Interpreting Pulse Oximetry Data

[bigalxyz]

Hello forum,

Looking for some advice. I have what seems like it might be a textbook case of sleep apnoea (British spelling, I hope you'll indulge me...) but repeated testing has not yielded a positive diagnosis.

I had two sleep studies carried out in 2013. The first of these gave a "borderline" result and the second gave a negative result.

In 2015 I had a heart attack (aged 45!). One stent fitted successfully, and I recovered quickly. Within about 6 weeks I was back to normal. The problem for me is that "normal" isn't very good.

I had another sleep study carried out about 6 months ago and was told that the results were normal, average spO2 during the night of 95%.

I recently bought a pulse oximeter with a recording facility, and started looking at the data using a piece of software called "spO2 Monitor" on my PC. I've spent some time looking at the data and I'd like to get some advice about what it all means.

A good example is from yesterday afternoon. I felt crushingly tired, quite suddenly, and slept fitfully for about an hour. This happens often for me. When I woke up, my upper body was quivering although it stopped quickly. I felt terrible - like I wasn't getting enough breath. My breathing seemed "lazy" - quite slow and shallow. No noticeable impediment to breathing, just that my body didn't seem to want to do it. Had a choking sensation - head/adam's apple/stomach. Felt confused & disorientated.

Looking at the data from the pulse oximeter, it's noticeable to me that my pulse and spO2 seem to be a little bit unstable. spO2 averaged 93%, but had a tendency to dip below 90% quite often (think the lowest number was about 88%) and then rebound quite quickly afterwards to 97-98%. My pulse was a little unstable as well, although within a narrow-ish range (5 percentage points or so).

A second example from last night, about 1am to 2:30am. For the first half of the period, my spO2 and pulse were *much* more stable. spO2 averaged about 93% again, but stayed within a very tight range (92-94%). My pulse stayed at about 65 and hardly moved at all. Then at around 1:40am they started to fluctuate (much like they had during the afternoon nap), dropping below 90% quite a number of times. and also rebounding up to close to 100% within a very short period. After about 45 minutes of this I woke up.

Waking every hour or two during the night is very common for me.

Today I feel tired, groggy, grumpy, disorientated, lethargic - as I do most days.

If I lie down flat on my back while awake, this "lazy breathing" I described is often there. And then suddenly I can feel a jolt inside and I'll take some deeper breaths. It doesn't feel right to me.

If anyone reading this posting has any experience of interpreting this sort of data and is able to offer any comments or advice, I'd be very grateful. My health is very poor. No doctor seems to be able to find anything wrong with me - all my blood test results are normal, nice BP numbers (110/70 ish), on paper everything looks good. But I'm so exhausted than I'm unable to work, or sometimes even to get out of bed. Occasionally the symptoms ease and I'm able to climb mountains, go on long bike rides, dig the garden, socialise, etc. but this is fairly uncommon, sadly. Sleep apnoea would do a very good job of explaining all my symptoms, but there's no positive diagnosis to be had, it seems.

Grateful for any advice...
Thanks
Alan

[Marillion]

While low SpO2 numbers can be one indicator of Sleep Apnoea, it is not necessarily the only indicator. I would recommend you get another sleep test done. Particularly an in lab test. There are many things that can disturb your sleep and your symptoms seem to indicate a strong correlation to sleep deprived effects. Whether that is due to Apnoea or not is another matter. Stay persistent in getting an answer, no one else can advocate for you but yourself and keep pushing until you get an answer.

[bigalxyz]

Thank you.

The recent sleep study I had done (about 6 months ago) was in fact quite detailed. The spO2 readings were only part - they also recorded my breathing (two little plastic tubes resting against my nostrils) + I had straps around my chest and waist which I think were to measure movement when I breathe + I think a microphone to record noise (looking for snoring/snorting/choking etc. I suppose). The doctor I spoke to about the results said that everything looked ok.

I actually did the test twice. The first time I spent a night sleeping at the local hospital, but unfortunately the mattress on the hospital bed was so hard that I think I only slept for about half an hour, if that - so they had to scrap the data and start again.  They asked me to do it at home instead, which worked better.

*something* is going on with my sleep, I'm sure of it. I always, always feel worse after I sleep - both at night and if I nap during the day.

I'm not sure where to go with this next. I suppose I could ask to see the detailed results of the sleep study (rather than just the quick verbal summary that the doctor gave me).

[trish6hundred]

Hi bigalxyz,
WELCOME! to the forum.!
Hang in there for more responses to your post.
I wish you good luck in finding out what’s going on with your sleep.

[Marillion]

Absolutely, it is your right to have a copy of the detailed sleep study results. It is a good idea to have that in your possession for many reasons and I would highly recommend that you do so.

