Post
by Ric » Sun Apr 09, 2006 10:22 am
I have the Nonin Onyx 9500 model. I consider it very accurate and reliable and easy to use. I too wish it would store the results to dump into a computer. I'm not sure how much better the 9550 model is compared to the 9500.
I have informally "calibrated" it against the two other pulse oximeters that I have, (Nellcor N-200, Nellcor N-395) and get essentially the identical values under all conditions, and across a range of test subjects (mostly friends and relatives). If there was a difference in the numbers I would consider the 9500 as probably more accurate because it incorporates their newest technology (the laser diodes and interpretive algorithms).
I don't use it as much as the few months after I got it. But what I learned was VERY informative. If I do a spot check at night when the APAP is doing its job, it's always 98-100. On my sunday morning jog (usually about 15 mi.) it stays a consistent 97-98. THAT was my first surprise after I got the "toy". I would've guessed the sats would take a hit. But nope.
The lowest readings I've seen were after a nap without the APAP and I awoke "gasping for air", (something I am quite familiar with). Lowest value I've seen was 88. Which considering it takes a minute or so to pick up the oximeter and get a reading. A continuously recording oximeter might have shown a lower value I would suppose, just because a minute of gasping for air is going to improve the situation.
Interestingly, I get readings of 94-95 routinely while sitting in my desk at work and banging on the computer for several hours at a time (almost NO physical activity). A short walk up the hall and back puts it back in the 97-99 range. A committee where I am doing a PowerPoint presentation: 99-100. A one-way "teleconference" listening to a speech by the new CEO: 94-95.
Another surprising finding early on, I just HAD to know, that gasping suffocating feeling when you run up twleve flights of stairs. (I work in a tall building). I was SURE this would drop the O2 sat significantly, and thus explain the feeling. The surprise, O2 stayed 98-99 the whole route, across several attempts, across several test subjects (myself, my 2 kids, and about 5 co-workers). My conclusion: that suffocating feeling is probably a "hypercapnic surge", a flood of CO2 due to sudden activity and before the system has had a chance to adapt. (my theory only). I don't consider this "study" to be very scientific. But at least it was informative. This would be hard to do with anything but a portable finger pulse oximeter.
I took it with me while running 2 marathons in the last few months and found (surprisingly) sats stayed in the range of 97-99 the whole route, even when I thought I was near "hitting the wall" as they say. Apparently O2 is not the limiting factor, at least for me. Probably just "out of gas", i.e. sugar. (Or just poor protoplasm). .
I got my Nonin on eBay for under $200, and some ferocious bidding. The older technology Nellcors I also got on eBay for about $30 ea, hospitals are dumping these routinely. But if you get one of these older units be SURE to get a cable with it, otherwise you will find a new cable is more expensive than the machine. (I have since misplaced/lost the N-395 cable, I'm thinking of making one from parts which are readily available, rather than spring for $100+ from the rip-off DMEs). These bedside units CAN be interfaced to a computer. Several here have done that. (Nighthawkeye?)
