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Guest Post: How the MiniMed 530G Changed My Diabetes Management (Without Ever Even Seeing it in Person)

SUM is being borrowed today by Christopher Angell, fellow PWD and creator of GlucoLift, so that he can share his thoughts on the Minimed 530G … without having ever seen or used the system.  What is he on about?  Find out …

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Leading up to the launch of the Medtronic 530G (and what a long lead-up it was) I kept asking myself “What’s the big deal?” It seemed like, apart from a new sensor (which some data had already shown to be a minimal improvement over their previous sensor, and a far cry from the already-extant Dexcom G4 Platinum) the only real innovation was the introduction of the low glucose suspend (LGS) feature, which shuts off insulin delivery after a series of alarms alerting the user about low blood sugar are ignored. “How useful could that possibly be?” I wondered.

We’re constantly told that, because of the action curve of our rapid acting insulins, changes in pump basal delivery should be calculated for events 30-60 minutes in the future. So how does shutting off my basal drip help me if I’m crashing NOW?

Still, my curiosity got the better of me.

Now, I don’t use a Medtronic pump (Tandem t:slim), or a Medtronic CGM (Dexcom G4), and I don’t even get all of my basal insulin from my pump (my current split is about 57% from my pump and 43% from a single bedtime Lantus injection). So my experience is probably in no way directly comparable to what someone using the Medtronic system would experience. Nonetheless, I started experimenting with what I’ll call MLGS (manual low glucose suspend). I didn’t use it for all of my lows, but there are a couple situations where I’ve found it to be rather useful.

The first is where my bolus and my food may be correctly matched, but are out of step. For example, say I bolused for a meal that’s mostly protein, fat, and some slower carbs, like a steak with sides of spinach and broccoli. Then after the meal, I notice a slow dip on my Dexcom, but I KNOW that once the meal starts digesting, there will be plenty of food to give the insulin I have on board something to do.

Previously, I would have eaten one or two proactive glucose tablets to keep the insulin busy while the steak and veggies get over their stage fright. Now, I’ll just unhook my pump, or set a temp rate of 0 units for 15-30 minutes. And as long as I didn’t way over-bolus, that dip tends to reverse on its own, and I’ve managed to avoid unwanted, unnecessary carbs (delicious though they may be). This is especially useful if I’ve eaten a late dinner, and don’t notice the dip until after I’ve brushed my teeth. I can still get into bed, unhook, and read until I see the CGM line flatten out, then hook back up, without re-fouling my pristine pearly whites.

The other situation where I find myself implementing MLGS is with my serious, all-hands-on-deck lows. You know, the ones where every second spared from their depths means less of a hangover, and more of my day returned to my control. There are two caveats to using MLGS with this type of low. The first is that, since I’m not at my most functional when these lows hit, I’m more likely to use the “unhook the pump” method than the “very responsibly set a temp rate” method. This means that it’s very important to remember to re-attach my pump after I turn the corner on the low. The second is that since disconnecting, even for a little while, leaves me more vulnerable to a rebound high, I always treat these lows with glucose tablets, as opposed to my fridge-clearing binges of yore. I know when I’ve eaten enough glucose to right the ship, but I have to be disciplined enough to trust it and not pile another 50g of future disaster carbs on top.

When I do those two things successfully, my bad lows feel less bad, and I seem to recover from them faster. Can I measure/prove this? No. Do I care? Not really. If it feels to me like it’s working, and I believe it’s an improvement, then it kind of is, even without hard data to verify or explain it.

So even though I’ve never used the new Medtronic MiniMed 530G, or even seen one in person (as far as I know), it has nonetheless made a positive contribution to my diabetes management toolkit, which, when you think about it, is pretty impressive.

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Christopher Angell is the founder of GlucoLift glucose tabs (I have a stash of them in my cabinet, and they are so much better than your average glucose tab) and a good friend, diagnosed with type 1 diabetes at the age of 30.  He’s contributed here before, exploring the t:slim insulin pump and both travel and dental woes.  For more from Chris, you can check out the GlucoLift company blog.  To taste test GlucoLift glucose tabs for yourself, you can purchase them from their online store, or write to for samples.  Tell ’em Loopy sent you.

