670G - Increased "Sensor Updating" Messages

Hi All! This is my first post here. Excited to find this forum, and hope that maybe someone here can help where Medtronic can’t.

I am on the 670G, and have been using it in conjunction with the Guardian 3 Sensor for 3 years. I’ve had my fair share of issues with the sensor, but recently something new has started.

Over the past 6 or so weeks, I’ve had a sharp increase in the number of “Sensor Updating” messages. A couple of notes on these messages for me:

  • The messages happen throughout the life of sensor, but get more frequent toward the end.
  • The messages are more frequent at night, when sleeping, but happen during the day as well.
  • It’s rare for the message to result in needing to actually change the sensor, but that has happened a couple of times as well.
  • The messages typically resolve in 30 mins - 1 hr, but can persist for several hours.
  • I thought maybe I had a bad Lot of Sensors, but this has persisted even after switching to a new Lot.
  • I insert in the back of my arm, alternating each week.

I am confused as to why this has become a recent problem, as I have not changed any of my personal habits.

Has anyone had a similar experience? Could this be attributed to something that has changed in my body, rather than with the technology?

These alerts are becoming very cumbersome, especially since they tend to wake me up at night, and the pump will alarm every 30 mins.

Appreciate any help than can be offered, as Medtronic has not been able to troubleshoot.

I had those.

A few possibilities:

  1. Bad insertion. Getting those things into the back of your arm single-handed (so to speak) can be tricky. The Guardian serter is unwieldy, and the oval tape is fussy, and you have to make sure the connection between the sensor and transmitter is covered so that it’s waterproof, and the whole thing can be a pain. You’ve been doing it for a while now, though, so you’ve probably got the hang of it. Still, might not hurt to brush up on how you’re doing it and maybe add an extra layer of protection on top, just to be sure. (I find these Nexcare bandages are just the right size for that. The paper frame on top is so nurses can write on it, but it’s designed to be readily removed.)

  2. Bad site. If you’ve been using the same site repeatedly, it’s possible you’ve got some scarring and/or subcutaneous bruising that’s causing the problem.

  3. You’re sleeping on it. IDK about you, but I often roll over onto my arm at night, and usually have it tucked under my pillow, with my head pressing down on it. That kind of compression can affect bloodflow to the area, which can cause sensor issues.

All of the above can potentially be addressed by putting the sensor in your abdomen. Give it a try for a couple of weeks and see if it helps.

  1. Bad transmitter. Medtronic doesn’t like to replace them because those things are worth $2k each. But they do have a lifespan. It’s possible it’s wearing out and needs to be replaced. In fact, about a year ago they came out with a software update for the transmitters. The only way to get it is to replace the transmitter. (There’s no way to do a firmware update from home.) Which they should do for free. If you haven’t yet, it’s worth asking tech support to do that for you.

  2. Transmitter needs to be re-paired. Tech support probably already had you do this, but it’s worth mentioning in case they overlooked it. Next time you change the sensor, delete the transmitter from your pump’s paired devices list. Put the transmitter on the charger. Tell the pump you want to pair a new transmitter. Immediately remove the transmitter from the charger. Doing so puts it in search mode, which should let the pump pick it up. Resetting that connection is the equivalent of “have you tried turning it off and back on again,” but it does sometimes help.

  3. Interstitial fluid trouble. Out of all the times I called Medtronic tech support, only once did I have someone mention to me the very important fact that if you’re dehydrated or sleep deprived, the sensor might have trouble reading you properly due to chemical imbalance. Certain medications (notably Tylenol/acetaminophen/paracetamol) can also interfere with sensor readings. Which they never actually bothered to tell me.

Hopefully something in there does the trick. Sorry you’ve been having trouble. That’s really frustrating. Especially when the alerts wake you up or repeatedly disturb you during the day. Good luck.

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Hello @dax9876 and welcome! I don’t have much to add to your problem but in electronics in general, always suspect the transmitter! I am not shocked that Medtronic isn’t overly helpful, you may have to push harder! Good luck :four_leaf_clover:

@WearsHats Really appreciate all the thoughts here. It’s possible the sites I use need a bit of a break. That’s one of the first things I will try. Also never thought about hydration / sleep habits. While I don’t think those things have changed, I am going to monitor more deliberately.

You say you “had those”… did you find a fix? Or are you on a different pump/sensor now?

I only had it happen occasionally. More often, I had trouble with the sensor readings being way off track. But all of the above have happened - I got more careful about site selection, which helped. They replaced the transmitter when it was really acting up (fortunately that was just as they were rolling out the software update). I had trouble getting a new sensor started a few times, and once they had me re-pair it with the pump, which did work. When she asked me if I’d been sleeping okay, I barely stopped myself from laughing out loud. (I’ve got a bunch of sleeping disorders and haven’t had a good night’s sleep in decades. Not much I can do about that.) The thing started to go on the fritz again early this year, but by that time I was already in the process of switching to a Tandem pump, and that’s worked much better for me.

Forgot to mention out of range issues as a possibility. If the transmitter is getting old, it might not have the signal strength and battery life that it used to. (Shortly before switching pumps, I had the battery fail a day early three weeks in a row, despite being fully charged when I started the sensor.) It’s possible there’s something blocking the signal or interfering with it. If you can, keep the pump closer to the sensor, on the same side of your body as the sensor, and away from anything that might be producing e-m waves.

I’ve been using the Medtronic 670g pump and guardian 3 sensors for years with few problems. I use the back of arm with fabulous results. It’s painless, bloodless and gives me a precise reading. Never had any luck with sensors in my stomach, but the pump works great there. Even though Medicare doesn’t pay for these sensors, Medtronic has a plan that charges you only $60 for a months supply. Early on I had problems with the transmitter, but got that fixed. Medtronic never hesitated to send me a new transmitter. Medtronic tech support is awesome and ALWAYS sends replacements for free and often with overnight delivery when needed. I’ve never had a sensor updating message so I can’t comment on that issue. Does Medtronic have some issues? Sure, but no more than Dexcom or Omnipod.

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