Technology failure is just part of life. I would say that high quality engineering can reduce the rate of failure, but failure is still something that will happen at some point because things do not last forever on this earth. We’re struck by cosmic rays that can do damage, as just one cause of this inevitable failure.

If you rely on diabetes technology like an insulin pump, CGM, Freestyle Libre, or other glucose monitoring device, then you will have to deal with its failure at some point.

This week I encountered a surprise error while trying to calibrate the sensor for my Medtronic 670G Insulin Pump. I use the Guardian 3 Transmitter with it for continuous glucose monitoring (CGM). It’s a wonderful feature of this pump because it will automatically adjust the insulin dose based on the sensor’s reading. Plus, I can see what my glucose is at any time by just looking at my insulin pump. However, this continuous glucose monitoring requires me to calibrate the sensor at least twice a day.

Since calibration is something I do several times every day, it’s become super normal and easy. I just test my blood glucose using a meter and then program that number into the pump and select calibrate. (I have one blood glucose meter that wirelessly connects to my pump and sends the number automatically, so that’s even easier!)

Calibration time varies. Sometimes it just takes less than a minute to calibrate. Other times it takes like 5 minutes or more.

I got this surprise error though:

“No calibration occurred. Confirm sensor signal.”

This was a strange error because the sensor reading was displaying on the pump, so obviously the transmitter was making connection with the pump. That is, sensor signal seemed fine.

I tried to calibrate several more times, but it was unsuccessful. I ended up solving this issue by deleting the transmitter from my pump and then adding it back and then going through the whole “start new sensor” process again. Basically, the solution here was a full reset. I also had to go through the 2 hour warm up period. So the result was that I was without a working sensor for several hours.

If you are dealing with this same error, you can call Medtronic and they will walk you through the steps. Medtronic’s phone number is on the bottom of the pump. The process is also explained in the pump’s manual. It’s also possible that this won’t solve your issue and that Medtronic will need to send you a replacement transmitter or other solution.

I also found this video explaining the process:

Reboot the Computer

Basically, I performed a “reset”. The transmitter is like a little computer. When computers aren’t working, what is the solution? Reboot it.

In all kinds of technology, a common solution to try during troubleshooting is to do the old reboot.

Turn it off. Turn it on.

Every piece of technology is different, so the equivalent of a reboot would be different. It may be checking and unchecking a button. It may be disconnecting and re-pairing a device. It may be restarting it. It may be unplugging the power and then waiting a few minutes and then plugging it back in.

Handling CGM Failure Gracefully

I’ve heard people refer to a CGM as a luxury. I know that not everyone who uses insulin has a way to continuously monitor their glucose. However, for those of us who are used to relying on a CGM for this, it can be very stressful to go without.

My goal is to make the outage as brief as possible. I keep back ups of supplies on hand. I call Medtronic when there is a problem that I can’t solve. They have overnighted me replacements before. So the quickest solution is to handle the failure immediately. For me, that might mean putting in some sick time at work so that I can deal with this.

The other thing I do is that I try to be more cautious when I don’t have a CGM. I test my blood glucose more frequently. I avoid exercise that could quickly lower my blood glucose. I may adjust the basal rate on my insulin pump to be more conservative, so that my blood glucose trends a little higher than I would normally like it, just so that I don’t go low at night.

I keep a juice box by the side of my bed. I also carry one with me anywhere I go. I do both of these things even when my CGM is working but it’s especially important to have one close by when I am without. I can feel a hypoglycemic event and respond to it quickly then.