Well, I performed my 780G upgrade last Friday afternoon. Overall, the upgrade process was fairly straight-forward. However, the instructions were a bit unclear in a couple of places. I ended up figuring those areas out on my own (didn’t have to call Medtronic), but some of them took a a little trial-and-error. They state that it will take about 2.5 hours, but my experience was longer than that.
The first thing I noticed was the Guardian4 transmitter was markedly more difficult to get attached to the Guardian4 sensor. It took a significant amount of pushing to get the two physically connected. As soon as the transmitter clicked into place, though, the pump recognized it right away, and started the warm-up period. I had the same difficulty getting the transmitter plugged into the sensor with both sensors that I have used (more on that below) … not thrilled about that, especially since the only supported insertion location is fairly difficult to navigate without assistance (and more on that below).
A few notes on the G4 sensors … From the first CGM that Minimed/Medtronic has provided for the past 20+ years, they only “supported” using them in the abdomen. Using them in the arms, buttocks, legs, or other areas were never officially supported. So, I just went ahead and put the first sensor into my abdomen … wrong choice! For the G4 sensor, the only supported location is the back of the upper arm. Seems a bit ironic that the most cumbersome CGM in the market to attach (multiple components, multiple layers of taping, etc.) is only supported in the most difficult place to insert it yourself without assistance. I look forward to when the Simplera hits the street to make this easier.
The first sensor failed in less than 24 hours. There was no reason given in the History, other than “Sensor not working properly. Insert new sensor”. Didn’t get any pushback from Medtronic support about using my abdomen when I called to get the sensor replaced, but they did confirm that the back of the upper arm is the only supported location for the G4 sensor.
I also experienced a pump error 53 on Saturday afternoon (“Delivery stopped. Settings unchanged. Select OK to continue. See User Guide.”). I didn’t have to change my infusion set, but did have to rewind the plunger and re-start the infusion set. Called support and we went through a few tests, and everything looked OK.
Had another pump error 53 today … the pump alarm woke me up just after 6am! Since I was getting up in 30 minutes anyway, I got up and called Medtronic support. Went through the same few tests, and everything looked OK. I never had any pump errors when I was using the same pump as a 770G. Told them that if more errors started popping up, I was going to request a new pump replacement. I won’t have a pump that shoots an error every few days. Maybe something went goofy in the upgrade process? We’ll see.
The second sensor is working fine after 3 days now. I still had a couple of days left on my Dexcom G6 sensor, so I left in-place so I could compare the readings. The readings were very, very close … many times they were the same value, but never more than off each other by 5 or 10. No finger-stick calibrations on the G4 sensor. That was impressive, and well beyond my expectations.
One thing to keep in mind if you start with a 780G … either new or as an upgrade. SmartGuard Auto Mode can be enabled at any time (I turned it on right after I upgraded and got all of my settings entered), but it does not activate until the system completes a 48-hour warm-up period while you use the pump to deliver insulin. This warm-up period begins at midnight after the pump starts delivering insulin. During the warm-up period, the pump algorithm collects and processes data that help enable its automatic function. I understand the reason for the 48-hour initial warmup period, but the midnight timing is a little bit bothersome. Using midnight means that you will be alarmed at midnight 2 days after you start the pump.
So, today’s my first full day on the 780G with SmartGuard fully functional. We’ll see how it goes. Right now, I feel a bit cautious with the initial sensor failure and multiple pump errors. Hopefully it is just initial upgrade bumps, and things will smooth out from here.
Has anyone else gone through the 770G to 780G upgrade process? If so, share your experience.