicker blood and hypertension risk factors).

So to take that thought line a little farther (hopefully without sounding paranoind ) as an airline pilot that sees 8,000 cabin altitude for several hours on about half the days of each month (call it 80 hours/mo), plus 10-15 hours/mo up in the same range in an RV, is there an additive factor to that adaptive reaction of generating more red blood cells and thicker blood (living at 4,500 feet plus flying a lot)?

Like I said, really just interested in the phisiology more than worried. I figure staying fit, eating right, etc., is the best way to combat hypertension.

And I concur with your comments on feeling un-impaired at altitude. As many know, one of the first signs of hypoxia can be euphoria. Its not for me, but I've learned to trust the numbers more than how I feel, and do think pulse-ox is well worth the investment!

Thanks, and cheers!
Bob
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  #48  
Old 09-29-2011, 05:01 PM
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Greg Arehart Greg Arehart is offline
 
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Having lived in Leadville for a number of years, I recall lifelong residents going to the hospital every so often and having a procedure to remove some of the red blood cells from their system to keep the blood from thickening up too much. I worked at between 11,500 and 13,000 feet and certainly could tell the physiological difference living at LXV compared to friends I had who were living on the Front Range (at 5000 ft). During my training, we never used oxygen even though we routinely flew between 10 and 14000 feet. I certainly would not do that now, being older and living at lower elevation.

cheers,
greg
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  #49  
Old 09-29-2011, 11:06 PM
N15JB N15JB is offline
 
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Originally Posted by rvmills View Post
Jim,

Thanks, you hit on the one side-effect I was talking about. Some history of hypertension in my family of sea level dwellers, and now I'm in Reno. Sounds like I may be in the middle ground where there is some benefit to living at higher elevations, but little of the downside (thicker blood and hypertension risk factors).

So to take that thought line a little farther (hopefully without sounding paranoind ) as an airline pilot that sees 8,000 cabin altitude for several hours on about half the days of each month (call it 80 hours/mo), plus 10-15 hours/mo up in the same range in an RV, is there an additive factor to that adaptive reaction of generating more red blood cells and thicker blood (living at 4,500 feet plus flying a lot)?

Like I said, really just interested in the phisiology more than worried. I figure staying fit, eating right, etc., is the best way to combat hypertension.

And I concur with your comments on feeling un-impaired at altitude. As many know, one of the first signs of hypoxia can be euphoria. Its not for me, but I've learned to trust the numbers more than how I feel, and do think pulse-ox is well worth the investment!

Thanks, and cheers!
Bob
Bob,

Keep in mind that essential hypertension (what most of us mean when we refer to hypertension or high blood pressure) and pulmonary hypertension are 2 entirely different animals. While you need to be watchful because of your family history of hypertension, it has almost nothing to do with your risk of developing pulmonary hypertension.

Re living at 4500 ft. and flying at 8000 ft. - our bodies make or destroy red blood cells(RBCs) anytime we change elevation/altitude. It takes our blood about 8 weeks to fully adapt to a new elevation(for instance, moving from Detroit to Denver), so while you are flying you will be making more RBCs and when you return to earth you will break down RBCs. Even with your 80 hours of flying/month. you spend approx. 88% of your time at 4500 ft. While you might have more RBCs than your non-flying neighbor, the difference would be too small to measure.

Jim Berry
RV-10
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  #50  
Old 09-30-2011, 12:08 AM
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Jim,

I wondered about that (PH versus EH), and just Googled it. Roger all, and thanks for the explanation. Makes good sense. Interesting physiology lesson!

So, in looking at your profile, are you a retired medical practitioner, or did you stay at a Holiday Inn Express last night. I appreciate the insight...thanks again!

Also interesting to hear Greg's comments about Leadvillian RBC removal...who'd a thunk!

Cheers,
Bob
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