Anybody had problems with their CMS-60D?

[jnk]

Pardon me if I'm restating the obvious again, as I am prone to do.

Right batteries, fully charged?

Malpositioning of sensor? (Is the LED centered over the nailbed on the nail side?)

Wet fingers?

Ambient light?

Motion?

[-SWS]

Pardon me if I'm restating the obvious again, as I am prone to do.

Right batteries, fully charged?

Malpositioning of sensor? (Is the LED centered over the nailbed on the nail side?)

Wet fingers?

Ambient light?

Motion?

Good list. I'd like to add bifurcation to that list if I may...

[OutaSync]

Pardon me if I'm restating the obvious again, as I am prone to do.

Right batteries, fully charged?Duracell, brand new

Malpositioning of sensor? (Is the LED centered over the nailbed on the nail side?)Yes and yes

Wet fingers?only when my pulse gets high, then I sweat

Ambient light?Only ight from my laptop

Motion?

typing with right hand, sensor hand in lap
Good list. I'd like to add bifurcation to that list if I may...Excuse me, I was hoping you didn't notice

[quote="Snoredog I have to tell her Mom shut up for a few minutes so you can breathe. She says oh are my lips turning blue? um yeah..

[/quote]Now that's funny! I'll have to ask my son if he thinks I talk too much.

[-SWS]

Well, here's that issue with very short averaging time explained in English:

Most oximeters offer the ability to change averaging times. In anesthetized, non-moving patients, a short averaging time will allow for more rapid recognition of changes in saturation. Longer averaging times when the potential for error is present (such as excess ambient light or movement) will minimize error, but also mean that the monitor will not respond as rapidly to changes in saturation.

http://www.clinicalwindow.net/cw_issue_19_article1.htm

Not that short versus long averaging windows are inherently inaccurate---just that if meters are not averaging the same you are comparing apples with oranges. It would be like camera settings A versus settings B to record "eyes-closed time". Camera A snaps a picture every 8 seconds and camera B snaps a picture every 1 second. They will both capture "eyes closed' during naps approximately the same. However, while awake, camera A will capture ordinary eye blinks far less often than camera B.

[jnk]

Thanks, Bev. Sometimes my fuzzy logic just needs a little scratch behind the ears like that. If you're not anemic and have good circulation in the extremities and the light and sensor have been checked to make sure they are clean, I'm fresh out of ideas. Must be that bifurcation thingy, then.

I am VERY interested in how this lands, though. I have been considering getting that oximeter myself one day. Or the version, from the same company, that plugs directly into the computer.

[feeling_better]

Bev, -SWS sent a pm asked me to look at this thread for you. I just got home, have only glanced at the msgs.


This meter takes a reading and records it once every meter. When the doctor arranged for an over night one for me at home, that meter was doing once every 4 seconds (Nonen, I think); not sure if Nonen has a settable sampling rate, but cms-60d does not have only one sampling. The difference in sampling could show a lot of spikes at the faster sampling.

I do not know if cms-60d or the other meter does any averaging at all; ideally they should. But they may not. I had noticed that there was much more rapid changes for cms-60d when I did the comparison, and had discussed this in my previous msgs in the original review of this meter. Now I think, the Nonen may be actually averaging -- I was a bit disappointed that at that time the Nonen looked like it was not sensitive and responding well; perhaps that is needed over the long haul.

I have recently noticed that when sensor is making a marginal fit on the finger (in between good contact, and the finger completely off), the meter gives a lot of spikes, it should really show blank.

The red led should be on your nail side; somewhere closer to the place where the nail starts, not towards the nail end; that is where I was getting better readings. And another important factor is the pressure of the clip on the finger, too much and tool little both gives unreliable response. A little too much pressure would cut off the blood supply, it looks like. I could not compare any of these with the other lab meter. BTW, the pressure problem may be much more sensitive now that the temps has got lower.

You can try the following during day time (not in the recording mode). Adjust the position of the finger and the pressure and watch the up and down bar on the right. If it is not oscillating in regular rhythmic pace, you contact is not right. Try also warming up your hand, and keeping your finger surface slightly moist. After all that, your meter may still be not functioning correctly.

[-SWS]

One more interesting article:
http://www.sleepreviewmag.com/issues/ar ... -04_10.asp

Apparently 4-second and higher averaging meters are losing favor in sleep diagnostics----to more modern 1 and 2 second meters:

Faster signal averaging time is perhaps the most important new trend that manufacturers are incorporating into their new pulse oximeters.

Previous generations of oximeters had 4-second or longer averaging times, but now oximetry companies are producing high-resolution pulse oximeters (HRPOs) with 1- or 2-second signal averaging times.

Motion and SpO2 signal issues:

"The older oximeters achieve motion tolerance by averaging the signal, and in essence, averaging away these little desaturations that came from motion. When you do that, you run into the high-resolution problem and you're not high resolution anymore. So they have to have a motion-tolerant algorithm product."

For the highly technical crowd, here's one of the newer algorithms that is claimed to better accommodate motion:
http://www.pubmedcentral.nih.gov/articl ... tid=553999

Moral of the story: if your modern SpO2 meter shows more transient dips than your doctor's, it just may be because your doctor's meter uses the older longer averaging times.

[OutaSync]

Jim's pulse is reading 220 with O2 in the 90s. His hands are cold, but mine were warm went it went up to 240 for me. It does take a minute or so to settle, but I was wearing it for 15 minutes when it was doing that. I dunno. Jim thinks its worthless.

