Tandem T-Slim X2 infusion sets

I started using the Tandem T-Slim X2 4 or 5 months ago, after 18 years on a Medtronic Paradigm. I used the Quicksets, and rarely had an issue. Now I’m having a horrendous time with the Autosoft XC sets, with high blood sugars (with repeated boluses to bring them down, with little effect) followed by lows that last for hours – even overnight. Then, rinse and repeat. I am not using CIQ because I’m on the G7 CGM, which is sounding alerts half the day as I experience ups and downs. I’m about ready to scratch the pump and return to my old Paradigm 515, or start on a multiple injection routine. Has anyone else had this experience?

Not me, could you post everything you do when changing the set? There may be something missing.

It sounds like you still have air in cartridge. I also came from Medtronic, and the most valuable thing I learned regarding their cartridges is removing the air prior to adding insulin. I had the same issues you are having until that time.

My bolus carb ratios went down, but that isn’t really to do with your question.

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I had a LOT of erratic BG readings when I started using my Tandem pump and it took me a while to figure out why. I had the advantage of using a CGM for a month with MDI before my pump, starting with Basal IQ, and I had a very predictable and uniform measured routine from day to day,

You didn’t change just one thing, but at least two.

Infusion therapy is sensitive to three things besides the infusion sets to work well. Settings, sites and readings. Even in “manual mode” the Tandem pump needs good settings. It is more precise in how much insulin it can deliver than most pumps. My initial settings had me out of range within a day. Until I adjusted them I had to override every bolus calculation, and I was above my morning target every day.

The Tandem pump in manual mode is reliable for delivering what you program it to deliver. If the internal settings are correct and if the BG values you enter are correct, it will infuse the correct amount of insulin. Your experience suggests that you probably have good settings, but maybe not.

You assume that the infusion set is the reason that the G7 is sounding alerts half the day.

Have you considered that the sensor readings may not be trustworthy? A bolus that you or the pump give that is based on bad data will be wrong and may cause yo-yoing BG readings as unnecessary corrections are made. (My experience is that If I get outside the actual 100-160mg/dL range, corrections become non-linear in magnitude and response time) .

“No calibrations required” and a “30 minute warm up” do NOT mean that every installed sensor is accurate and reliable after 30 minutes. Those claims make no statement about quality of data for a single sensor. They are statistics based on clinical trials.

They are empty promises. There is no way to know whether an individual installed sensor is accurate and doesn’t need calibration without finger stick tests.

The trials with the G7 did not improve on the G6 statistics, they were submitted to the FDA equally safe and effective. Even if the G7 is better than the G6, it uses the same technology. It can’t be perfect, and even if was, your body isn’t. After 18 years of using infusion sets your interstitial layer isn’t uniform.

The advantage of a modern pump is that if the sensor readings are accurate,and frequent enough, it can compensate for infusion site inconsistencies. If it doesn’t have accurate readings the bolus calculator will produce bad results.

I can’t trust the G6 sensors for a minimum of 12 hours to be stabilized, and I can’t trust any of them to be accurate without two calibration checks, one at 100 mg/dl and once at 180 mg/dL,l bitj done with my BG stable.

I never use my Tandem pump with Control IQ enabled for the first 12 hours after I start a new sensor. If I did I’d never get any sleep the first night after installing a new sensor.

I shut off the low alerts on the pump when I install a new sensor. I always change sensors late in the afternoon I can disable CIQ knowing that my basal profile, ICR and CFs are correct, that fingerstick meter and and technique are correct. I use fingerstick readings to calculate boluses until I’ve have proof that that particular CGM sensor - installed on my body- is reliable and accurate. I need to see a smooth accurate curve.

This is a small inconvenience for 12-18 hours after I install each new sensor, after which I can rely on it -while i am in range - for +9 days. I average 97% TIR with my worst control during the 18 hours after a sensor change. In the past 19 months I’ve had to replace too many sensors to ever again trust one to control a pump, without testing it.

I do a fasting calibration after +12 hours and a peak calibration after breakfast. If four hours after my morning bolus my CGM and my BGM match within 10mg/dL (usually they do) THEN I re-enable CIQ and the alert. If not I calibrate after my previous bolus has worn off, eat and check after that bolus has worn off.

Maybe you’ve been as careful as I am in testing your G7 sensors.

If so I suggest that you try using Tru-steel infusion sets. I’ve had fewer infusion site issues since I changed from Autosoft XC.

I never had luck with spring loaded infusion sets esp the ones that go in at 90 degrees. I use the ones I can put in manually at a steep angle. Vari soft for the tandem users and silhouette for Medtronic people. I use 6mm cannula because it’s less likely to kink.

The other benefit is that there is a small window on the set and you can see if it’s still in, if u are exercising or if it gets pulled, you can actually see if it’s in or not.

Mostly when you do it manually, you can feel if you are entering a vein, and abort, there is no snap, just easy push just like taking an injection. So you can avoid gushers or that sting you get when it’s in a vein.

It’s especially good for lean people who don’t have enough fat to handle the 90 degrees, that’s why I started using them, I’m sure I have enough fat now, but I still think they are a better choice.

I have almost no site failures with this method.

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This may be due to cannula getting bent on insert, and doesn’t penetrate skin fully. I pinch up skin on insert, and no longer have issue.

Another tip is to gently twist the cannula cover and gently remove cover straight out.

Thank you so much for your detailed response! The sensors (G7) have been quite accurate, and I make sure to insert the new sensor hours before the previous one ends, and then I compare the numbers when I switch from one to the other. (I occasionally confirm readings with fingerstick, as well.). I got my hands on one single Tru-steel, and I’m moving it around to a different site every time my BS starts escalating inexplicably. That seems to be working! I’m awaiting receipt of an assortment of sample infusion sets with different lengths of catheters and needles from Tandem, so that I can place a meaningful order at the end of the month. My doctor has upped my prescription to one set a day. I know that I can’t keep moving this single TruSteel around as needed, so I’m about to try some Varisofts that at left over from when I first received the pump and supplies. They didn’t work satisfactorily, but that’s all I have left until I receive my samples!

Thanks. I’ll try that.

Did you know that stress will make your BG rise?

If you have a typical initial infusion set RX for Autosoft, it will provide 40 sets for 90 days. That’s based on an average time between changes of 2-1/2 days.

TrusSteel has a recommended change frequency of 2 days, so 40 sets is an 80 day supply. The insulin supply that was estimated for Autosoft, if it was a close estimate, will also be inadequate over 90 days because of the increase in insulin lost from extra cartridge changes.

If you find that TruSteel works more reliably for you then record how much insulin you put into your sets for 10 days. * Divide that number by 100 and round it up. That is the minimum number of vials of insulin you’ll need every 90 days.
Your RX pump daily dose will be 10*(number of vials).

(*Also note before each change the amount of units the pump says is remaining. If it’s always more than half your TDD, during a full lunar cycle, you’re probably filling the cartridge with too much. )

Then contact your doctor for new Rxs, for TruSteel every 2 days and the amount of vials you calculated - 90 day supply, with 4 fills.

btw:Once using TruSteel continuously, under History/pump history look at your TDD for the past 10 days. If it’s pretty consistent for the two days a set is in use, you may be able to alternate between 2 and 3 days between changes.

It’s worth knowing if you can do this because it will give you flexibility to accommodate travel or holidays where changing sets on a rigid schedule may be very difficult, and do this without worrying.

Re: Alerts, if you have an Android phone, the XDrip+ app has customizable alerts (levels, loudness and tones) that are much easier to live with than the fixed high/low/rise alerts of the Dexcom app.