Tandem T-Slim X2: I am having to change the site more often than I used to

[RobertJ]

I have been on the Tandem T-Slim X2 for over a year. I have been on the closed loop system with the Dexcom G7 since June.

Sometimes I've had great periods of results. I've occasionally had days 100% in range. Recently, however, a terrible thing has been happening where I have unexplained highs by the third day of an infusion set. This makes my life more stressful because if I am travelling about, I don't know if I can trust the pump to work by day three.

I am careful to check the site and I try and move them around a lot. Do sites stop being able to absorb insulin after a certain amount? I have noticed after large meals (with large doses) I sometimes have to change the site early.

Here is what happened today. I woke up on a reading of 7.8mmol/L. After a shower it rose to 8.8. My breakfast was about 30g of carbs so I put that into the pump and dosed for it. By the time I sat down for breakfast it was 9.5mmol/L. Two hours later it's 16.6mmol/L, and this is after Control IQ raised the basal and gave me a correction dose an hour ago.

So basically I have had a completely normal morning and I'm sitting here on a reading of 16.2mmol/L for no reason. This isn't supposed to happen on the closed loop system after a small meal.

 

[Richard F]

I have a similar problem but with Omnipod, sometimes ok sometimes not a bit unpredictable.
Frequent site rotation does seem to help though.

 

[Hopeful34]

Which cannulas are you using @RobertJ and do you use extended bolus at all?

 

[RobertJ]

Which cannulas are you using @RobertJ and do you use extended bolus at all?

I am using the plastic ones, or basically the ones that aren't steel. My levels have remained about 10mmol/L even eight hours after they rose. I've changed my infusion set an hour ago but nothing has improved yet.

I actually think this was an issue with bubbles in the tubing. I think I'll be more careful with how I load the syringe with insulin and how I extract air from the cartridge.

Saying that, I'm not yet sure my recent site change has worked. I am also not yet confident I'm going to successfully resolve this wider problem. It would be great to get back to a full three days of the pump working well though.

 

[searley]

I don’t see any reference to the insulin you are on

The pump is only approve for insulins. Novorapid and humalog

Novo is a day set change
Huma is a day set change (can often get days)

Other insulins are not approved and some like fiasp can cause problems

 

[RobertJ]

Hello, @searley. I am on Novorapid.

I should say, things have been normal again since I changed my site. I think it was an issue with bubbles. I read the manual and watched a video on changing the infusion set, and I think I need to be a bit more careful with this process from now on.

 

[RobertJ]

Perhaps I spoke too soon. Even after a site change, I am experiencing another three-hour high (and counting) after a meal. I had a cooked breakfast at a cafe with two cappuccinos.

I began on 5.8mmol/L, so a good reading. I must have underestimated everything but three and a half hours after starting the meal my Dexcom says 14.4mmol/L and a finger-prick test says 13.3mmol/L.

This is supposed to be the closed loop system. It's supposed to be an artificial pancreas! This doesn't seem right.

 

[Juicyj]

Hi Robert,

I have to admit that both using Novorapid and the Tandem Slim with control IQ, I too was experiencing similar, however mine were more regular than just every 3 days and with highs being stubborn to bring down, at the time Ljumjev wasn't licensed for the Tandem but was happy to try anything, my DSN agreed to me trying this and it's changed my control massively, I was hitting 65% TIR on Novorapid and now getting 85% with Ljumjev, it's licensed now according to online sources so shouldn't be an issue, it starts working immediately and does sting due to the preservatives in the insulin but worth a go.

 

[EllieM]

I'm getting the mid 80s with humalog. My main issue is that I am a lot more insulin resistant if I go up to 9 or 10 so need to manually correct highs. Don't quite have the nerve to alter my correction ratio because I don't want to risk lows... But it basically means I do manual corrections for most highs. Livable with, and much better than the state of affairs when I was on MDI, when I would get highs that lasted for hours.

