Tandem, Insets & Dexcom G6

My son was diagnosed 20 years ago and has been on a Tandem pump for about 12 years. Four years ago he started on the Tandem T-Slim with the Dexcom G5, then upgraded to the Dexcom G6. Some minor glitches over the years, but generally very reliable. He uses Control IQ.

We have had so many problems in 2022.

We have had two incidents where the pump was reporting his BSG as high while he was sleeping only to do a finger stick and find that his BSG was critically low. He was almost non responsive.

We have repeated issues with the Dexcom G6 sensors/transmitter losing connectivity with the pump. Our average time with a sensor has been four days.

We have repeated issues with his insets. We are using Autosoft 90 and tried Tru Steel. We rarely get 3 days out of a site now. We are at about 30 hours per site before his BSG skyrockets to over 300. We have tried new locations, and also the Tru Steel in case it was an issue with calmative scar tissue, but the results are still the same.

We are in the process of getting a new pump because the current one is at the end of the warranty. At this point, the pump is the only thing that we have not replaced and that is in common with all of our issues. Could the pump be that problematic? We have had a pump completely fail and need to be replaced, but could it be malfunctioning this badly?

We have tried to get advise from the doctor’s office, but it takes days and they are only responding to the specific matter of the moment. Any insight would be greatly appreciated.

Hi @Shyla1228 . I’m so sorry to hear about your issues. I haven’t had any of those problems but wanted to share a couple of thoughts: I like to switch up my infusion sets from time to time: I prefer the 90 degree overall (I use Autosoft XC) but use the Autosoft 30 now and then. I don’t know if there’s any validity to it but my theory is that using different angles might help avoid scar tissue.
The abdomen is typically the most used site, but even with site rotation over the years (close to 30 pumping, and 30 on shots before that) some spots may be better or worse than others; so sometimes I use my thigh or even my upper arm. Use of those muscles may speed up insulin absorption though so a CGM is extremely helpful. I think I’ve heard of people having problems with the G6 that they didn’t have with the earlier versions. The only thing I can suggest is that you try the Freestyle Libre2: it doesn’t work with the pump but does give continuous readings and alerts. You could try it to see if it is more accurate than your Dexcom.
Another option would be Medtronic’s pump which has its own CGM.
I hope you find some answers!

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Thank you. He has been using the Autosoft 90 for years with just the occasional issue. He has been relocating his insets to upper buttock, upper thigh, and still we are getting about 30 hours out of any location.

We tried the Tandem Tru Steel inset because the doctor’s office suggested it once we started having problems. We had one successful use, and then three failures where insulin was just not making it in to his system. If the Tru Steel needle is not making it through, and it is just an inset problem, then we might have hit a wall with pump use and need to go back to syringes and a pen.

I had another thought, which might be a stretch but you never know. First let me share a personal experience:
I had a body oil I absolutely loved; but I had to stop using it when I was diagnosed with sensitive skin. Nothing else worked as well, so I tried some store brand generic version to see if I could use it. I don’t know what they changed, but some small difference in the formulation made it wearable and I’ve used it ever since! So I wonder if a different formulation of insulin might work. Humalog and Admelog are insulin Lispro formulation and Novolog is Aspart formulation and these three are generally interchangeable for many, but perhaps small difference in formulation in one of the others might work. [corrected] I go with what my insurance lists as its preferred formulary so I don’t know if others are available but there may be some.
You could start by seeing if it’s the insulin or the delivery mechanism by correcting highs with injection instead of using the pump. By the way, when I’m over 300 (that’ my number - your son’s may be lower)) I find no amount of insulin will bring me down unless I drink some sugar free fluids. If that’s still problematic you could see about trying another formulation.

@Shyla1228 Hi Christine, and welcome to the JDRF TypeOneNation Forum!

It is too bad that these issues have all been with your son for so long. I also currently use the t-Slim / G6 / Control IQ combination and have had very good experience; I began CIQ within a week of its release and experienced very few issues and for almost all “issues” the blame was my clutzy placement of an infusion set. Most of the time G6 sensors react the way you mention is when they are mounted too close to a “hard spot” on the body such as rib-bone, and when outside pressure applied - especially by rolling onto the transmitter/sensor when sleeping. The “out-of-range” signal loss occurs when the sensor is obstructed by the body and the pump receiver is worn with the face aimed toward his body rather than properly facing out. Most likely your son could avoid these issues by being more aware.

You didn’t mention what Tandem Technical advised about his thought about a malfunctioning pump; he should call Tandem. He should also talk with Dexcom about his many sensor issues. He is too young, only a short 20 years injecting / infusing insulin to have developed noticeable scar tissue to cause so much difficulty.

Hi again. My thoughts come in bits and pieces and I just had another idea: have you tried using a different cannula length? The shorter ones are recommended for leaner bodies bodies and the longer ones for bodies that have “a bit more tissue.” But even if you are using the recommended one, you could try the other just to see. Your pump rep might be able to give you some to try out.

