First hours with Dexcom, first problems with Dexcom

Diabetes Technology Glucose Monitoring
1

I finally got it, my Dexcom G4 and an Animas Vibe to go with it, replacing my Medronic Paradigm and Medtronic Enlite sensor.
Getting the pump set up, with a nurse here to explain me everything, was a first challenge. The buttons on the Vibe are too sensitive, but the results are not displayed simultaneously with the button press, meaning that you hold down a button till the correct value appears. You release, and a value much different is displayed. So finally you give up holding down on the arrow keys, and go step by step.
Pump set up and active. Next step the Dexcom G4. Placing the Dexcom was a first challenge. I push the needle in, no problem. But then the nurse didn't remember how to remove the inserter. I tried a few things, but nothing moved. Then the nurse figured it out, and was done.
I moved, and a pretty good pain in the area where I placed the sensor, side of the belly. I neglected it, thought that it would go away, but, no, instead it got worse. When I move, is like there is sitting a needle in my belly. I very annoying. I called the nurse and she told me to wait and replace the sensor if the pain doesn't go away.
2 hours after placing the sensor, the Vibe alerted me for a calibration, and the nurse had told me that the Vibe would ask me for 2 initial calibrations, with 2 blood drops taken from a different spot. However, when I confirmed the demand for calibration, I was simply taken to the CGM Menu. Ok fine. I push the BG Cal, and enter a first value, 71 mg/dl. I confirm the calibratation, and that's it. The Vibe did not ask me for a 2nd calibration. So, I repeated manually another calibration, 79 mg/dl.
I wait a minute and I push the button to see the value, 71 mg/dl. So for some reason, the 1st calibration value was taken.
5 minutes later, an alert. I check and it tells me 56 mg/dl. I do another BG, 72 mg/dl. So fine, I neglect the warning. A few minutes later I recheck, and is now 68. Ok I thought, maybe the pump is in some iteration to calculate the correct value, and I wait. A bit later, another alert, 56 mg/dl.I wait. A bit later I recheck, and I get question marks. And they stayed for about 3 hours before a value was displayed, a wrong value. The value displayed was 117 mg/dl. A BG gave me 56 mg/dl.
So what the heck is going on with this sensor. I had hoped, and this was confirmed on this forum, that the precision would be better than the Enlite, but this is my first sensor, and it is already giving me bogus numbers. And the thing is still hurting.
Is there anyone with Dexcom experience, that can tell me if this is normal?

And the Vibe, why the heck couldn't they simply add an escape button or a home button. You get crazy from going through the menus. What a step backwards in user friendliness compared to the paradigm. Although, the Vibe has some nice features which the Paradigm doesn't have. So what do we do? Reverse engineer both pumps, and combine the good parts of both into a new, perfect pump?

2

We don't have the Vibe but do have the Dexcom. My son has had it for about 3 years. I have only worn one sensor, but it definitely didn't hurt after the initial insertion - and my son has never complained either. Also - we rarely get ??? readings anymore so I wouldn't be surprised if something didn't go right with the insertion. Did you watch the videos online for the insertion? I watched that thing over and over until I was sure I could do it - I wouldn't necessarily trust a nurse who forgot how to do it . . .

However, as far as accuracy - although it is very good - I wouldn't expect perfection, especially in the first hours. That's when it's likely to be more off. We usually get good numbers in the first day, followed by much closer ones after that. I wouldn't write it off for accuracy yet.

3

Your dexcom can definitely take some time to start syncing with your glucose readings, usually after the first 24 hours, so don’t toss it until you’ve given it some time to acclimate to your body and get everything aligned. You can’t expect it to be perfect from the get-go! I just inserted a new sensor two days ago and had my most frustrating experience yet since starting on the g4. The first 36 hours were filled with the ??? symbol and no arrows and blah blah blah. It finally settled down and has been working well since then. I think it can often depend on where you do the insertion and your calibrations. Just make sure you aren’t over-calibrating because that can cause problems as well.
Also, I know dexcom says the sensors are only approved for the stomach, but I’ve had much better readings and less pain using them in my top upper thigh. The couple of sensors I wore in my stomach didn’t last as long and seemed to be less accurate. They irritated me as well.
As far as the Vibe goes, I don’t have the integrated pump/cgm, but did just switch from MM paradigm to the Ping and I HATE it for all the reasons you described and more. It is just not user-friendly at all. Hang in there, give it some time, and good luck!

4

Like Shelby, I take readings in first 12-18 hours with a grain of salt. Assuming the sensor inserted okay, your readings should improve eventually.

I think Animas is constrained by patents from improving their ergonomics. I imagine it is a harder adjustment since you are used to a different pump.

