My T:slim and Dexcom Journey: Observations, Questions, Compliments, and Concerns

I know there are a few threads around here about transitioning to the T:slim, but I really think I’d like to make this my official one. So I can dump it all in here… because there’s going to be a lot to dump. :smiley:

I have so much to say, and I’ve just been a little overwhelmed the last few days and haven’t felt like saying much at all. Things are starting to look up a little though, and I’m ready to talk. So take cover. :smiley:

I guess I’m going to bulletpoint stuff because it I don’t, it’s going to turn into stream of consciousness… as usual. :roll_eyes:

-I did my first cartridge fill the other day, and it was really quite a scene. I had problems with the syringe and managed to plunge about 40 units of insulin all over my phone and IPad and pump instead of inside of it.
*I did my second one about 2 days ago, and it went much, much better. Thanks to @Thomas’s idea, I was careful not to tighten the needle too much in the assembly of the syringe, and then I was also careful to pull back the plunger all the way, therefore getting all of the air from the cartridge. I don’t think I did that the first time. I was afraid I would pull the plunger out if I went all the way because that is what happens with my Medtronic plungers. This one stops though, and I think pulling it to the end was all the difference in the pressure and the ability to push it back in with ease. I’m just thinking out loud here. But with bulletpoints. :smiley: The point is, I think the cartridge fill is going to fade off into a “second nature” kind of thing that ends up being no more time consuming or any more involved than other fills. I’ll probably plunge 100 units into my eyeball on the next change just because I’ve jinxed myself.

-Basal IQ… I know it was recommended to stay out of it, and I was staying out of it— and very happily so. I’ve been wearing my pump for about a week, carrying my reader, and just getting used to some of its sounds and the feel of it all (love the touchscreen, by the way— it’s addicting) :smiley: Anyway, the point is, I thought I had it turned off. Turns out, I just hadn’t started the sensor on my pump yet. So I just wasn’t thinking when I hit “start sensor” from the pump… that it was going to change anything. I know this isn’t doing wonders for your confidence @Thomas or @Jattzl, but I’m getting myself together— it’s just slow. ANYWAY, i didn’t realize what I had done and was surprised to see, upon waking up from my nap, that I was 40 minutes into a suspend. Surprised and a little startled. I wasn’t ready. I’ve kind of been in since only because I’m curious now. It might be too soon though because I find myself wanting to override everything, and I think that’s carry over from what I needed to do with the 670G. In limbo. I’m in limbo, and either I need to get in and let it do what it wants so I can see what that is, or I need to put it away until I’m ready. It’s a tough decision, but I’m also not hitting “off” so maybe I’m already making it.

-My overnight Basal IQ was great last night, and there were a whole lotta suspends. That part looked really good. I was struggling a little with my sensor yesterday evening though, and I wasn’t quite as happy with that part. My sensor was showing a low reading even though I wasn’t that low. It was actually showing a 43 when I was at a 98. It was in a suspend. I decided to calibrate to try to get it out of it, but it took at a 70— and put me right back into it. I decided to override and just watched for a while, and after some time, it got back to where it should be, and it has been great since. I’m curious though what others do with that scenario. This was a common scenario with the Guardian, but I’m not sure if it is with the G6. Should I have calibrated, or should I have just done an override? Today is good, so I’m comfortable with what I did, but I do hear from others they don’t calibrate at all…

I had a lot to get out. Sorry for the length. There’s a little catch up talking to be done. :smiley: There’s also coffee and running to be done, so I’ll be off to do them.


I love bulletpoint.

When you remove this cartridge, use it with water. Practice filling it.

Correct. By default, this is on. And just waiting for a transmitter to start sending data. Tandem has done everything they can to make this easy. If you are going to use the Basal-IQ right away, my suggestion is to see what it does. Turn the two Basal-IQ alarms on (off by default) so you are alerted when it suspends and resumes. Once you get used to it then probably you won’t need them and especially at night they would seem to serve no purpose.

If you are going to use the Basal-IQ then let it go. Do not anticipate that it cuts in too early or resumes too soon. Give it a try. Maybe it will simply work. It works for us. Just bear in mind that Basal-IQ can obviously not overcome everything. If you have excessive IOB then just suspending basal is clearly not going to prevent a low. You have to be reasonable.

