This is probably going to be my number one complaint of the t:slim pump since my old number one complaint is being fixed soon. This is an issue that I doubt will ever change, though I wish it would.
Traditionally, when you fill an insulin pump reservoir, you fill it to about what you need, and the pump – when it loads the cartridge- will show relatively what you have placed into the pump. If you fill it to the 150u line, then typically, the pump will recognize about 160-140u in that cartridge (because they’re not exact and you are sort of eyeballing what you place into it). The t:slim is a bit different.
Upon loading the cartridge, the system removes any air that may be present in the cartrige. It then tells you to fill it. This is where it gets a bit wonky in the system. You yourself have, for instance, drawn up 200u of insulin for both priming (which it takes about 20u or more to do with the t:slim) and just use, but you also have to account for 20 to 30 units that becomes hidden in the pump. So. Let’s see. You’ve filled it with 200 usable units, but you’re only going to actually have access to about 150 of it after loading and priming.
This bothers the crap out of me. I already feel that it wastes a TON of insulin to prime, almost twice the amount, but to hide 20-30 units as well? I understand why they do it… as it was explained to me that since the system uses a bag, it’s similar to a ketchup bottle or a jelly packet… you can put 100% of whatever into it, but because of the nature of the container, you’ll never get 100% out. But we’re not talking about ketchup or jelly. We’re talking about expensive-as-heck insulin. We’re talking about enough insulin, that over the course of a month, is being thrown away, and enough to keep me a live for another 36 to 54 hours (day and a half to two days). For some, they have to pay out of pocket for this insulin, and to simply have to throw life sustaining liquid out into the trash is simply wrong (though some have found ways around this by reclaiming the old insulin and using it to pre-prime the tubing for the next site change).
I wish there were some way around this. Especially since the pump does not always only subtract out the given 20u, but sometimes more… I’ve had it make 50u disappear before. Honestly, I wish we could load the pump with the insulin and type in how much we filled it with. And, if we filled it with 200u, we could type that in, and the pump would subtract maybe only 10 + how much ever we primed (just say 20u) and then show a total in the cartridge as being 170u. I know this probably wouldn’t happen since it would introduce another layer of human error, but it would help us save a lot on this expensive life juice that we use every day. I mean, really…we’re so blessed to have it, and yet we’re having to throw so much away because of a safety measure…, when the amount being thrown away could save a life.