So I am on Pump Vacation

So many of you might have followed some of my new adventures with the 640G over the past 6 months…

Continuing the discussion from Medtronic 640g - Offical Details and photos:

While @Brent seems to have awesome results, and I had awesome results for a few months myself, i am back to square 1.
So a short summary: I started on the pump on May 29, and had immediate struggles keeping my sensor alive for more than 3 days. i was in close contact with my pump educator, and she was a great support in those times, kept sending me replacements, etc, and was really nice. after about 2 months of faulty sensors, i finally got a batch of working ones, and from about August had a little over 3 months of awesomeness with the 640G. back in November i started to get faulty sensors again, and last week, after having called medtronic about 3 times in a week, decided to make a drastic change and go back to MDI for a little time to give myself a break. The sensors were unfortunately not consistent enough to make the experience a pleasant one, and i just was so fed up with all of this technology that i went back to “stone age” :wink: the problem wasnt the accuracy of the sensors, but they kept failing after 3-4 days.

I still strongly believe in the 640G system, but Medtronic needs to make strong improvements in the consistency of those sensors, it isnt enough if they manage to sell 50% of working sensors and the rest is replaced by their customer service, who is nice, but takes too much time.

i guess i will go back to the pump eventually, just for convenience, but to appreciate the whole thing, i feel like i need to miss it for a while :confused:

just wanted to give a quick update, as some of you have closely followed the other thread and seemed very interested in the user experience.
i also wanna state that i do not encourage anyone to switch treatment on their own without the advice of a professional (like i did), i was on MDI shortly back in fall 2014 and felt confident enough to attempt the switch on my own, but i do not advice this to anyone.

wishing everyone Happy Holidays and a good start of 2016. :christmas_tree:


I’m sorry the sensors were so problematic @swisschocolate! I have been using them for 7 days and have had very few problems with them. I had one wonky one recently however that was the last sensor out of a batch that likely lasted about twice as long as they should have. I get 3 days each, this w/ the 523, so I restart them on the fourth day. They will make it through 7 days but usually run out the battery on day 8. I could untape and reboot them again, however I didn’t see totally excellent results the one or two times I did that so I haven’t done that very often. I had already thrown out all of the packing materials so I am not sure if the sensor was officially “expired” or not either.

I think it’s sort of odd that Medtronic doesn’t address their “sensor gap”. I haven’t perceived problems with their sensors and found that, at least for me, they were more useful than Dexcom in a short c. 50 day comparison, although I wonder if that might be because I have figured out lifestyle “workarounds” for the Medtronic sensors that are not compatible with the way Dexcom 4 thinks? At conferences, I’ve tried to chat up the Medtronic folks about this issue however they have been utterly silent, across the board, although the last two were quite chatty about their new products, which they indicated would be the 630 in the US?

Swiss chocolate, why not just dump the CGM and use the pump instead of injections, does it not work without CGM?

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Or better yet, use your Medtronic pump and get a Dexcom CGM. Quite a few folks use Medtronic pumps with Dexcom.

@JC14 @rgcainmd
of course i am aware of the fact that i can use the pump without the CGM, but i was just overwhelmed with the whole tech stuff so i decided to take a break from everything
and the Medtronic 640G system does not work with the dexcom obviously, and the decision to put the pump aside has come pretty quickly so i didnt even have time to start the whole process to get another CGM anyway, and as mentioned, the system, which is so awesome if it works, doesnt work with a dexcom, so there isnt really a point in getting it.

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and yes @acidrock23 i do feel that medtronic is not trying to improve the situation. they are, in my eyes, as of now, sitting on their high horse of the 640G, which is, again, an awesome thing, but they are not willing to see that there are problems with the technology of their sensors. if i call in to report a faulty sensor, they ask for the serial number, tell me they replace it and done. they dont seem to see that there is a problem with the sensors, they just take the faulty sensors as a normal occurrence and dont seem to be concerned by that.

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Wow! Thanks for sharing @swisschocolate.

Yours is a classic tale of a company failing to deliver on a promise. I hope that Medtronic can get this sorted out for you and other 640G users.

