Does the closed loop suspend all basal if necessary? Our problems are night time lows if we don’t suspend it altogether for 5 or 6 hours per night.
Also it sounds like you have reliable CGM readings. This isn’t our case.
It would depend on the algorithm, but, in general, a closed loop algorithm would deliver little or no insulin when it predicts a low in the near future (or when you are low of course).
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yes, the closed loop frequently suspends all basal, sometimes for hours if necessary.
To me, that’s the huge benefit of a closed loop, or at leas the suspending for lows feature, and why I can see something like the T-Slim with Basal X-2 working for at least some people for whom the CGM isn’t always accurate. It would just be doing what I’d imagine you do sometimes at night anyways – suspending basal for several hours based on the CGM numbers. And unless someone is testing their BG literally every 30 minutes or 1 hour, I don’t see why they couldn’t see a trend on the closed loop (say, the algorithm wants to turn off basal), test with a finger stick to confirm, calibrate if necessary, and then let the closed loop do what it does, with the extra reassurance that the numbers are anchored to something “real.”
I guess it depends on how often and when the CGM is off for y’all though. For instance, for us, we have two types of situations where CGM can be off: A) things are changing rapidly, there might be a lag and a difference in how fast it’s dropping. B) If Samson is quite high and seemingly flat for a while there can be drift, where he’s actually about 20% higher than CGM reports. Sometimes when he’s high he can be flat and actually lower than the CGM says (like if it says he’s 300 he might be 200). But in that situation, the T-slim doesn’t do anything, from what I understand, as it’s not adding insulin dosing, just suspending basal. So in that scenario it would still be the same – finger prick to decide if there’s a correction needed.
For us, I wouldn’t mind having Samson’s basal suspended at night if, say, his CGM reads 80 but he’s actually 120. Because we’re fine with him being at 150 all night – happy even – so the risk to me is lessened with a program that can suspend insulin but not deliver extra.
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But I think most closed loop systems have a maximum time without insulin? Most people with Type 1 can’t go five or six hours with no insulin without risking DKA. Like I know the 670G will go no longer than two hours, and I think the t:slim may be similar. I’m not sure about the open-source options, but I think they’d have the same sort of safety system built in.
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Is there a maximum amount of time at which it cuts off for safety reasons?
From what I have heard about the 670G, part of the reason people hate it is that it can sometimes give so little insulin for extended periods of time (although my understanding is that it will only give no insulin for up to two hours) that people end up extremely high for hours.
My blood sugar starts skyrocketing after about an hour of no insulin, though at times if I’m running low, I do suspend for 30 minutes or an hour. Usually I can’t go longer than that without going super high and/or developing high ketones.
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Interesting fact… as long as the 670G is delivering .025 units per hour, it’s not being counted as “Minimum Delivery” in Auto Mode and can continue on until the reservoir is all dried up… Just .025 units per hour, and it’s under the radar. I’ve seen so many people’s Carelink reports and graph screens where it’s a barren landscape where there should’ve been a little insulin… where people have gone 8, 9 hours, if not longer, with near nothing. It’s a loophole, and it’s crazy.
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So 0.2 or 0.225 units over eight or nine hours…how has no one gone into DKA? That would definitely be my outcome (or close!) if a pump tried to do that to me.
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We have to suspend basal ALL NIGHT LONG (or at least 6 hours of the night), 3 to 4 nights of the week to prevent Liam from going low. So any system that doesn’t turn off and stay off when necessary would always be a problem. Even .025 would be too much during the nights where he’s just running low with zero IOB.
As far as how often our CGM numbers are off, I can only say it’s off 75% of the time when we do an actual finger stick. It also for whatever reason gets more drastically off if the CGM is asking for a calibration and we do not do so ASAP. In an hour, it can be off as much as 100 points.
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I think this sounds like a conflict between honeymooning and non-honeymooning Type 1s… Most non-honeymooning Type 1s would not want a system where insulin could just turn off and stay off for hours at a time. There is no way I would trust a system that could shut off (virtually) all insulin delivery for six or nine hours at a time. That is just asking for DKA for me.
I wonder if in a few years when Liam is older, not honeymooning anymore, and less sensitive to insulin, and there are better CGM systems and algorithms and maybe better insulin as well, whether you’d feel more comfortable at that point. Technology is changing SO fast…it’s hard to tell what things will be like even ten years down the road.
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I never say never. But at present, I just like the total control that I have with the Omnipod + CGM + fingersticks for verification of any treatment.
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I have 3 people in my group who have.
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There is an infinite amount of possibilities. Algorithms are all in software, so there is no limit. It would not be hard to conceive of closed loop systems where the maximum amount of time you can be suspended is a setting, and where there is a minimum amount setting for insulin delivery outside of a suspend window.
Really, when discussing these “features”, it almost has to be system by system: what can you do with the 670, with Loop, with OpenAPS etc.
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Interesting fact… the 670G, upon reaching its true limit of Minimum Delivery (less than .025 units per hour for a total of 2.5 hours), will require the user to put in a BG in order to remain in Auto Mode. If one fails to put in a BG upon request, one will be sent to Safe Basal until doing so. Safe Basal is another Auto Mode function where your delivery is calculated by the algorithm based on recent history. You can remain in Safe Basal for up to 90 minutes, but if you have failed to give it a BG before that time is up, you will be deposited back into Manual Mode, full Basal settings restored, without and suspends. The only way to activate your suspends upon leaving Auto Mode is to manually turn them on. It’s a major concern of 670G’s users— the fact the pump will not keep your Suspend feature saved. So in theory, one could experience a low blood sugar in the middle of the night while in Auto, be handed the limit of 2.5 hours of Minumum Delivery, be asked for a BG, fail to provide one due to being asleep or otherwise incapacitated, have been receiving insulin throughout that 90 minute period, and then be deposited back into Manual, full basal, without a suspend to catch them. And that piece about sleeping through the 90 minute Safe Basal?? Happens all of the time. Serious design flaw.
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@Nickyghaleb, I am simply amazed by how deep your understanding of the 670g is. I don’t think I have seen you phased yet!
You and @docslotnick with xDrip+ 
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You didn’t see me when it was attached. 
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I am definitely into the idea of a closed-loop system if it actually works well. My preferred diabetes management style would be one where I can put the lowest amount of day-to-day time and energy into it while still maintaining good control (which for me, I’d call <7% A1c, minimal time low) and eating whatever I want. For now, t:slim w/ Basal-IQ is checking all those boxes for me, and I look forward to seeing how the balance between control and effort required for Control-IQ stands up to Basal-IQ.
I am fascinated by Loop/OpenAPS but the idea of using (and needing to find) an out-of-warranty Medtronic pump is a no-go for me. I’ve already shown that those plastic pump bodies aren’t sturdy enough for me, since I semi frequently have my pump fall out of my pocket and bang around on stuff
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im also am intrigued about close loop. i have the cgm and love the tech. i look at it like i can always suspend it if im low. why not let the pump deal with my garbage calculations and math for awhile. cant be worse. i go low daily and high daily. maybe this thing can do a better job.
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I’m on DIY Loop with OmniPod and Dexcom G6 and it works well for me. It helps to keep me in TiR 90+%, but it still requires diligent monitoring and taking appropriate actions to achieve this. It is just a lot easier with more immediate actions by Loop!
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