LifeAfterDx--Diabetes Uncensored

A internet journal from one of the first T1 Diabetics to use continuous glucose monitoring. Copyright 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016

My Photo
Location: New Mexico, United States

Hi! I’m William “Lee” Dubois (called either Wil or Lee, depending what part of the internet you’re on). I’m a diabetes columnist and the author of four books about diabetes that have collectively won 16 national and international book awards. (Hey, if you can’t brag about yourself on your own blog, where can you??) I have the great good fortune to pen the edgy Dear Abby-style advice column every Saturday at Diabetes Mine; write the Diabetes Simplified column for dLife; and am one of the ShareCare diabetes experts. My work also appears in Diabetic Living and Diabetes Self-Management magazines. In addition to writing, I’ve spent the last half-dozen years running the diabetes education program for a rural non-profit clinic in the mountains of New Mexico. Don’t worry, I’ll get some rest after the cure. LifeAfterDx is my personal home base, where I get to say what and how I feel about diabetes and… you know… life, free from the red pens of editors (all of whom I adore, of course!).

Wednesday, May 23, 2012

A spectacular failure

Sorry, but this is why I don’t expect to live to see an artificial pancreas. As most of you know, I’m probably the #1 fan of CGM and I think they’re just damn fine 95% of the time.

Uh… but then there’s the other 5% of the time.

Like last night.

Let me tell you about my Night of No Sleep and why if I hear that fucking xylophone noise one more time I’ll scream.

The trouble started at 2:20 AM. Well, actually, come to think of it, I had some minor trouble shortly before midnight. And some in the late afternoon before that. But, well, let’s just say the real trouble started at 2:20 AM with a down slope alarm. And it just went to hell from there.

Over the next 45 minutes I had six alarms and watched a breath-taking drop in my sensor glucose on the mySentry monitor.

There was just one problem. My blood sugar was rock-solid around 160 mg/dL the whole time. Can you see it in the photo above? Sentry has me at 57 with two arrows down. The Fingerstick meter has me at 164.

What. The. Fuck.

Now usually when something bad happens like this, and it doesn’t happen often, it’s at the end of a sensor’s life, when your body has devoured all the little enzymes and stuff that make the sensors work. But this puppy was on day two. I checked the ISIG, the raw signal coming of the sensor. I expected it to be very, very low. Maybe a six or so, to give me sensor readings this low.


What. The. Fuck.

Sunspots? Cosmic rays? Static electricity?

Then, forty minutes into the debacle, with no calibration sticks or anything of the kind on my part, the tide went out again and:

The sensor glucose reversed itself and surged upwards. I checked the ISIG again:

Note the red plug in the now-neutered pump. That’s were insulin used to go. But Revel is not really endearing me as a stand-alone CGM. Especially at this very moment.

And then, one hour and two minutes after it started, Revel gave me this message:

Are you kidding me? First you wake me up to tell me I’m about to die of a low, and now you’re bitching at me that I’m above target?

What. The. Fuck.

Screw you, Sentry. I silenced the monitor, threw the Revel into the laundry hamper, rolled over, and…

…and couldn’t get back to sleep.


Blogger Jonah said...

You know, I think that's one major advantage to Dexcom... it says ??? instead of claiming I've dropped low when the sensor performance changes drastically.
I would feel way more comfortable with something like a low suspend with a Dexcom sensor vs a minimed one; my highest blood sugar ever on record (594) happened after I kept treating lows based on CGM readings.
Although I kinda wonder what's going on with your data, 'cause Minimed CGM, at least when I was using, just used an ISIG * a factor determined by calibrations, to get its SG. So sometimes twelve hours after a calibration I'd get an abrupt jump in SG as the factor changed. Maybe that happened here? Otherwise I'm very confused as to why an ISIG that's 3/4 of another ISIG showed a sensor glucose of 1/3 the the other one.

8:53 AM  
Blogger Wil said...


That confuses me, too....

8:59 AM  
Blogger Scott E said...

I'm not entirely convinced that the fingersticks don't feed into the calibration algorithm even when I select "No" to the question if I want to recalibrate. Many times, I've seen quite a deviation, and after a fingerstick and a Don't-Recalibrate order, they come right back into line.

Maybe it's that I've just rolled out of bed and my interstitial fluid started flowing again. Maybe it's because I don't dock my sensor in my FDA-approved abdomen. Or maybe it's secretly calibrating itself to make it look better.

Damn, I really need to read your book.

9:55 AM  

Post a Comment

<< Home