Pulse Oximeters (oxygen saturation finger probes)

[ALUK_Nurses]

Hi all,

I hope everyone is well and staying safe😊 .

We wanted to post something about the use of pulse oximeters as these generate lots of discussion on here.

For Asthma: pulse oximeters are NOT currently recommended as part of an asthma care plan (unless specifically directed by an appropriate health professional), this is because they can prevent people from accessing emergency advice by giving a false sense of security. The best way to monitor your asthma is with a Personal Asthma Action Plan (PAAP) asthma.org.uk/advice/manage..., being aware of worsening symptoms, extra use of your reliever inhaler and drops in peak flow readings - these should direct you to get extra support/help from a health professional.

For COVID: Dr Andy Whittamore, clinical lead for Asthma UK and the British Lung Foundation, said, “At this stage, while the use of pulse oximeters in response to COVID is still being examined, it remains really important that before testing at home, people talk to their health care professional. Home use oximeters, which are available for sale online and in chemists, and can be used to measure the levels of oxygen in your blood, can sometimes give poor or inaccurate measurements. It is vital that anyone with questions on using a pulse oximeter at home speaks to a health care professional for advice. Any monitoring done at home needs to be part of a clear management plan and is not a substitute for clinical advice. Anyone worried about their symptoms should speak to a health care professional.”

Updated advice March 2023:

According to UK and US Asthma guidelines there is NO PLACE for routine oxygen monitoring in people with asthma. In the rare cases where it is useful, it will be on the advice of a hospital consultant who is specialist in asthma.

When someone is having an increase in asthma symptoms or starting an asthma attack there are lots of things that change in the body before oxygen levels drop. In fact, your body breathes faster and your heart pumps faster to help keep your oxygen levels within normal limits.

Symptoms, the response to medication and peak flow are more reliable signs that you need to take action (contact your GP surgery or 111, or follow your action plan). Once your oxygen levels have dropped you are in a life-threatening phase - any action should have been taken long before this.

Many people were given oxygen monitors (oximeters) when they had COVID19. This is because the pattern of that disease, which is very different from asthma, did cause drops in oxygen levels in some cases. Having a monitor at home allowed people with covid19 to keep an eye on how covid was affecting their lungs and oxygen levels without having to leave the house and risk infecting other people.

Updated advice Jan 2025

Some people may have oxygen monitors (oximeters) for monitoring other lung conditions . If monitoring is recommended in other lung conditions, this is usually agreed between their health care professional and the patient with a plan to support their care ( safety netting advice, etc) Oxygen meters are not appropriate for everyone and the guidance on the use in asthma remains unchanged .

So for asthma, follow your personal plan and act on increase of symptoms, drops in peak flow and/or need for extra reliever medication. asthmaandlung.org.uk/condit...

[hilary39]

What is the reason behind the false sense of security oximeters can give asthmatics? Is it that it's possible to be worsening or in a severe attack and still have normal blood oxygen? I'm assuming that's the case, just confirming.

[Lysistrata Administrator Community Ambassador in reply to hilary39]

Obviously the experts can confirm but from personal experience that's definitely the case! I have also had some interesting ABGs with relatively low PaO2 while the hospital sats monitor said everything was great (and sometimes the % on ABG is lower than the sats probe too).

It's a shame that the message about good sats but severe attack hasn't always got through to some healthcare professionals. I had an unfortunate situation at a usually good hospital in Feb where I was left for ages struggling because sats were 96% so I must be fine🙄 never mind the lack of ability to talk properly. (Yes they were busy but the triage was really not appropriate, and the sats were all they went on until I finally got to see a sensible nurse!)

[hilary39 in reply to Lysistrata]

I feel like we've compared notes about this on other posts, too. I totally agree. And I am always amazed at how few nurses and doctors in urgent care settings seem to know about the basics of asthma.

