670G: No Bolus For 268?


#1

I was recently high (I’m not sure why, maybe it was just one of those time when my body felt like delaying using the bolus). My CGM said 309, and my meter said 268 (I know these are somewhat different, but when the numbers are that high sometimes they are less in sync). But either way I knew I needed to do something. So when my meter (the Contour Next Link) sent the number to my pump, I told it to do a bolus. It said a bolus was not necessary and that the bolus would be cancelled! I may have felt pretty much OK, but when it comes to my BG I trust my meter (and usually my CGM) enough to know that something needs done for 268. I could, of course, have lied about my carbs to do a bolus (although doing that can screw up future performance), or I could have temporarily switched into Manual Mode (but we all know how much of a pain it can sometimes be to get back into Auto Mode). Has anybody else ever had a scenario like this? If you have, what did you do when it happened?


#2

First check to see how much insulin you have on board. You don’t want to over Bolus.

If I feel there may not be enough, I go to Reservoir and Tubing and click on Fill Cannula. I then click on Fill and set Fill amount to the appropriate units and then Fill Now. However, Remember to adjust the Fill amount back to your regular number so you don’t over fill the next time you change the Reservoir.


#3

My Active Insulin was 0.0, so that was definitely not the reason. And even if I did have any, I think it would need to be a pretty big amount to cancel out a number like 268.

That’s an interesting idea, since it wouldn’t affect the supposed learning the pump claims to do. I might try that next time (which hopefully means never, but are any of us that lucky?). Thanks for the idea!


#4

i don’t know if it is a setting or not, but whenever by BG is over 150, I always get a recommended Bolus amount if my on board insulin is 0. Sometimes as little as 0.1 units.


#5

I usually get the Recommended Bolus message for numbers above the desired range (I don’t know exactly what that range is, but that’s not really the point here) as well. And I can guarantee that 268 is above my desired range. I would do almost anything to be able to see the exact algorithms used by the developers. Tech support tells us things like if you do this it will do that, and they tells us some of the intended ideas & concepts, but seeing the exact algorithms would definitely help me sometimes figure out what I did wrong or should do differently next time.


#6

I’ve not used the 670 pump but can offer some more general points. Diabetes is a dynamic disease yet the technology does not fully cover that characteristic.

Insulin sensitivity or the amount that one unit of insulin will drop your glucose level is often a setting that doesn’t get periodically re-examined. Many of us have observed that high blood sugar levels, especially those over 180 (10) cause a marked increase in insulin resistance. For example, if my usual insulin sensitivity factor is 40 (2.2), when I am above 180 (10), my insulin sensitivity is often cut in half. In these situations I can often cut my pump ISF factor from 40 (2.2) to 20 (1.1).

If high BGs have increased your insulin resistance, then that’s also eroding your basal insulin delivery and creating a deficit there.

What if you adjusted your insulin sensitivity factor when you’re experiencing high BGs so that you’d make it more aggressive? I’m not aware of how the 670 algorithm works so this suggestion may not be appropriate.


#7

It sounds like you’ve checked everything you should have to check. One of my problems with the 670 was how miserly it is with correction boluses, and getting that “no correction necessary” message when I was stuck over 200 used to drive me nuts. Reducing my AIT to the 2hr minimum helped that a bit, but if this is just a one-off problem then changing that setting wouldn’t make sense. If it’s showing that you have zero IOB and is saying you don’t need a correction at 268, let alone the 309 the pump is getting from your CGM, that really seems like a glitch and not one I’ve ever heard of. Are you otherwise feeling like you have your 670 pretty well dialed in, or are you still acclimating to it?


#8

I’ve had this exact scenario happen to me about 2 months ago. I don’t remember the actual numbers (very high 200s), but based solely on my history with the 670, I could find no reason it should not have calculated a bolus for delivery (and neither could Medtronic). I was driving, and had no access to anything but my pump and BGM. This went on for the better part of two hours until I was able to bolus w/a syringe. Came down as expected shortly thereafter.

Called Medtronic… went through the dreaded “script” and repeating what I was seeing several times, I got transferred to a higher tier support level. Went through the entire scenario again with this rep who stated “that doesn’t sound right, I’m going to sent you a replacement”. New pump the next day, no issues since.