FEV1 v O2 sats. Can anyone help?

Can anyone help me? I went to Oxygen assessment yesterday where my blood gas levels and sats were taken, and they were all better than previously, altho heart rate was very high. The o2 blood level was actually just above the threshold of someone getting extra O2 prescribed, and I can't understand since lung function is normally around FEV1 26%. I have had o2 at home since being diagnosed 7 years ago, and get very breathless. The nurses told me that being breathless doesn't necessarily mean that my o2 levels are low. The nurses were very nice and tried to explain but I must be a bit slow because I just can't get it! Can anyone help explain how this can be?

15 Replies

You may be reassured by speaking to the BLF nurse when the helpline opens after the bank holiday. 03000 030 555 10am-6pm weekdays

The nurses you've spoken to are correct, the two do not always go together. Someone with a very low FEV1 percentage may have very good O2 saturation levels and simply not need additional oxygen. It's not always to do with being breathless.

Thanks for answering and I'll call the helpline after the holiday. So in that case if only I could stop being breathless I wouldn't have a problem, providing every day was a good day like yesterday must have been! Gina

FEV 1 the reading shows how much breath can be pushed out in one second a measure of how the lungs function moving the air that has been breathed in and out of the lungs.

Blood gas transfer giving the saturation levels depends on the amount of functioning alveoli in the lung which can be accessed by the air that has been breathed in. Giving the FEV1 (function) V O2 sats (gas transfer) readings as separate part of information guiding treatment with lung condition.

Calling the helpline for advice on being breathless and controlling techniques.

Thank you, chang. I'm just surprised to have such an improvement in blood gas levels compared to prior readings.

There can be a blip in the readings. My arterial blood gas levels have been pretty consistent except for one which showed much higher levels of oxygen saturation. I was told that the reading can alter depending on a lot of things and that one high reading taking in isolation should be rechecked on another day to make sure that the alteration is not just a blip.

Yes, thanks Janet. They did say that I would probably be called back in 3 months to check the levels again. I was just panicking about having o2 stopped when I get so breathless! Gina x

In agreement with Gordon57 oxygen therapy is not given for breathlessness which is why using a pulse ox is the guide for oxygen requirements not how out of breath we feel.

Both FEV1 and O2 sats can change during inflammation / infection with some needing oxygen during an exacerbation then having no further need once they have left hospital with safe levels returned.

I have taken my own oxygen sats for so long that I know by how I feel what the pulse ox reading will show as they provide a warning when I am not so well and rise when my exercise regime is doing whats aimed for.

I've also learned roughly what to expect by the way I feel which is why I was surprised. Anyway, thanks Hergernt for your response, and ta to everyone else who answered!


You can always get yourself an oximeter to test yourself everyday.I got mine from a firm called ClinicalGuard.com. Ther are many other firms selling them. Just Google oximeter. Mine was £28.99. Hope this helps. Bob

Thank you! X

I am on oxygen and still get very breathless this is because, to put it in layman terms, the oxygen does not help your breathing but makes sure your other organs get enough oxygen to function normally. Hope this helps. Keep smiling.

Carole x

Thanks, but the oxygen is the only thing to really help me when I get so breathless I'm gasping like a fish - but I know what you're saying! Ta. X

When you get like that, drop your shoulders take ' the position of ease' lean on a worktop or something of a similar height, breath in through your nose and out through pursed lips until your breathing calms. Try not to panic as that will make it worse. Hope this helps.

Carole x

I agree with Carole here, you shouldn't be assuming that using Oxygen is 'the cure' to being breathless. It normally serves a different purpose altogether.

You need to get more advice on what to do about preventing becoming breathless in the first place, and how to deal with it if you do get short of breath. The helpline should be able to go through it all with you and give you information to feed back to your GP or consultant.


Hello Ginachron, I've recently been prescribed amblatory oxygen for when I'm exerting myself,dog walks etc; and I don't find it helps with breathlessness,I still have to keep stopping for breath but my sats recover quicker and they don't seem to be dropping as low and fast when I am doing the walks and housework,gardening. I am looking forward to PR to strengthen the muscles around my lungs and I find breathing exercises have helped me a lot.xxxxxx

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