I typically have a pretty silent chest and don't wheeze even in severe attacks and that alone has led nurses to take me less seriously even if I'm really struggling. A lot of people in this group talk about having a normal(ish) peak flow, normal oxygen, and not wheezing strongly while still having a horrible attack that necessitates steroids and weeks of recovery so it's been really helpful for me to see I'm not alone in that-

[Lysistrata Administrator Community Ambassador in reply to hilary39]

Same - I am sad not to be alone in having this issue but at least it makes it easier for me to believe it's not in my head after bad experiences!

Disturbingly the ambulance service in my area still uses wheeze and sats for their guidance re giving nebs/whether or not it's asthma. Some paramedics are sensible and know better (I usually get nebs anyway) but not all, and this really shouldn't be in their official guidance.

I also think some medics (whether paras/nurses/drs) cannot actually tell the difference between normal and 'clear because silent/too quiet'. I have had later/different ones say oh still a bit quiet post-treatment when pre-treatment it was 'all clear no wheeze'. I highly doubt I was more quiet *after* the treatment - that is one of the few times I may actually wheeze!

[Melanie1989 in reply to Lysistrata]

I could have wrote this word for word!

[Monty89 in reply to hilary39]

I’m so glad this post was pointed out to me. I felt so stupid after I called for an ambulance a few days ago. My inhaler wasn’t relieving, and I’d never felt this bad with asthma before. It was scary but I felt like I’d wasted their time when the ambulance to go me and the paramedic took my sats and said your sats are really good, they couldn’t get much better. Then one said you don’t have a wheeze either and I just felt like I’d wasted their time. Because they said my sats were good and given the current COVID situation I elected not to go to hospital, but reading all of this I probably should’ve and in future will go with how I feel.

[ALUK_Nurses Partner Administrator ALUK Asthma Nurse in reply to Monty89]

Hi Monty89, sorry to hear you had a problem recently - I hope you are ok now? It sounds like you absolutely did the right thing calling 999. Have you seen or spoken to your GP since - if not I would recommend doing so. asthma.org.uk/advice/manage...

[Monty89 in reply to ALUK_Nurses]

Hi. Thank you for your reply. I managed to speak with an asthma nurse yesterday who was brilliant and very understanding. She arranged for some prednisolone and said she will call me in a few weeks to look at my asthma plan. Just hoping the steroids kick in over the next day or two.

[ALUK_Nurses Partner Administrator ALUK Asthma Nurse in reply to Monty89]

If you are still getting lots asthma symptoms and your reliever inhaler is not lasting 4 hours - please call back your GP or 111 today

[Monty89 in reply to ALUK_Nurses]

Thank you I will do.

[EmmaF91 Community Ambassador in reply to hilary39]

You can have severe or even life threatening attacks whilst your sats are still in an acceptable range. I have a friend who can have CO2 retention high enough to be classed as near fatal but have oximeters (even on the hosp monitor) still saying her sats are in an acceptable range... then she crashes hard (she’s lost count how many times she’s now been intubated). Typically with asthma sats don’t drop until you’re in dire straits, by which time what may have been an ‘easily’ dealt with attack can kill.

I personally have had multiple life threatening attacks (according to BTS guidelines) but it’s rare for my sats to drop below 94 during attacks and the only time they dropped below 90 they very nearly intubated me. As I’m normally 98/99, a drop to 96 usually means I should be seeking help, even tho it’s still in the completely normal range on the NEWS.

As asthmatics are body compensates really well, right up until it really can’t, and waiting that long til you seek help is very dangerous. But many people do not realise this and so think they are fine and don’t need to seek help (despite bad symptoms +/- meds not working +/- low PF), as their sats are still deemed as acceptable, hence they get the false sense of security that they are fine, when they are not!

As Lysistrata said, there are still some medics who don’t know this either, and so may comment ‘sats are fine’ as if that’s a gauge of control for asthma.

Hope this helps explain, and hopefully the experts here can confirm!

[hilary39 in reply to EmmaF91]

So interesting and helpful to hear your experience.