The reason for the suggestion was to give you time to get the pump configured. Trying to use Basal-IQ with a pump which is not yet configured and does not yet have the proper basal rates can not possibly work. You must have a well configured pump. Think of Basal-IQ as fine-tuning the configuration in the pump which you are already running.

IMHO what you are looking for are multiple smaller suspends. @Chris has some really good pictures up for what appears to be a well configured pump running the Basal-IQ. You see it cutting in and out. A bad configuration would be the Basal-IQ going into suspend mode for two hours solid then timing out for 30 minutes then kicking back in for another two hours. That would be bad and means you are asking Basal-IQ to do something which it can not do.

I decide the reason for the 43. If this is a compression low then you can not calibrate out of a compression low. Trying to do so (IMHO) will screw up the calibration long term for the duration of the session. If this is a compression low (which potentially is worth another thread if you want to get into the details of that) then I wait it out. First, shift the body (usually a sleeping body) to roll to the other side or something like that. Remove the pressure. Then give the Dex 30 or 45 minutes and it usually comes up. Then check with a meter to ensure the numbers are back where they should be. In the meantime, I would have checked with a meter on the spot and if I saw Dex=40 and Meter=110 then I would turn off the Basal-IQ while I work with the Dexcom compression low issue.

Hint. When I turn off the Basal-IQ then I set an alarm on my phone for an hour. Otherwise, I can get distracted and forget to turn the Basal-IQ back on. We might turn it off for a compression low or other sort of Dexcom issue. We might also turn it off when eating if we are using an extended bolus based on the food type and starting with a good BG. Otherwise the Basal-IQ can easily kick in for a very short period and immediately cancel the extended portion of the bolus. So we might turn it off for an hour but the key thing is to remember to turn it back on - hence the phone alarm. If I assume that I will forget than I mostly eliminate another issue.

I only use calibration on the G6 if I truly feel the calibration is off. Not if there is a problem due to other circumstances. I very rarely use calibration on the G6. I am more apt to wait it out for an hour maybe and then recheck with a meter. That is quite effective however I am sure this can be quite different from individual to individual.

And it depends on how many days the G6 sensor has been running. If the sensor is at the end of its useful life then calibration still is not going to help. For us.


Another trick I used after that was to inject a little insulin into the cartridge and pull it back out and bubbles would come too. I’d repeat that; the bubbles got smaller and smaller, to suds then champagne and finally basically no more air. Then I’d remove the syringe from the cartridge, fully expel the air (rapping it with a pen and so on or however you liked to get air out of Medtronic reservoirs). Then I’d reinsert the syringe into the cartridge to fill it up.

Sounds like the Basal IQ might be working ok for you. Why not continue with it unless it’s really causing a problem?

Was it a new sensor? With a new sensor sometimes there’s a significant drop like that during the first several hours, but it corrects itself. They say that the local trauma from inserting the needle causes a bit of tissue damage, and the repair process needs energy so it sucks up glucose from the damaged area until the repairs are done. If you calibrate during the false low, then you’ll get a false high a few hours later, so I generally just wait it out (with slightly gritted teeth during the alarms.)

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That’s really interesting. I’ve never heard that but it makes sense. My first 4-12 hours with the G5 artificially trend towards drops.

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As usual, you guys have said 1000 good things. I want to respond to it now, but family has just arrived, and I’ll need my wits about me to survive the visit. :grin:

I’ll drop in a couple of my pics and then will be back, assuming they haven’t broken my spirit, to respond to what you’ve said. It really was good stuff.

12 hour was my overnight, 6 hour was my morning, 3 hour my run prep, and 1 hour was my actual run. And it was a tough run. All of them included suspends, and numerous suspends at that, and it’s just been pretty stinkin’ good.

Sorry for the pic dump, but the family is beginning to come through the door. :grimacing:

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This is a great idea. I’ll hang onto the next one.

