My son has a Dexcom CGM. He had been mainly wearing it on his buttox with no issues. We tried having him wear it on his stomach to give us more site options but kept having the sensors fail. One lasted only 3 days and the other lasted 4 days before we got a sensor failed error. I have contacted dexcom and they are sending me replacement sensors thinking there may have been a bad lot of sensors. I'm still not sure if it is a sensor issues or a site issue. Has anybody had any issues similar to this?
CGMs, all brands like to stay in the same place under the skin and need good interstitial fluid exchange/movement. Therefore, a site in the stomach may have issues because the skin flexes so much that the sensor wire will move up and down in the shin, causing failure or inaccurate readings. If there is pressure on the sensor, such as sitting on it or sleeping on it, the exchange of sugar between the blood and interstitial fluid will slow down and the reading will be low and calibration issues may arise.
The best place for a sensor is an area where the wire and sensor end remain fixed. For me the outside or back of the arm work great. Also, I understand that the there is not need to rotate the sensor place because it is not creating scar tissue like a infusion site. All it does is create a small hole that will easily heal. The only thing you need to be careful of is putting it in the same hole the old one made.
I just listed to an MD from UCSF, who is an expert in CGMs, state that most people have a spot that works best and the trick is to find it and use it.
My daughter is on her first sensor ever at the moment. It failed after 3 days. We left it in. It started working again a day later. No idea why. We got an actual failed sensor message. We made sure she kept the receiver in range for a few hours and it started working again.
We're only on our second sensor. The first lasted about 8 days, and we're on day 10 with the second. She's only been interested in trying her tummy (won't let me use arms or legs for her pump either), but it's pretty pretty accurate most of the time.
In Feb, 2010, I had the same problems with my Dex. Very little agreement with my meter, and sensor failure in less than a week. Then I found a Dexcom users group on the http://www.tudiabetes.org website. If you join that site and then click on "Groups", you can join the Dexcom group. The group has more than 600 members and you can get very good info there. There are many things I learned that were not in the Dexcom manual. By the end of Feb I was having much better agreement with my meter, and the sensors were lasting two weeks on the average.