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Just got off the phone with the Medtronic Hotline. This time the responder was very nice, trying to explain to me why the sensors fail, but atm i feel like there shouldnt be an excuse for those failing sensors.
she went on to give me some tips, she wanted to be helpful for sure, but most of those tips have been shared with me before, and i am really just tired of everything.
She did promise that they were working on the problems, that the sensors are too sensitive and in the beginning of 2016 they should be better, but i have heard this so many times before, not sure if i can believe her.
going to try again for sure, and see what happens. keeping you in the loop if possible of course :wink:


Thanks for the honest assessment of the 640G experience. I can understand your desire to go back to MDI and give yourself a tech-break. It’s too bad that Med-T is having sensor problems. The predictive action of the 640G is the first step towards an artificial pancreas in the real world. Your experience is a sobering one as we all look with hope toward a working artificial pancreas. This is not going to be an easy development without significant challenges. It may take a few years longer than we all hope.

I am encouraged by the experimentation of the we are not waiting movement including the Night Scout project and the Do It Yourself Pancreas System ( Both of these efforts are home-brewed open-source projects. The DIYPS claim about 20 people now using their closed-loop protocol.

Perhaps Medtronic would be better served with using the Dexcom sensor. I know the DIPYPS system uses a Dex sensor combined with older Medtronic pumps for their closed loop system.

Thanks for the post, @swisschocolate. Good luck with your MDI therapy. I think I could learn a few things doing that; I haven’t been on MDI in almost 30 years. Enjoy your holidays. Can we expect to see an MDI report from you? I, for one, would be interested in that.

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Ha, ha! LOL (but with sadness)! I think it would be the proverbial cold day with double hockey sticks before that will happen! Think of the investment that Medtronic would have to essentially flush, plus the licensing with Dex, the integration, etc, etc …

I think the bigger question is if this sensor problem is unique to @swisschocolate, or one that is widespread and understood by MedT, where they have a plan in place to rectify it.

:laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing: :laughing:

Ah, just to clarify for those who might not be aware of the context, Terry Gregg, currently the Executive Chairman of the Board of Directors of Dexcom and before the Dexcom CEO for many, many years, was an executive at Medtronic before moving/jumping to Dexcom.

Terry likes to jab Medtronic with a verbal elbow now & then by pointing out that Dexcom is completely open to discussing licensing terms with Medtronic at their earliest convenience.

I expect the reaction over at Medtronic is something along the lines of “Like hell we will!” muttered through gritted teeth. (If they actually notice. My feeling is that Medtronic is one of those companies which gets caught up in its own underwear.)

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I figured it might also be worth clarifying that one can’t necessarily connect the problems Swiss is having with the experiences of anyone in the U.S. The CGM system she is using outside of the US is not the same as the one that is still :rage: being used in the U.S.

There are two differences. I think most people are aware that the 640G pump is still not available in the U.S. What might be less commonly known is that the CGM transmitter used with 640G is also new. Medtronic calls it the Guardian 2 Link and, while it looks the same as the MiniLink used with Medtronic’s pre-640G pumps, there are significant internal differences.

The sensors used apparently everywhere else outside the US also differ. Medtronic refers to them as the “Enhanced Enlite” versus the “Enlite” which is what we get in the U.S. Since the details about CGM sensors are always muddy, at best, I’m not really sure just how big a difference there is. But the Medtronic Canada press release did contain a bullet claiming that the Enhanced Enlite has “New chemistry pattern and layers, designed for more consistent daily performance through the life of the sensor”. So I expect something different occurs during their manufacture.

as mentioned above, the medtronic hotline today told me they are somewhat aware of the problem and promise an improvement with the sensors in the upcoming year.
also, a friend of mine has just started with the 640G and has used 4 sensors in one week, she is not happy at all. in fact, i will meet several young T1s this upcoming friday in a local meet, some of them are also newly (or not so newly) on the 640G and i will try to understand how widespread those problems are.
as said before, i did have awesome times with the sensors, where they worked perfectly, and now am experiencing again a batch of bad sensors, so its pretty much a thing about being lucky whether it works or not, i think.

Could you provide a bit more information on how your sensors “fail”. Is this something you notice by getting bad results from the sensor over time? Or is there now, with the Guardian 2 Link transmitter, a non-negotiable sensor error reported by your pump?

Also, as I asked you earlier in another context, has anyone at Medtronic ever run you through any diagnostics for the Guardian 2 Link CGM transmitter? I am curious since I am not even sure that this can be done with the new transmitter.

But I’ve also been musing lately on just how much better my Enlite sensors seem to be working for me since Medtronic replaced my MiniLink transmitter. I used to think only in terms of sensor failure, but now I am less certain it is always the sensor which is at fault. Could you possibly have a wonky transmitter?