Oh, well, at least my apetite is back.

Bev

[-SWS]

Jim's pulse is reading 220 with O2 in the 90s. His hands are cold, but mine were warm went it went up to 240 for me. It does take a minute or so to settle, but I was wearing it for 15 minutes when it was doing that. I dunno. Jim thinks its worthless.

I agree that fifteen minutes is plenty long to get past any required settling time, Bev. I also think your meter is waaay out of spec regarding pulse measurement, assuming non-motion (see red text):

Pulse Rate:
*Measurement Range:25 ~ 250 bpm
*Resolution:1bpm
*Accuracy:(+/-)3 bpm (non-motion)
*Alarm Range:25 - 250 bmp
*Refreshing Rate:1s

These meters don't seem very motion tolerant according to feeling_better or the above spec requirement of non-motion. Sounds like yours is just bad, though. Bifurcated beyond all repair...

Oh, well, at least my apetite is back.

Hooray!

[ozij]

It's conceivable that you can exchange your CMS-60D meter for an identical CMS-60D with the same design characteristics and operating nuances.

Yes, I too was thinking that should be done.
O.

[ozij]

You may have a job where you do a lot of talking, that means while you are talking you may not be breathing. My 90yr old mother does that, she talks so much her lips turn blue from not breathing, I have to tell her Mom shut up for a few minutes so you can breathe. She says oh are my lips turning blue? um yeah..

Very good point!
I used to have a habit of talking till I ran out of breath, and then I'd pause, take a deep breath and continue, till I ran out of breath again. A Feldenkrais teacher of mine noticed it happening when I talked with her (that was about 30 years ago!), commented on that, I started breathing more and better while speaking and bingo - had far less headaches since!

It's no so much "shutting up for a few minutes" as it is being aware of the need to breath while you're speaking.

O.

[ca_hosehead]

I have a CMS 50F. I get some wild swings right when I put the device on, or when it loses signal for even a second. You can see in the on-screen report that the line turns grey for a moment, this indicates no signal. Usually 02 goes way low and pulse goes way high. It settles quickly, in about a minute.

Your variations are much greater than anything I've seen with my device and I don't see any loss of signal. I would check to make sure the LED on the finger probe is centered over the nail bed. Other than that, I think checking it against another device is the best idea.

Overall it doesn't look right. I don't see how 02 could be that low and heart rate that high and you don't notice anything.

You could also take your pulse the old-fashioned way and compare.

[mindy]

I'm curious about this - hopefully one of you can answer this one. I have the SPO7500 and from the directions, I am under the impression that this pulse oximeter is intended for sleep use primarily. It records % motion and the reports show that - does that mean the accuracy is affected by motion (such as would occur when awake & up and around)?

thanks,
Mindy

[feeling_better]

I'm curious about this - hopefully one of you can answer this one. I have the SPO7500 and from the directions, I am under the impression that this pulse oximeter is intended for sleep use primarily. It records % motion and the reports show that - does that mean the accuracy is affected by motion (such as would occur when awake & up and around)?

thanks,
Mindy

Bev, Mindy, I do not have any experience with spo 7500, but I know that -60D is EXTREMELY sensitive to motion. The most sensitive motion is when you even slightly flex the finger on which the sensor is (partially open/close the finger). I think this is because the blood flow changes at that time dramatically, and the normal very low blood flow changes as a result of the pulse is used by the meter to trigger measurement. I suspect even if you do not flex the finger, but swing the arm it probably will have similar effect. If seems that the 7500 identifies these wider flow swings in blood flow and tags it as motion, essentially warning that the other readings are not correct at that time.

You can easily test this by looking at the number as you flex your finger.

Bev, for the same reason, you get more reliable results when you are sleeping, ideally with the sensor hand under your blanket to prevent it from getting cold. If your wide varying results are all from day time testing, you may want to try even this particular model at night (and if your sleep study is soon, at that night too), before even returning the machine to get exchanged. Even at night at those times when you move around you are going to see big variation.

You can minimize the finger flex variations by gently taping the lead wire to back of your hand at two places. Remember finger twiches are much faster than 4 seconds, so an old fashioned 4-sec sampling meter would smooth those out (either unwittingly because they are too slow, or by design).

BTW, one can compute the 4 second average relatively easily. If I remember correctly, you can save the data in .cvs comma terminated format (for excel) and then simply average every 4, and plot. You would be very surprised how smoother it might get.

[OutaSync]

I do tape the cord coming out of the sensor to my finger so it doesn't bend and wrap the cord to my wrist with a velcro tape. At night I sleep with it under the covers and don't roll too much. That chart #3 above was from a period of time during hte day while I was sitting still at the computer. The screen showed my pulse going from 90 to nearly 200, rapidly changing, and yet the chart never shows it going that high. I should run a recording on my friend and see how his shows up. Right now it's hard for him to take this seriously when his pulse goes up to 220.

My charts follow pretty much how I feel. When the O2 dips, I feel like crap.

Good news, my DME is delivering a pulse/ox to my office this afternoon. Aerocare had it lined up in less than 2 hours. The DME that my Dr. called, APRIA, never returned my call, and when I called them, they said that they could not do 24 hour testing, only overnights. They didn't tell my doctor that.

Bev