Asthma UK community forum

Oxygen and flying

Recently my gp completed a health form for me as im off to Lourdes in a few weeks. On it he stated i required oxygen for flying, how did he come to that decision given that i havent had any tests as such?.

I know that recently my sats have been lower but my con has said no to home o2 at the moment so at what stage do things differ when flying?

any thoughts?

6 Replies

Hi Hops,

Sorry to hear you've not been so well, but congratulations on being brave enough to leave the country even though you're poorly! I hope you have a rewarding time.

I'm not really sure why your GP would say that you need oxygen on the flight. The lower cabin pressures do mean that there can be slightly less oxygen available, and this can be a problem if you are running on borderline sats to begin with. Most lung function departments will do an assessment where they put you in an atmosphere that simulates the cabin atmosphere and measure your sats - usually known as a 'fitness to fly' assessment. It's often done on people who are on home oxygen to begin with, but it is sometimes done on people who do not qualify for home oyxgen but have borderline sats.

It sounds like your GP is guessing a bit, maybe it is worth persuing a proper assessment. Apart from anything else, most airline companies charge for the use of oxygen.

Take care

Em H


Thanks Em thats what I thought.

I wouldn't have to pay as im going with a charity called Hosanna House Children's Pilgrimage trust who take sick and disabled people to Lourdes( a place of Catholic pilgrimage) Coming with our group we have 2 Drs and 3 nurses (one of which has met with my community matron and knows all about me)so im fairly comfortable going away even though im still not great. There is now way i would risk it otherwise!!!

As for a proper assessment I was told when i asked that there wasn't a hope of getting it done before i goon the 18 July so maybe thats why GP erring on side of caution???

Just out of interest what are classed as borderline sats??


It might just be a precaution and a warning to the cabin crew to keep an eye on you. It doesn't mean you have to use it just have it there on stand-by just in case you have a problem. Have a great trip and hope it helps. Ange


Hops, to answer your question about what constitutes borderline sats - it depends very much on the individual, the nature and severity of their lung disease, what their sats normally run at, and the presence of any complications of chronic hypoxia such as pulmonary arterial hypertension (PAH) or right heart failure. These last two are extremely rare in asthmatics, but if they are present, the threshold for acceptable sats or pO2 (blood oxygen concentration) is higher.

As you probably know, 'normal' sats would be 96 - 100%, and a normal pO2 would be 11 - 13 kPa (the two are closely related, but the relationship is non-linear, so determining one from the other is not usually possible - which is why we get put through those painful blood gases to determine our pO2, even when they know our sats!). Doctors usually worry when sats go below about 90 - 92%, because this is the level at which the pO2 starts to drop off rapidly - although again, this is very variable and they may not worry so much in someone who is chronically hypoxic, as the body does compensate to a degree.

The fitness to fly test involves breathing through a mouthpiece that supplies an oxygen concentration of 14.8 - 15.1%, which is equivalent to that found in an aeroplane cabin at altitude (compared to 21% at sea level and normal atmospheric pressure). The test continues until your oxygen levels equilibriate, which can take upto 20 minutes. Your sats are monitored throughout and a blood gas (usually a capillary sample from your earlobe) is taken before and afterwards. A drop below a pO2 of 6.7 kPa, or sats of 83%, is considered to be a positive test and an indication that supplementary oxygen is likely to be necessary during the flight.

Hope this is of some help

Em H



Yet again you have answered my questions perfectly, during my last stay i was checked for PAH as i have quite a bit of lung damage from previous PEs and my con wanted to rule it out as a reason for a deterioration in my asthma over the last year or so. Since my last stay my sats seemed not to have returned to their normal which i think may be contributing to my GP s concern . As i have a nurse who will be with me throughout the flight it has been decided that she will monitor my sats and i will have the o2 if i drop below 90 as has now agreed by my con as well. Thanks again


Hello Kirsten, I have flown recently and I did notice that after an hour I was short of breath. It was on a Ryanair 737 and I put it more down to the fact that it was a smaller plane and more people stuffed into a smaller space, thus they were using up all the O2. It happened both ways on my recent trip to Italy. They did offer me O2 on the way home when I said I needed to get back to my seat for a neb. I was grounded in a seat by the loo ( Which I never managed to use ....) due to turbulence on the flight. They did get me back to my seat.However on a larger Boeing 747, I had hardly any problems, only on take off as it was one of the oldest flying 747s and there was a bit of a smell / smokey / oily on take off which set me off a bit. With a bigger cabin, there seemed to be more 'air' circulating and less person per metre or so of air.The eight seaters I fly on don't fly high enough to compromise O2 LOL!I am sure you will be OK and Hope you enjoy Lourdes, just ignore the tacky souvenirs! (Went for a day many years ago)Kate


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