Basic pump questions

My endo has been quite enthused about the Medtronic 670G and I am expecting to start the process of obtaining one and testing it out sometime this spring/summer. I’ve never used a pump and have some very basic questions about pump use in general, would appreciate some feedback:

  1. How common are the “bad infusion sets” I’ve read about? Are they preventable or do they just randomly surprise people? I can anticipate a high and prevent/correct pretty well on my current MDI and CGM setup. The whole “bad infusion set” risk bothers me as one more variable that can throw things off.

  2. I play ice hockey and have not found a good answer on line: Should I leave the pump on (strapped around my torso or ??) or do I take it off? Total time disconnected would be about 2 hours max. FYI I’ve found that if I play with no insulin on board I am going high after hockey. My usual routine is about a 20g carb snack with bolus about 1-1.5 hours before playing. Can that routine be replicated using a pump? How complicated is it to re-install after a game…is there lots of resetting or is it “plug and go”?

  3. The only thing that wears me down mentally with the CGM is scheduling the routines of changing or restarting sensor, and timing expiration of transmitters. I don’t want to let those hard deadlines hit me when inconvenient so I plan around them Will there be more hard deadlines using a pump?

Thanks in advance!

I have some very strong opinions on this particular pump. I’ll share them when I have computer access.

I am a bit hesitant to share my thoughts on the first publicly available closed-loop pump because I know how excited people are about the prospects for this. But from what I have heard, some of the aspects of how they are implementing it are deeply troubling to me.

First off, I have never used the Medtronic pump. But I have discussed it with an Endo that is a big-shot with Medtronic. He does a lot of their clinical trials, he is an advisor to them, he is a big Medtronic proponent (has nothing but Medtronic stuff on the walls of his exam rooms).

I went to see him, not as a normal Endo visit, but just to glean information from him. I met with him a few weeks ago. I didn’t tell him anything about my regimen, just asked him all about his pump and insulin recommendations.

So this is what he told me for the new 670g:

When you are in closed-loop mode, you can’t bolus. You have to let the pump make all the decisions for you. The only thing you can do is tell the pump how many carbs you are eating. If you want insulin, the only thing you can do is enter carbs. That is all.

I asked the Endo, how do you correct? He said, in closed-loop mode you can’t!
[starting to feel troubled]…

So you enter your carbs for a meal, but later after you have eaten, you want to add some more insulin. Maybe the plate was bigger than you thought, or the food was a bit sweeter. Maybe you just think you will need more than originally estimated. Maybe you snuck a few bites off your date’s plate. Maybe you are starting to spike. You can’t simply add insulin or correct!

Here are your options. You can either:

a) Wait until you go above your BG target and let the pump correct automatically for you (and I don’t know how much control you have over how aggressive you can set those type of corrections).

b) Enter more carbs, “pretending” you are eating more, just to get more insulin. Kind of tricking the pump.

c) Exit out of closed-loop mode and do a manual bolus.

So option c) sounds like the easiest way to go, right? Just exit out of closed-loop mode, enter your bolus, and then go back into closed-loop. Easy right? No. From what he told me, it takes about 12 button pushes to exit out of closed-loop and do a manual bolus. And then I am not sure how many button pushes to get back into closed-loop mode.

To me, this sounds crazy. I can’t take a 0.15 unit bolus? I can’t add just a little bit of insuln? If I see myself starting to rise, I can’t correct that?

A couple other things.

The only BG target values are 120 or 150. So if I am 90 and going up, I have to wait until it gets to at least 120 for the pump to do anything. And even then, I have no guarantee of how aggressively it will correct.

All this is based on CGM interstitial readings, which can have a big lag. If I test and see a BG number I want to correct, I can’t. I have to wait for the CGM to catch up with my BG meter test. Argh!!!

Keep in mind, I have never used it, this is just what the Endo told me. It’s possible he is totally wrong about all this. After all, the pump is not out yet, so maybe he is basing all of this information he told me simply on his discussions with them during the design phase. I don’t know for sure.

But if what he said is true, I am troubled. Not that I have to use the pump, but I know how these companies work. If one company does it a certain way, a good chance all of them will follow the same path. :worried:

What would you think of such a design? I know for some people it makes sense, they don’t need to ever do anything except enter carbs, that is all. But for people who like to manage things a bit more tightly, it seems like a bad setup. Plus the limited options of 120 or 150… Another “Argh!!”.

I learned of all these things a few weeks ago, but didn’t know if I should share it publicly because it just seemed bad to me and I know how excited people are about the prospects of closed-loop and AP.

I don’t want to talk anyone out of it, but some of these things just bothered me.

Anyway, would love to hear your thoughts, and I apologize for not being all happy about it.


If anyone wants to read, here is a link to the user manual for the 670G.

I don’t think this is true. In Automatic mode you can enter a BG or Carbs per page 244 of the manual. However you are limited to the pump correcting you to a target bg of 120, which is higher than most people I know would like it set. I figure these limitations will be removed in the second generation devices making these much more useful for mindful patients.

