I have no recollection of that bolus, Senator

I woke up low yesterday morning.

Which, ordinarily, is no big deal. It happens. I’ve been pretty aggressive with my pre-dawn basal rates, actually trying to program a Super Bolus into my regular basal pattern (jack up my basal rate really high one hour, then cut it down to almost zero for the next) so I wouldn’t need to play those games every day at breakfast.  That hasn’t been working too well, but that’s not why I woke up low.

This is why I woke up low.


Apparently, for reasons I can’t remember, I decided to give myself a shit-ton worth of insulin at 3:25 in the morning. Without entering a BG. Without entering carbs. Just straight, unjustifiable Novolog.

For me, at that time, 6.1 units is good for a full 73-carb meal. (Admittedly, those ratios are unproven, as I can’t remember ever having a large meal at 3:25 am to test it out, but still…)

To reiterate, this was for reasons I can’t remember, because I honestly can’t remember even doing it. Nor can I ever remember bolusing that much insulin without having either a BG or a Carb Count on which to base it. (Unless a bolus got interrupted for some reason and I needed to resume it later).

Something like this happened once before, and I wondered if it was really me or if it was the pump.

This time, I am quite confident that I did something stupid.

The reason? Because an hour and a half later, I do remember waking up to a CGM alarm, glancing at my BG, and indiscriminately taking a bolus of one unit to bring it down (yes, without a fingerstick to verify). This I remember.

And I distinctly remember, at the time, seeing the lower-left corner of the pump screen indicate that I had 4.0 units of “active insulin” on-board, thinking to myself “hmm, that’s odd”, and going ahead with the correction bolus anyway.

To be fair, at the time my BG was high (said my CGM alert) and based on that, I did need a correction (and, also to be fair, the night before I overtreated a low with cake and cookies and chocolate and had fought subsequent highs and… you get the picture). But not that big a correction.

Still, recalling that bolus and knowing it was “real” suggests to me that the previous one was also real. Or intended, which is probably a better term.

So…. what happened?


When I took that first bolus, my CGM was still ringing the “High Glucose Alarm” that had begun a half-hour earlier. (And displaying HIGH-165 MG/DL with the alert, even though my sensor glucose, by then had gone up slightly to 170. More on that in a moment. )


By the time I took the second bolus, my sensor BG had fallen to a much more comfortable 121 mg/dl, as I found out hours later while analyzing forensic data through Carelink. But at the time, the unacknowledged alarm from an hour earlier was still bellowing HIGH-171 MG/DL.

Hence, I gave a 1 unit correction for the 171 rather than for the 121.

This was on top of the 4 units I still had on-board (you can see by the numbers how quickly I was dropping).

On top of the basal which had just increased by 60% (as prescribed).

That’s a lot of insulin, and that’s what led to this:


And then, as you can likely imagine, this:


But not before nearly polishing off this:

Empty glucose tabs

Or, if you prefer for me to summarize the whole ordeal graphically, then this:


So, in conclusion, my point(s) is(are) this(these):

  • I have no idea why I bolused for 6.1 units in the middle of the night, but I’m sure I did
  • I have no idea why I shrugged off the 4 units on-board when I bolused that later 1 unit
  • I wish that obsolete CGM alerts didn’t appear as “valid” ones
  • It’s always a good idea to verify a BG before correcting
  • When I woke, I tried hard not to overcorrect. I had just four glucose tabs. Then a couple more. Then one more. Because…
  • Knowing that I’ve given myself a total of 7.1 units of insulin in the middle of the night, for no reason whatsoever, is terrifying.
  • I still entirely trust my pump to do what I tell it to do, and to tell me what I’ve told it to do.
  • I find myself questioning whether I trust myself to tell my pump what to do.
  • I made it through, and tomorrow’s another day. Carry on…

* * *

A few notes on the behavior of Medtronic CGM alerts: I keep my pump on “vibrate” all the time. When alerts and alarms (they’re not the same, but I tend to use them interchangeably) are triggered, the pump vibrates. If no action is taken, it vibrates again. Eventually and gradually, the alarm/alert escalates to an audible alarm. Pressing any button (during a vibrating or audible alarm/alert) is like hitting the SNOOZE button on an alarm clock. It’ll stop, but it won’t clear, meaning it will come back in a few minutes. Only pressing the ESC-ACT button combination will do the trick. 

