OXIMETRY - Interfacing the CMS50 with your CPAP Therapy

[4betterO2]

(CPAP here is meant as a general term, covering APAP, straight CPAP, Bi-Level/Bi-Flex, ASV and any such assisted ventilation therapy for home use)

Oximeter Basics:
The purpose of CPAP therapy, effecting optimal ventilation, is to oxygenate the blood. But our CPAP machines do not measure that result, so more and more PAP users are turning to oximeters in order to see their blood oxygen levels.
The CMS50 series is the most prevalent oximeter for home use, and comes in several models (with different letters at the end od CMS50).
Its data is uploaded and shown by the SpO2 Review software, normally shipped with it or downloadable from cpap.com, pulseoxstore.com or other sites; make sure you download the version for you particular OS version, apparently they are not interchangeable.
Note: the cable supplied is a UART cable at one end, not a true USB cable; the right version of SpO2 will automatically load the UART driver software, and you will see it in your Device manager under COM ports, if you want to verify it's loaded.
I would recommend to have no other software running when doing the install, do it with administrator rights, and then reboot the PC twice in a row, for optimum results.

How to get nighttime data recorded:
Use your CMS50 all night long in "Record on" mode, do not turn that off when getting up during the night, just take it off your finger then put it back on without stopping the recording.
That's because each time you start, or restart, a recording session, all previous data will be erased, so you have to keep it recording.
When you get up in the morning, turn the recording to OFF, to give you clean data; if let's say you kept the recording on, but waited 1 hour to get it into your computer, you would then have a long artifact at the end of your wave...

How to get your CMS50D+ data read on the PC:
__the CMS50D+ must be ON; (but NOT recording!) - an easy way to ensure that, is to got to the menu and leave it there, with nothing selected.
__load the SpO2 Review software, (the green SpO2 icon),
__plug the device on the PC using only the cable supplied with the CMS50 , no other USB cable,
__open new session (click on the magnifying glass icon; note the filename you give it!)
__see when the software says the device is connected, - a second or two later it will signal it is loading the data.
__when finished, turn the CMS50D+ OFF; an easy way to ensure that is to read your pulse, with your finger in the unit, then take your finger out
__after looking at the reports, click on the magnifying glass icon to end the session, don't forget to save your session.

SleepyHead also uses data from the CMS50 series.
(AFAIK the cheapest data-storing model in that series is the CMD50D+, you know right away if you have one as you can see its USB mini port - though it may come in a box labeled simply "CMS50". If you have another CMS50 data-recording model and the statements here do not apply, please add that information)
In my experience, SleepyHead did not pick up data from the device directly, but it did load the needed .spoR data file from the \SpO2\Data directory of the SpO2 Review software, where you have (hopefully!) saved your last session. (if you did not save it... that data will be erased on the CMS50 when you start your next recording session)

INTERFACING OXIMETRY WITH CPAP THERAPY

First, software tech support question:
How to synchronize the CMS50 data with the PAP SD card data, in SleepyHead, Encore, or other viewers?

Then, comes the essential part, understanding the clinical impact:
How to interpret the SpO2 data, in itself but especially, in how it relates to your CPAP therapy data, for greater understanding of its effectiveness, of new needs you may develop, and of the impact settings changes may have, etc...

[Turning to the experts ]

From the creator of SleepyHead software:

Oximetery is quite complicated at the moment, mainly because they use a serial protocol, and there is quite a bit of stuff to do to get that to work.

Most of the current code is designed for the CMS50D+

Now I've got a new CMS50F, I've got quite a bit of work to do to make them behave properly (has a different transfer protocol). Hopefully along the way I manage to find a way to simplify things a bit.

Unfortunately oximetry will always be tricky to get to sync with CPAP data.. It requires both devices (CPAP & Oximeter) starting to record at the same time, and then the following morning, having CPAP data imported first, then the oximetry, which will pick up the start time from the CPAP data.

Part of the UI confusion is there are three methods of importing data, 1) from data files saved by the Windows SPO2Review software, 2) Live Serial view (connected to a running computer with a USB cable all night), and 3) Serial Import, which reads from the devices internal memory.