How much did you count the capuchinos carbs at @RobertJ ? Personally I find cafe's easier if I swap them out for a long black with milk (ie a small amount of milk in a black coffee), their carb content always seemed to be much higher than I was expecting...

 

[Chas C]

I can have these issues (on odd occasions) and I'm pretty sure its site related, I rotate sites using my stomach and find that I can get just about 1 month on each side so each side gets a months rest. If I get a bleeder and forget then even after a month going back to same location can cause issues. I'm pretty strict with rotation order as my legs suffered badly in the 70's and 80's when I took no notice.

 

[RobertJ]

I can have these issues (on odd occasions) and I'm pretty sure its site related, I rotate sites using my stomach and find that I can get just about 1 month on each side so each side gets a months rest. If I get a bleeder and forget then even after a month going back to same location can cause issues. I'm pretty strict with rotation order as my legs suffered badly in the 70's and 80's when I took no notice.

Thanks, @Chas C . I think my problem has been more to do with changing the infusion set rather than overusing sites. I think in recent times I haven't been careful enough removing bubbles. For example, it was only recently I discovered that you're supposed to put the pump upright when you fill the tubing. This is because, when I first got the pump, I didn't bother reading the instructions. I had some lessons from my diabetic clinic and wrongly assumed that was sufficient.

 

[Chas C]

Thanks, @Chas C . I think my problem has been more to do with changing the infusion set rather than overusing sites. I think in recent times I haven't been careful enough removing bubbles. For example, it was only recently I discovered that you're supposed to put the pump upright when you fill the tubing. This is because, when I first got the pump, I didn't bother reading the instructions. I had some lessons from my diabetic clinic and wrongly assumed that was sufficient.

Good to hear your getting sorted. I always draw out any remaining air in the cartridge with the syringe before I load up with insulin too, this works well for me.

 

[RobertJ]

I have another question for fellow users of the T:Slim X2 who are on a closed-loop system with a Dexcom G7.

If your blood sugar goes above 13.5mmol/L, how long does it take to go down? I ask because, once it goes above around that level, it seems to be guaranteed that I'll be high for three hours minimum. Is this normal?

 

[sninge]

Mmm well yes for me if I leave it to closed loop alone to bring it back in range! To be fair I was talking to my friend earlier who is on Medtronic closed loop and it's the same for her! We have both been pumping over 16 yrs so we over ride our pumps to help speed things up as we were used to being more hands on. I think this is easier to do on tslim as we can just put half a unit into a bolus without having to lie about carbs! For me I need to do this as my insulin active time is less than 2 hours not what the pump is programmed to believe, which I think is something like 4hrs!!
Closed loop is a long way from perfect but a massive step in the right direction and personally I wouldn't want to be without it now after 2 yrs on tslim closed loop!

 

[EllieM]

I have another question for fellow users of the T:Slim X2 who are on a closed-loop system with a Dexcom G7.

If your blood sugar goes above 13.5mmol/L, how long does it take to go down? I ask because, once it goes above around that level, it seems to be guaranteed that I'll be high for three hours minimum. Is this normal?

It would be normal for me too but once I go above 10 I find myself a lot more insulin resistant so just manually extra bolus.... Unfortunately there seems to be no way for me to tell my pump that insulin to bg change ratio at 10 or above is very different from that at 6 or 7....

 

[sninge]

That would definitely be something that they can improve on with future pumps, and especially insulin active time. It is early.days with closed loop and so much better than anything we have ever had before!
There was a time when we wouldn't even have been able to work out we were more insulin resistant above 10!

 

[megan]

I have another question for fellow users of the T:Slim X2 who are on a closed-loop system with a Dexcom G7.

If your blood sugar goes above 13.5mmol/L, how long does it take to go down? I ask because, once it goes above around that level, it seems to be guaranteed that I'll be high for three hours minimum. Is this normal?

I have this. It takes ages to come down