670G Bolus wizard seems broken

Hey guys, I’ve been lurking and finding all the answers to my questions over the years here, this is an awesome forum. But I finally seem to have a question that I can’t find the answer to: I’m about 24 hours into running the Medtronic 670g system. I haven’t met the time requirement (48 hours) for auto mode, but the way the bolus wizard works is puzzling me. For example, I bolus for and eat 50 carbs. An hour later my bg is 170. When I use the bolus wizard, it only takes into account the amount needed to cover the high, not the entire amount. In this case, at one hour I have 1.9 units active, but the bolus wizard only subtracts 0.9 units to cover the bg, not the entire 1.9 units. If I change the bg amount (which is easy to do since I have to input it manually unless I’ve just tested :roll_eyes:) then amount of insulin rises or falls with that number. In addition, adding carbs to the mix does not seem to be affected by the active insulin number: it always adds the full amount per my carb ratio settings. Am I over-thinking this? I tend to do that. I’ve been using the bolus wizard on my Dexcom/Nightscout setup over the last year or so which also takes carbs on board into consideration as well. Perhaps the difference between the way the two algorithms work is where my confusion lies. Or maybe I’m just dense. Someone show me the light :thinking:

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This is an important question, but I do not have the answer. How much insulin would you expect to take for 50g? My doc said theres a way to override the bolus calculator…people dont all know how, but its there, I think.

Hi @vastocean, what is the duration of active insulin time set on your pump?

You can give yourself a manual bolus instead of going through the wizard.

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The 670G in automode operates differently than a typical manual mode pump. Basically in automode you have to forget much of what you knwo about current pumping.

I know you said you are not in automode, and it operates a bit differently also. The first thing to remember is that the 670g will want to correct you higher than 100, it wants to correct you to 120 constantly. This makes the first 3-5 weeks a little rough to get used too.

I am not exaclrty following your question however. so you shoudl call the help line. They will walk you through the correction logic. However I advise calling M-F not on a holiday.

Here is what i noticed when I was learning mode. I noticed it was not nearly as aggressive as I wanted and that my carb ratios and sensitivity were way off. Many people are finding that sensitivity is reduced beyond what we have previously thought. Mine is set at 2.5 hours. However many people find 3 hours or 3:15 is about right. You must take care not to jump to much and always with the care of your CDE or doctor. Mine hates the 2.5 hours, but it works.

so here is what i suggest, call the helpline for an explanation on the bolus method in manual mode and call your CDE for advice on lowering or lengthening (yes people have found that 4 hours is too short) your sensitivity.

Note: I am a Medtronic ambassador. My opinions are my own. They did not pay me to say nice things. OK, they sent me a shirt and a cup but even I am more expensive than that.

Sorry guys, was out of town and away from computers for the weekend. @warmsnow: IOB is set at 3 hours. I could give myself a manual bolus (provided I’m not in auto mode), but for the latest and greatest pump I don’t feel I should need to do math in my head. @Rphil2: Now that I’ve been in automode for a few days I can see that it truly is a completely different animal. My question was my attempt to express concern that the wizard wasn’t counting all of my IOB, but the automode seems to make that a non-issue.

After running this rig for 3 days now, I have to disagree with most of what I’ve read: the cgm part is wildly inaccurate at times when it shouldn’t be (first thing in the morning and 6 hours after eating simple carbs for two examples). More than half the time the disparity is greater than 50 points, and often around 100 pts off. I’m on my third sensor due to this. I’ve used a Dexcom for almost 2 years and have never had these kinds of issues. I could calibrate the thing in the worst of times and it would still be within range. And I now see that the new T:slim pump works with the G6 (wish I would have known that before I went with Medtronic). I’ll give this thing a few more days, but if it continues to be this off it’s going to go back to where it came from.

As a sidenote, I did talk to the tech support team who suggested I put the sensor elsewhere on my body. I responded that I never had to do that with the Dexcom, and having it anywhere other than my abdomen doesn’t work for me lifestyle-wise. He gave me the rundown about the ISIG, so I guess I’ll try that for a few days but I don’t like the idea of putting more work into an “smart” pump than I did into a “dumb” one.

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Exactly why I’m not planning to upgrade to 670. Not unless they give me a free trial, free supplies, and no hassle return. I would run in parallel with dexcom.
I used the earlier Sof-sensors (before Enlites), and also learned about ISIG, but from other users, not Medtronic.

