Just curious…I recently switched from a Medtronic pump to a Tandem tslim. One big difference I saw immediately is the reservoir filling procedure. The Med pump always took just 6 units to fill the tubing whereas the T pump takes at least twice that.
I need to keep better data on the rate at which I’m going through a vial but my rough unscientific sense so far is I’m using up a vial at least a couple days sooner now than before, with no significant change at all in the amount of insulin I’m actually INJECTING. And if that’s true, I’d bet one reason is I’m “throwing away” nearly 36 units every three fill ups, or about every ten days or so. So in a month I’m blowing through about 100 units!
I’d like opinions on this if anyone else also feels like a lot of insulin is getting used but not injected.
When I started using the t:slim I stopped priming a new set of tubing whenever I changed an infusion set. Instead, I just reuse the same tubing by moving it from the old set to the newly inserted infusion set.
I do prime a new set of tubing whenever I setup a new cartridge. I suppose I could continue to use the older tubing, but I know that after enough physical stress the tubing does wear out. So I don’t try to use my tubing as long as possible.
Not sure if it makes sense, but this is the compromise approach I have used.
All pumps waste insulin. It’s the nature of the beast. I don’t have experience with a Medtronic pump myself, but I see the wastages compared as equal often. I would rely less on the numbers you’re told/see, and pay attention to the rate at which you actually go through insulin vials. It’s possible there’s just a lack of transparency somewhere, or a variation you don’t notice. The infusion sets are all nearly identical, except for little proprietary differences, manufactured by Unomedical on the same lines with the same materials. There shouldn’t be a difference in fill volume, unless you’re using a radically different set or tubing length. Maybe it’s just that the fill volume is measured from a different starting point?
There is definitely waste, though, and we’ve all got our tricks to circumvent it. There’s 15-20 units of “unusable insulin” left in every cartridge after it reads zero. It’s a margin of error safety thing. I actually suck that insulin out with the syringe, then add enough new insulin to that syringe to equal the volume for a new cartridge. It’s definitely against official protocol because insulin degrades in the cartridge, but many of us do it without noticable detriment. I just can’t stand to throw expensive insulin away.
You can’t skip the fill tubing step, to my knowledge, but you can eject the cartridge just before hitting the “fill tubing” button. The cartridge has already been checked after the load cartridge step and the software doesn’t check it again before the fill tubing step. You can’t stop the fill tubing step without the cartridge seated in place, though, or you’ll get an error. After the screen reads at least 10 units of insulin that it thinks you pushed into tubing, but really didn’t because the cartridge wasn’t in place… You just watch the piston moving in and out. When the piston is fully retracted, you quickly snap the cartridge back into place.
Learning that trick means you can reuse the old tubing that’s already filled with insulin and save those 11+ units. It helps with those who change infusion sets independently and run a full 3ml cartridge for as long as it lasts. Often the cartridge will run out while the infusion set is still fresh. It also lets you accomplish my other bad, penny-pinching habit… Reusing the entire cartridge/tubing setup. It’s the fastest way to change things in a hurry with the least amount of waste. I literally just stab the existing cartridge/tubing with a new syringe of insulin and go through the loaf process, with the aforementioned trick to avoid the fill tubing stage. I can apply the new set while the tubing is doing the fake fill thing, plug in the old setup and go.
You’ve got to be a little rebellious or at least willing to bend the rules if it works for you and not one of the super-sensitive-to-insulin people, though, if you want to minimize the waste. I went at least 3 years on the X2 before I started realizing it doesn’t cost me anything in terms of my care or control to be less wasteful. I think my TDD is fairly average at 35-50 units, depending on what I eat. Someone using much less than that, though, would definitely be more affected by the small residual amount of degraded (but still effective… Just not as much) insulin in the cartridge.
