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Dexcom ??? - always a harbinger of doom?

Discussion in 'Continuous Glucose Sensing' started by suej, Aug 6, 2015.

  1. suej

    suej Approved members

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    We have had such a good experience with Dexcom for the last 4 months. Good accuracy, each sensor lasted 12-16 days. Use back of arms, and overtape everything with hyperfix.

    This weekend a sensor died D8 (recurrent ???). Disappointed but thought that in the larger scheme of things we should be grateful. Sited new sensor Monday evening and after 2 hour warm up got ??? instead of calibration prompt. Not pleased, was already bedtime. Luckily cleared after 45 min and calibrated and seemed to work for the next 16 hours. Then at 4pm went ??? again for 2 hours, threw out 2 readings (funnily enough correlated to BG) then went ??? again so pulled sensor. I noticed that the sensor had a drop of moisture on one of the contact circles (not sure where from, Ben had not bathed and it is winter here and cold). Sited new sensor and working but accuracy a bit dodge at present.

    1.Should I have dried the transmitter and clicked it back in and tried again?
    2. Are ??? invariably a harbinger of doom?
    3. Has anyone had ??? right at the beginning when initial calibration due?

    I would be grateful to hear your experiences
    Thank you
     
  2. Megnyc

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    I get ??? rarely but when I do I have very little tolerance for it. My experience has always been that even if they resolve, it will just keep happening unless the reason was that the transmitter was snapped out or my blood sugar was changing incredibly rapidly. At this point I pull sensors after about 1 hour of ??? It is so rare for me (every few months) and I can get 2 boxes of sensors a month covered by my insurance so I don't call dexcom about it to request a new sensor. In the US they say wait 3 hours with ??? and then they will replace. Not sure what the rule is where you are about replacements.
     
  3. njswede

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    Not always the harbinger of doom. It simply means that the sensor picked up readings that didn't make sense. The software in the receiver is feverishly trying to establish a new baseline and will succeed if it gets enough "clean" data. In depth description of how it works here: http://www.nightscout.info/wiki/labs/interpreting-raw-dexcom-data
     
  4. njswede

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    This morning was a good example: DS slept on his sensor and we had a compression low. The software quickly realizes that dropping from 120 to 40 in 5 minutes isn't right, so it gets into question mark mode. After about an hour, we have normal numbers again. Rumor has it that the adult version of the software is a lot less restrictive in terms of displaying dubious data, so it will question-mark a lot less frequently (Disclaimer: This is just based on chatter on the Nightscout developer site. I haven't been able to verify it). Rumor also has it that the 505 update of the pediatric software will have better recovery from noisy data and behave more like the adult version (same disclaimer applies).
     
  5. selketine

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    We inevitably get the ??? on restarted sensors at some point but really never in the first week. Anytime I get the ??? it doesn't recover enough to be accurate USUALLY - I'm sure there is an exception there over our many years of use but typically they have to be pulled. If you're having problems with a new sensor I'd call Dexcom and have them send a new one. I am also wondering if there's any change your transmitter could be failing? They will last 6 months and typically a good bit longer but it seems to me when our first one started failing I was getting more ??? and it never gave me the warning to get a new transmitter like it should have. Rather it just up and died. Just make sure to have a new transmitter on hand if you're past 6 months.
     
  6. caspi

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    The ??? could also be due to dehydration. We've had that happen a few times and a bottle of water cleared it up.
     
  7. Michelle'sMom

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    1. We've removed the transmitter many times to dry it after my dd's marathon baths/showers or swimming. Moisture under the transmitter can definitely cause ???s.

    2. Not always. When we got the ???s with the Dexcom 7+ we would move the receiver out of range. When we brought it back in range it would almost always give a reading. If it didnt, it usually meant the sensor was failing. The same applies (& works) with the G4, but we have to move the receiver much farther to go out of range. We rarely see them with the G4, but most of the time it's due to a big discrepancy between the number we enter for calibration & the current reading on Dex.

    3. A handfull of times. Twice the sensor failed after warmup. The other times, it continued to work fine.
     
  8. Michelle'sMom

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    Are you completely covering the transmitter? We tried that a few times, but had too many problems with condensation under the transmitter.
     
  9. suej

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    Thank you for all your insights.

    Meg, our ??? were usually about Day 12- 14 and signalled to us to change sensor. Do you get them in the first week?

    Michelle'sMom, yes we are completely covering the transmitter. I tried cutting out a middle segment for the transmitter, but ben complained that it caught as he changed his shirts. And then someone posted that they covered it all and worked fine. I must search and see who that was and check with them.



    Many thanks
     
    Last edited: Aug 7, 2015
  10. Megnyc

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    If I get them it is either during the first 3 days or if I leave a sensor in for 3 weeks (in which case I don't even give it time and just pull it).
     
  11. MomofSweetOne

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    We had a sensor recently go into ??? and then sensor restart repeatedly the first night. We pulled it. Dexcom replaced it without hassle. Have you talked to them? Their customer service is a completely different experience than Medtronic. I wouldn't spend too much time fighting ???. We usually don't see them until day 9 or 10 at the earliest and then sensor death comes within 24 hours.
     
  12. suej

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    Thanks - I agree no real point fussing if past 7 days, sadly can't talk directly to Dexcom as no back up in SA, have to fill out form and send via distributors.

    The second sensor also went ??? on Day 3 so I had to replace it (it never rains but pours). So I am a little worried about the transmitter too. It is 4 1/2 months old.

    One thing I noticed is that both the failed sensors has a small (but bigger than usual) dried out blood clot at the insertion site - anyone with any wisdom as to how that may affect a sensor?

    Thanks
     

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