I honestly wasn’t planning to do it this way. I thought it was a great idea to start with it turned off. Then I was in, and then there I was. Someone in my group, because I did actually go back and ask how both the T:slim people and 670G people handled their suspends, gave me a name for my current condition… said I was struggling with PMSS, or Post Medtronic Stress Syndrome. I laughed, but I am. I was a wreck when I saw the first couple of lines on my screen—- but just 36 hours later, I’m getting cozied up. I think I’m going to like it, and I do have all of my alarms and alerts set so I can used to what it does. I really am feeling better about it all and am thinking I just might like it. I’m repeating myself.

I don’t know how not to be. :smiley:

Excellent information. Mine is cutting in and out. That’s the part I was hoping would be great, and I’m starting to think really is great. I won’t ask it to do my job for me. I just don’t want it making my job harder.

More great information. This was not a compression low. I was just sitting in bed with nothing on or against my sensor. My sensor was just struggling a little. It was bad enough I was starting to think about calling Dexcom and seeing about a replacement. Then I calibrated, and it got itself together and has held on since. I do plan on seeing whether or not calibration helps the cause. I know many people say no, but I’ll enjoy checking it out for myself.

And now I see you talk about it right here. Yes, I think I’d like to try it with numbers that just aren’t right but have been struggling for a substantial amount of time. I also won’t try to calibrate when there’s a discrepancy due to a rapidly changing blood sugar, and, I’ve never had this before, but if it looks like I’ve got a compression thing going on.

Thanks for all of your pointers. I appreciate your taking the time!


That sounds great… but I’d be afraid to try it without actually seeing it, I think. I could see myself really fumbling this. Although I could maybe give it a try on the cartridge I’m keeping to use for practice with water, right?

I can put in a little practice with this. I think that’s what I’m hearing.

I’m doing just that. I think I just got cold feet there at those first couple of stripes. :smiley:

It actually wasn’t the first day of the sensor. It was more than 36 hour in. This is really interesting though. I’ve read a lot about FBR, or Foreign Body Response that occurs when we first put in a sensor but nothing about the glucose stuff you mentioned. I’ll have to find some reading on it. I’ve yet to have the problem yet but wouldn’t be all that surprised if that changed.

Falling asleep and probably not still on topic. Sorry. :slight_smile: Must sleep now.

Aaaand I’m awake again. :woman_facepalming: So close.

I realized I left you a heap of pictures of my trends but nothing of my suspends. Wow, and @Eric’s got me thinking in diabetes rhymes.

Here’s what the last 12 hours has looked like for me— and I should mention I had a big run at around 1, so this really would be more than usual, but in terms of the duration— how’s it looking??


It looks good.

Perhaps a bit more “red” (ie - active Basal-IQ suspend) then you might want. Two of the areas, I would be a bit concerned about but perhaps would make more sense with the associated information (ie - activity, carbs, insulin). The first sustained low that looks to be about 3PM or so and the last portion with the rapid rise and fall looks to be around midnight.

But without all the other information it is hard to really say.

How much do you use extended bolus? I don’t recall if we spoke on that but extended bolus take extra special care in conjunction with Basal-IQ. The rules around such, I do not consider “good” or “bad” but rather the rules are what the rules are. IMHO the most important thing is to completely understand how extended bolus works with Basal-IQ. And then use those rules to your advantage while making sure they are not being used against you.

On the other hand if you don’t use extended bolus then save that for later when you have more time under your belt with the entire X2 system.

In that graph your BG is falling all by itself every time the insulin turns back on. That would say to me that you have too much basal, except that it’s likely caused by your big run. Maybe you could have avoided this by taking a bunch more carbs and insulin right after the run to replenish the glycogen (the “refueling” that Eric talks about), or lacking that, it might have helped to use a lower basal for this night. [Edit because I was wrong; hat tip to Thomas. The suspend cancels an extended bolus but it does not cancel a temp basal. The temp basal will resume when the suspension ends.] But as has been mentioned, the first suspend would cancel a temp basal, so instead of using a temp basal to reduce the insulin overnight you’d probably want a different basal schedule for big exercise days that lowers the basal overnight.

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Slight correction - possibly just terminology.

The Basal-IQ when it kicks in will cancel an extended bolus and will suspend basal including temp basal.

