670G waking at a set time EVERY NIGHT


(Katie) #1

Wondering if anyone has had the same experience with the Medtronic 670G in automode. I have been using it for about 4 months and for the last 3 or 4 weeks it wakes me EVERYNIGHT at 4am saying “BG REQUIED” then about half the time wants a calibration shortly after. My A1C went from 8.8 to 7.1 in 3 months so I need to use it but it is driving me crazy! I have tried proactively entering a BG only at bedtime and then a calibration without resolution of the problem. It is not happening only in the situation of high or low sensor readings prior to the request and it is not in the situation of max or min insulin delivery. Any ideas? Thank you!


(Sal) #2

Is there any alarm message along with “BG required”?

Can you check your alarm history and see if there was a message?


(Katie) #3

It says…
BG required.
Enter a new BG for auto mode.

There is nothing about being high or low or max/min insulin delivery.

I thinks it’s usually about 6 hours after my bedtime check( approx 4am)

Thank you for responding!


(Sal) #4

This is indeed strange. I’m going to go out on a limb here and say that you either have a faulty transmitter or faulty pump. I would ask Medtronic to replace the transmitter, and if that doesn’t work then have them replace the pump. They might drive you crazy with troubleshooting questions but hold your ground and say you want them to replace the transmitter.

Once they send you the new transmitter, change to a new sensor and see if the problem still occurs. If it does not solve the problem, ask them to replace the pump.

Bear in mind that with a new pump it will take a couple days to get back into auto mode.


(Katie) #5

I will have to get my energy is for the fight.

Thanks for thinking about it and for your input.


(Sal) #6

Another thing you can try is to go out of auto mode for 24 hours then go back in. Maybe reprogramming it by going out and back in will fix that problem. (Does it ask you to calibrate at 4am even when not in auto mode?)

Either way it doesn’t hurt to get a replacement transmitter. It’s covered under warranty for a year. For me, the new transmitter fixed similar issues I was having where the pump kept asking me to calibrate and enter BG at random times.


(maryelizabeth) #7

I would call the Medtronic 24 hour hotline. They can definitely solve this for you. Or call your 670G trainer.


(Emily) #9

Omg me too, 4:11am every am for a week…then it chills out for a few weeks, then back at 4:11am for a week or so. Glad I’m not the only one! I get fed up and exit automode, I’m not getting up to test at that hour…


(Jess) #10

Same here. I will just enter the reading from the sensor (which the pump is displaying, and shows is still in calibration) under the Enter BG screen, then go back to sleep. I’ve maybe had 3 or 4 uninterrupted nights sleep (8 hrs) since I started using the 670G (about 6 months now).


(Katie) #11

Hi — back again. Ended up trading in my pump for a different 670G. For a couple of weeks it was fine and now I’m back to the old “BG required” at 3 am and sometimes again 2 to 3 hours later. There is no reason for it. No event like min or max delivery or low BG. I put my audio options in “silent all sensor alerts” for 9 hours overnight and at least it doesn’t wake me til it exits auto mode. ( of course Medtronic would not recommend this because I guess it’s not so safe… but I can’t take the constant waking. )My A1cs have decreased by 2.8 points since starting 670 G… so I wonder if some people’s insulin needs( like mine) are so variable and unpredictable that automode “can’t believe it” and has to make you Check to be sure it’s true! Medtronic help line is absolutely useless in trouble shooting this issue.


(Linda) #12

I cannot trust auto mode because my sensor readings are always way off what my finger stick blood readings are. I have se real times been given a low warning of 70 and when double checking this reading with a finger stick blood test have gotten 100 or 110 readings. It’s a real problem.