[Melanie1989 in reply to hilary39]

I am the same as the others, in fact i have only ever dropped sats once. My last attack i was about to be placed on Non invasive ventilation and sats were 98.. Asthmatics are very good compensators and so oximetres can provide false reassurance. I have even had a normal ABG before however did show compensation.

If only i could remember this mid attack when i don't think i am bad enough 🤦‍♀️

[hilary39 in reply to Melanie1989]

It does seem like false reassurance. It’s a good way to put it. I wish there were more ways for doctors to accurately gauge how bad our attacks are because I have definitely been sent away from the hospital while still feeling wretched and after just one quick neb (but I’m american and our system as you know is particularly cruel / ruthless—I was once finishing a neb in a hospital when they brought to my bed [i kid you not] a bill for $500 and a credit card swiper. And I had good insurance! In the states we have a high copay every time we go to the hospital).

I often am unsure how bad I actually am when my oxygen and peak flow are normal but I feel like I can’t get full breaths.

[Eibhlinn]

Hi everyone, I had pneumonia in March and breathing difficulties 10 days later. My doctor was worried about me and among other things sent me an oximeter to check my sats 3 times a day. Every day the doctor rang me to see what they were. They were at 89/90 for 3 days and I was hospitalised for 4 days With oxygen and the nebuliser and steroids. Apparently my blood gases were extremely low as well. I was told to keep the oximeter to check my sats if my asthma got bad again. With doctors not seeing patients at this time, only I had that oximeter I dread to think what would have Happened. I am very glad that I have it. I think everyone who has asthma should have one.

[twinkly29 in reply to Eibhlinn]

It sounds to me as if the GP was concerned initially about your sats in relation to having the pneumonia rather than your asthma (actually wondering if it could have been covid given the breathing worsening after 10 days...but maybe they ruled that out?)

As the Asthma UK nurses have said in their initial post, they're not really recommended for asthmatics to use routinely to monitor their asthma so doesn't sound ideal that your GP has suggested this as a good management tool - please make sure you don't just go on the sats if your sats are reading as ok! My sats, for example, were largely ok a week ago in A&E and I still went to ITU because my asthma certainly wasn't.

[ALUK_Nurses Partner Administrator ALUK Asthma Nurse]

Hi All,

I Hope you all had a great weekend! Glad to see this has generated a bit of chat!

Yes as a few of you have rightly pointed out on here (including EmmaF91 - our new Community Ambassador😀)oxygen saturation is often the last thing to drop in an acute asthma flare so please don't rely on these, and dont be falsely reassured by normal readings…. be guided by your symptoms and response to your medication - follow your asthma plans 👍

On the other side inaccurate/low pulse oximetry readings may occur when any of the following factors are present:

-Excessive patient movement

-Exposure to bright ambient light

-Nail polish/false nails present

-Skin pigmentation

-Cold hands / poor peripheral circulation / Raynaud’s phenomenon

-Certain cardiac arrhythmias

-Severe anaemia

Whilst Pulse oximeters most certainly have an important place in medical care please be very cautious about using them yourselves at home (without specialist medical guidance) and especially for asthma.

Best wishes to you all ☺️

[B_Asthma]

As for me, I have a pulse oximeter and only use it when I have a flare up to see if it is causing any issues. Normally, it sits about 97%; however with flare-ups it goes to 93% and sometimes as low as 87%.

The one frustration for me, in the UK there is an over-reliance on asthma nurses and asthma plans. In the USA, while being treated for asthma I was given a flow meter and taught how to manage my asthma. I believe, teaching asthma self-management in light of the impact of COVID is something the UK can learn from the USA.

[EmmaF91 Community Ambassador in reply to B_Asthma]

The aim of the asthma plan IS to allow for self-management of asthma. It tells people what to do and when to get more help, until they know how to deal with it. The reason we have annual reviews to to spot deterioration or improvements so maintenance treatment can be changed, as well as the fact the UK has some of the worst asthma fatality stats in Europe (worst for child mortality and 6th worst mortality overall - 3 deaths a day). 2/3 of deaths could be attributed to poor care/management/overview by medics and 1/3 were patients not seeking help in time. For year/decades in the UK asthma has been underrated/undertreated as people don’t understand what should be normal.

