New to CGM

[Ark nana]

First time to post. I have had the CGM for only three days and so far so good. I got a new sencor alert this morn. but just clicked on new sencer and it worked. Anyone out there have any advice for me? ARK NANA

[poodlebone]

After the second 3 day cycle is up you can either carefully remove the tape/dressing to recharge the transmitter or you can start it again for another day. The transmitter will time out 7 days after you've first attached it to the sensor, not when you first started/calibrated the sensor. If you start getting Weak Signal alarms, you'll know it's time to recharge.

Do you know about checking the isig and figuring out the calibration factor? The CF is your BG (from a meter reading) divided by the isig. In order to calibrate that number (the calibration factor, not the isig) must fall between 2 -20. If it's too close to either end you may still get an error.

Insert at close to 60 degrees rather than 45. The longer you let the sensor get wet before starting it up, the better. A sensor's accuracy will often imrpove after a day or two so even if your results aren't that great at first, just keep it going. If you do experience real problems during the first 3 days call Minimed right away. They will often replace the sensor. They won't talk to you about it if it's been in longer than 3 days.

Opsite Flexifix is a great dressing. It comes on a roll that cut to size, rather than individual pieces like Tegaderm or IV3000. I find it holds much better than either of those.

[Ark nana]

Thank you so much. You gave me more info than the nurse did. I knew I could count on you guys for help.:)

[poodlebone]

If you have any questions, just ask. I know we have a bunch of MM CGMS users here!

[Ark nana]

Thanks for a quick reply. You said something about the isig sensor.All she(nurse) said was "You dont' have to worry about that". Do I, and what do I do if it's not in range? Also, why is the kind of tape important? She didn't say anything about that . Just where I should put the tape. Thanks a bunch!!

[poodlebone]

The isig is important. First of all it will let you know in advance if you'll be able to calibrate (by dividing your meter BG by the isig). The more common problem with the isig is that it's too low. Having an isig that's too high doesn't happen nearly as often. A low isig can be due to a poor insertion (not deep enough, not in a good area), the sensor not yet "wet" enough or a sensor that is nearing the end of its useful life. If your isig is low when you try to do the first calibration, just turn the sensor off for several hours, then turn it back on and try again. Sometimes they really have to sit & soak in the interstitial fluid for awhile before they're ready to go.

When you first attach the transmitter to a sensor you can check the sensor status screen in those first two hours , before it's ready to ask for the first calibration. The isig will often have wild swings, going from very low numbers to really high ones. Don't worry about it; that's normal. It should finally settle down around the two hour mark but as I said, it can often be low. As long as you can calibrate (bg divided by isig falls between 2-20) then go ahead. You may find your sensor readings don't track very well at first but often the isig & accuracy will improve. You can always call Minimed if it doesn't.

The tape choice is a metter of preference. As long as it holds the sensor & transmitter securely and doesn't annoy it, anything will do. I find that the IV3000 peels up too easily so I don't like to use that. Now that it's summer all of those clear dressings have been bothering my skin. Sweat collects underneath and loosens both the dressing & the sensor underneath. I've lost several sensors this summer that way. I now use Hypafix, which also comes on a roll that you cut to size. It's like cloth, similar to the built-in adhesive on infusion sets. It breathes & dries quickly so no sweat collects underneath, no irritation and it doesn't peel up. During cooler weather the Opsite Flexifix works well for me. The stuff that comes on rolls is also cheaper. Since my insurance doesn't cover the dressings I look for cheap options! I get all of mine on eBay.

[Ark nana]

Thanks again for your help. I did the math like you said and it was good, within 2-20. Have you had your CGM long? You seem to really know a lot of info about it? I'll be more at ease after a while, esp. with help from people who live it. It seems as my BS goes up, so does the isig. I guess thats O.K. Thanks again!!:D

[poodlebone]

I've been using the Minimed sensors for 14 months now. It really does get easier once you learn the tips & tricks. The isig is the measure of the sensor current. As your BG increases, so does the isig. As BG drops, so does the isig. It's the raw data the pump uses to calculate the interstitial glucose. When a sensor is near the end of its life, the isig will drop to a low number and you'll get very low sensor readings even if your BG is normal or high. The sensor graph will pretty much stick at a low number in a straight line. My sensors will often die very suddenly. They'll be tracking well, then just take a nosedive.

If I suspect a sensor is dying and I'm not in a position to insert a new one (like if I'm at work, or out shopping), I'll turn it off and then turn it on again in an hour or so. I've been able to resurrect some sensors that way but most of the time they really are dead.

I had a new experience just this week. I have a sensor in my upper thigh and for the first week it was wonderful. Several days ago I woke up and rolled over and heard the pump alarming. It showed a reading of 54 with two down arrows. Just 20 minutes earlier on the graph it had been in the 150 range, in a flat line for hours all night. I thought it was odd that it suddently dropped from 156 to 54. I tested my BG and it was in the 150s. I looked at the isig and it was low, around 7. I knew I would get a calibration error if I tried to calibrate so I turned it off. Turned it on again later and the isig was back up and I was able to calibrate. The same thing happened to me the next two mornings. Turnes out I slept on it an was in a deep sleep so I didn't move around at all. The pressure caused the isig to drop for some reason, which then gave fals low readings. The second two mornings I didn't turn it off. I just cleared the alarm, dranks some water, massaged the area around the sensor and waited awhile. In a short time the isig and readings went back up to normal. I've never had any issues sleeping on the sensor so it was new to me. So, that's another thing to think about if you get false lows. Make sure that there's no pressure on the sensor, whether from sleeping on it or from something like the waistband of your pants. Drinking water, moving around & gently massaging the area can help to get the interstitial fluid moving again.

[Ark nana]

Good info.again. If I didn't know all this, I'm sure I would waste a sencer or two,and that would not be a good thing. I can't believe how much they cost. My ins. company will pay 80/20 AFTER I meet my deduct. Which has only been done twice since I've been dx. I've met my duct this year so trying to stock pile supplies.
One more question...Do i need to keep the sensors a certain temp? Some have said keep them in the fridge?? Your thoughts?

[poodlebone]

Minimed says that they no longer need to be refrigerated. Since I first started last summer (June 2008) I put them in the fridge because my apartment can get very hot. I got a thermometer for the fridge to make sure it wasn't too cold in there, and they've been fine. I've left them in the fridge year round ever since I started. If your house stays at a moderate temperature, you can probably just leave them out. If you do refrigerate them, make sure you take the sensor out of the fridge and let it sit for 15-20 minutes to come to room temperature before inserting it.

My insurance covers them 100% and I was told by Minimed that I'm approved for two boxes (20 sensors) every 100 days. That averages to 5 days per sensor, which is of course more than Minimed says they should be used for. I only order them as needed. I have used expired sensors and they worked just as well as non-expired sensors so if you do stockpile, don't worry about the date. They do have a short expiration date, 6 months I think. My CDE said some of her patients have used sensors that were 2 years old and had no problems.

[Ark nana]

Good to know. Thanks again!!