Asthma UK community forum

O2 Sats Pretty Normal In Attack???

I am really confused because sometimes when I have an asthma attack when the paramedics/a&e doctors take my o2 with that thing you put on your finger they're pretty normal! They're usually around 99/100% but then other times when I have an attack they're around 73%. I was just really confused because a doctor once commented that it couldn't be asthma if my oxygen sats were high, although I felt like it was asthma. So, I was just wondering if it could be asthma if my sats are high or if it is something else?

Thank you!


4 Replies

Hi Rachel,

I can see why you’d be confused! A sats probe, measures the amount of oxygen in the blood however they are not particularly reliable which is why doctors sometimes take blood from one of the arteries in the wrist. This method is much more accurate.

Sats are not helpful at deciding whether a patient is having an exacerbation of their asthma or not. This is a diagnosis made by a doctor or nurse after talking to and examining the patient.

Sats are however helpful at determining how severe an attack might be. It is entirely possible to have normal sats during an asthma attack. Please do not feel that simply because you have been told you have ‘normal sats’ you are not having an asthma attack and have sought help inappropriately.

I hope this helps you,




My son rarely has reduced sat O2 and can look and feel dreadful with sats on 95 and above. He has been known to have appalling lung function with good sats??? How he does that is beyond me! At RBH one time he did a lung function that started at 27% and reduced to 24% as it became worse each time he did it but had normal O2 levels.

We have had a number of 'fights' with the local hospital as when he is struggling he needs nebs to make a difference - but they have a policy of not giving nebs if O2 is above 92%. So we spend days having 10 puffs with a spacer every hour not getting any better (or any sleep) then end up on IV's as his breathing and pulse rate have increased too much.

So must admit the whole O2 thing confuses me.

Take care.


It is confusing - one of our close friends with severe asthma can get to the stage where her lips are turning blue and end up with SATS levels which are *more* than she would normally show!

Some time ago, I wrote the following about it:

""Oxygen saturation levels only drop far too late in the attack for them to be a useful indicator of anything being wrong. By the time they drop outside of the ""normal"" range, it will be very apparent that an asthma attack is in progress - if they drop at all!""

Asthma UK's protocols for dealing with asthma attacks on the Kick Asthma holidays don't utilise SATS reading at all.


Thank you all!! All your replies have been extremely helpful!


PS - I'm glad it's not just me!!!


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