Yeah, the T:slim X2 is sounding better and better. I have all the same gripes about the 670 as everyone else has already posted. It’s a hard sell for my wife to let me send it back though: she’s ecstatic about me not running high all night (which happens more often than I’d like it to). I would also like to see how the wizard comes up with the bolus amount (like the Animas did). Black boxes and the magic numbers they spit out make me nervous.

I’m looking into the tslim x2. I’m currently on a clinical trial with the 670G and not interested in purchasing this pump when my warranty is up and the clinical trial ends in December.

First of all, keep in mind that Auto Mode is an entirely different way of using a pump & sensor. First of all, “lying” to your pump (entering extra carbs and/or incorrect BG) to get the desired amount of insulin will confuse it (maybe not in Manual Mode, but it can be a bad habit). Since many parts of Auto Mode are based on data from your last 2 weeks or so, incorrect data will just make it worse. And Auto Mode will take some time getting used to, since the settings involved are not all the same ones used in Manual Mode, and it can also take time to figure out the best values for these settings. You can’t analyze a month of data when you’ve only been collecting data for one week.

This will always be true, when you add more carbs, it assumes you ate more food. When you switch to Auto Mode, just be patient, it can take time to adjust to. When I switched to the 670G & Guardian 3, my range went from about 30-400 to about 60-240, it just took a couple weeks of tweaking the settings. I often refer to Auto Mode as “Artificial Intelligence for Insulin Pumps”. Perfect numbers won’t happen overnight, but if you are patient, learn your pump, and let your pump learn you, it will all be worth it in the end.

@njsokalski: You bring up some good points, but I think I’m going to return this bad boy. Last night the sensor said I was 206. Finger stick checks out as 82. This happens 4-5 times a day. I’ve changed sensors, sites, and gone through the whole laundry list of reasons why it might be doing that. A disparity like that happened once a month (maybe) with my Dexcom G5. End of story.

I have the 670 and I want it to go back to Medtronic I have been trying to return it. They say I had 30 days to return it, so its to late. I have had it now for 4 months since then my A1C went from 6.3 to 7.1 and I am high 24/7 with it. I tried the sensor and I am allergic to the tape i can only keep it in 3 to 4 days.
My doctor had me cut my carbs to 50, try all these tapes, had me go back to the person that trained me, try all 3 infusions Medtronic has to offer.
Still I ran HIGH once in a blue moon I had a low and I refused to turn on the Auto because if this pump can’t control my blood sugar with out auto, its not going to work. I can’t go over 180 and I can’t go below 70, my happy is 130 and animas did a pretty good job.
Last week I went back to my One Touch ping and wow I am back on track. I had a couple of highs but its my fault, they need to keep animas products going.

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I’ve been using the 670G for 4 months. Over this period I have only had a few issues with sensors, maybe 4 or 5, that have had issues calibrating, impacted by blood, etc… Having used the enlite, prior to this, I’m familiar with the insertion techniques, good locations for accuracy, etc… and also when to calibrate (and more importantly when not to calibrate). For the majority of the time, I feel that the sensor accuracy is better than the enlite, but still tends to read lower than meter bg.
Just had my A1C this week, and it came back at 7.0, after being in the 6.5-6.9 range for the past several years, this was disappointing.
Having tried a few different times in Auto over the last 3 months, I’ve decided that the algorithm isn’t aggressive enough, as it targets 120, and only corrects to 150. Adding on that the SG always seems to compare between 15-30 below meter BG, when testing, it just seems that its focused on preventing any lows, at the expense of maintaining a higher overall BG.
I’ve decided to use it in manual mode only. The suspend before low feature is a positive, as I find it does prevent some of my lows. I also have three different basal patterns that I use, depending on my daily activity, and also utilize temporary basal rates when working out.
My opinion, after using the pump in auto, is that if you have been actively managing your bg prior to the 670, with a history of A1C’s in the 6’s, that the auto mode is not going to do what you hoped it would.

I have been on the 670G for about 10 months. In the early months, it seemed to keep my BGs higher than when I was on the 630. However, after six months or so, the 670 seems to have “learned” my habits and my BGs now seem to be averaging lower. Could be I have learned how to better manage the 670 or the 670 has learned how to better manage my BGs.