Inaccurate cms50 readings, compared to hospital equipment

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Permalink Reply by Kath Hope on December 31, 2011 at 13:52

Very interesting Philip.  I have to confess I've not used my Pulse Ox lately as I check my machine's software to monitor my apnoeas.  My first thoughts are that how do we know the hospital's equipment was the correct one?  When I did use the Pulse Ox regularly, the oxygen desats coincided with the AHI readings on my machine's software, so it's safe to say that mine was accurate.  Another thought I had is that it's very unusual for anyone with OSA to have no apnoeas at all.  Even people without OSA usually have some.  Of course I'm not an expert, but I shall do some investigations with my contacts.

Do you have access to the readings from your CPAP?

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Permalink Reply by Philip on December 31, 2011 at 14:20

Hi Cath

I had been using the cms50 records to monitor my apneoa and  try lots of different things to see if I could improve my readings, with the benefit of hindsite using incorrect information which is a bit worrying. My CPAP does not produce apneoa readings (it is a remstar m series). I was diagnosed with apneao at Papworth following the as it is called 'gold plated' sleep study measuring a wide range of things. I am told my apneoa is now 'in control'. The stopping breathing and waking up with a start episodes must be happening due to something else.For example the consultant tells me gastro reflux (which I have) can close the larynx and stop breathing, but does not last long enough to record a desaturation of 4% for ten seconds (the recogonised standard for an apneao). There are a range of other physical and physchological reasons for stopping breathing. Using my Cms 50 (as the consultant suggested to prove the point) it took me 45 seconds minimium of holding my breathto drop my oxygen by 4%. 

When I had the gold plated sleep test at hospital , I agreed to also voluntarily wear a hospital home oximeter which is how they check the calibration of their home test oximeters and the very sensitive gold plated sleep study equipment.

 

Phil

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Permalink Reply by Tigers Fan on December 31, 2011 at 19:17

As far as I am aware, Phil, oximeters do not /cannot record apnoeas - the events they record are different to apnoeas by definition.

I take it that you, like me, are not a medically trained person. This means that our home oximeters are a guide to what is happening in our sleep. I use mine to give me a time line for my wakenings and de-sats (which could be apnoeas). 'Guide' is the key word. I adjust my pressures according to the de-sat results and get good stat results - meaning good sleep.

I suspect you are not likely to get totally accurate results from a piece of kit costing £60 when a good one costs - what - hundreds.

My 'M' Series happily records apnoeas - it takes software and a reader to get to the data in my old one. The new ones make it much easier. Mine's an APAP - the NHS 'M' Series CPAP I also use does not record anything except hours of usage.

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Permalink Reply by symmit on December 31, 2011 at 23:25

I'm not a doctor...

don't pay much attention to the printout, as it records "events" that are not necessarily apnoeic events. Youn need to be looking at the readout by hand - look for a drop in saturation that goes below 90% (or even lower), that is followed by an increase in pulse and a sudden rise in saturation. That would be a typical event.

.The CMS oximiters seem fine to me, and also correlate well with the data from my machine.

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Permalink Reply by Kath Hope on January 1, 2012 at 22:51

Well, I've done some asking from users of the CMS50 who also have software for their CPAP machines, and they all say theirs are pretty accurate when comparing the De-Sats recorded on their Pulse Ox with the AHI Data on their machines.  Like TF pointed out, the Pulse Ox's don't actually record apnoeas - they merely give a good indication that they have happened.  However, it is still possible to have apnoeas without big oxygen de-sats.  Symmit also points out that his seems accurate too.  I'm wondering if yours is perhaps faulty and it might be worth speaking to your supplier.

If you have the Remstar Pro and anything above this model, then data can be downloaded from the CPAP machine, but you obviously need a smart card in the machine and the software.

Have a look HERE at what Dr Steven Park has to say about reflux, and how it goes hand-in-hand with sleep apnoea.  Are you able to raise your bed head slightly with books under the legs or mattress to see if that will help your reflux?

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Permalink Reply by Isla Deuchar on January 2, 2012 at 0:44

Pulse oximeters is a non invasive method of measuring oxygen in your blood or haemoglobin..we call it saturations and we use them to measure for hypoxia in patients routinely but more so if they have respiratory problems...when you have an apnoea because you are not breathing, there is no oxygen at that minute getting to your brain...so your sats will be lower so having a low Sa02 (saturation of oxygen).  I do know that mine was very low when I had the sleep study but have not checked it overnight since.  Sorry though Phil I cannot really answer your question as I do not have or know the CMS50, but I believe Kath has found out for you.  Just my thoughts on pulse oximetry

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Permalink Reply by Philip on January 3, 2012 at 11:17

Kath,Isla, Tiger Fan, Symmit. Thanks very much for youir helpful responses. It is appreciated.

Kath's link to Dr Park is interesting. Reflux can desensitize nerve and pressure endings predisposing one to osa.

I also find that while dozing, but awake enough to be aware of my breathing, I breathe in and out steadily for a while and then at the top of a breath when I would start to breath out, I suddenly breath in again quickly. Sometimes happens during the day too. My consultant said it is a habilt I need to break, possibly with breathing training.

Can anyone explain what is happening when I take this double breath. While by definition it cannot be an apneoa as I have not stopped breathing, I suspect it can wake me at times.

Thanks again everyone.

 

Phil

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Permalink Reply by Kath Hope on January 3, 2012 at 20:30

Difficult one for us untrained people in this area to answer, but it doesn't sound like a habit to me if it's happening in your sleep.  However, finding a specialist in breathing, like the Buteyko practitioners or even Yoga sounds like a sensible idea Phil.  I still need to train myself to breathe through my nose now I'm able to after the operations, as being a mouth-breather is no easy habit to get out of - especially when I keep forgetting to work at it.  By the way, I sometimes find myself not breathing for a short while when I'm concentrating.  Wonder if that's a habit I've picked up from all those apnoeas in my sleep :D

Philip said:

Kath,Isla, Tiger Fan, Symmit. Thanks very much for youir helpful responses. It is appreciated.

Kath's link to Dr Park is interesting. Reflux can desensitize nerve and pressure endings predisposing one to osa.

I also find that while dozing, but awake enough to be aware of my breathing, I breathe in and out steadily for a while and then at the top of a breath when I would start to breath out, I suddenly breath in again quickly. Sometimes happens during the day too. My consultant said it is a habilt I need to break, possibly with breathing training.

Can anyone explain what is happening when I take this double breath. While by definition it cannot be an apneoa as I have not stopped breathing, I suspect it can wake me at times.

Thanks again everyone.

 

Phil

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