We have been able to get his BSG down by using Humalog with a syringe, so I think the insulin is fine. It also will come down with a site change. For example, yesterday at lunch his BSG was over 300. He went home and did a site change and his number was down to 170 at dinner and 177 at bed time. He woke up this morning at 303 so I gave him four units of Humalog with a syringe and he came down to 155.

That is one thing we have not thought of (the length of the canula)
so we will try that.

Thank you for the welcome. I wish I had found this site years ago. Tandem does want to replace the pump as it is at the four year out of warranty period, so we are in that process now. My son did contact his doctor’s office and did an upload so they are supposed to be reviewing the data to try and ascertain what is happening.
We have experienced all of the issues that you list, but these issues with the sensor is different. The signal will be dropped and picked up through out the day, and then just give up after three days.

Worse, when we have the sensor on, and the reading has been ‘low’ only to do a finger prick and find that he is over 400. Or a sensor reading of over 300 but a finger stick reads 150.

He went away to college for four years with no issues with the Tandem T-slim and the Dexcom. It was so reliable. The last few months we have just had more and more bizarre issues.

Hi @Shyla1228 and welcome. You’ve received input from the best but I’d like to add to a thought @wadawabbit brought up. Dehydration, even mild dehydration will cause wild differences between CGM and finger stick and can cause real trouble with blood sugar control. This could be caused by a shift in diet, exercise habits, medication, illness, environment, etc. I’m going to recommend tracking water intake for a week (just watching it could change the outcome) ideally, urine color should be nearly clear -in addition to the stuff already recommended. Cheers and good luck :four_leaf_clover:

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Sorry to hear about your issues. Yes, when CGM and pumps work well the system is great but when there are problems they seem to come in multiples and the cause is not always discernible.

We find hydration can often be a major factor with CGM connectivity, often as diet and fluid intake changes with differing seasons especially going into and coming out of Summer. The other suggestions previously given to use a shorter cannula and using a syringe to inject insulin if the delivery by pump is not seeming to lower levels, have also worked for us.

We use the True Steel infusion sets but were told that they only last for 3 days and at the end of that time the sensitivity to insulin can decrease due to the amount of time the surrounding cells have been bathed in insulin. In these situations we were advised to change the site or use a syringe to give a quick correction if required.

We also use the Tandem T slim and Dexcom G6 but turned off the Basel IQ as the BGL often sits in the triggering range to pause insulin delivery and when the insulin was paused for two hours and then restarted for half a hour that in turn started to throw everything else out of sync.

Yes, in 2022 we have also had more sensor fails and large fluctuations between CGM levels and BGL from the finger prick test than in any previous years.

Hope you get some answers that are helpful.

Thank you. We are closer to getting a new pump but now I am worried that the technology is no longer trustworthy. Could it be a lack of quality control? A software issue? The pump, the inset, the sensor, the cartridge? I am beyond frustrated and exhausted.

As of this weekend, my son is now on Lantus and Humalog. His numbers are pretty good, much less erratic. I bought a Dexcom G6 receiver which arrived today. We meet the endo tomorrow, and we will see what’s next.

I don’t know whether this would help but perhaps you could try a different supplier. If there’s a problem with production in a certain region, a supplier in a different part of the country might have better quality. That might be a longshot but you never know.

Sorry to hear about the problems your son is having. Regarding the sensor loosing connection with the pump, does he wear his sensor on the back of his arm? I often loose connection between the devices when the pump is in my pocket on the opposite side from the arm where the sensor is placed. It is fine on the Dexcom phone app, but I don’t think the bluetooth receiver in the pump is well suited in moving too far away from the sensor transmitter.

Ditto. I occasionally lose signal if my sensor is on one side and my pump is on the other - particularly if my pump is in a denim pocket. Not always, but I try to remember to keep my pump on the same side.

I use Tandem t:slim CIQ with Dexcom G6. I had problems with occlusions only when using Novolog but not with Humalog. I can use Novolog with pens and have no problem bringing down high sugars but in the pump, it doesn’t work. Novolog has aspartic acid and Humalog has proline amino acid. My body won’t accept the Novolog through the cannula whether it’s steel or plastic but I can inject Novolog with a pen and it works. That’s frustrating. I must be mildly allergic to the aspartic acid.

Update: My son is on a pump break for three months. His endo feels that he has built up too much toughened tissue under the skin, particularly on the right side. My son is 25 and has very little body fat, which the endo feels is a contributing factor to the skin not been receptive to the Autosoft inset. The Truesteel worked but we also had more bleeding issues, so we are off pump until the end of September.

My son is doing okay on Lantus (18 AM, 15 PM) and Humalog with meals. He is still on the Dexcom G6 with a receiver, which seems to be working okay.

Lots of people do quite well on shots so hopefully your son will too.
I had hand surgery many years ago and was left with a huge knot of scar tissue that was ugly and uncomfortable. My husband suggested I try raw shea butter - I massaged it over the scar at least a couple of times each day and eventually the tissue healed.
I don’t know if it works as well with subcutaneous scar tissue but it couldn’t hurt to try it. There are products that include she butter but we use the raw form - it comes in a tub and there are various consistencies from soft to firm. I don’t know that it makes a difference which one you use.