I’m thinking I don’t agree with you in the context of the 670G. As far as I recall, there were a few knobs that can be turned, although I don’t remember what they were. Maybe two of the following three? ISF, I:C, duration of insulin action. If there are any knobs at all, they can be turned to explore cause and effect without actually knowing anything about the algorithm in the black box. And then there’s always lying about the number of carbs consumed, even to the extent of announcing phantom carbs that were never eaten.
That said, in the context of the 670G I’ve only read two kinds of user experiences. Folks who basically just let it run by itself for a week and it worked ok by their standards (A1C between 7 and 8?), and folks who tried to get tighter control by adjusting knobs and who were largely unsuccessful and frustrated.
I think the concept of basal testing is perfectly sensible in the context of the 670G. Several hours away from exercise and food, watch what the CGM graph does. If it stays more or less flat at some half-way sensible BG, that would be interpreted as correct basal delivery. If the BG consistently climbs all by itself, that would be too little basal. If the BG consistently falls all by itself, that’s too much basal. And if the CGM graph just wanders randomly out of range every which way, that could be evaluated as “this closed-loop algorithm is worthless junk.” Although before totally giving up on auto mode you may wish to turn some of the knobs (ISF, duration of insulin action?) to see if they make it work any better. I can’t give tips on how to do that, except to point out that if you say you have a smaller insulin sensitivity they will tend to administer stronger correction doses (possibly overcorrecting a high into a low) and if you say that your insulin only has a duration of 2.5 hours they will tend to give less of it up front for a meal, kind of like more of a square wave instead of a regular bolus.
You recall quite well. This was why I thought to ask these questions here. These were the things I wasn’t willing to change the first time around as my overarching concern for eternity is driving myself into hypoglycemia. It felt like turning these knobs when my body didn’t need me to do so would result in more unpredictable lows than what I experience in manual. My lows are abundant in manual, but they are not unpredictable.
I’m in and out of auto right now, and it’s just a higher maintenance mode with less control. I have talked to many people who are in auto and who are happy, but the longer I engage in conversation, the more information surfaces. Many of these people are not happy with auto alone, they’re happy with auto AND manual injections. I’m not sure, actually, that I’ve met a single person who is having success in auto who has not admitted to using one (or all) of the tricks. There’s no shame in it. For myself, however, if I’m putting in this amount of time and energy, I’d like it to contribute to my understanding of my body and disease. Can’t get that in auto. There’s just too much mystery.
Thank you. I can’t expect good answers to a bad question, but I think you got what I was trying to communicate. The main argument about people’s high blood sugar in auto is that their “basal settings in manual mode were wrong and that their basal was carrying the weight of incorrect carb ratios*. I watched time and time again, without ever touching a bite of food, my numbers hit the 200s-300s (or 400s). I was sure that explanation was gaslighting, but I wasn’t sure enough not to come around here with the question. I easily can run a basal test in manual and get a decent result. I can’t think of why I wouldn’t get an excellent result, but I’ll say “decent” just to be safe. I have done hours on end in auto without consuming anything and have ended very high. I felt that should be an adequate summary that auto mode is not able to determine and deliver an appropriate basal rate in my case. It is my understanding, generally speaking, that we need a good basal before we attempt tweaking our active insulin time and carb ratio. This is the opposite of what we are encouraged to do in order to get auto to work.
As I explained, I talk about these things all day long in my other group. I don’t plan on staying in auto for any longer than it takes for me to confirm what I can and to correct any misconceptions. So I’ll do my basal testing, as best I can, and see what auto does without adjustments. I’ll consider the next step once I see that.
At least it isn’t able to do it immediately. I’ve heard some claims that it takes a week to adjust itself and figure out what it should be doing, but if you use tricks to force it to behave, that will foil its learning strategy and it will never learn how to do it by itself.
For myself, I wouldn’t have the patience to watch it badly botch my BG for a week and I’m not allowed to intervene while it tries to work things out. I get along fine with the LOOP software because it is quite transparent and straightforward in its behavior. I understand it well enough that when it is doing it wrong I can overpower it and surf my way out of trouble, then let go and it will settle back to its usual good behavior.
I left it alone for a good month. Just let it go. It didn’t learn. The thing I DIDN’T do was change the settings. I talked to Medtronic a couple of days ago and asked about the settings adjustments and if one could expect better results in changing them, and her answer was basically, “no”. Unfortunately, every phone call into Medtronic potentially yields different answers. I don’t think Medtronic knows what is going on either.
