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Need a Multi-Session Recording Oximeter that Won't Die
Need a Multi-Session Recording Oximeter that Won't Die
I realize that there are past threads that discuss or review oximeters.  However, I would like to have some updated input with particular concerns regarding my experience with defective Contec 50IW units.

I really wanted to use my oximeter to correlate O2 and HR data with my periods of hypercapnia when using the AirFit P10.  But unfortunately my two Contec CMS50IW oximeters no longer worked.

I had bought these because after being diagnosed with OSA myself, I began to look very carefully for it in my patients and back when it was harder to get a sleep study for a patient, or when some patients were a bit resistant to doing an in-house study, I would send them home to get 3-5 days of oximetry recordings to at least screen them for OSA. I made up an instructional guide for them and found that the results were often quite useful.  I would also screen them when they had had a sleep study some time ago and were told they had "mild" OSA, but I clinically suspected that apnea might be interfering with my treatment of their mood or anxiety disorder.
But when I pulled out my oximeters I found that they no longer could hold a charge and when plugged in to the USB charger the display was so faint it was not usable.  I contacted ContecMed and just got this reply:

hi friend, all CMS50IW has the problem, the screen is burn in , you need change the screen again, thank you 
please send the machine to my company remove the old screen, but you need pay the extra fee, thank you

So that was rather disappointing.  I know that others have written about the Contec CMS oximeters, particularly the CMS50F.

I would like to know if others have had problems with loss of battery charge or dimmed display with their CMS recording oximeters.  Mine were about two years old, but with only light use during their lifetime. 

Better yet, do others have recommendations for newer technology.

I think the best would be a product that wirelessly ports to your smart phone since then all the battery, display and software will be from the phone, which should be much more reliable, than in the cheap unit itself. (I think I have seen one for Iphones, but I use an android phone.)

Anyone have any input on either of these devices:
iHealth Air

I'd really like to get something to use incase I do more CO2 readings, and to use with patients, but I don't want to pour money down the drain for unrealiable stuff.

Any recommendations would be appreciated.
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RE: Need a Multi-Session Recording Oximeter that Won't Die
Might I suggest you contact my go-to guy for pulse oximeters -- Kevin Cooper at Supplier #19 in the supplier list in the top menu bar. He is knowledgable about pulse oximeter issues and provides excellent advice and follow-up customer service.

The only Contec products I have had issues with were ones purchased from out-of-country vendors -- namely China. 

I am puzzled about your use of a pulse oximeter in connection with Hypercapnia which is CO2 retention --  normally measured using arterial blood gases. Do you show O2 desaturation or abnormal heart rates during these episodes? Also, since pulse-ox units are error-prone with certain heart arrhythmias and physical movement, how do you screen out the artifacts? Wouldn't SleepyHead give you more insight into what was happening during sleep? 

As for the use of a pulse-ox with patients as a screening device for OSA, I thought that was not recommended because it was so error-prone and the results inconclusive.
"The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." -- Marcus Aurelius
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RE: Need a Multi-Session Recording Oximeter that Won't Die
My two Contec CMS50IW units also came from China, directly from the manufacturer.

Regarding the use of an oximeter while tracking CO2, I am not measuring arterial CO2 or even end tidal CO2, but rather  I am detecting intraluminal CO2 as a way to detect if the AirFit P10 nasal pillows vents obstruct during rain out conditions.  This results in rebreathing and a precipitous rise in CO2 as measured at the junction of the P10 short tube and the supply hose.  Please refer to my other thread for more details:


The reason I wanted to concurrently track O2 is that I have read that when the inspired CO2 reaches 40,000-45,000ppm there is the danger of displacing O2 at the alveolar level, so I was just interested to see if there was any evidence this might be occuring. Obviously this lacks precision of a medical grade oximeter, but it might detect gross abnormalities.

Technically, I suppose it's incorrect to use the term "hypercapnia" since I am not directly measuring arterial CO2, but I think its probably safe to infer that the CO2 is raised when the inhaled CO2 reaches these levels.

Regarding the use of the oximeter to screen patients.  While it is not fully reliable, I thought it was useful in patients that were having difficulty getting referred to get a sleep study ordered by their gate keeper MD (was more common when insurance only covered in house studies), or when they have had studies and were told they were normal, or only had mild OSA and I wanted to see if there was any evidence of emergent OSA or worsening.  In the patients that had prominent abnormalities on their screenings, they have subsequently almost always had positive sleep studies in my experience.  Others are equivocal, and there may be some false negatives, but these have often been patients who already have had sleep studies, and I am just exploring why their depression, hypomania or anxiety is not improving with usual treatment.  

I haven't used the oximeters recently since it is easier to get studies for people now days since doctors seem more aware of the risk of OSA and insurance now seem to often pay for take home studies. That's why, when I checked them after a prolonged period I found neither of them worked any longer.
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