OXIMETERS

[Severeena]

It seems the test I was to have last winter was a flop due to the fact my data was eaten up by a bad program. I have been bugging these people as to when I would finally have my test and still no software yet and it has been over 8 months.

My hubby wants to get me my own Oximeter so I can find out if I need O2 at night or not.

I would like to find out which Oximeter is the best for the money.

Thanks in advance.

[SleepLessInKansas]

Any insurance?

[Severeena]

Yes, but they will not pay for the machine since this was to be an in home study which failed misserably of the part on the equipment.

I even sent the machine into a frantic tizzy when my bp set the alarm off for going way to low.

[SleepLessInKansas]

I'd check ebay or yahoo. I didn't see any on yahoo, but I may not be searching on the right word. Are you wanting to wear it all night and download the results to your PC?

[Severeena]

I saw one when I was searching that wasn't expensive and it even gave a print out.

You have to wear it all night on room air only.

I will check e-bay.

[snork1]

A very popular one seems to be the Nellcor N-395.
I picked up mine on Ebay for $260 with cables and sensor. It records the full night, which can be viewed on its display, but isn't set up for printout or download without extra effort and dollars.

I am still working on putting together cables and software for downloading to a computer.

[Bingo]

If you currently have a relationship equipment provider, I would check with them.

Often they will loan one out to a patient for a night or two at no charge.

Not a guarantee of course, but it's worth a shot.

However, if you do not currently have a relationship with one in your area, I doubt any of them would but you could certainly try.

Bingo

[snork1]

If you currently have a relationship equipment provider, I would check with them.

Often they will loan one out to a patient for a night or two at no charge.

Not a guarantee of course, but it's worth a shot.

However, if you do not currently have a relationship with one in your area, I doubt any of them would but you could certainly try.

Bingo

This is a good point that if you only want it for a night or two, you can ask your doctor and they will often have a "courtesy" deal worked out with a local DME for a free loaner if the data is going directly to the doctor.

For my own use, I wanted to get trends and have it for long term "experimentation" as I attempt to get off of CPAP and into a dental apnea device.

A pulse ox is not necessarily the most user friendly device for figuring it out and reading it.

[Guest]

Try capturing o2 data with digital camera hooked to computer taking a frame every 6 seconds. when view in a file folder preview you could pick out when it varies. I think the cameras are from $10 to $90. the cable length could be a problem.

[snork1]

Try capturing o2 data with digital camera hooked to computer taking a frame every 6 seconds. when view in a file folder preview you could pick out when it varies. I think the cameras are from $10 to $90. the cable length could be a problem.

I think the cable length is the least of the problems with this idea.......

[Guest]

If you can get your DR to order a nocturnal oximetry and send it to a DME company, they will do the test for free. It is not a billable service. There should be no charge to you for that service.

[brasshopper]

The Nellcor 200 is about $200 on eBay with preamp cable AND reusable sensor. They are frequently less. They seem to be old workhorse devices.

They supposedly have 12 hours of memory that can be dumped out through a nine pin serial cable. I have not yet tried to access that memory. I have managed to make the serial port work.

I bought one on eBay. The preamp cable and sensor cable that came with it were both overly sensitive to movement - any twitch of the hand being monitored would make the readings go nuts. The company replaced both the preamp cable and the sensor and this one seems not affected by normal sleep movement. It can be dislodged, but a velcro strip holds it in place fine.

I had what I thought was the right cable - a male-female nine pin - got it to plug in by breaking off the screws on the N-200 end since they interfered with it being plugged in at all - anyway, I plugged it in and nothing came out.

I read the manual that is online for these meters and I have also looked at their cable pinouts. I originally could not understand whether they were claiming that they are DTE or DCE (Are they trying to look like a computer or a modem?) since they had both pinouts and I allowed myself to be confused. Normally, a modem uses female connectors, as this device does, and a computer uses male connectors but I bought the right cable for connecting a computer to a modem and I could not get it to work. I found a reference somewhere that made me think that this device uses a DTE pattern connector but with female connectors - in order to talk to it, I need a MALE-MALE 9 pin straight through connector and a null modem cable.

Which I happened not to have around.

However, it is not impossible to build this cable - with an old cable and a soldering iron. Which I did have around.

If people want me to, I will offer people a package of a comm cable and and simple software that they could use to track the readings all night into a computer, laptop or regular computer with a serial adapter - it will deal with time issues and so forth. You can certainly get a USB-Serial adapter on eBay or (for three times as much) at CompUSA - or your system may have a serial port - it will not be cheap - see me by PM if you are interested. It will, of course, include remote help, including my remote access to your system if needed to fix it. It will be for "amusement" - if you decide to use this for medical purposes, you are on your own. (Yes, I find it amusing - the beeping sound reminds me of the Weird Al song Like A Surgeon.)