If you feel comfortable with it, you could post the results here (obscuring any personal details) and some of our resident experts could have a look to see if anything pops out at them. I myself am fairly new to the Apnoea world but have done my best to educate myself as much as possible and to keep learning. I will offer whatever advice I can.

There are many reasons for disrupted sleep. As I mentioned before it may not be sleep apnoea that is causing yours. The main thing is to advocate for yourself and don't give up. Ask your doctor to refer you to a sleep specialist, do whatever it takes to get help!

[srlevine1]

Have you considered that maybe your issue is not sleep apnea, but something else .. like a cyclic hormonal issue or cardiac issue? Have you had a recent echo cardiogram to check blood flow? Have you looked at your thyroid function? Is it possible that the issue is positional and/or related to blood pressure fluctuations? Do you show any signs of anemia, iron deficiency, or polycythemia (too many red blood cells to compensate for low oxygenation rates)?

Do not be the man with a hammer where everything else looks like a nail. Consider a multidisciplinary medical workup if that is even possible under your healthcare system.

Best of luck on getting answers and feeling better.

[chill]

*something* is going on with my sleep, I'm sure of it. I always, always feel worse after I sleep - both at night and if I nap during the day.

I had a similar experience and mentioned it to my sleep doc.  He said this is a classic symptom of sleep deprivation.  So the root cause would seem to be lack of quality sleep.  It is not that sleep itself is making you worse.  Sleep apnea is one of many possible explanations.

[bigalxyz]

Have you considered that maybe your issue is not sleep apnea, but something else .. like a cyclic hormonal issue or cardiac issue? Have you had a recent echo cardiogram to check blood flow? Have you looked at your thyroid function? Is it possible that the issue is positional and/or related to blood pressure fluctuations? Do you show any signs of anemia, iron deficiency, or polycythemia (too many red blood cells to compensate for low oxygenation rates)?

Do not be the man with a hammer where everything else looks like a nail. Consider a multidisciplinary medical workup if that is even possible under your healthcare system.

Best of luck on getting answers and feeling better.

Thank you.

Yes, I've discussed my symptoms at length with my doctor. Have had a bunch of blood/urine tests. Nothing unusual showed up - thyroid function seems to be ok, no sign of anemia or polycythemia, blood counts etc. are all normal.

Testosterone a little low, however.

Have had a 24 hour urine test for a rare hormone secreting tumour (pheosomethingorother), but that came back negative.

Some overlap with symptoms of anxiety/depression, can't rule that out.

Also my doctor has suggested that some of my symptoms feel migraine-like to him, but a change of meds to try to stop these has had no effect.

Doctor has offered a referral to a neurologist which would then permit MRI/CT scans on the brain, etc. I suppose.

Echocardiogram - yes, I've had two of those. The first was about a day after my heart attack. They measured the "ejection fraction" and it was down at just over 30%, which was a pretty bad number. A few months later it had improved to around 45%, still a little bit low but noticeably better. I don't have any of the usual symptoms of heart failure, however - and all the sleep-related symptoms I've described pre-date my heart attack, so I'm minded to think (as is my doc) that my heart isn't the current cause of my woes. Still, who knows?! Can never be sure of these things.

I'm trying to keep an open mind & to rule things out, one by one, I suppose.

Thorough treatment is available on the NHS here, and my doctor is supportive - the only grumble is that the system's finite budget can make things sloooooow...one has to be very persistent to make things happen sometimes ("the squeaky wheel gets the grease", and all that).

Having said that, I'd happily put my hand into my pocket and pay for private care if it seemed likely to make a difference. Haven't been convinced of that (yet) though.

[bigalxyz]

*something* is going on with my sleep, I'm sure of it. I always, always feel worse after I sleep - both at night and if I nap during the day.

I had a similar experience and mentioned it to my sleep doc.  He said this is a classic symptom of sleep deprivation.  So the root cause would seem to be lack of quality sleep.  It is not that sleep itself is making you worse.  Sleep apnea is one of many possible explanations.

Thanks. Yes, there's a number of possible causes here but I do think sleep quality is in the mix somewhere. I'm in no doubt about how important good quality sleep is to health.

[Hojo]

Alan:  Pardon me but let me be frank; as long as I didn't miss something, you had your heart attack 2  years ago, a few months after you had an ECHO with an ejection fraction (EF) of 30% and shortly later improved to 45%.  Now, pretty much 2 years later your looking at your pulse ox and seeing some low numbers.  A lot could change in 2 years to your cardiac function.

The oxyhemoglobin dissociation curve is a sigmoid shape curve, wherein small changes in saturation can actually be significant changes in the actual oxygen content in the blood;  Your saturation of 93% compared to 85% is actually a large difference in how much oxygen is circulating in your blood.

If you are seeing your saturation go that low during the day, I would call the cardiologist.

Look at the oxyhemoglobin dissociation curve here;

https://images.search.yahoo.com/search/i...tion=click