dexcom G7 on pump (tandem Tslim x2) and phone

[EllieM]

I've recently changed to use the dexcom G7 sensor with my tandem Tslim x2.

I preinserted the first G7 16 hours ahead and got a fail on start up (sigh) so had to immediately insert a new one and had my usual too low readings for its first 12-24 hours.

The sensor is due to end at 2pm today so inserted a new one at 10pm last night.

I started the current sensor on my tandem and then on the phone, and was thinking that I could start the new sensor on my phone while leaving the old one running with the tandem for the full grace period. That way I get an early warning for if the sensor fails to start (seems to be my main issues with G7s).

So am wondering if I still have to start the sensor on the pump first .... However, I noticed that when I calibrated the sensor via the pump a few days ago the changed readings went through to the phone automatically, so presumably the pump is sending info to the sensor somehow ???

Any thoughts? Is anyone out there using a G7 with their pump?

 

[searley]

When you calibrate on either pump iron phone that data is send to the sensor.. the calibration is sensor not software.. so yes that will get passed to the phone too so both match

 

[sninge]

Hi Ellie
Im also on my second g7 sensor and have the same issue as you with low readings for first 24 hrs and have always put my sensors in day before activating them to solve that so my first g7 experience was awful for 24 hrs and had to turn closed loop off. I had a long chat with a very helpful person from Dexcom re dealing with the issue, so what I did with current sensor was to start it at 10pm, I know by then my sugars are in range and closed loop will keep them there all night, being in range first 24hrs helps the readings settle. I start it with my phone, kept the old one working with the pump and then connected it to my phone in the morning at about 9am, this I was told needs to be done within 12 hrs of insertion. It worked well. I was also advised not to calibrate for first 24hrs.
I am hoping this is the key as I live how accurate g7 is, I thought g6 was good but g7 seems to puck changes up quicker, hence control IQ reacts quickly and less hypos or highs!

 

[EllieM]

this I was told needs to be done within 12 hrs of insertion.

I inserted mine last night at 10pm and activated it at 2pm the next day so am not sure the 12 hours is correct, but sounds like I am safe to activate on phone first next time. (Did pump then phone this time). I have decided to insert mine at 9 or 10pm in the evening and then use the grace period from the previous sensor to mean I don't have to activate till the morning. Hence it'll have a full 24 hours before the next evening. (Of course, that assumes the sensors don't fail early, always a bit of a risk.) Maybe your method of starting immediately with the phone would avoid immediate failed sensors?

Thanks again.

 

[stephen99999]

The G7 sensor starts counting down 10 days +12 hours grace immediately the sensor is inserted. If you wait too long to start a new sensor on your pump the sensor will error and not be usable.

 

[sninge]

I think that is possible what they were trying to tell me. It wasn't so much the pump had to be connected within 12 hrs just that something had to be connected in that time scale!
Let me know how you get on, it is slightly scary to think your phone is connected but you can't then connect the pump.
Teething problems and I'm sure we will make it work for us!

 

[EllieM]

I'll contact dexcom and ask before starting my next sensor and report back what they say.

 

[EllieM]

Just updating. 12 hours isn't a thing but if you end a sensor on pump or phone it will be ended on other device. It shouldn't matter whether you start on pump or phone first, but given that once a sensor is ended it's ended on both devices then there is no point in trying to keep them separate....

 

[sninge]

Hi Ellie. It's so confusing isn't it, I ended the sensor on my phone last change over and it continued to work for 12 hrs on my pump until I ended it! So presumably dexcom told you this and also the 12 hrs isn't a thing!! Im going to start my next sensor before bed this eve and plan on starting on phone again and leaving pump working with old sensor for nearly 12 hrs before swapping over in the morning. I'm just not brave enough yet to leave the pump longer, perhaps when I'm sure I have a spare sensor in hand.

 

[EllieM]

So presumably dexcom told you this and also the 12 hrs isn't a thing!!

Straight from the mouth of the dexcom rep. However I suspect experience from users may be more accurate?
Do let us know how you go overnight.

 

[sninge]

Great news Ellie!!!
Having discovered I had enough sensors to risk losing one and having read online from Dexcom how to connect a replacement pump to an active g7 and obviously what you had said I decided to risk it and left connecting my pump for 16hrs and I'm pleased to say it works perfectly!! It was interesting to see the difference overnight between old and new sensor, old sensor on the pump kept me at a perfect 6 all night, the new sensor was quite erratic and had 1 hr when it said I was between 3.1 and 3.3 had it been connected to my pump it would have stopped my insulin. This is what I had with libre and g6 and why I always put them on the day before Starting, I'm pleased to say that after 16hrs the sensor was spot on, probably after 14 actually. Im really pleased to have worked a way to keep using the g7, it is great not to have the 2hr warm up and for me the readings are the best ever, I would say almost up to speed of BM! Good luck with yours and thanks for sharing your info.

 

[megan]

I'm going to start on g7 in about a few weeks and I understood that it's a quicker warm up time.... but this isn't sounding good if you have to put on new g7 whilst still using old g7 for a number of hours.... sorry I'm a bit confused. I've had difficulty with erratic, incorrect and complete cutout of blood results with g6, which has made for very difficult days, so Dexcom suggested g7
I appreciate any info

 

[EllieM]

I'm going to start on g7 in about a few weeks and I understood that it's a quicker warm up time.... but this isn't sounding good if you have to put on new g7 whilst still using old g7 for a number of hours.... sorry I'm a bit confused. I've had difficulty with erratic, incorrect and complete cutout of blood results with g6, which has made for very difficult days, so Dexcom suggested g7
I appreciate any info

I've always had issues with dexcom in the first few hours of wear. Sometimes it's fine, other times my skin reacts and it reads low while it "beds in". This is a known feature with cgms (I had to stop using libre 1 because I became allergic to it so suspect it's partly my body). The G7 has a "grace period" of 12 hours so if you want to you can put on a new sensor while still wearing the old one and so avoid the period of relying on possibly dodgy readings from a brand new sensor. Even better, if you put on a new sensor before the old one has completely expired you can avoid the warm up period altogether, as long as you've had the new sensor on for the warm up period it will be already warmed up when you activate it.

Anyway, I suggest you just try it out and see.

 

[sninge]

Hi megan. There is no need to put g7 on hours before if you dont need to let sensors settle in to avoid erratic readings for the first few hours, some people do and some don't it just depends how your body reacts, ive had to do it with libre 1&2 and dexcom 6 as I get way out readings for 10-12 hrs. The g7 has a half hour warm up so if you don't need to put sensors in early then definitely a great benefit. Don't be put off by the way I have to deal with it, I just sleep one night with 2 sensors in and that works for me and I still love the sensors.