Guardian Real-Time CGM System

Ken Roe
By Ken Roe Latest Reply 2009-12-11 08:14:04 -0600
Started 2009-11-14 14:17:57 -0600

Is there anyone out there that is currently using the above device? I would appreciate getting some answers before I "hook" up to it. I was surprised at the "step-back-in-time" insertion of the slanted needle,it seemed long and painful. It was also a hour to hour activity to try to get it calibrated, and then keeping it that way. I believe only once did the meter reading match my Real-Time reading, is that normal? Can anyone give me a little advice?

6 replies

SeansMom 2009-12-11 08:14:04 -0600 Report

We looked at all the CGM and found that the Navigator was the best one to use. It was easy and the Freestyle strips and meter were all in the CGM. Unfortunately my son is allergic to adhesive so he can't use the CGM or the pump. I know that you can't change devices but I just wanted to give you my thoughts on the Navigator. Our nurse who has diabetes has tried them all and loves the Navigator. Good luck.

Crashnot 2009-11-14 16:56:01 -0600 Report

I've had the CGM for a month or so now and use it off and on. There are a BUNCH of things they don't tell you in the manual or the training session!

1) That needle does look wicked, but if you find a pad of fat to plant it in, it's amazingly painless. The HARD part is pulling the inserter out after you fire it in! Go through a few practice runs before you actually put it in so you'll know the angle to slide the inserter device away when you're on high adrenaline from putting it in. Withdrawing the inserter needle has been the hardest part for me, but once I figured out the angle it was very easy.

2) After you have it in and are sure it's not bleeding, anchor the plastic sensor head firmly with a piece of first aid tape or band aid type adhesive. I have had trouble with it going bad on me after a day or two from being wiggled around too much by clothes. The tape will keep it in place.

3) Put the sensor in at bedtime, attach to the transmitter, and put the tape on. DO NOT START IT YET! Wait until you wake up the next morning. If you want it to calibrate correctly, you have to not eat for at least 2 hours before calibrating, and at least 30 minutes after. So when you wake up is about the best time of day for it. It will not take away from the 3 days the sensor is supposed to run.

4) Do not calibrate your BG to the sensor more than 2x/day. Otherwise it goes whacky. The Medtronics person filled me in after I ruined a few sensors doing this.

5) If you have it anchored securely, you can easily get 6 days out of your sensor instead of 3. Some people get 9 but I haven't managed that yet. At the end of day 3, when it says Sensor is done, just tell it to Find New Sensor (be sure to do this when you wake up the next day!). It will ask you to recalibrate shortly after that and go another 3 days.

6) If you do manage to get past 6 days, you will need to remove the transmitter on the 6th day and recharge it. Then plug and play as if it was a new sensor.

When using the sensor multiple times, be sure to monitor if it's within close range of your BG tests.

Also, I find that if I'm really high or really low, it's not in synch with me. It's best when you are in your your target ranges. The extremes it is slow to display, so don't count on it to catch highs or lows, keep doing finger pricks as usual and use your CGM results to help calibrate insulin to your trends over a series of days.

Hope that helps!


JeffHarkness 2009-11-14 22:30:20 -0600 Report


Here's one trick I've found with your No. 4 problem so you don't ruin sensors after inserting them and getting a bad or wacky reading :

4) Do not calibrate your BG to the sensor more than 2x/day. Otherwise it goes whacky. The Medtronics person filled me in after I ruined a few sensors doing this.

If the sensor gets out of whack on readings from too many calibrations (I agree, more than 4 for me sends it out of line with my blood meter) here's something I do. It also works if you get a Sensor error, Lost Sensor or Bad sensor reading.

Leave the sensor in place instead of removing it and go to your pump, Go to sensor settings and turn the sensor off under edit settings. Wait about 10 minutes then go to the sensor settings again and turn the pump back on. Then simply start a new sensor. You'll have to do a blood reading in a few minutes after restarting the sensor, but it should clear out the bad readings and the sensor should be ready to go as normal.

And one other thing I've noticed: The sensor is good for about 14 days off the charger, although you don't want to go that long. I've found that I can go the full 6 days with no problem, and if you are pushing for another day or two, you are going to be all right. I'd definitely leave the sensor on the charger overnight if I was going to go more than 7 or 9 days straight, however.

