Stretching out my Enlites past 6 days

I’ve tried searching for this in past articles, but I am curious for those of you who wear your Enlite past the 6 days of recommended “life” of your sensor go longer. I am using mine with the older 523 pump (if that matters). So, I wore my sensor 7 days and then I think the battery needed to be recharged. I very carefully cut it out of the tape, unplugged it, and charged it. It didn’t take long to charge, and then I hooked it back up very carefully and taped it back up. Under the ‘sensor’ feature I used “link new sensor.” I figured I would probably have to wait the 2 hour warm-up period? However, my ISIG values were like 270?! Is that normal? I ended up just ripping it out and starting a new one. I thought I would consult the “experts” (you know who you are). So how do you do it???

Yes, use “start new sensor”. charge the transmitter for each 6-day wear period, as the xmitter will not make it to day eight on one charge. When you say ISIG hit 270 was that just one of the ISIGs you saw during warmup? Warmup ISIGs will vary from zero to quite high. Ignore them. What counts is the ISIG value at the time of the first calibration. I restart Enlites all the time for additional 6-day wear. I’ve gone 25 days on the best sensor. Sadly, I’ve had some great sensors get dislodged during xmitter removals or just from sweating. Yesterday I lost one from sweating–MM is sending me TWO sensors when I called yesterday. Not bad!

If what you are asking about is as phoenixbound described then,yes, it is completely normal, even expected.

It would work the same way if you checked your ISIG immediately after your pump connects to a new sensor. In my experience the first one or three ISIGs will always be very high but will fall to zero relatively quickly. What I believe is happening is that the transmitter is attempting to find a “zero point” (for lack of a better term) for the sensor. I posted about this once back in May. The quote below is taken from that post.

<ISIG value> @ <time> every 5 minutes during 2 hour Medtronic sensor WARM-UP.
ISIG 123.12 @ 13:34; 43.94 @ 13:39; 00.04 @ 13:44; 55.66 @ 13:49
ISIG 00.00 @ 13:54; 00.00 @ 13:59; 02.14 @ 14:04; 25.02 @ 14:09
ISIG 30.36 @ 14:14; 32.08 @ 14:19; 35.32 @ 14:24; 38.46 @ 14:29
ISIG 40.38 @ 14:34; 42.18 @ 14:39; 43.26 @ 14:44; 45.40 @ 14:49
ISIG 47.06 @ 14:54; 47.04 @ 14:59; 48.04 @ 15:04; 46.76 @ 15:09
ISIG 45.78 @ 15:14; 46.74 @ 15:19; 47.92 @ 15:24;

I believe the extremely high ISIGs immediately after connecting the transmitter is an illustration of why Medtronic urges folks to connect the transmitter as soon as possible after inserting an Enlite. What they probably want to discourage is the habit some had with the older Sof-sensor (aka Harpoon) of inserting in the evening and then waiting until the next morning before connecting the transmitter.

Medtronic claims letting an inserted Enlite sit that long without connecting the transmitter could damage or even destroy it. Apparently when the sensor is not connected to the transmitter there is a buildup of hydrogen gas around the probe. The transmitter drains the charge from the sensor preventing the accumulation of the hydrogen gas. In fact, the current from draining this charge from the sensor is the ISIG. (The symbol I is commonly used to represent electrical current. Thus, ISIG is probably shorthand for “current SIGnal”.)

@acidrock23 I would be curious what ISIG value you get when your pump first connects after you have inserted a new sensor. If I recall correctly, you always wait at least 15 or 20 minutes between inserting and connecting while waiting for the transmitter to charge. When I used to do something like that my first ISIG was always ~400 or larger.

Yep. That’s the bottom line.

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MM tech support is free. I suggest to anyone not conversant with ISIG’s, that is using either of the MM sensors, to grab a notebook and pen, and give MM a call. Option 1, “stay on the line”, and then Option 2, to speak to a sensor support person. It may take more than 3 or four calls to extract all the proper information you need to fully understand the best way to calibrate (and knowing when not to calibrate, which goes beyond the basics of “if your bg’s are moving too fast”). there is no possible way for MM to explain the algorithms that convert the readings into sensor glucose, when you calibrate, because that happens to be unexplainable. that bugs me, because I like hard facts so that it all makes sense. So we do the best we can with the info that MM IS willing to share, on their various CGM systems.

Keep in mind some techs will contradict what you’ve heard from others. At some point, you’ll get a feel for who is giving you legit info, who is misinformed, and who is just bs’ing their way through the call. I’ve talked to so many techs I couldn’t begin to determine how many that would be.

If you aren’t “techy”, just do the best you can and hope for the best.

The dumbest comment ever from a tech was that IV3000 was interfering with the signals between the pump and xmitter. Shoot me–just shoot me. I tried to explain to her that the signals are not impeded by the dressings and NO ONE at MM or elsewhere has ever made such an outlandish claim.

Yes. It wasn’t in very long, and I saw the # and just kinda freaked out. Wish I would’ve kept my sensor in and just waited. I think it was also a bad time of night…I wanted to eat dinner and relax instead of fasting and stressing and making sure my #'s are all good before I calibrate. Sigh.

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Thank you everyone for your help. I will try again. I was sick this past weekend and I noticed my CGM was having a hard time keeping up with my high’s and low’s (seriously, I was like a roller coaster!). BTW- does anyone else go low when they get sick??? My bs plunges when I feel bad. I haven’t really experienced a flu or anything that severe w/ diabetes so maybe I just haven’t been sick enough to be high. Anyways, the sensor seems to be working better today so maybe the site is okay and I will try extending past 6 days with this one. I cannot wear these things anywhere on my abdomen- way too much scar tissue. I’ve been wearing them on my sides and back. I might try the arm eventually.

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I do probably wait that long however I don’t ever look at ISIG. It’s one of those numbers that’s there and interesting but I have enough numbers to keep me busy. I just stuck a new one in yesterday so it’ll be like a week before I do it again but I’ll check and see. I wonder if the value sort of “cooks off” as it gets working?

Yeah, that’s sort of what happens.

It’s more like pressing down on a spring and then releasing it. The ISIG value “bounces” around a bit before eventually closing in on a more steady state. I’m just curious how high the initial ISIG might get … not that the number would mean anything specific to me. Oh, well. Thanks for listening.

@phoenixbound: To answer your question, I started the “new sensor” about 20 minutes ago and saw a 184.10 about 10 minutes after that and now it’s at 33.74 so it would seem to “cook off” pretty quickly.

now zero 50 minutes out from “new sensor…”

Just started the sensor at 113 and now 18.98.

And, to the large,orange Discourse suggestion box suggesting that I edit my prior posts rather than writing many sequential replies, I think that multiple replies helps convey the passage of time…

I like multiple replies, myself. don’t let anyone prevent you from posting in this fashion, please.