That’s why we have reviews (usually with asthma nurses as a lot can be better trained than GPs, and it also frees up GP time to do less maintenance and more acute appts), and plans (to tell people when they need help, so they don’t risk things turning fatal). A lot of people still don’t have plans/reviews, and they are shocked that what they live with isn’t ‘normal for asthmatics’ when they do see someone, get 1 med change and ‘it’s like they don’t have asthma’.

Over reliance on salbutamol is a leading cause of death in the 1/3 cause it masks the underlying issue. This is why home nebs are deeply frown upon here (unlike the US) where only really the most severe uncontrolled get them approved of by consultants, and even then they usually come with strict rules/plan as to when to get more help.

We are usually encouraged to use PFMs as self-management, but using Sats for asthma is a safety issue, because most people with just asthma don’t desaturate until they are heading towards life threatening/near fatal attacks.

[Lysistrata Administrator Community Ambassador in reply to B_Asthma]

Hopefully you would still get medical help if your sats didn't drop but you had other signs you were struggling, and not rely on the.sats probe alone. As the Asthma UK nurse and others have said, it isn't necessarily a reliable indicator as you can really be struggling but still maintaining sats. Even for someone who does drop usually it's still worth bearing in mind, and is why they tend not to be recommended for asthma.

I'm a little confused by you saying there is over reliance on asthma plans in the UK instead of self management. A personalised asthma plan is a tool for self management. A nurse or doctor should be creating one with you, and then you use that to manage your asthma and decide what you need to do. At some point that may include contacting a doctor or nurse or going to hospital, since even with COVID, sitting things out at home as you get worse with asthma is not a good idea. But the plan should give you the tools and confidence to manage what you can at home, and get help when you can't/shouldn't self manage.

It also doesn't necessarily need to be peak flow based, since not everyone does well relying on peak flow. For some people it's very reliable; for others like me less so - and I find sometimes the UK can get a little too hung up on peak flow raw numbers and not see it in context as it should be used. A plan with both symptoms and peak flow works well even for people who do have accurate peak flows (again not just relying on one measurement), but research has shown symptom-based personalised plans can also work just as well for people who find peak flow less helpful.

[Claire-Rose]

I have been adviced by a respiratory doctor to always check my sats as when I go to a and e I have very low sats to the point I need to be on 15L o2 in a non rebreather mask and then slowly weaned to mask that has different coloured tubes for different amounts of oxygen and then a nasal cannula days later I think it’s because my sats are only at 94/95 when I’m well is there anything I can do to increase my sats as I can spend days in hospital feeling well but can’t go because of my sats which is very frustrating

[EmmaF91 Community Ambassador in reply to Claire-Rose]

Do you have a breathing dysfunction? I know I went through a period where I’d have low Sats as a baseline so drops were worse with flares, then we realised I had a BPD which involved out-breath holding. Fixed that and now my normal sats are 97-99 and only drop to 93ish during attacks. Just an idea and may not be useful for you 😅

[Claire-Rose in reply to EmmaF91]

They said I have something wrong with my breathing pattern but at the time they checked my sats maintained around 97 it’s only been the last 3 months that they have been this low same as my peakflow my highest use to be 450 I felt really well the other day and it was only 250 and the highest I get when I leave hospital is now 300 it’s so strange

[ALUK_Nurses Partner Administrator ALUK Asthma Nurse in reply to Claire-Rose]

Hi Claire-Rose, do feel free to ring the nurses on AUK helpline 0300 2225800 M-F 930-445 if you want to discuss your asthma

[B_Asthma]

My GP is asking that I monitor my pulse oxygen levels for asthma. Can you please advise on the best way to do this?

