Looking for priming techniques on the tslim pump

I am just curious what is the best techniques for priming the tslim pump to get the air bubbles out. Is there a way to do it without losing so much insulin

How many units are you using to prime now for what length tubing? Are you still on the luer lock or have you switched to the t:lock connectors?

I think we are probably pretty standard in our approach. We use 16 ~ 18 units for 23 inch tubing and are still with the luer lock connectors. We do not reuse cartridges or tubing.

My daughter only changes tubing when she changes the cartridge. She rarely changes infusion sets & cartridges at the same time, so that helps cut back on waste.

As for saving on the actual prime, the only thing I can think of that helps is to do everything possible to prevent bubbles during the cartridge fill. Room temperature insulin. Withdraw as much as air as possible from the cartridge before filling. Keep the cartridge upright & allow it to sit a few minutes before starting the prime so any bubbles move to the top.

1 Like

As far as the connectors, we are finishing the luer locks that we have before going to the new type. It usually takes at least 20 units even going as high as 30. We are also using 23 inch tubes. We change out the tubing and cartridges at the same time. I didn’t even realize you could reuse them. Thanks for the input. I guess we’ll just have to figure out the right technique. Do you pull air out of the cartridge prior to filling? We always do.

We pretty much use all use the exact same methods you have mentioned. We’ll just have to find the technique we are missing. Maybe we aren’t holding our mouths right while doing it. Maybe more of a fish face would work better. Lol! Thanks for the reply!

We had all kinds of issues with occlusions when she switched to t:slim 3 years ago. For a while we resorted to tapping the side of the cartridge with a screwdriver handle. I read about it on someone’s blog. Same effect as thumping a syringe.

My daughter changes infusion sets every other day. Cartridges last 4-6 days, depending on how much she’s at home. We reused tubing even when she was on the Ping.

It takes me 16 units to prime my tubing, always. I use 23’ tubing. I cant understand why it is taking so much for priming unless there is air in the cartridge that must be purged out.

How old is your pump, mine is fairly new and I believe I am using the latest fill method, Part of the current procedures calls for using the syringe to remove any air from the cartridge before filling, instructions for older pumps did not include this step. This video might help explain.

The older pumps actually pushed the air out of the cartridge as one of the fill steps, although I can’t say it did it very well. When we updated the software last year, it switched to manually withdrawing the air via syringe.

One difference I do from the video is at the end when it says (@ 4:40)
“Turn your pump so it is vertical. This allows any residual air left in your cartridge to be pumped out first.”

From the time that I fill the cartridge with insulin, I always keep the cartridge vertical. It is a little awkward tapping the buttons on the vertical pump but really just a mindset of looking at the pump sideways. I slide the cartridge into the pump with the cartridge/pump still vertical, and keep it all vertical when connecting the tubing and tapping the buttons on the pump.

My thought is the longer the cartridge is vertical and the less turning and shaking, the better chance any air in the cartridge has to get out right away.

1 Like

When you say this, what is the reason you keep priming past 17 and sometimes going to 30?
Is it that you do not see any insulin coming out the end or that you still see air bubbles in the tubing or some other reason?

Still seeing bubbles. Very frustrating!

They are tiny. It’s seems they are coming from the lock. They get smaller as I tap the lock. Is it okay to have a little bit of bubbles?

I also ALWAYS require 16 units to fill the Luer lock and 23" of tubing and I NEVER see bubbles originating from the Luer lock.

How tightly do you twist the Luer lock? While I can’t give you a torque specification , I would say that I tighten mine as if it was a toothpaste tube about to fly in luggage with my best clothes … no pliers, but firmly twisted.

Good luck,


They are super tiny. Champagne bubbles would be a good description. I will try to slow it down the next time I do a change. I know the lock is tight so that can’t be it. I think maybe I’m making a mountain out of a mole hill here, so to speak.

My Tandem trainer told me to place the pump on its end and hold the tubing up in the air (holding the leur lock) until the leur lock was filled with insulin, which takes me about 9U. This helps air bubbles to get out and through the leur lock.

When I prime with the pump on its side, I sometimes see bubbles come up out from the cartridge later in the priming, and get stuck in the lock.

How does everyone keep the pump vertical without knocking it around while flicking? I’ve thought about building some sort of little jig. I currently use the box for the cartridges to hold it in place and keep it sticking out. Could I be flicking too hard. I have a hard time lightening up sometimes. I over compensate for everything even when I don’t need to at all.

I literally hold the infusion set and let the rest hang as I fill the tubing.
I can sometimes get drops coming out around 15 units. I usually push out a few drops, if there are any air bubbles, they are the first part to come out.

My secret is to pull most of the air from the cartridge with an empty dry syringe.
Then I do it AGAIN with the full syringe.
When I pull a vacuum on the syringe and I have it full, I TAP the syringe on the edge of the desk/table a few times.
Tapping it like this with the vacuum on it, I can see all the really SMALL bubbles go to the top of the syringe (towards the plunger of course, I always hold the cartridge vertical for the entire process.)
You will see, when you let go of the plunger, what little air is left all goes into one bubble. Make sure that when you push the insulin into the cartridge, to not push any of that air in with it.
BTW, I do this with insulin straight from the fridge. No issues and I KNOW my insulin will last longer by not warming it up.

I’m almost positive I had been looking to hard. I have perfect vision, and still unintentionally trying to get a closer look. (Now that i think about it) Trying too hard. One of my downfalls. Its hard for me to relax. I will make sure to do the next change and see if it shows up in a pic. I appreciate everyone’s patience, and willingness to help me! Hammer: I’m trying to understand. You pull the air out (of the cartridge) a second time with a full syringe? It’s worth a try. I think technique is huge in this situation, just like it is at my work.

I just did a new cartridge, first drop out of the infusion set was at 14 units. I ran it until 16 to make sure I was good.

:grin: Thanks again.