The Date edit stuff is so the oximetry sessions can be manually adjusted. Maybe a little "advanced" checkbox that pops that stuff up will help.
The Reset button after the date is just to undo changes made to the date when editing re-opened records.
Best to avoid those Date settings if you are using the start-at-the-same-time sync method.

SpO2 & Pulse shows the maximum pulse and lowest SpO2 %, and the little "Save" disk button writes the open oximetry data to a SleepyHead session record.

The Serial port/Rescan ports is needed in case the device is plugged in after SleepyHead starts, as Serial ports don't automatically send a device connected signal. (I could in theory just keep scanning while there's no oximetry device detected, and the user is in Oximetry page, but the drop down is still needed for users who use multiple USB/Serial devices)

Suggestions on how to improve the User Interface in Oximetry are very welcome

[4betterO2]

P.S. The original post will be edited further as new info arrives, to summarize it, (with proper crediting).Sorry I can't write more info on the topic at this time as I'm a newbie myself . It is useful to users across CPAP machine types and brands... I'm hoping it will receive more info and will become a sticky, so CPAP users who want to start oximetry can jump to it?

[cosmo]

No need to merge everything. I just keep the programs separately side by side. Easier for me to read. I have dual monitors so its no problems having multiple large windows open.

Obstructive apneas always boots me into light sleep if I'm not already in there or wakes me up.

[4betterO2]

No need to merge everything. I just keep the programs separately side by side.

Software tech support
Yes you can correlate the two because you are getting real clock-time values, at least in the Flow Rate if I'm correct?
(Are those real clock-time values, or some point from 0:00 during the duration of the graphed period?)
The data I get from my ASV has a totally wrong time, do you know how that can be fixed? ...It makes me look like I sleep during the day!
But it wouldn't be a problem if I could simply change the time data correspondingly to it, in the SpO2 Review... How to do it?
Or can you change the time zone on the CMS50 device? which model do you have? I use a CMS50D+.

btw, I see you use the SpO2 software to view the data, and you are using the XP version.
Using that same version, under XP SP3, I found that the SpO2 values, when shown in the SpO2 Review program, were about 10 above the real values (I had looked at my finger quite a few times during the recording). On the other hand, when picking up that same data file from the Oximetry icon in SleepyHead, I did get the real values....(?)

Clinical interpretation
I would like to see your flow rate at 9:57 to correlate with your SpO2. I've had spikes like this where the O2 falls very low, and at the same time the pulse rises up a lot. Do you know what that means? How does it affect your body?
It happened 1 minute after an OSA event, in your graph. But was the O2 event due to that, or was from an other circumstance, like, turning over in bed?

[4betterO2]

Here is a SpO2 image that I hope someone could help me with?
I see this big drop of O2 before the black line, which is when I woke up and took the finger off the CMS50D+.
Is this plunging period representing REM sleep?
If so, is it normal to have such a deep drop during REM sleep? How serious does it look?
I was not using my machine that night.

[HoseCrusher]

The drops at 1:25 and 1:35 should be the ones you need to focus on. In general you want to maintain your oxygen at or above 90%.

The huge drops at around 1:43 look like the oximeter was moving around on your finger and is probably an artifact and the data ignored.

[4betterO2]

The huge drops at around 1:43 look like the oximeter was moving around on your finger and is probably an artifact and the data ignored.

Thanks for your input! What I'm wondering though, is I have seen this pattern for several days, a huge drop lasting several minutes up and down, sometimes longer than on this graph, just before I wake up, and usually, I wake up from a dream. Is it usual for people to move around so much, as to disengage the CMS50, when dreaming or before waking up? I do find the CMS50 properly placed when I wake up. Or is it REM sleep, -- does the REM sleep period happen usually last, before waking up? (Sorry I know so little about noraml patterns of sleep)

[Pugsy]

does the REM sleep period happen usually last, before waking up? (Sorry I know so little about noraml patterns of sleep)

REM can appear to happen last depending on when we wake up.
We actually go through multiple sleep cycles each night.
http://en.wikipedia.org/wiki/Sleep
Look over at the hypnogram on the right below the sleeping kid for typical sleep pattern.
Of course number of REM cycles is also going to depend on how many hours of sleep we get.
As the night progresses we have more frequent episodes of REM and they tend to last longer with the most REM occurring in the wee hours of the morning. If someone happens to be an early riser it is very likely that REM might be the last cycle before they wake up.