[Wheesy]

I can take your point to a certain extent, but have a oxymeter which was provided by my consultant who explained how to use the oxymeter correctly and know how to use the information in relation to my severe/brittle asthma. The meter which I have links to my phone and also keeps the last 15 readings in the memory bank. This is most useful with paramedics and other medics say that my SATS [I believe this means oxygen sturaton] are fine which they posssibly are at that time [4hrs when staff take observation readings] and you are fine but I can proove that I am not with saved data of time date oxygen level and pulse rate that I do have a problem and it does need sorting out. I also think that a person always knows their own bodyand the oxymeter confirms what we are saying but medics do not likE to bE proVEd wrong and these meter are not accurate. I can always overide this by using my oxymeter and let the medic use theirs and compair readings 99 time out of 100 they will agree and possibly now and then a discrepancy of 1 digit will be found. We are not stupid and know when we need medical assistance and only use the oxymeter so that we can tell the emergency switchboard the redings and help them even before depatching the ambulance.

[Lysistrata Administrator Community Ambassador in reply to Wheesy]

I think the key point, as mentioned above and reinforced by an Asthma UK nurse, is that it is reasonably common for people with asthma to have normal sats, even when other signs and symptoms show there is a problem and they need emergency help - the sats monitor does not necessarily reflect what is going on.

So even if an oximeter is accurate and all your home readings have been fine, no one - not patients, paramedics, or hospital staff - should be over-relying on sats to determine whether someone is ok or not or needs emergency treatment for asthma.

[Wheesy in reply to Lysistrata]

I take your point but trying to get your point through is like geting a new job as a fog platter, and any form of amunition in our favour you must agree cannot be dismissed along with us knowing our own bodies and should not ignored

[Dimitri4691]

Yes. But good luck to anyone trying to access support. At the moment it's easier to call up the Prime Minister.

I have a blood pressure monitor, oxymeter, stephoscope and ECG. Relying on your GP or health professional is fruitless as at the moment they don't exist.

[Lysistrata Administrator Community Ambassador in reply to Dimitri4691]

I realise this post is a year old, but I've seen that people are still reading the thread, so I'm replying to this for anyone reading.

Having home medical equipment is not a substitute for medical care, especially if you're not trained in how to use and interpret it (and if you are trained, you should know when to call in help). I appreciate it can be difficult to get seen still in some areas, but please don't rely on equipment you've bought for home.

[Pipsqueak77 in reply to Lysistrata]

Hi All

This is an interesting post.😊

I am aware and absolutely agree with Asthma UK’s advice on oximeter use in asthma. I also don’t think they are of particular use to me personally for my asthma.

However I really wish that there could be some kind of consensus amongst medics!

I say this as I am completely frustrated by my GP’s insistence that I purchase an oximeter, against seemingly even the advice of AUK…!

So far I have managed to avoid an all out disagreement with him - but I’m sure it’s on the way!😬

It’s just seems that in this post covid world it is difficult to get anyone (esp medics) to see beyond covid anymore so all respiratory treatment rolls into one??

So I understand people’s confusion when the advice is so contradictory.

😊👍

[Lysistrata Administrator Community Ambassador in reply to Pipsqueak77]

Completely agree - and I'm concerned that guidance on what is an appropriate oxygen level has already 'leaked' from COVID and COPD into asthma - not the same range, and what would be ok as a number for the first two may need treatment asap if it's seen in asthma.

I've already felt from some posts that COPD and asthma can sometimes be treated as interchangeable when they're not (for example, having good spirometry because it's a good day means you 'can't have asthma', or can't have severe asthma, even though asthma is variable and even severe asthmatics can be capable of reaching their predicted or more on a good day.)

I also agree it can be generally confusing with asthma advice when people's GPs or even consultants are telling them one thing, and ALUK and this forum is saying another! Unfortunately wrong advice is not less wrong when a medical professional says it, but it does diminish trust in their advice I find if they get something basic very wrong.