I don’t either. I’m trying to gear myself up for a couple of days all in knowing I could do way worse by my own hand. The last rep I spoke with actually recommended trying it this way—spending a week going in and out of auto so it could learn how much insulin I need, and THEN to try to stay in. We’ll see.
Hence my suggestion to read through @drbbennett posts. His are rather extensive with really good information. In my opinion he was extremely non-biased in his approach.
Just two, actually: AIT and I:C ratio. The latter settings can vary by time of day, but officially only affect bolus calculations. AIT is the most powerful in terms of making the pump more aggressive about corrections and keeping you at target, but it bottoms out at 2hrs–if that doesn’t do it for you, too bad. And it didn’t for me.
Why thanks. I wanted it to work, and tried to give it as fair a chance as I could. I didn’t resort to any of the tricks like “phantom bolusing,” because if I was going to have to resort to fooling the thing it was hardly fulfilling it’s promise to learn my metabolism and take the guesswork out of managing my bg. I did get very assiduous about counting every carb I could, maybe erring on the high side just a leeeetle bit.
One thing is that they do measure success with it in terms of time-in-range, which is the right measure as a lot of us have been arguing for some time. And a lot of the people who are happy with it are feeling that way because their t-i-r is much better than it was before. So that’s a good thing and nothing to scoff at. But if you were doing pretty well on that measure beforehand it may not seem so hot. Thing is, you can go along spending a lot more time at the top of your range than you’d like and still have it count in that percentage. I heard “Well, you’re time in range is pretty good,” from my trainers quite a bit, but it was as good or better before I went on the 670 and less of it was spent cycling up along the top line.
They told you whaaaaat? Kinda wishing I hadn’t arrived late to this party–I’ve been scanning the posts trying to determine what adjustments you’d made to AIT, because that’s the key. If I can summarize what I’m getting: your original question about basal testing arose because you’re seeing your numbers drifting up and up even when you’re not eating, so something is out of whack. And you’re right. The answer to that is to try adjusting AIT downward. Someone spoke of the fact that the algorithm takes some days to integrate changes, which is correct (and frustrating) so don’t go too crazy. I eventually took mine all the way to the 2hr minimum over a couple of weeks. It did make a huge difference, so that’s the first thing to work on.
The thing you have to understand is that, to paraphrase Inigo Montoya, “That word doesn’t mean what you think it means.” I’ve written about this elsewhere, but the difference between microbolus and basal rate is huge. Yes, it’s calculating each little blip every 5 minutes, but it’s important to know that AIT is a critical element of that calculation. Most of us start off with it set too high. The concern is that if AIT is too short, each microbolus will overlap too much with the previous and the next one, essentially insulin stacking, so as alwaysalwaysalways with this stuff they start you off at a very conservative rate and adjust incrementally with great caution. Almost NO ONE ends up with it at the same setting they had in their manual pump.
Thing is, we’ve been taught to think of AIT as the actual amount of time insulin is effective in your system, but it’s better to just think of it as a dial you can turn to make the pump more or less aggressive. Because in terms of how the thing works, what you’re actually adjusting is the amount of deliberate insulin stacking you need it to do to get the results you want. You’re saying Yes, I want you to stack these doses, it’s just a question of how much. This is why it isn’t like a “basal” adjustment where you’re just saying gimme .75 units spread out over the next hour. With microbolusing it could be .75, it could be 0, it all depends on your metabolism at the time. But if your AIT is set too high, like whatever it was in your manual pump, the algorithm is not going to allow itself to deliver as much insulin as you actually need to catch up with your between-meals BG.
Hey Nicky, I saw a post on the /r/diabetes subreddit today that may be somewhat related to what you’re trying to do. The original poster was essentially looking for a way to get data about the 670G microboluses out of the pump to help them adjust their manual mode basals. Somebody posted a picture of their Nightscout graph while in automode, it looks like that could be somewhat useful in looking at how much insulin you’re getting out of the thing vs bloodsugar. The person who posted it also seemed to say that the graph wasn’t that useful though so I don’t know.
Not sure how helpful this really is since setting up Nightscout is kind of a technical process and I know you’ve said before that you’re kind of technology challenged I could try to help you with it if you’re interested though
This might be the line that convinces me to try the AIT change. I’ve been in auto, more or less, for about 5 days, and it’s really been a waste of my time. I can’t say it’s because auto mode is so terrible (though that’s usually my guess) because, in truth, I don’t have the time to observe while it settles. I am a different diabetic this time around… and part of that is just being much busier.
I’m going to sit and read your information. It’s certainly thorough and communicated clearly enough that there’s something in it to try. I appreciate your taking the time. The only way this is going to work is for me to disconnect from everything ELSE (FUD and Facebook) for a couple of days and free up some time to just observe.