5

Thanks you guys, or better girls. I hang on to it. Is still hurting like hell, especially when working in the garden and when I was refinishing an outdoor table, but, I can hold. It may pass, both pain and inaccuracy.
I did 2 more reading, and way off. So, did 2 more calibrations. Knowing that they use a slightly modified linear regression, I don't understand how too frequent calibrations could upset it, but we'll see. Is worth the test.
Medtronics advices too not to calibrate too often, but when talking to one of their top technical executives recently, he adviced me to calibrate more often, in order for the calibration factor to adapt better to the real situation.
I had to smile when I read the remark about patent constraints. How the heck can it be allowed to take a patent on ergonomics. Reminds me a patent which I job wise ran into, for a swing. Describing how to hang a piece of wood with 2 strings, and the patent was that you can swing using this invention. I was deeply impressed. The guy or woman must be a trillionaire by now, if everyone pays him the usage fee for their swing idea.
What is missing from the G4, is the isig value. I asked Dexcom about that 2 weeks ago, still haven't received a reply. For me the isig is as important as the glucose displayed, as it tells, in combination with glucose, the glucose sensitivity of the sensor (in reality the glucose insensitivity of the sensor or calibration factor), it tells you about the degradation of the sensor as a function of time, and the end of life, it tells you when your glucose is stable, assuming the enzymes in the sensor stay active in the same manner.
What is a petty too is that there is no indication if the sensor is connected. The Paradigm shows the antenna when connected, and that is the 1st thing I check when placing a new sensor, if it connects. Here you have no idea. You place a sensor, wait 2 hrs while you watch the progress bar advance, and you hope to be asked for a calibration.
Well, I'll be building up my list with improvements desired, and I'll find a top guy to communicate them too. In this aspect it may be good to combine our forces, and hear all Comdex/pump users what they would like to see improved. Should I start a new topic for that?
Did another reading, 73 mg/dl from Decom, 61 mg/dl from Accucheck. I getting closer.

6

The isig is one of medtronic's better features along with other more customizable elements. Pity we can't just meld the two! Not sure about patent constraints, just my theory since otherwise it doesn't make sense.

It shouldn't be hurting anymore, so it may indeed be a bad insert...but they cost $, so I guess you should keep it for now.

7

I can only speak to the dex. The first time I inserted it I must have done something wrong because it really hurt for hours (still not sure what I did). Dex told me to remove it and try again and sent a replacement and a nurse. I met with the nurse who showed me how to do it properly and it has never hurt again in 7 months of use, Call dexcom and tell them it hurts - they may have you take it off and send you a replacement. Also, ask for another nurse that actually knows how to use it to show you how to properly do it. I watched the video but didnt feel comfortable until after the nurse, I agree with other posters that the numbers can be off at first, so do give it a try a little longer, I wouldn't recalibrate unless off more than 20 percent. Also, if your bg are fluctuating alot when you first put it in, it takes the meter longer to start giving you accurate readings hope this helps

8

Well, we are half a day further, and the pain has mostly disappeared. Sensor readings have been unpredictable, closer than suddenly a drop. doesn't seem to behave very stable. And the last couple of hours it told me that the value was below the minimum, so I added another calibration, 70 mg/dl. We'll see how it continues.
jmhnyc describes exactly what happened after insertion. I just watched the insertion video for the 1st time, looks very simple. So I don't understand how something can go wrong.

9

Another remark to jmhnyc. Getting another nurse is impossible for me, as there is apparently only one for the whole area that knows, or should know, how to do it. So I think that we'll have to manage ourselves.
Had a similar issue last year, for the Enlite, and insulin pump. Squeezed nerve in my elbow, left hand paralyzed, a 2 month wait for surgery. So how do you manage? Simply the daily activities were already a great challenge. I needed a nurse to come at home. But, there was none that had had training. The Medtronic distributor formed in a rush course one nurse, but it still didn't work out. I had to tell her every step, and if I didn't watch carefully, she made errors.
And no, I'm not Tarzan's neighbor, I live in France :-(.

10

SOrry to hear they cant find you a trained person. Maybe they could have someone video skype with you? Glad it isn't hurting anymore. Remember that the dex will be slower to adjust to large changes in bs (especially at the low end) then a metered number because it takes longer for that change to make it to the tissues. If you use the dex software it will tell you what the average deviation is for the dex. This will give you an idea of what the range will be for the numbers. Mine is usually around 30 to 40 - so if the dex is showing a 70 my meter will give me between a 30 and 110. I know I wish it was closer but it still is really helpful for me. When I started with the dex the deviation was averaging 70 and has steadily dropped as I have used it over the past few months. I do think it takes time

11

Well, I've got some good news. After a difficult birth, the sensor settled, and results are amazingly accurate. I think that I must have done about 4 or 5 calibrations, and almost all day, I stayed in between 40 and 70 mg/dl, but the sensor followed closely, and I would guess that the average deviation is around 1% for the about 15 BG measurements that I have already done today. For me this is a Dexcom victory compared to Medtronics. If now we can get this confirmed by a 2nd and a 3rd sensor, than we're rockin and rollin.
The Dexcom doesn't give an ISIG, but I made a quick engineering fix, based upon my knowledge of the Medtronic, where the initial calibration factor, or more accurate, the initial glucose insensitivity BG/ISIG, is 2.5 ... 3 mg/dl/nA. If we assume that this is identical for the Dexcom, which uses the same operating principle, and we take 3 as an initial value, no degradation, meaning that the 3 is maintained, then we can calculate the ISIG, and based upon CMG value and ISIG, we can calculate the calibration factor that the Dexcom uses.
The Medtronic degrades pretty fast, and starting from 3, you may have 4 after one day, and this keeps for the ideal sensor increasing till the end of life. Above 6-7 it can be assumed that results are not accurate enough anymore and that the sensor has for a large part lost its sensitivity to glucose.
Well after a first day, the CF of the Dexcom hardly moved. There are the little drops when glucose goes low, there are the rises when glucose changes fast, but overall I can already say that the Dexcom has a much more stable behavior than the Enlite, is more predictable, and much less degradation over time than the Enlite.

