I began using the Tandem t:slim X2 insulin pump in mid-December. In February I wrote a mostly-favorable review of the pump, but indicated that I was struggling with user-error problems and occlusion alarms that stopped insulin delivery. In March I wrote a post indicating that I had found a solution to the false occlusions, but it may have been a premature claim to success. I am now 5+ months into using the pump and thought I’d give an update on my experiences.

Overall Satisfaction:

I am happy with my Tandem pump.

The things I liked before I still like. I enjoy the contemporary looks of the pump and the touchscreen menu navigation. I appreciate being able to fine-tune settings although I don’t always take advantage of that capability. I like being able to easily see my Insulin on Board with one button push. I like that I can see the pump screen when outside in bright sunlight.

I have trained myself to avoid most of the user-error problems that I previously discussed. After filling the cannula of a new infusion set, I patiently wait until I arrive at the screen to resume insulin. I still get occasional Incomplete Bolus alarms when I put in a BG number to see if I need a correction. If I don’t need a correction I often forget to back out of the bolus menu and end up with an alert. I now get an A+ in remembering not to detach my pump in the middle of a bolus. It has been an adjustment moving from the fast bolus delivery of Animas pumps to the delayed delivery of a t:slim, but I have adapted.

Still Annoyed:

I still hate the pigtail on the pump tubing. It often makes the tubing stick out of my pocket which is unsightly and a doorknob risk. I also dislike how long it takes to fill a cartridge. I know that the X2 is faster than the original t:slim, but it is not a one or two minute task as with previous pumps.

Tandem recently announced that it will convert the luer lock connector at the pigtail to a proprietary connector called the t:lock. The purpose of this change is to reduce the time and insulin required to fill the cartridge and tubing. The downside of this conversion is that only Tandem proprietary infusion sets will be compatible. For me that is no problem because I use Comfort Shorts, a Tandem-supported set. I also understand that this change should help Tandem’s financial bottom line and I can’t oppose that. Some t:slim users, particularly those using non-supported sets such as the Cleo, Orbit 90, and Animas Inset, are enraged that Tandem is going the Medtronic route of proprietary sets.

I continue to dislike the Min Basal alerts. They happen a minute or two after I have set a temporary basal of zero and are annoying. I suspect that the alerts are the pump sensing the basal amount rather than the result of what I have just programmed. So maybe it is a safety issue. But it’s still annoying. If the pump questioned my temp basal amount right away, it would be better than interrupting me a few minutes later. At least this alert doesn’t stop insulin delivery, so it stays in the “annoyed” category.

Avoiding Occlusion Alarms:

When I wrote my initial review of my t:slim X2, I was unnerved by the fact that I was experiencing weekly occlusion alarms that resulted in a stoppage of insulin. Having pumped for 12 years with no such alarms, I knew that they were false and related to the pump not my infusion sets. In March I wrote a blogpost describing what I thought was a workable solution to the problem. I began using a Nite Ize clip and keeping the pump out of my pocket. The blogpost of course jinxed me and I had 3 occlusion alarms the next week. However, in fairness to Tandem, those alarms all happened with the same infusion set and maybe it was a site problem.

When I flew back to Minnesota in mid-April, I set off the TSA metal detector. As a PreChek traveler I am used to never declaring my pump and speeding through security. The downside of the Nite Ize clip is that it can’t be removed and ensures an airport pat-down every time. Because I set off the metal detector on my only other flight with the t:slim, I am afraid that the pump itself might have enough metal to always alarm, but I hope not.

I decided to remove the Nite Ize clip which wasn’t tight enough anyway. I wanted to go back to carrying the pump in my pocket and knew that doing that without a case was a recipe for occlusion alarms. Meanwhile a Tandem tech suggested the removable part of the t:slider case for use in my pocket. He indicated that the occlusions were a temperature problem and this case would resolve that. It is essentially a t:clip case without the annoying clip. I have used this case with my pump in my pocket for 6 weeks without a single occlusion alarm. For working out I put the pump in a Running Buddy Mini case on my waistband.

I made one other change that might be responsible for eliminating occlusion alarms. Rather than follow the Tandem instruction video for filling my cartridge, I do two things differently. After pulling air out of the cartridge with the insulin-filled syringe, I do not release the plunger as instructed. I hold it tight so that the air stays at the top of the syringe as I remove it. Then as directed I hold the syringe with the needle up and tap it so that all air moves to the top. At this point, I reinsert the syringe into my insulin vial and slowly push the air bubbles back into the vial. When there are no more air bubbles, I pull in enough insulin to measure my desired amount. If I see more air bubbles, I repeat the process. This eliminates the messy loss of insulin when shooting the bubbles out into the air.

I have not done a scientific test to determine whether it is the new case or the alternative method of filling the cartridge that is working for me. All I know is that with the combination of the two changes, I have not had a single occlusion alarm in 56 days.

Please note that the t:slider case is sold out according to the Tandem store although I wonder if the tech reps still have access to them. A new case to replace the t:clip case is in the works but I don’t know when it will be available.

Wishes:

One change I would like to see is the ability to customize the preset temporary basal setting. It always reverts to 50% now and 50% over 2 hours. That is a preset I never use and I override it every time. I would like the option to program my own preset or to at least show the last-used setting. This should just be a software change, so maybe it could be a future fix.

I anxiously await the software update to integrate my Dexcom G5 into the pump. Because it looks as though CMS will not allow the use of a smartphone with sensors purchased under Medicare (stupid for sure!!!), it would be nice to have my CGM as part of my pump even if I have to carry the Dex receiver also. I haven’t heard anything on when this update will be released.

My Favorite t:slim Hack:

I live in an older house and have few electrical outlets in convenient locations. Many people charge their t:slim pumps while showering. Our bathroom has only one outlet that is overused with hair dryers, a straightening iron, razors, and electric toothbrushes. I can sit near an outlet in the family room while watching TV, but then it is a PITA to unhook myself when I get up to do something. Charging in the car works fine when I remember to do it.

My newest solution is to use an Anker PowerCore back-up battery which I bought this winter for hiking. After owning it for a month or two, it dawned on me that I could use it to charge my pump! I keep a compatible cord attached to the Anker device and just plug in when needed. I can tuck the charger in my pocket or waistband and move about the house as needed. The charging is just as fast as from an outlet.

A great solution to a minor problem.

Conclusion:

I am satisfied that I chose a Tandem pump in late 2016 and think that I would make the same choice again. The only serious problem I have had with the pump is false occlusion alarms and that has mostly become a non-issue. The constant rumors about Tandem’s financial status are concerning, but my fingers are crossed that the company will overcome its problems and remain an innovative player in the diabetes tech world.