But not overnight… You and I have had this discussion before. Auto slows down all of my insulin overnight, and it causes me to rise. It wasn’t my ONLY problem with auto, but it was a big one. I think I remember you saying that even after you had maxed out your AIT, you were still struggling with the mornings. If this setting actually does make such a difference, why wouldn’t it also affect that period of time?
I said I was going to disconnect, and all I’ve done is sit around and continue to “like” everyone’s comments. I’m going to put my phone down and back away. Now.
Because the source of the problem was not the setting but the sensors. I found them generally accurate, except overnight when they would pretty consistently run lower than reality, lagging badly as DP kicks in toward morning. If the pump “thinks” you’re at 110 when you’re actually pushing 160, it doesn’t matter what the AIT is set to.
I tried a couple of things, like waking up and re-calibrating at 3-4am, and someone at MT said you shouldn’t lie on the side with the sensor, but FFS: if I have to force myself to sleep uncomfortably and wake up in the wee hours in service of my pump, that hardly seems like “auto” anything. I finally just couldn’t think of anything else to try and starting off so high first thing in the a.m. was throwing everything else off. That was pretty much the last straw.
ETA: since that time I’ve switched to pumping with Fiasp insulin, which I like a lot. Some people are using it in automode and reporting better results. I haven’t tried it, partially because I’ve gone back to Dexcom CGM and switching back and forth is a big pain. Not sure the benefits of auto are worth the effort.
On this part, I respectfully disagree. I’m not trying to be difficult, but it’s a big difference of opinion. I agree there’s a lag. Of course. Mine can be terrible. I also agree the sensor, particularly in auto, tends to run lower overnight. This, in my opinion, only makes the problem worse. The part I can’t agree with is that the problem isn’t in the setting. Auto isn’t responding to my dawn phenomenon over night. It’s responding to its own delivery. You actually helped me clarify this point many months back. It’s the same thing it does throughout the entire 24 hour period. It gets attached to “dawn phenomenon” only because it coincides with those hours. If I happen to go into my night high, it’ll deliver a lot of insulin early and will have to slow itself down in response as I near awaking. If I happen to go in low, it’ll hit the brakes early, which will cause a rise closer to waking, which will result in more insulin. On those particular mornings, I’d wake up and start to trend downwards. These mornings are part of it, but they are far more rare than the first scenario.
The only reason I keep coming back to this is because it changes the likelihood that adjusting the AIT has a truly global efffect. If it influenced the size of micros the way you explained, and I loved your explanation, by the way, then it should continue to do so throughout the night. If it fails to do so, then there is something else to the change. It would be my guess that during waking hours, at an adjusted AIT, it would mean getting more insulin along with the corrections. It’s a way to just get more insulin on board. It would fail to do that at night unless you’re correcting at night as well.
With all of that being said, I’ve resigned myself to just leave it to do it’s thing for the next 2 days. It’s driving me high already, but if I’m being honest with myself, it’s certainly not doing anything I can’t do to myself. In 2 days, I’ll hit the AIT. I don’t think I can bring myself to slowly tune it over weeks, but I’ll try, at least, not to be stupid. I test enough to not be in any danger. I’ll have a few days to compare it to prior to the change and a few days following it.
I agree with your final judgment… that it’s just not worth the effort, but I would also like to put my “did I give it a fair shot?” thing to rest.
Nicky, if you have a chance, after you have read his comments on this thread, have a look at @drbbennett’s 670G thread, it is the best thread I have read on the net discussing 670G issues.
Hopefully it will be a help! I am cheering for you to be successful with it.
Thanks, @Michel. I actually have read it. In fact, it was the piece of the discussion about PID controllers that got me thinking about joining this group (that and @MM2’s calibration information). I had just finished reading the 670G patent at the time and had begun some reading about controllers and how they worked. I was thrilled when I came across the discussion here as it was right in line with what I was learning.
I know you might believe I don’t know much about the 670G, but I do know quite a bit. @drbbennett has definitely posted very interesting ideas about it, and I just wanted to discuss the overnights again. It was, I believe, the only piece I didn’t agree on 100%. Although I seem to be talking in circles, I am drawing myself up a plan. Because drbennett presents such a convincing case for the AIT change, it will include that. It also will require, though I don’t know how I feel about it yet, a longer stay than what I initially anticipated.
Just clearing my conscience here. I would never tell anyone Auto Mode won’t work for them, but when I say it didn’t work for me, I want to know I tried everything.
I could try to help you with it if you’re interested though
I would love your guidance. 