(Thomas) #13

I’ve been on the 670G in auto mode for about 6 months now and have had the same problem. My BG control is better than it has ever been, but my sleep hygiene has never been worse - literally every night my pump wakes me up between 3-4am asking for a calibration, despite me consistently entering a calibration immediately before going to bed (~10pm). I don’t think that this early morning calibration request is due to any faulty equipment or software, I think it is simply a side-effect of the algorithm’s design that it requires a calibration every ~6 hours or so regardless of the time of day, but I might be wrong. If anyone has a solution to this issue I would love to hear it, because otherwise I plan to find a new pump/CGM solution and forego the benefits of closed loop control until there is an alternative on the market that doesn’t require me to sacrifice sleep to keep the algorithm happy.


(Ryan) #14

Thomas have you tried different site locations for your sensor? Days 2-7 should allow 12 hours between calibrations. Your more frequent requests indicate that the pump isn’t trusting your sensor. Switching from abdomen to thigh or upper arm for the next sensor could help you out.


(Kathy) #15

One of the Medtronic support people told me that auto sometimes wants a “diagnostic calibration”. I’ve had this happen a couple of time but nothing like what you are seeing although they did happen in the middle of the night. You might want to call tech support and ask them to help you figure out what is causing the issue for you. If you still have contact with your trainer or a 670G knowledgeable CDE they may be able to help.


(Thomas) #16

Interesting, I have actually never placed the sensor anywhere but on my upper arm (abdomen is valuable territory for infusion sets for me). I didn’t realize that the pump would adjust time between calibrations according to it’s “confidence” in the readings. Anecdotally, I heard from my CDE recently that many of her patients on the 670G were having trouble with their sensors being abnormally inaccurate recently, and that she suspected a manufacturing issue. I don’t put too much stock into this explanation, however, since it is just speculation at this point.

So It sounds like the root issue here may be sensor inaccuracy. Other than sensor location, is there anything else that you all have found to have a strong influence on sensor accuracy? One factor that I have identified is pressure on the sensor itself - oftentimes if I lay on the arm that has my sensor on it my readings will shoot dramatically up or down.

Also, other than frequent middle of the night calibration requests, do you of any way to gauge the pumps “confidence” in sensor readings? If I had access to such a metric I could avoid this issue by simply changing sensors when the pump tells me it doesn’t like the one that I am using.


(Ryan) #17

Sleeping position could have an impact as you have noted, Thomas. Staying hydrated is another key to getting good data from the interstitial fluid.

Two imperfects clues that a sensor is on its way downhill: sharp changes in the numbers between meals when you expect to be steady, and the dreaded “sensor updating” alert.


(Thomas) #18

Good points, I hadn’t thought about hydration affecting sensor readings but I suppose that makes sense. I have also noticed that the “sensor updating” alert is essentially an early warning that my sensor is circling the drain.

On a separate note, have any of you on this thread switched to a different (i.e. non-Medtronic) pump or sensor as a result of these middle-of-the-night errors? My frequency of errors has somewhat decreased since my original post 11 days ago but I was still woken up last night and the night before. As a former Dexcom user I am aware of just how cumbersome the Medtronic device is compared to other products on the market and am strongly considering simply forgoing closed loop in favor of better sleep until a competitor’s product is approved by the FDA that uses a sensor that isn’t so problematic.


(Ryan) #19

My hope is that Medtronic’s updated transmitter gets FDA approval soon. That may help with these errant sensor alarms and the loop.


(MichelleP) #20

Hi
I too get woken up often and my sleep is constantly interrupted!!! Same BG required and calibration alarms. I too have the 670G. I was told by one of the nurses at the practice I go to (MGH -Boston) that it could be the signal is getting lost as I turn in bed - i.e. pressure on the sensor causing signal disruption.
My sleep is so interrupted I have taken the pump off remote mode and put it on manual for the night or I silence all the alarms for 8 hours, neither of which is ideal. Sometimes I think it’s not worth the hassle but I do really like knowing what my BG is at all times and seeing it trending.


(Dennis J. Dacey, PwD) #21

Ryan @rpm3313, don’t you mean it the other way around?
That Medtronic improve its sensors and transmitters so that those devices can get FDA approval?
That I think would be really good so as to complement their awesome software successes.