I can totally understand them not knowing the finer points of asthma biology off the top of their head, or not immediately being able to recite the criteria for biologic treatments. I'm less forgiving and more inclined not to trust my care to them if they're telling me I can't have asthma because I don't wheeze, or insisting I use my predicted instead of my personal best peak flow! If they don't know the answer, they should be willing to say that and check (but I do think healthcare professionals can feel pressured to look like they have the answers, which is a problem with the system).

[Blueforest23]

Out of interest if observations such as sats, wheezing, peak flow are not reliable to identify the severity of an asthma attack, then what objective markers are reliable if someone presents to hospital with a asthma attack? What objective assessments should be used by staff?

Also if the above are not reliable indicators how can someone with asthma objectively identify the start of an attack?

[Lysistrata Administrator Community Ambassador in reply to Blueforest23]

I think part of it is looking at the big picture. There are charts in the guidelines for healthcare professionals that give lists of things like 'any one of/more than one of the following: peak flow at X% of best/predicted, heart rate above 110, resp rate above 25, unable to talk in complete sentences in one breath, how you're sitting indicating work of breathing etc'. Admittedly they're often not very easy to use or clear a lot of the time, as they can often give the impression that you need everything on the list, but they are meant to show professionals that you don't need all the signs and symptoms.

For more severe attacks, a clued up doctor or other healthcare professional will also be listening not just for wheeze but for things like reduced air entry, reduced air exit, or prolonged expiration. Asthma attacks tend to start with difficulty breathing out, so if they're listening carefully they may be able to hear signs of that even with ok air entry and no wheeze. They may also do a blood gas - again, not infallible, but if they know what they're doing they will be using it as part of the big picture, not just looking at oxygen levels alone (what is the carbon dioxide level, as that can build up? Do other measures show compensation?)

I'm not a doctor, but after a lot of experience with attacks I've noticed that some doctors limit themselves to a narrow checklist, expect a certain presentation, and don't know what to do if that isn't there - they'll want a yes/no answer that may not be there. They may also not be very good at listening to chests and so miss subtle signs. More experienced/better doctors and other HCPs look at the whole picture and the whole patient, not just the numbers - and may also be better at picking up subtle signs and interpreting them.

Peak flow can be reliable for some people in some cases - so if that's you, then use it! I have a friend whose peak flow is more reliable than her symptoms as she isn't good at perceiving symptoms. Mine isn't just based on percentage of best alone, but I have learned that for me it's not about the numbers by themselves, it's about the response to medication. If I'm heading into an attack, I find that my response to medication gets smaller and won't be lasting for as long - even if the number on its own isn't too bad (in relation to my personal best, not my predicted or anyone else's peak flow). Many people might also notice as something like: the blue inhaler helped my breathing, but not for long. And if you're too breathless to speak, eat or sleep then you need to seek medical help urgently.

Here's ALUK's advice on attacks, at this link: asthmaandlung.org.uk/condit...

You’re having an asthma attack if:

your blue reliever isn't helping, or you need to use it more than every four hours

you're wheezing a lot, have a very tight chest, or you're coughing a lot

you're breathless and find it difficult to walk or talk

your breathing is getting faster and it feels like you can't get your breath in properly.

You may have all of these signs and symptoms. Or you may have just some of them. For example, you may not wheeze.

Hope this helps. I think the thing to remember is that it's not about 'do you have this one sign yes/no' for asthma attacks. Just like heart attacks can present differently in different people (women might not have jaw or arm pain or even chest pain), so do asthma attacks - so look at the whole picture, and hopefully so will your doctors.

[Mandevilla in reply to Lysistrata]

And this was why it took me so long to get diagnosed. I hardly ever wheeze (and when I do, it's when I'm recovering, not when I'm really bad!) and my normal peak flow is much higher than the average, so every time I got rushed into hospital with breathing difficulties, I'd get the 'you're not wheezing and your peak flow isn't too bad, so it's not asthma. I kept being told it was a 'virus' or 'stress'!!!