Also, if somehow you hadn’t picked up on it already, CGM alerts sit in a queue until acknowledged. This is how my HIGH 171 alert persisted, even after my glucose level dropped well below 171. It also has led to me waking up to a sequence of alerts: LOW PREDICTED / LOW PREDICTED / LOW 78, whereby only clearing (ESC-ACT) one will bring up the next. During some of my more wild nocturnal BG swings, I’ve had some really unusual sequences of alerts in the queue. Clearing a HIGH to immediately reveal a LOW is quite an odd experience (and would’ve happened if I’d let that HIGH 171 linger a bit longer). I would love to see this corrected somehow, but I’m not sure that discarding unacknowledged, even if outdated, alerts, is the best idea.

* * *

In case you were wondering, I generally have my Threshold Suspend feature turned off on my pump, mainly because I find it to be a real annoyance. If I could set the threshold to 50 or put it on a timer to work only at night, I might use it; but I consciously drop below 60 often enough (and treat it), that the siren becomes a nuisance. This choice of a low-threshold of 60, I understand, is the FDA’s decision, as the similar Veo pump offered in other countries allows a much wider choice of low-suspend thresholds.

* * *

I have a relationship with Medtronic. See my disclosure here. However, that relationship has no effect on this blog post (except that the equipment was provided by them), and they have not been afforded the opportunity to pre-screen or offer any input on it. Their first chance to read it is also your first chance.

Oh, and one more thing. CareLink is awesome. All of those tables and charts you see above (except for the photo of the pump itself) came from CareLink Personal. It’s great for forensics and to figure out just what the eff happened.

Posted on March 13, 2015, in Continuous Glucose Monitor (CGM), Diabetes, Insulin pump, Mistakes. Bookmark the permalink. 7 Comments.

  1. Diabetes is a pain no matter how you look at it, but it’s pain enough during the day without your subconscious/half asleep brain trying to help out! I have never given myself an accidental nighttime bolus but I have disconnected, rolled up the tubing neatly around the clip of the pump, put it on my nightstand and woken up in the morning with ketones before. I hope tonight is a more restful one for you and your blood sugar!


  2. Wow! This was like reading a diabetes thriller novel, except it’s real life! Could you put a lock on the screen at night somehow? Perhaps have Medtronic take a look to make sure the pump isn’t dialing up a bolus if you are lying on it in your sleep? Regardless, glad you are okay!!


    • Thanks for the comment Ally! Just to elaborate, I am quite certain that the 6.1 unit bolus didn’t come without my doing it The main reason for this is because I distinctly remember taking the second one-unit boluse (and seeing the 4 units on board), and because I do remember silencing alerts through the night. After the fact, I pulled up the raw data from Carelink, and it matches my “usage pattern” — in that I use the bolus-wizard for pretty much everything (bypassing carb and BG screens, then dialing the bolus in manually) which I find much easier than scrolling down to the “Manual Bolus” menu item.

      The key-lock is an interesting thought. I’m not sure if it would unlock to allow a response to an alert or alarm, though. Personally, I’d suspect that, over time, it would get to be too cumbersome that I wouldn’t use it – or that I wouldn’t take correction boluses because of the added steps needed to unlock it.


      • The infamous “sleep bolus”! I dream about bolusing all of the time and I’m surprised I didn’t do it while on the pump. This weekend I had a dream that someone injected me with Lantus. It was so vivid that I had to check my pens the next morning! Guess diabetes truly never rests! 🙂 Glad you are okay and thanks for sharing this story.


  3. Yikes – glad it all turned out ok. And I also LOVE the Carelink reports. Love that my CDE can just log in and look at them so we can discuss, also. 🙂


  4. Scary stuff, that middle of the night bolusing with no memory whatsoever. Sorry to say that I’ve done it too. I also woke once to find I had turned my CGM off completely. Not muted the alarms, but turned the whole thing off. And when I found it off, I tested and my blood sugar was in the 30s. Technology works, but I guess my brain doesn’t while I”m half asleep!!



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