An Oximeter is like having every night be a sleep study

[sleepy1235]

I am very happy with my Oximeter. I am able to see how much SpO2 I am getting all night long.

1. You can see how the SpO2 varied under all sorts of conditions.

2. You can see the relation between AHI events and drops in SpO2. Not a very good correlation at all.

For example: Did the SpO2 drop each time my sleep software decided I had an event? The answer is no. In fact mostly not.

For example: Did it report an AHI event each time I had a big drop in SpO2. The answer is no. In fact mostly not.

If I was looking at the AHI, I would often just have one or two an evening and think everything was fine. Looking at the SpO2 is another story.

3. I do have drops when I have high resistance. I don't know if I woke up. Would the pulse rate go up?

4. it does seem to indicate that 8.0 pressure isn't sufficient to prevent extended periods of dragging O2. Interesting how three expensive sleep studies didn't detect that. Though it may be the calibration of the SpO2 instrument. It shows me starting out initially at about 94% and dropping from there.

But I do occasionally have SpO2 drops.

5. Many nights I start the night spending about 1 to 1.5 hours with my SpO2 levels climbing from low to high even though there aren't events or resistance.

6. I do have drops when I have small leaks that the software indicates is okay.

I can see each morning what the sleep is doing.

[SleepyCPAP]

Wow sleepy1235, that's great that you are checking.

Are you noticing you feel better on nights with fewer (or less severe) O2 drops?

-- SleepyCPAP

[chunkyfrog]

The oximeter is fun to use when exercising.
When I start feeling draggy, the pulse rate goes up and the oxygen drops.
Pursed lip exhaling raises the oxygen while lowering pulse rate; and I feel better as the numbers improve.
Coolest toy ever!

[JDS74]

... 2. You can see the relation between AHI events and drops in SpO2. Not a very good correlation at all.
For example: Did the SpO2 drop each time my sleep software decided I had an event? The answer is no. In fact mostly not.
For example: Did it report an AHI event each time I had a big drop in SpO2. The answer is no. In fact mostly not.

That's why home pulse-oximetry is not diagnostic in nature. There are too many variables for the data to be completely reliable. Apnoeic events need to last quite a while before they show up in the SpO2 data. Or they need to come in clusters that don't allow you to recover from the air interruption. Try this experiment: with your pulse-oximeter on, take a breath, breathe out, then stop breathing (that's what a central apnea looks like) and see how long it takes for the SpO2 level to respond. In those conditions, you will likely feel like you 'have to' take a breath before there is much of a reaction.

That said, it is a good indication of what is going on. If you are getting consistent drops in SpO2 levels that last for a while, it's a good topic to talk to your doctor about.

There are quite a few things that can make the SpO2 report way off. If you compress your arm, the blood flow is reduced and the SpO2 in that hand reports a drop. If the sensor is not placed just so or moves in the night, same thing. In the sleep lab, they use a taped sensor on your finger so that they can be sure the readings are correct. They also can watch you to make sure other things are not interfering with the measurement.

Bottom line: its a good thing to measure but don't get carried away with the implied precision.

BTW I use my CMS-50F oximeter quite a bit and try to correlated the data with that coming from the machine.

[stillsleepdeprived]

Thanks for the informative post.....What is the best and most economical Oximeter to purchase? I have been doing research and there is so much information its hard to make a decision. Thank You!!

[Pugsy]

most economical Oximeter to purchase?

Probably the CMS 50 DPlus...the Plus is important as the regular 50-D models don't records all night.
EBay or Amazon sellers from China are probably the cheapest.

The "best"...is whatever suits your needs.
You can start looking here
http://www.pulseoxstore.com/Downloadable-Pulse-Ox.html
This is where I got my CMS 50 D Plus...costs a little more but Kevin is real good to point you to the exact software that is needed.
Since I knew going in I would only be using it randomly and rarely...the finger thing didn't bother me.
There are other more expensive models that do more and maybe wireless and have a different attachment to the finger but this one suited my needs.
I had no intention of wearing one every night.

[icipher]

most economical Oximeter to purchase?

Probably the CMS 50 DPlus...the Plus is important as the regular 50-D models don't records all night.
EBay or Amazon sellers from China are probably the cheapest.

The "best"...is whatever suits your needs.
You can start looking here
http://www.pulseoxstore.com/Downloadable-Pulse-Ox.html
This is where I got my CMS 50 D Plus...costs a little more but Kevin is real good to point you to the exact software that is needed.
Since I knew going in I would only be using it randomly and rarely...the finger thing didn't bother me.
There are other more expensive models that do more and maybe wireless and have a different attachment to the finger but this one suited my needs.
I had no intention of wearing one every night.

I just ordered this, thanks for the recommendation.

What numbers are you seeing on this one?

[sleepy1235]

1. I have a resmed adapter for the S9 Elite. I can't say it is the best out there, but it did cost me some money.

2. JDS74 claims are hard to respond to since I don't know what he is claiming specifically and makes many general assertions.

The oximeter I have is embedded in a rubber sleeve which fits snuggly on a finger and doesn't move. I think it is just as good as the oximeter tapped to my finger in a sleep study and more comfortable and you or your insurance company isn't being charged a fortune for a rather simple measurement.

The AHI events simply don't correlate with SO2 drops. It is a simple observation of facts, not "carried away." I am having SpO2 drops without AHI events.

The whole point of the CPAP machine is to maintain the SpO2. The SpO2 is the final output. Low SpO2 is what is supposed to be waking us up and causing us not to get the sleep. So the SpO2 is what is relevant.

People with Apnea can be walking up 30 times an hour. That means the time scale of an Apnea event is roughly 2 minutes or less from stopping breathing to having an SpO2 low enough to trigger waking. It is simple mathematics.

There is a phase delay between an event where breathing stops and the SpO2 event is detected. But it is about 2 minutes.

When I say they don't correlate I mean an AHI event will occur and no SpO2 drop will follow.

Also, there will be an SpO2 drop and there will be no preceding AHI event.

I am an engineer and use data logging systems all the time. This system seems to be good. I think it is possible to get good information and not have to be paying some large fees.