16 Comments Post a comment
  1. I have a really hard time remembering to turn off a suspend setting after the low fun is over, so I rely on the 0% temp basal, too.

    I know it’s not the point of the post, but I am seriously intrigued by your Lantus/pump routine!

    02/18/14; 11:00 am
    • Me too, Jacquie! And to the tune of 57%/43%. I hope we get to hear more.

      02/18/14; 11:41 am
  2. Kim #

    “Future disaster carbs”. We are well acquainted.

    02/18/14; 11:15 am
  3. “…changes in pump basal delivery should be calculated for events 30-60 minutes in the future. So how does shutting off my basal drip help me if I’m crashing NOW?” YES—this is the question! It has been driving me nuts.

    MLGS sounds way better that machineLGS because we won’t have to wait for the zillion alarms and the shutting off once it’s basically practically almost too late anyway.

    You are a genius.

    02/18/14; 11:38 am
  4. I almost always suspend my son’s pump when he’s low until he’s back in range. I love the idea of the auto-suspend but love his old Ping and his current t:slim’s features more. I’ll keep doing the MLGS for him…

    The Lantus/pump combo is something I’ve been wanting to do for a while. My son’s doctor made me feel like a fool for asking for her help getting started with it. Now that I see that someone else actually IS doing it successfully, it’s time to find him a new endo.

    02/18/14; 12:02 pm
    • I’ve never heard of anyone doing that either. I wouldn’t find a new endo over that, sometimes what adults try or adults have aren’t recommended for children. You might see if he puts out more detailed information and print it out to take to your son’s endo. Let the endo look into it instead of making a split second decision. Unless you have other reasons! 🙂

      02/19/14; 2:46 pm
  5. Manual Low Glucose Suspend – It’s been a thing, even before it became a thing #MLGS

    02/18/14; 12:18 pm
  6. Yay! I always love when Chris guest posts! 🙂

    Thanks for the really interesting perspective on all of this, Chris.

    Next guest post topic? More about your split basal approach…

    02/18/14; 12:38 pm
  7. Cherise #

    Interesting read. I want to learn more about your spilt basal rates:)

    02/18/14; 1:10 pm
  8. As a user of the 530G, I can say that 1) in my experience, the sensor is not as good as the G4, but is better than the old SofSensors which brings me to.. 2) I actually prefer MLGS over the pump doing it for me. The sensor can be off a lot at times, and if it reads you’re low when you’re not, you can go higher than you already are. Case in point, it was bugging me all morning that I was in the 50’s. BG was actually 130-140 range. If I had LGS enabled, I would have been higher. But when it reads right and actually does suspend when I need it to, it’s actually pretty cool. I use the sensor for when my hubby is away on business, so I have a backup CGM. It has actually helped me through quite a few overnight lows. I have an unwavering fear that I’ll pass out and my son won’t know what to do. When he’s older and can be trained (even if it’s just to use the telephone to call someone and to know to unlock the door), I may not rely on it so much.

    BUT – to the topic of the post – I do find that I don’t have to treat the low with quite as much food/glucose if I do let the pump suspend or if I do a manual temp basal at 0% ( I can’t remember to unsuspend it if I’ve done it myself) rather than going with an eat-all-of-the-food-supply approach.

    02/18/14; 1:26 pm
  9. Sarah #

    I love the MLGS! I’ve always done something really similar using my IOB countdown on my t:slim. When my blood sugar is low/in nerve wracking near-low territory, I take care of it with glucose as sensibly as I can, and I set a temp rate of 0-35%, depending on the severity of the low, for as long as my pump says I still have active insulin on board. As long as my glucose consumption doesn’t spiral out of control, like it’s sometimes been wont to do, I end up with a really nice flat line around 130 or so throughout the night. I LOVE MY TECHNOLOGY.

    02/18/14; 3:35 pm
  10. When I started pumping, I remember explicitly asking my trainer if I should stop my basal if I’m experiencing a low (this was before I had any sensor, much less one with LGS). She answered with an emphatic NO — that by the time the basal-stoppage took effect, it would be too late and I’m better off just treating the low.