I have read some claims (in the manual, probably trustworthy) that there are lots of data being recorded in the device. There are also some switches on the back that seem to control things - for a while, I thought that the switches would allow me to switch the RS232 interface from DTC-DCE, but that seems not to be true. I have not tested these memory claims yet - but I have been able to get the following to work.

I took an ordinary male to female 9 pin serial, used for attaching a computer to a modem with a 9 pin female serial cable and I cut the wires in the cable (some of them, not all) swapping

2-3, 4-6, and 7-8 - that is, 2 on one side was connected to three on the other and vice versa.
4-6 was cross connected - same deal, 4 on one end connected to 6 on the other and vice versa.
7-8 also cross connected same way - 7 on one end connected to 8 on the other and vice versa.

These connections were all isolated - no three way connections were used - Some null modem cables use them but here they do not seem to matter.

Other wires would include ground and RI - I allowed those to go straight through.

I also modified the cable as I mentioned above - wrong gender == wrong screw position - I just have the cable plugged in without screw support at this point, eventually I will do something.

This is close to a standard so-called null modem cable. But you can't just buy such a cable because it won't work - generally null modem cables are female-female and the gender on the N-200 is also female. (To make it clear, males plug into females but males do not connect to males and females do not connect to females.)

Maybe a null modem and a 9 pin straight through male-male gender changer could be combined. I have not tested that. The above setup works for me.

Once I built the above cable, I turned to configuring the N-200. There are two banks of dip switches. I left the bank of 2 switches set up-up - I believe that they work for analog output - like an Analog to Digital or a strip chart recorder.

The other dip switches are in a bank of 8. I set them as follows:

Code: Select all

1 up 2 down 3 down 4 down 5 up 6 down 7 up 8 up 

(which should mean adult defaults, (1)
long output format, ( 2 - 5 )
pin six no meaning, (6)
7-8 up for 19200. ( 7 - 8 )

19200 used to be fast serial, now it is slow. With today's computers. I would suggest that 19200 is the best speed - YMMV. If you see random errors, then cut the speed down. If the errors go away they were speed related - but seriously, once 19,200 was blazing - back in the PC/AT timeframe. Now it is not.

Anyway, then I wanted a quick and dirty program to see what was happening and to capture the output from the N-200, if there were any. I started hyperterminal, which is a standard windows program that allows you to communicate with a serial interface in a simple manner. If you have installed it, you should find it as Start->all programs->accessories->communications->hyperterminal. If you can't find it, use help to determine how to install it in your system.

Anyway, I determined that the USB-Serial connector had been configured as COM4 by looking at the hardware map in control panel->system->device manager->ports and then I had what I needed to configure hyperterminal.

I told hyperterminal to connect to COM4 (in my case) using 19200, 8-N-1, hardware flow control (the rest of this corresponds with what I read in the manual for the N-200).

I plugged the box in, power cycled it, and it started spewing forth messages such as

Code: Select all

17:14:08  MONITOR:  RATE = 00 %O2 SAT = 79 PULSE AMPLITUDE %FS = 06
          MONITOR STATUS: NORMAL, ECG NOT IN USE
*         ALARMS ACTIVE:   LOW RATE    LOW SATURATION
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:14:21  MONITOR:  RATE = 00 %O2 SAT = 80 PULSE AMPLITUDE %FS = 10
*         MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
          ALARMS ACTIVE:   LOW RATE    LOW SATURATION
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:14:30  MONITOR:  RATE = 40 %O2 SAT = 86 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
*         ALARMS ACTIVE:   LOW RATE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:14:42  MONITOR:  RATE = 57 %O2 SAT = 95 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
*         ALARMS ACTIVE:   NONE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

After it had been operating properly for a while, it then had messages like:

Code: Select all

17:21:00  MONITOR:  RATE = 73 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100

17:22:00  MONITOR:  RATE = 71 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100

17:23:00  MONITOR:  RATE = 78 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100

17:24:00  MONITOR:  RATE = 71 %O2 SAT = 97 PULSE AMPLITUDE %FS = 59

17:25:00  MONITOR:  RATE = 64 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100

17:26:00  MONITOR:  RATE = 68 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100

17:26:08  MONITOR:  RATE = 54 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: NORMAL, ECG NOT IN USE
*         ALARMS ACTIVE:   LOW RATE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:26:16  MONITOR:  RATE = 55 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: NORMAL, ECG NOT IN USE
*         ALARMS ACTIVE:   NONE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100
17:26:32  MONITOR:  RATE = 54 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: NORMAL, ECG NOT IN USE
*         ALARMS ACTIVE:   LOW RATE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:26:44  MONITOR:  RATE = 49 %O2 SAT = 96 PULSE AMPLITUDE %FS = 100
*         MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
          ALARMS ACTIVE:   LOW RATE
          LIMITS:  LOW RATE = 55  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:26:51  MONITOR:  RATE = 50 %O2 SAT = 96 PULSE AMPLITUDE %FS = 100
          MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
*         ALARMS ACTIVE:   NONE
*         LIMITS:  LOW RATE = 46  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:26:55  MONITOR:  RATE = 62 %O2 SAT = 96 PULSE AMPLITUDE %FS = 59
          MONITOR STATUS: AUDIO ALARM OFF, ECG NOT IN USE
          ALARMS ACTIVE:   NONE
*         LIMITS:  LOW RATE = 39  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:27:00  MONITOR:  RATE = 64 %O2 SAT = 96 PULSE AMPLITUDE %FS = 100