[Slartybartfast]

Wow! Those are freakin' HUGE excursions! I've never seen anything like that. What jumps out to me from that is the question why isn't your heart reacting to the oxygen desaturations. It's just ticking along at 75 +/- 5 beats per minute. Just for grins, sit yourself down in a chair and strap on your oximeter and note the oxygen level and heart rate. Then simply stop breathing. Don't take a deep breath and hold it, just stop breathing and watch what happens. If you're like me, you'll start seeing spots before your eyes as the SPO2 drops below about 85%, and your heart rate will be soaring. Ok, you can breathe now.

Is a puzzlement.

[Jay Aitchsee]

Here's how I do mine - I simply snip the reports I'm interested in and paste them into a draw program (I use Open Office). In the draw program, I size the snips so that the time lines are equal and align. This allows me to correlate an event from one source to another. For the CMS 50, which doesn't have a real clock, I create artifacts (by puttiing it on and off) at noted times at the beginning and end of the recording. Then I size the CMS 50 time line so that the known times of the artifacts match the other reports.

Here's an example from the build a lab thread in my signature viewtopic.php?f=1&t=68747&p=638020&hilit=+build#p638020

[Jay Aitchsee]

And here's a bit of different look. Same idea.

Liz, if you're watching, I thought you might be interested in this. This is a shot of a night where I got a little more deep sleep. The Zeo reported 17 minutes, but the default graph (in the middle) only shows about 5. Curious as to where the rest of it was, I downloaded the detailed data and graphed it (in blue). The detailed data is in 30 sec intervals. The default graph is in 5 minute intervals. The downloaded info is kind of a mirror of what we're used to for sleep graphs but you can see the legend.

Anyway, there's my deep sleep right where it should be at the end of the first sleep cycle before REM. Only problem is that it is fractured. Any duration would have to be longer than 2.5 minutes to show up on the default graph. Finally, toward the end of the night I get some fairly uninterrupted deep sleep.

Before Zeo, I thought REM was interrupting my deep sleep, but clearly it's not. Doesn't appear to be apnea either. I didn't show it, but there are no leaks or abnormal pressures during this time. So...? Maybe pain?

BTW, the download part is easy. You just select "export data" from the website and you get all the data to date that you've uploaded.

Jay

[HoseCrusher]

The next step in evaluation is to zoom in on a 10 or 1 minute time frame and take a close look at your saturation line. If you see gray segments it means that the oximeter lost signal and it is an artifact. Zoom in and let us know what you see.

[torontoCPAPguy]

Looks just like mine before I got an oxygen concentrator and started infusing O2 into my air stream which kept me above 90% all night. What is happening is likely that as you enter REM you are awakening, likely without knowing it, and your oxygen level is increasing due to deeper breathing. REM will also create apnea events which you need to analyze, but to me, you are in urgent need of supplemental O2 infused into the airstream at night to keep you up around 95%. Your sleep will be sounder, your BP during the night will not spike as it most assuredly is; your pulse rate will be steadier as an indicator.

If you are not sure of this, you need to get in for a sleep study asap. Your are in stroke territory here. No question. The lower SpO2 will raise blood pressure (I have just worn a BP monitor for 24 hours to check mine out).

Nothing to be guessed at nor played around with. Tonight I suggest that you tape the CMS50 to your finger with blue masking tape to ensure it remains steady on your finger (I do it every time I check SpO2).

I am at the point where I can look at my blower and see it at 0,0; so I check myself out only periodically. HOWEVER, I have regular ECG's, regular bloodwork, etc. I keep close watch of what is going on with my body. And you want to be doing the same. The best oxygen concentrator I have found thus far is the one I list in my signature. It is quiet and has a monitor built in as well as a manometer.

Educate, Contemplate and Advocate.

[4betterO2]

Bump - please ask your oximeter questions on this generic, centralized thread, so answers will be easy to find, for others to benefit from! Thanks

[cosmo]

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