{"id":339,"date":"2011-09-24T02:35:24","date_gmt":"2011-09-24T10:35:24","guid":{"rendered":"http:\/\/www.tranzoa.net\/~alex\/blog\/?p=339"},"modified":"2011-09-24T02:35:24","modified_gmt":"2011-09-24T10:35:24","slug":"playing-with-the-cms50e-pulse-oximeter","status":"publish","type":"post","link":"https:\/\/www.tranzoa.net\/~alex\/blog\/?p=339","title":{"rendered":"Playing with the CMS50E Pulse Oximeter"},"content":{"rendered":"<p>All devices are toys. So, I played.<\/p>\n<p>Here is a picture of the kind of waveform I would suppose you want to see from this device.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.tranzoa.net\/~alex\/blog\/images\/poxi_ok.png\" alt=\"OK pulse\"\/><\/p>\n<p>Fine, fine.<\/p>\n<p>Now, let&#8217;s start with the first thing that made no sense.<\/p>\n<p>Starting at, say, 96% SPo2 and doing a breath-out-hold, the SPo2 level goes up! Ditto, for the whole duration of a big-breath-in, breath-hold. The device&#8217;s 30 second lag confuses things. You stop holding your breath and start breathing &#8211; the SPo2 level goes down! Well, it&#8217;s just then reporting on the old, breath-hold blood.<\/p>\n<p>Big-breath-in hold is peculiar. The SPo2 level never really goes down, but the pulse rate can go from 60 to 80+. It appears that my body, if not yours, compensates for no air by simply beating the heart faster.<\/p>\n<p>Which brings up the really wild thing that this device showed about my body.<\/p>\n<p>Here&#8217;s the deal:<\/p>\n<p>After racing around <a href=\"http:\/\/www.mylongview.com\/parks_rec\/parks\/parks_lake.html\">Lake Sacajawea<\/a> late one night with Strom a couple months before going in to the <a href=\"http:\/\/www.af.mil\/\">service<\/a>, I had some ice cream and hit the sack. Soon, my chest felt very uncomfortable. It was plain that my heart had stopped beating. This can be disconcerting to an <a href=\"http:\/\/www.acetj.com\/features\/stupidnews.php?feature_id=23967\">18 year old<\/a>. I felt my pulse. Nothing. It lasted several seconds at least. Who knows. Time passes slowly when you think your heart&#8217;s gone south. Two lessons learned:<\/p>\n<ol>\n<li>Don&#8217;t eat ice cream before bed.<\/li>\n<li>If your heart stops, sit up.<\/li>\n<\/ol>\n<p>Of course, I wasn&#8217;t about to tell anyone about it. In fact, I pretty much forgot about it &#8211; but did remember the two lessons.<\/p>\n<p>Years later, Scott&#8217;s just born. Imani is at the hospital. I&#8217;m home and going to sleep. Maybe I had ice cream. Dumb, sure, but hey, the lessons may have slipped my mind under the circumstances. Anyway, guess what. Yeah. I sat up to fix the problem. Bit of a scare.<\/p>\n<p>Years later, I hooked up a heart monitor on the chance of seeing some indication of what was going on. Nothing. Still have a textbook-clean, ECG from <a href=\"http:\/\/www.physio-control.com\/\">Physio<\/a> in a drawer somewhere.<\/p>\n<p>Now, here&#8217;s the other half of the deal:<\/p>\n<p>Some time recently when going to sleep, I noticed a half feeling like the heart-stop thing. Not dramatic, but not normal. This has been going on for some time, but it had never really bubbled up to daytime notice.<\/p>\n<p>So, what does this <a href=\"http:\/\/www.contecmed.com\/paypal\/product_show.asp?id=23\">CMS50E pulse oximeter<\/a> display? A graph of heartbeat action. And it beeps when it senses a peak &#8211; at beat time &#8211; matching wrist-pulse and general senses perfectly.<\/p>\n<p>The other day, I was up at Mark M&#8217;s and got him to try the device. Maybe the device was bad. The SPo2 level didn&#8217;t drop below 94%, after all. But, on Mark, the device worked just dandy &#8211; the SPo2 number went down as one would expect, though delayed a few seconds.<\/p>\n<p>So, now what?<\/p>\n<p>I put the device on me and turned on heart beat beeping. Mark&#8217;s like: &#8220;What&#8217;s with that?!&#8221; The beeping could have been a random number generator. Not all the time. But some times. No logic to it, though I suspect that things even out as soon as I do something other than sit still. Anyway, I&#8217;d already seen it for hours the night before. Several seconds, no beat. 5 steady beats, miss a beat, 5 steady beats, miss a beat. Couple weak beats. Etc. Random. Weird.<\/p>\n<p>So &#8230; interesting. I&#8217;ll take the device for a walk as soon as it appears that the &#8220;kidney stone&#8221; can take shaking. (Postscript: Yes, erratic all the way around <a href=\"http:\/\/maps.google.com\/maps?q=http:%2F%2Fwww.tranzoa.net%2Falex%2Fgps%2Fhikes%2FMaplewood_00053.kmz&#038;hl=en&#038;ll=47.394195,-121.988797&#038;spn=0.025246,0.037766&#038;sll=37.0625,-95.677068&#038;sspn=59.50923,77.34375&#038;vpsrc=6&#038;t=h&#038;z=15\">Maplewood<\/a>.)<\/p>\n<p>Here&#8217;s a waveform without much flatlining:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.tranzoa.net\/~alex\/blog\/images\/poxi_rough.png\" alt=\"Rough Pulse\" \/><\/p>\n<p>And, that&#8217;s not the only oddity.<\/p>\n<p>How to get a solid 99% SPo2 instead of a wimpy 97% or 98%? Just sit there bouncing a leg on the toes.<\/p>\n<p>And:<\/p>\n<p>Speaking of toes. The device works on toes as well as fingers. That&#8217;s nice, since you can&#8217;t type with the device on a finger. Coding <a href=\"https:\/\/www.tranzoa.net\/tzpython\/tz_cms50.py\">tz_cms50.py<\/a> involved a lot of un-clip\/clipping.<\/p>\n<p>So, what about the code?<\/p>\n<p>Another post, is what.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>All devices are toys. So, I played. Here is a picture of the kind of waveform I would suppose you want to see from this device. Fine, fine. Now, let&#8217;s start with the first thing that made no sense. Starting &hellip; <a href=\"https:\/\/www.tranzoa.net\/~alex\/blog\/?p=339\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,6],"tags":[],"class_list":["post-339","post","type-post","status-publish","format-standard","hentry","category-bloggy-things","category-product-reviews"],"_links":{"self":[{"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/posts\/339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=339"}],"version-history":[{"count":23,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/posts\/339\/revisions"}],"predecessor-version":[{"id":362,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=\/wp\/v2\/posts\/339\/revisions\/362"}],"wp:attachment":[{"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=339"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=339"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tranzoa.net\/~alex\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}