Huh? What was the rep referring to when she said that “the sensors are too sensitive”? :confused:

My current personal theory to explain Medtronic is that their corporate goal for innovation is to always strive to be aggressively mediocre. :blush:

No they aren’t inaccurate (or very rarely). the thing that happens is that i get a notification on my pump:
SENSOR STOPPED WORKING. PLEASE REPLACE. (paraphrasing translation)
that is what gets me up the trees, or smacks my pacifier out, or whatever you call that in English. it. just. stops. working.
i can restart sensors, but usually my success rate (especially with the faulty ones) is extremely low, and depending on when in the day my sensor fails, i lose quite some time of sensor data.
sometimes i get “prewarned” by notifications that the sensor signal is weak, but i cant even explain that, because sometimes the sensor is at a 70% battery and literally 2 inches from my pump, so how could there be a weak signal?

she basically told me that the sensors are so sensitive that they “hear” other sounds than just the glucose (other stuff that swims around in our ECFV, like idk, protones, Sodium, etc.
so apparently they get distracted by other stuff and decide they are confused and stop working. not my theory, the hotline woman explained this to me like that.

i am hoping to get this done this weekend maybe, or over the holidays, i was so busy until now. i did get that thingamajig to test it i think, but i still have to find out if it works and if i am able to do it on my own. maybe youll find something, either a result or a help note in your inbox the next few days :wink:

It is pretty clear Medtronic will never license Dexcom technology. What could happen, however, is that Medtronic could acquire Dexcom - after all they have been in the mode of gobbling up smaller companies for some time. This could be good news or (much more likely) disastrous news - in case they decided their financial interests would be better served by simply acquiring Dexcom and then shelving Dexcom CGM technology. Antitrust laws should rule out such acquisition, so I hope my concerns are not well founded.

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Medtronic’s sensors are utter tat. They only use a single electoid for starters which is why it can’t continue working if you skip a calibration unlike the Dexcom and things like the Libre. The new transmitter on the 640g is solely a move to a different frequency so it can eventually talk directly to phones and other devices down the line and didn’t improve any of the Enlites issues it’s had for so long.

Now would I love a 640g to work with a Dexcom, yes, but as discussed above that’s not likely. But the issue between the two of them highlights a problem covering the entire medical (and other) technology fields. Far to much proprietary greed from companies at the expense of the patient/customers. The only solution for this is for governmental to force them to behave and all to work via a open standard. Likely hood of that is sadly none existent though :frowning:


I think the we are not waiting movement and the do it yourself pancreas open-source movement is a unique and healthy wildcard that could keep these competitors a little off balance. The private enterprise/government regulator dynamic was missing the critical customer ingredient. The open source do it yourself movement lets the other players know that they are not the only actors in the market. I like that!

I have also spoken to Medtronic reps at conferences - Medtronic are well aware (and thier reps admitted to me) that their sensors lag behind Dexcom’s both literally (there’s a greater lag when BG is changing fast) and in terms of overall accuracy. They are clearly trying to address the problem. Apparently there’s a new Enlite 3 in the pipeline which will integrate with the upcoming 670G pump. In terms of at least limited Artificial Pancreas capability for pumps, Medtronic are clearly miles ahead of the others, and I am sure recognize that they are being held back by the limitations of their CGM sensor technology (and software). The Dexcom G5 and the Freestyle LIbre are both now certified for treatment decisions - Medtronic need to attain a similar reliability if they are to take advantage of their lead in Sensor Assisted Pump technology.



We can stir things up a little yes, but the issue is that while the software could be open source easily enough what occurs with the hardware becomes a bit more messy. A handful of home users making things themselves is ignorable to the companies, they lose more to competition anyhow. Thus it’s more of an issue needing scale, both of production of the devices and also user numbers. To get those it’s going to need someone with the funding to get a pump/AP certified which isn’t likely to occur sadly, which would return us to the needing to make profits. Or for someone to go the whole head long dive into it and get the the bucket shops in China or India to start production of them on the cheap and flooding eBay with them. At that point it would become very interesting indeed to watch the large corporations panic, lawsuits fly as they attack whoever developed it, and the certification bodies after them and anyone “injured” due to them even though those using them know it’s well an eBay cheapola pump/AP etc. Sadly though that’s a big step.

Personally think governmental/certification bodies enforcing open platforms though would both increase competition for the companies (why they hate it), help open it up much further to the open source/community projects, and also lower costs through competition all round for insurance companies and government/health agencies. Probably basically why no governmental type would ever do it. Although personally think the opening of it would actually be one of the biggest steps forward for our care since the development of the pump.