When the Basal-IQ turns back off due to the start of a rise in BG and insulin delivery is resumed, the extended bolus does not resume as that was completely cancelled. However the temp basal does resume including whatever temp setting was previously running with the one exception if the timer on the temp had run out.

In summary, Basal-IQ cancels extended bolus but only suspends basal including temp.

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Thanks for the correction. I got it backwards and will edit my previous post so I don’t spread the error.

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@bkh, is there nowhere on the screen to see boluses though? Because I also do a little insulin when I’m treating for a low… sometimes. I don’t do it all of the time, but if I know something I’m eating during a low is going to cause a big rebound, I do some insulin while I eat. I think the boluses in there might also be why my blood sugar turns downward again at those points, but I have no way of knowing without checking bolus history— right?

At some point, I’m going to have to look into these report things. I used to use Carelink for Medtronic religiously. It was a great resource in helping to identify some of my big problems, but I have no idea where to start here. Do you use any of them?

Do you use the T:slim?? :grin: I should know, and now I can’t remember…

Home screen shows IOB.

History will show detailed info about bolus.

We will also use insulin at times when low depending on how many carbs. Sometimes low with only 6 carbs just for a little BG bump then no need for insulin. Sometimes low and hungry anyway and want 35 carbs then insulin. That part is probably not specific to the X2 and I would assume similar to anything whether another pump or MDI or whatever.

With one exception. On the X2 and with Basal-IQ active due to low BG (or predicted low) then insulin delivery is suspended. Meaning no bolus. The fix? Turn off Basal-IQ. Bolus. Immediately turn Basal-IQ back on.

Which is another interesting tidbit. By now, you know the X2 is super slow (compared to other pumps) when it does a (regular) bolus. Slower than the Animas Ping in slow mode. lol.

So, assume low BG and Basal-IQ is active.

Insulin delivery (all) is suspended.

You want to eat 35 carbs with your low BG.

Turn off Basal-IQ (just a couple taps on the screen - super easy and fast).
Immediately bolus whatever insulin you determine is appropriate.
Bolus starts but will take maybe a minute or couple minutes to finish.
That is ok. You can still immediately go back to the Basal-IQ screen and immediately turn the Basal-IQ back on.

Even with Basal-IQ on, the bolus will complete. Basal-IQ even when active will NOT stop an active (non-extended) bolus from completing.

Make sense?

That is one of the detail portions not worth getting into right at the start but you are moving really fast with the X2 (and by all appearances doing very well) and you brought it up so I mention it now.

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I did, and preferred it to the 723 I had previously, but to run LOOP I needed to go back to an old 722. So the t:slim is still in warranty but sitting on the shelf for now. If the 722 fails I’ll pick up the t:slim again.

I’m so glad you mentioned this… I do have some questions about this. The suspend feature on the 670G becomes unavailable for some time after you override a suspend. It was a nuisance because if you felt you didn’t need that particular suspend, you were canceling out the suspend for at least a half hour afterwards (and I think longer). So I have been very curious about what happens when you override a suspend on the X2. For the last couple of days, I have only decided to override when I’m treating a low with a good amount of carbs and don’t want to miss that bolus (just like you mentioned). So I override the suspend and give the bolus. Last night (and I thought I’d seen this a couple of times over the course of 3 days), Basal-IQ immediately suspended again after the bolus was done. Maybe I’m wrong, but I was hoping I had seen that correctly. I would love to have this thing helping me slow down the insulin during one of these periods but without making me decide whether or not to get a bolus. Now I know I can do what you’ve suggested in such instances, but is there any chance I won’t need that? Any chance it is allowing me to jump out of a suspend to give myself a bolus only to return me to it again as soon as it’s finished? I’m heading out for my run now… I imagine I’ll have some opportunities today to observe. I’ll make sure to pay closer attention.

It does, and I appreciate it. I’ll reread your comment when I get back. I appreciate all of your information.

You are not wrong.

Super easy and quick to turn it off and back on.

The only reason you would think otherwise is from your 670g “AUTO” experience.


You are really doing excellent with using your all of your experience to your benefit while at the same time not allowing the other experience to confuse and drag you down.

Big thumbs up !!!



Thanks, @Thomas. I appreciate that.