Crashnot 2009-11-16 16:52:01 -0600 Report

That's great to know, thanks! These things can be persnickety, so helpful to get a few new tricks.

JeffHarkness 2009-11-14 16:48:31 -0600 Report

I started using the Real-Time system about a month-and-a-half ago now, and I'm liking ti so far.

The needle looked intimidating at first, but I really didn't even feel it at all when I inserted it. It goes mainly into the fat and sort of skims along under the surface layer of skin. My insulin pump infusion needle is shorter, but more painful, in my opinion.

The numbers on the real-time system are not meant to be 100 percent accurate on what your meter check would be. Instead, it can show you when you are starting to rise or fall. It's kind of a wave-length pattern that you look at and judge if you are going up or down, or up and down quickly in some cases. The real-time system sends a number to your insulin pump every five minutes, so there are something like 288 checks in the course of a day. You can see how you'd start to get a lot of information from a graph with those kind of numbers. It would be like sticking your finger every five minutes and reading the result.

The calibration on the sensor isn't so bad once you understand it. Here's my routine: I insert the real time sensor (about a 10-15 minute process). I wait a couple of more minutes to let the system get started (basically allowing the test strip that stays under the skin once the needle is removed to get wet with the interstital fluid beneath the skin). Then I tape down the sensor. I then tell my insulin pump I've started a new sensor. Two hours later, the pump signals that it's time to check my blood using my meter (a check I would likely have made anyway) and enter that number into the pump to calibrate the pump and the real-time sensor. That's it. You only need to calibrate the sensor about 4 times per day — so I do it once before each meal, then once before bed so it doesn't start beeping overnight demanding a blood test. That is enough to keep it within 20 percent of my meter's blood test. (If my blood meter says I'm at 100, my sensor might be saying 90 to 110; it's pretty close. You just have to learn to ignore the number and look at the graph's rising or falling line). I leave the sensor attached and taped to my skin for 6 days. Medtronic says 3 days, but it's like an oil change in that you can go longer. They just don't tell you that (but my real-time specialist recommended, although you can't get any questions answered from the company on how to re-start it if you plan to wear it for six days. It's easy, though, where you just skip all the insertion steps above and tell the pump you are starting a new sensor. In about 10 minutes — instead of the normal 2 hours — the pump tells you to do a blood test on your meter and record the result. That starts the sensor for another 3 days.) Six days is about it, though, before the test strip attached to the sensor runs out and you need to replace the sensor site. Also a good idea to change injection sites at that time to avoid skin problems.

Here's a couple of tips on how I get over inserting the needle. First, if you take aspirin regularly, hold an ice cube wrapped in a towel on the site for the injection. This keeps bleeding to a minimum (you don't want the sensor sucking up blood). It also numbs the skin when the needle goes in. Hold the skin taut, so that the skin is tight and the needle inserter sits flat against your body. This helps the needle go in without much pain, too. After you insert and remove the needle, hold pressure on site to keep the bleeding down. Maybe a minute or two.

With the real-time sensor, I'm able to go between meals without really worrying about if my blood is going high or low (a problem for me, unfortunately). I get a nice signal and buzzing overnight, too, for some low readings then. It wakes me up, which is something I wouldn't have gotten before relying just on the meter. Since it checks every five minutes, it really does provide a pretty accurate representation of the ups and downs you go through. You can see it rise after a meal, then dip back down to a baseline 100 or so. I've set mine to sound an alarm if my blood sugar rises above 220, or dips below 70. That way, I get a heads up and can correct or eat something to get back to that baseline before I go too far out of whack.

It took me a week or so of learning what the sensor could do — and the first time I inserted the needle on my own was an interesting experience as I tried to make it all work as normal. Just have to be patient, but it does get easier. And since I change just once every six days, it really doesn't seem too bad. The sensor is water-proof as long as it's attached to the injection site, so you can shower without worry. You just leave it attached and go. Once it is hooked up, it's pretty worry-free for those six days.

Good luck and give it a try.

Harlen 2009-11-14 15:13:51 -0600 Report

I wish I was able too
but with all the checking that gose with it I just do the checking thing best wishes