Prefilling tslim x2 cartridges

Is there any harm in prefilling a few cartridges? Has anyone done this? We’re new to pumping!

I don’t prefill, but I do completely fill the cartridge (300 units) and use that until it is empty(about 10 days). I haven’t experienced any issues with that approach. I still change my insets every 3 days.


how long does it take to prime the tubing & set, Jim? I’ve heard that the Tandem pumps are comparatively slow to prime.

Takes me five minutes.
I take my time.
Not worth rushing.
That includes opening the packaging and priming.

Certainly a different process from the Animas. But like anything else. You get used to it. No big deal now. I still don’t rush it.

I have heard of people doing it.
However, I would ask for what reason do you want to do it?
I would not do it without a very good reason but I could imagine a few particular scenarios where it would make sense.

@Sprocket1 - What are your thoughts on this where you had the question?

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It’s notably slower than Medtronic, but like Tim the entire process (Cartidge, infusion set, priming) is probably 5 mins. I’m still new to it, so still getting the hang of it. Medtronic I was probably able to knock that out in about 2 minutes.

Good point. They don’t necessarily have to be changed at the same time do they? If we have 100u left after 3 days, we may just give that a go.

Well I just thought it would make the mid-week site change a little quicker. If on Sundays we fill two cartridges, while we’ve got everything out, we could just fill another for Wednesday’s change. Or, if she was on the go, she could just bring a filled cartridge and just change the infusion set.

But if you change just the set/tubing, how long does that take? Isn’t that what you said you do because there is so much insulin in the reservoir that it lasts longer than you want a single set to be in you?

I only change tubing when I change cartridge ( approx. every 10 days). Changing only the inset, time wise, is no different than changing a Medtronic inset.

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I thought about this but then I realized insulin degrades in plastic vs glass so I decided not to do it. That is why 3 days is recommended for cartridge changes. I have had a few instances where I was close to dka due to insulin degrading in the cartridge.

 I started my Tsiim:x2 last October.  I asked the same questions thinking I could fill the cartridge completely, which would last at least 6 days for me, or pre-fill a couple of cartridges to make changes quicker.  The Tandem trainer here in Orlando, Fl said neither is recommended.  She explained that the plastic material used to make the pouch inside the cartridge will start reducing the potency of the insulin after 3 days.
 The most I have occasionally gone past three days is an extra 12 hours to avoid wasting leftover insulin.  I have not seen any noticeable difference in those extra 12 hours.

BTW - I don’t fill the X2 cartridge to capacity (300 units).

I put what I expect will be needed for 3 days plus a bit extra.

Lately I have been filling around 180 ~ 200 units which seems to be a good amount.

Sorry I can’t agree with that statement. Pump reservoirs are not going to be reactive with the PROPER insulins. 3 days for set changes helps avoid scarring of the infusion site tissue. You could use insulin from the same reservoir for a week and unless u lay out sunning yourself with the pump in direct sunlight so long that it gets quite hot, you are not going to have an issue with bg control. I’ve even had my pump, many times, in 110+ weather for hours without incident. My wife, because she uses so little insulin regularly goes 5 days with one set/reservoir w/o issues. Recommendations from manufacturers are always ultra conservative.

That is great it works for you.

I have zero reason to ever use the same cartridge for a week.

No upside and potential downside.

Easy decision for me.

I didn’t say I use a reservoir for a week. I said it wouldn’t ruin the insulin. What we have here is a FAILURE TO COMMUNICATE.

Sorry - not in the mood today. Another day.
Continue on without me.

LOL! take care.

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I’ve used cartridges in my Diesetronic and Animas pumps for up to five days without issue. I also pre-filled on occasion. Insulin can chemically degrade, but it’s a pretty robust molecule. The pump mechanism is about as simple as you can get- just a syringe pump.

Now with the X2 cartridge, I’m cautious, only filling enough for three days. I also won’t pre-fill. The cartridge design is very different. The reservoir is a small thin-walled bag and the micro pump is built into the cartridge. The pump head has two small chambers and a reciprocating piston. That’s a rather complex mechanism. While I’m still not worried about insulin degradation, I could see issues with the micro pump if insulin or the excipients adhere/build up to the pump head walls or otherwise reduce or block the flow path. I imagine air could slowly diffuse into the reservoir through the thin walled-bag potentially forming bubbles at some point. All this is informed speculation on my part (I’m a chemist and used to design micro-pumps), but I don’t think it’s worth taking the chance.

The fill procedure and the insulin delivery method used in the X2 is what gives me the most pause. I’ve heard more than a few complaints about delivery failure and I can see that it takes a while to prime a new set. I like Medtronic’s design better–its just that I can’t stand their sensors and don’t like their newest pump; hence my plan to switch over to Tandem this year. I hope I don’t regret it, but then I can already foresee that I’d dislike the 630/670 so my options are limited. i.e. it looks like I’ll just have to suck it up! :slight_smile:

That is great for you guys. I believe it is documented though that it degrades in plastic. And since it has happened for me on a fairly consistent basis that my bg goes high if I don’t change the cartridge etc., I don’t let it go longer than 4 days at the most. I certainly would not prefill a cartridge knowing this.

For me it is dangerous because I have been close to dka and I go into it easily, so I am not going to take that risk. 2 times last autumn, and insulin degrading was a factor in at least one event.