17:27:44  MONITOR:  RATE = 69 %O2 SAT = 97 PULSE AMPLITUDE %FS = 100
*         MONITOR STATUS: NORMAL, ECG NOT IN USE
          ALARMS ACTIVE:   NONE
          LIMITS:  LOW RATE = 39  HIGH RATE = 140  LOW SAT = 85  HIGH SAT = 100

17:28:00  MONITOR:  RATE = 70 %O2 SAT = 96 PULSE AMPLITUDE %FS = 100

17:29:00  MONITOR:  RATE = 73 %O2 SAT = 98 PULSE AMPLITUDE %FS = 95

You can tell, if you look, that there were a bunch of one liners, and that I then got a "low rate" alarm (I get them a lot) and then I reset the low rate.

The one liners seem to come out once a minute. There is a condensed format and some others. The point is that hooking this to a computer would allow you to quickly extract it with something like awk or something else into a spreadsheet or R format.

The N-200 manual is available online - I have a copy of it and, if you can't find it, please ask by PM and I'll put it somewhere that you can get to it.

Also, I do not believe it is possible for me to set the clock (I think it is possible, but it may take some gadget I don't have). In actual fact that does not matter. You can just record the computer's clock at the beginning of the run and at the end, and determine the time offset - if it does not change, then you can just apply the offset to all the reading times that the device reports. If it changes a small amount you can pick one and if it changes a large amount, you can, well, work from the end and the beginning looking for the reset. Or, if you are recording with a program, you can finx the time in real time.

Anyway, if nothing else, you could simply tell hyperterminal to "capture data" and get all the data from the device into a file - then post process it by whatever means you like.

Hope this helps someone. I am more or less interested in what my overnight lows and if and how they cycle are and this will allow me to capture that.

Finally, snork1, after reading all the side effects of dental devices, even under the control of dentists who believed that they were fully qualified to deal with the matter, I would only consider a dental device if I could not use a CPAP at all. But everyone is different. I've known people with TMJ jaw joint malfunctions and the pain that comes from that and, well, ouch.

[snork1]

[quote="brasshopper"]The Nellcor 200 is about $200 on eBay with preamp cable AND reusable sensor. They are frequently less. They seem to be old workhorse devices.

They supposedly have 12 hours of memory that can be dumped out through a nine pin serial cable. I have not yet tried to access that memory. I have managed to make the serial port work.

I bought one on eBay. The preamp cable and sensor cable that came with it were both overly sensitive to movement -....snip

[dsm]

<snip all>

Brasshopper, you are a gem. I have all the cable gear, break-out box, pin-out diags, comm-set up data & an N200 but lacked the time to just complete the wiring & begin analysing the output. You just saved me an enormous task - thankyou.

I also have several async comms programs (procomm zoc telix etc:) so have the software to do the comms interfacing & data capture (I designed & developed the async dial-in order taking software used by my employer - ZOC + Object REXX) Just in the throes of rebuilding that in RUBY & withe Ruby-on-rails, can turn it into to mysql data & web pages.

But - so much to do & so little time - it is a great relief to find you here who has the time, the knowledge, the expertise & the will to share.

I repeat, you are a gem

Cheers

DSM

[brasshopper]

...about taking boil-and-bite devices off prescription as has been done in England and, I believe, Canada. My discussion is here and it references the original discussions by the dentists who build them with the FDA panel.

Their basic argument is, "We are the best in the business and we get a ton and a half of side effects, there is no way that an end user, using an inferior device, can get a good fit and skip side effects."

For me, the real issue is, "Given all the side effects that they get, disfigurement, permanent deleteorious changes in the TMJ joint, undesirable tooth movement, loosening, and frank loss, jaw issues, and on and on, why are these things legal at all?"

Personally, given all the side effects described, and the percentages, I feel that you should only be offered this therapy if you completely fail with xPAP or have a lung disease that precludes CPAP and then you should have to sign a complete disclosure. YMMV. I strongly disagree with the first speaker who claims that dental appliances should be the first line therapy of choice - because their cost estimate does not take into account treatment of side effects.

Those are my opinions. Read through the discussion yourself and you might form different opinions. But you should read that frank discussion before you decide that this is your therapy of choice.

In any case, it sounds like you are going to the snoring dentist frequently once this is done, maybe every three months to look for the onset of permanent changes and the direction of those changes, and are they acceptable.

IMHO, you see the CPAP doc way less than the snoring dentist.