Blood Oxygen Levels

[Entaxei]

I suffer from low blood oxygen levels due to COPD (Used to be called Emphesymea - wrong spelling!) - the problem is when flying by normal Airbus or Boeing at 38,000 ft, my oxygen level can go down as low as 79% - average 84%, against a norm of 94%, I monitor this by a calibrated Oxymeter clipped onto a finger - this can be worrying over a 2+ hour flt LHR to Oporto, it seems to be a feature of current large aircraft to operate with minimum levels of oxygen, (cost savings?).

Recently I flew to SOU - Jersey by Dornier 28?, which flew at 15,000 ft, magic - no problem, oxy level 94% all the way. Now I wish to fly from SOU to Perpignan on Flybe, can anyone tell me if the cabin air is likely to become pressurised such that the oxygen content will go down?, I understand that Flybe only use Dash 8-400's.

Cheers :ok:

[Chesty Morgan]

Well the Q400 will cruise at about 25,000' on the way to Perpignan. If I remember correctly (I haven't flown it for a few years) the cabin altitude at that height will somewhere between 4-6000'. Probably a bit higher than on your trip to Jersey but not as high as your trip at 38,000', which would have been up at 8,000' cabin altitude.

Not being medical at all I can only surmise that your O2 levels will be somewhere inbetween the two extremes that you mention. However, the flight to Perpignan is about 1 hour 40 minutes so depending on how your problem manifests itself that may have some bearing on it.

Hope that helps.

[harrowing]

In the Q400 at 25 000 feet, the cabin will be at 8 000 feet and the ac system is at maximum differential, so at that altitude nothing can be done to change things. If you are on a shorter segment at around 18 000 feet, you will be at about 5-6 000 cabin pressure.
Have you considered carrying supplemental oxygen?

[Bad medicine]

Most airlines have information available on flying with various medical conditions. They include guidelines for treating doctors, and potential requirements for inflight supplemental oxygen. For example, QANTAS has this:
http://www.qantas.com.au/infodetail/flying/beforeYouTravel/mediform.pdf

Try the airline :ok:

[Entaxei]

Thank you guys for your help and information, I will dig further into oxygen! - if not trains and boats, although a Portuguese friend did say 'Portuguese trains were not built for passengers!'.

Cheers :ok:

[Milt]

Minimum blood oxy level.

Does anyone know the % oxygen level at which the average person at sea level will lose consciousness. I guess about 50% and I've been there twice with ejection imminent.

[homonculus]

i All commercial cabins pressurise to about 7800 to 8900 feet. So if the aircraft is above this altitude, this is what the passengers get. This effective altitude can be reduced, and we do so in air ambulances, but it is not offered nor practiced on commercial aircraft.

Most passengers will desaturate to the low 80s on a pulse oximeter. This has no adverse effects. The monitor is not linear and has multiple variables so unless you are a doctor I would throw it away.

If you have significant emphysema or get breathless in flight, you need to take medical advice. Otherwise forget it.

Loss of consciousness is very interesting - with massive decompression you lose consciousness in about 10 seconds - the CAA say 2-3 seconds but this is not borne out from practice. The reason is not only the loss of oxygen but multifactorial

In gerenal low oxygen levels produce symptoms similar to drunkeness. The level required for LOC will depend on the individual and rate of decline. 50% oxygen is 2.5 times normal, but 50% of normal is not enough