The Benefits of Tandem’s t:slim X2 Insulin Pump


When it comes to type 1 diabetes, my husband and I have always been resistant to change. A year after Bisi was diagnosed, when it came time for her to start on an insulin pump, we dawdled, because we felt used to and comfortable with the routine of multiple daily injections. But once Bisi started using the Omnipod, we quickly realized how much easier it was, both for her and for us.

Last winter, Bisi started saying she wanted to try a different pump. She didn’t like the Omnipod interface, which hadn’t changed in the five years she’d been using the system. She said that when she ran around, she could feel the pod (and the cannula in her skin) bouncing around. And a few times during sports, the pod sheared off her body. Again, Mark and I were resistant to a change. The Omnipod is so convenient: we could easily give Bisi boluses or change her basal while she slept. She didn’t have to worry about taking it off for sports, swimming, or showers. It was so easy to wear, without any of the negotiations of a tubed pump in terms of how to attach it to your clothes. For several months, Bisi pressed us to initiate the change, but again we dawdled.

But, about a month ago, she finally switched—from the Omnipod to the t:slim X2 (and, less of a big deal, from the Dexcom G5 to the G6). Once again, Bisi was right. The change has been great for several different reasons.

Bisi started on the Omnipod when she was seven. While she understood how to bolus, she was young enough that Mark and I were in full control of the pump and its settings. Because the Omnipod controller wasn’t attached to Bisi’s body, it was very easy for us to do many of the boluses and temporary changes in basal rates ourselves. This was super convenient, but I think we didn’t hand it over to Bisi as quickly or as often as we should have. It is her body and her disease, and while part of our goal was to bear as much of the burden of it for her as we could, I think we undercut her ownership of it a bit too. This time, as a twelve year old, the training was geared specifically towards Bisi, and Mark and I were watching from the sidelines. She has a better understanding of the t:slim than we do, and she does almost everything herself. She’s more interested in the pump and how it works, and she’s paying more attention to her blood sugar than she was before. It’s true that it’s more of a pain to bolus or turn off her insulin at night. The t:slim is also significantly harder to change than the Omnipod: what used to be a two-step process is now multiple steps. But Bisi takes pride in doing each step herself, and the change has been worth the extra trouble.

The biggest and most welcome surprise is that her glucose control seems to be better with the t:slim X2 than with the Omnipod. Her BG, as shown by her Dexcom, seems to be more even. And her excursions out of range seem to be shorter. With the Omnipod, we would often have to give Bisi multiple corrections to bring down her BG, and we would often give much more insulin than the pump algorithm called for. Now, we give her exactly what the t:slim calls for, and corrections usually seem to work on the first try. I’m not sure why this would be. Perhaps the t:slim algorithm that calculates insulin dosage is somehow different (and a better fit) for Bisi’s needs. Or perhaps the t:slim delivers insulin in a more efficient way, so it’s absorbed into the body more quickly. Whatever the reason, based on our experience over the last month this pump seems to work better for Bisi. That said, we’ve had two issues so far with the infusion set not working or failing. The first time was the first site change we did ourselves. It turns out Bisi didn’t have the infusion set pressed hard enough to her skin, and the cannula didn’t enter properly. Now she knows that if she hasn’t felt the cannula enter her skin, the insertion hasn’t worked. We also had a problem just recently where the site ripped out in her sleep. In this case, Bisi hadn’t used as much extra adhesive as she usually does. Both times, it was alarming how quickly her blood sugar (and ketones) rose, in just a few hours. That said, we had problems too with Pods failing, being torn off during sports, or cannulas coming loose from her skin.

At around the same time she switched pumps, Bisi upgraded from the Dexcom G5 to the G6, which will let her take advantage—once we can get through what feels like an endless and difficult to navigate approval process—of some new features on the t:slim. Soon, her G6 will be integrated with her pump, so she’ll be able to see her glucose number on her t:slim, and it should be able to alarm in a more subtle way than her iPhone—which is important to a preteen who doesn’t want alarms beeping or buzzing, reminding everyone else that she has something going on that sets her apart. Once she has the next update (which can simply be downloaded from the Internet, once we get approval, as opposed to getting a whole new piece of hardware, as you’d have to do with other pumps), she’ll be able to start using t:slim’s new Basal IQ technology, which will shut off insulin 30 minutes before a predicted low, and turn it back on once her blood sugar starts coming back up. (See here for a review.)

While Bisi loves the slimmer profile of the G6, and the fact that it is much easier and less painful to insert than the G5, we have had more problems with compression lows with this transmitter than with the previous generation. We’ll all be asleep, and be woken up by an alarm that she’s 50, double arrows down. But when we test her she’ll be something like 100. It takes a while for the CGM readings to recover from the compression lows, and if we calibrate it, it sometimes stops working for an hour or two. The compression lows are particularly worrisome for when the pump is integrated into the CGM, since presumably the Basal IQ will have the pump turn off even if the low isn’t real.

After a few years of feeling like nothing much was changing in terms of the technology Bisi was using, we’ve once again had a big learning curve over the last month. It’s so far so good, albeit with some bumps in the road (though with diabetes, when are there NOT bumps in the road?).  We’re hoping that things will get even better going forward. And the next time Bisi tells us she wants to make a change in the management of her disease, I’m thinking that we’ll listen to her the first time she asks.

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2 years ago

Thank you for the insightful and personal review. My son and I are considering a move from Medtronic to the tslim and we will consider your experiences in our assessment.


3 years ago

Thank you for this article. My son has had the Dexcom G6 for a few months and the T Slim X2 just arrived yesterday. I was looking for advice and ran across this. I was particularly interested in the combination of the 2 units to see what we have to look forward to.

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