Well that sounds a little better. Like I said, I don’t know, I am just reporting what the Endo told me. It wouldn’t be the first time an Endo gave bad information…

But some of the things in the user guide are also horrifying to me. How does this strike you?

Block Mode when in Auto Mode
The Block Mode feature allows a caregiver to block the patient from changing
settings or delivering a bolus directly on the pump.

The Block Mode feature does not allow:

  • Bolus delivery or entry unless prompted by the Bolus Recommended screen

  • Changes to Auto Mode settings

  • Manual BG entry

For the Block mode, make sure you don’t ■■■■ off your Significant Other, lest you wake up from you nap and find yourself apologizing and begging for the code to unblock the Auto mode. :confounded:

the blocked letters should read: p i s s

The Block mode is there I am sure to make dementia patients more compliant, but really troubling if you don’t have dementia

Sorry about my other post which was somewhat a side-note and did not directly address some of your questions.

It happens occasionally, you can get a bad site or a infusion gets knocked loose. Also on some people, the insulin becomes less effective as the time progresses. Day 3 can be not as good as day 1. This can just be the site not absorbing as well, or the insulin sitting in the pump reservoir for several days. And some sites are less effective than others. It just takes monitoring and paying attention. And it varies for different people.

During games do you get to sit on the bench ever? Or get sent to the penalty box?! :slight_smile: You can quickly attach, bolus, and disconnect. Also, you wouldn’t need to stay disconnected for 2 hours, if you have breaks between the periods. I know most pro games the periods are less than an hour, so I think you’d only need to be disconnected for that much at a time. I wouldn’t want to go the entire game with no basal, that is almost a guaranteed spike! I have never used this pump, but most of the tubed ones use a luer lock connector that lets you disconnect and reconnect the tube super easy (like for a shower). The Medtronic has their own proprietary connection, but it is basically the same as a luer lock.

But let’s get a sports question about this on the exercise page and talk about it in detail!

Most pumps give you a grace period. Like the OmniPod gives you 8 hours. Again, I am not familiar with the Medtronic, but I would assume you have some leeway there. I defer that question to a Medtronic user.

John, My son plays baseball which has similar issues - 2-3 hour games, and he is a catcher so we have many of the same contact issues as hockey. Our approach for this season was going to use some lantus to establish a baseline of 24 hour insulin appropriate for his exercising dose, and then turn down the basal rate in the pump accordingly, so that we could safely disconnect for the whole game while still having basal insulin onboard. In the meantime, a kind soul loaned us the Omnipod system to try, and it works well. If sports are really important to you, you may want to look into the Omnipod.

So it looks like the Endo expert missed a little bit.

From the manual:
The Bolus feature in Auto Mode requires you to enter either carbs or a BG value.

So basically he forgot to mention that you can bolus with a BG entry in addition to a carb entry.

I still would not be entirely happy with the extra button pushes required to take insulin. One of the selling points for the omnipod was that I could do it while running.

But it is good to get the perspective of others. It sounds like you are not too troubled by these things?

No, I think the button pushes and the heavy handed way Medtronic is locking in health insurers, thereby limiting patient choice sucks.

We use a Tandem and an Omnipod, and are praying Tandem stays in business to continue disrupting the big boys.

I also think the inability in the 670G to adjust the target bg in auto mode from 120 (or 150 temporarily) is a deal breaker for us.

I also don’t have a great impression as a former employee of big blue, while I watched numerous coworkers with company pumps get terrible service from their own company when they had pump problems. But that is a subject for a different day.

I totally agree about the limited BG targets.

I appreciate you clearing up the bolus thing. It’s so funny how I can talk to an Endo who is a supposed expert on that particular pump, but the people on this site still give better information! That shows a lot about this group.

Thanks Eric for the ideas…my hockey is known as “beer league” so there is not much time on the bench or between periods. We go hard the whole time, its a great workout. That said, I generally like to be ready to go and stretching at least 10 minutes prior and I am usually too exhausted to fiddle with a pump for at least 15 minutes after, so my only downtime would be before or after the 2 hours.

Chris, I’ll check out the Omnipod info, thanks!

Is your league rough enough to keep you off the pump while playing? Would it get messed up?

I do think the OmniPod is a great option for sports.

And BTW, I think OmniPod is about 1200 times better than anything Medtronic makes.

Eric, My best option if I get a pump is to wear it while playing. Roughness is not a big issue (this is an age appropriate activity for me and my friends), but falling, hitting the boards, or getting hit with a puck or stick are pretty common. I wear my Dex receiver in a waistband that is well protected under some pads. Only problem I’ve had with that was dropping it while sneaking a peek.

It seems like the best pump option for me is to.wear pump while playing so I can keep some IOB. I’ll see about the OmniPod, I hope to figure out how to test out a loaner from my endo. I’m curious if it would provide any benefit for me versus current MDI.

Let’s talk about best ways to manage exercise with MDI. There are a lot of tricks to doing that!

I sent you a PM. Would love to put you in touch with that hockey player in Minnesota.