Sensor is still hurting, but it doesn't match up to the $97 which I paid.

I am a bit shocked with the av deviation that you gave me, jmgnyc. If this were truth, then I would loose my trust immediately. I assume that it is simply some kind of safety measure for them, such that people can't sue them is a sensor gives a wrong result, resulting in a severe accident.
You better not look at it !!!

I didn't get the IR reader to transfer the data from my pump. Hopefully soon.

12

Nice! Look forward to a better experience for future sensors. It really isn't typical for sensors to hurt very long or to take so long to settle in accuracy-wise. I usually stop feeling a new sensor within minutes.

13

Another remark to jmhnyc. Getting another nurse is impossible for me, as there is apparently only one for the whole area that knows, or should know, how to do it. So I think that we'll have to manage ourselves.
Had a similar issue last year, for the Enlite, and insulin pump. Squeezed nerve in my elbow, left hand paralyzed, a 2 month wait for surgery. So how do you manage? Simply the daily activities were already a great challenge. I needed a nurse to come at home. But, there was none that had had training. The Medtronic distributor formed in a rush course one nurse, but it still didn't work out. I had to tell her every step, and if I didn't watch carefully, she made errors.
And no, I'm not Tarzan's neighbor, I live in France :-(.

14

This interesting. The sensor came back for a sec, just long enough to tell me that the value measured was below the low set by user, which is 60 mg/dl. As I rather felt high, I do a BG, and ... 151 mg/dl. And by then the ??? had already returned. Is this a sign into the direction of what I mentioned in my last post?
Any feedback any one?

15

And we've got new problems. The sensor functioned perfectly for 2 days, I get up in the morning, and ... the 3 questions marks are displayed. The reason, I have no idea. At 2 am was still working. I did notice that I was laying on the sensor this morning, and there is people stating that pressure put on the Medtronics Enlite sensor is the reason for false results with hypo indication. This was confirmed to me by 2 people, non-diabetics, that were testing the sensor, although I have done the test myself, and I have never seen any relation pressure vs clycemic reading.
But the Dexcom, has anyone ever seen that laying onto the sensor resulted in the question marks being displayed? Is just a haunch, but is the best that I can come up with.
I'll just keep wearing the sensor and we'll see if it revives.

16

And the story continues. About 5 hrs after the single heart beat, the Vibe starts screaming at me. I check: "error 0", no further information. I was not at home, so I confirmed the error. The error 0 kept returning, but I had no idea what it meant. As soon as I came home, checked the user guide, but no error codes are listed. Googled it, and ... the dexcom website says that it means that the sensor has to be calibrated. If it then happens a second time, then the sensor has to be replaced. I did this calibration an hour ago, and I am not getting any value yet. The Vibe displays BG, whatever that may mean. I searched, but nothing to find.
I give the sensor another few hours, and then we'll try to replace it.

17

Yes, your hunch is correct, laying on sensor can throw off the readings or cause ???. Blood circulation slows down during sleep and impairs the sensor's ability to effectively read the interstitial fluid. Even without direct pressure on a sensor, I find that accuracy is less reliable at night.

You should experience better luck with your next sensor.

What you are experiencing with this first sensor is not typical.

18

Hi Don,

That's very interesting what you tell me, but, the pressure thing. It would sound more logical to me in saying that the effect is mechanical. You have the Enlite, with little catheter vertical, and you have the Dexcom, where it is sitting under 45 degrees. If now you put pressure on the sensor, which is think, then that pressure is very localized, and it would not surprise me at all if the catheter is simply bend under the pressure, such that fluid has an issue in getting through. If the catheter is sitting vertically, then chances for this to occur look much less to me.

19

The error 0 kept coming, so I replaced the sensor. And ... the new one is hurting even more than the other one. As long as I'm not moving, it is OK, but as soon as I need to bend or get up, then it is as if someone is putting a knife in my belly. This is weird, and I have no idea what is going on.
The accuracy of this new sensor is also much less than the 1st one, and I would say that I am again in the Medtronic accuracy range.
Based upon the fact that the sensors can not be tested individually before being shipped out, already tells us that every sensor will have it's own characteristics and response. Just like Medtronic.

20

The insertion usually does not hurt, but sometimes it is really uncomfortable. It took me several months to get really good at removing the inserter..it is difficult and awkward. The more readings you add to the receiver the better it will get at reading your sugar. Just be sure to add readings when your arrow on the receiver is level (not pointing up or down)