    With that said, I’ve been practicing “pre-emptive MLGS” lately. If I’m at about 95 and decreasing, or maybe I’m at 110 with a slight decrease and a lot of insulin on-board, I’ll set a temporary basal of zero for about an hour….

    We can all learn from new features, even if we don’t use them.

    02/18/14; 6:00 pm
  11. I love this idea! This is what we should be doing with current technology. The only way that we can control this disease is if we experiment, and as much as (my) doctors hate this, I can’t stop. Sorry, I’m not sorry doc. We are the masters of figuring out what works for us, and just like you said, it might not be measurable or quantifiable or whatever, but if it works, you should stick with it.

    02/18/14; 9:57 pm
  12. We have also been using these MLGS techniques with good success since before the 530G was released. In addition, we have experimentally determined (for N=1) while developing the #DIYPS that the body has an effective maximum carb absorption rate (grams/minute). That means that once you have eaten more than a certain amount of carbs (~24g) it will take some time (~1h) to absorb them all, and eating extra carbs won’t make BG go up any faster, it’ll just result in more of a rebound later. So if you’re heading (or already) low with plenty of carbs on board, a zero temp basal / suspend is the only way to mitigate the low further.

    One other thing we found is that MLGS is useful for preventing gradual nighttime down slopes from turning into lows. If we set the CGM alarm to say 90, then a 1h temp to zero will usually keep BG above 70 without causing a big rebound.

    02/19/14; 2:34 am
  13. I love the MLGS (in the form of very low or 0% temp rate). I’ve been using it for years to prevent lows but not to help treat them. Perhaps I am lucky to only very rarely have lows that are so stubborn I would use it when actually low. I probably use this technique most often just before bed when blood sugar is in the 70s or in the 80s and dropping slightly. Befor using a CGM, I even would do two tests 20 min apart or so to check the drop factor.

    02/19/14; 5:52 pm
  14. Tatjana #

    I’ve been using MLGS with my Cozmo:
    – when my bg level was falling and there still was a significant amount of acting time on the last bolus left, I’ve set a temp BR of 0% for the duration of the remaining acting time of the last bolus to keep the BR from adding to the surplus of Insulin. This would not result in a lack of basal insulin, since the overly generous bolus applied before already filled that gap. This would definitely save me some carbs I would otherwise have had to gobble to counted the low.
    – when my bg level already was at rock bottom, I’ve taken carbs first, and then a temporary BR of 0% for one hour that would revert to my lowest “normal” plateau after that hour as a safeguard if I would forget to turn the temporary BR off afterwards. Again, due to the overdosed insulin earlier, during that hour there’s no fear of a lack in basal. Depending on the real amount of basal insulin needed after that hour though, a gap might start to form in the hours to follow if I forgot to turn the pump back to its normal basal pattern.

    Why it works (at least according to my doc):
    Both time to act, and duration of action depend on the amount of insulin applied. I.e. a bolus of 12IE will take longer to reach its peak than one of 4IE, and also take longer to wear off.

    In the high U100 concentration, a certain amount of molecules will stick together even with the fast acting insulins. To disaggregate, they need to get diluted. This process happens by osmosis from the tissue around the injection site. A small dose of insulin gets diluted faster than a large amount, and thus is able to pass into the bloodstream a lot faster. Based on this chain of reasoning, the minute amount of the basal rate gets absorbed pretty much immediately. The reason for the BG level rising about an hour after a lack of basal insulin is not due to the direct bg-lowering effect of the insulin given in that basal rate an hour ago (that has effectively passed), but the increasing lipolytic effect the lack of insulin is setting into action. An increased amount of fatty acids then means that the insulin currently available (from the basal rate right now, or a bolus) will also have to tame those beasts before it can do its job bg-wise. And there’s your resistance to insulin, and why it takes more insulin to get out of that condition than there was lacking that hour before.

    (Sorry if I’m seriously lacking in vocabulary to explain my limited understanding in the passage above. Keywords for further reading would be: hexamer-monomer/dimer shape of the insulin molecule and its absorption, and lipolysis and the role of insulin in it)

    06/11/17; 3:12 pm

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