Hi Susan. I just joined this “group”, and saw your post from a couple weeks ago.
When my adhesive begins to fail, I let it go until there’s about 1/4" of loose Sensor pad. (For me, it’s nearly always along the top edge.) Before that point, there really isn’t enough surface area to glue down with success; and after that point, you’ve let the pad get so loose that the Sensor wire is already moving inside your skin-- and that makes it die quickly.
Mastisol (from Ferndale labs) is the best fix I’ve found. It’s a very old product, which was in use for hospital IVs long before insulin pumps were even invented. If you buy it, though, you should also pay some “adhesive remover” pads: there’s a liquid remover, which probably works very well, but I like Smith and Nephew’s “Remove” pads for cleaning up the left-behind mastisol gook when I finally remove the Sensor. (You DO NOT want to try scrubbing off Mastisol with mere soap, it won’t come, you’ll have to basically strip that layer of skin off with scouring powder.)
The important secret about using Mastisol is this: You MUST let it dry, completely, on both surfaces BEFORE you stick them together! If you push the Sensor pad back down on your skin before both surfaces are dry, it WON’T hold. Wait at least 40-60 seconds (I wait an entire minute), and be sure that you have bent the pad away from your skin so that it doesn’t touch by accident before it’s dry.
Buy the bottle with the dribbling top, NOT the spray. (For repairing an already-inserted Sensor pad, you need control-- not a spray which goes all over everything.) You don’t have to do any cleanup of failed Dexcom adhesive, you just paint right over it. Drip a couple of drops at a time onto one end of a q-tip, paint the adhesive onto your skin. (Usually takes just two drops for skin, two more drops for the loose part of Dexcom adhesive pad, two more drops for the re-coating.). After the skin, get another drop or two from the bottle, and be sure to bend the failing Sensor pad AWAY from the skin at ninety degrees-- they must not touch until you’re ready to stick them together. Paint the pad.
If you only expect 2-3 more days from the Sensor, you can start waiting right there. But if you want to hold longer (up to 10 additional days), let it dry about 10 seconds more: Then get another two drops from the bottle and re-paint (especially the sensor pad, where the fiber tends to absorb some of the first coat).
Now comes the critical waiting. Do not press them together for a full minute! Then, use a different, CLEAN q-tip and roll the painted pad down onto the skin, with good pressure, starting from the “bend” where it was still attached and working your way out to the edge. Do not use for fingers for the “pressing down” job, because you might be getting sticky mastisol all over your fingers. (Yes, mastisol is really great at sticking fingers together!) Throw this q-tip away too, and you’re all done. The hold is instantaneous.
I’ve been doing this for 2-1/2 years, and my 2-oz. bottle is not even 1/5 used yet. (One bottle will last practically forever). I’ve hardly ever needed to re-attach the same part of pad twice, but if you ever do need to do this, remember: DO NOT use an “adhesive remover” to clean off the nasty blackened sludge left behind by the first use of mastisol-- mastisol dissolves old mastisol very well, you only need to waste one extra q-tip to scrub up the gunk. (First q-tip with 2 drops gets dirty with cleaned off gunk, throw it away and continue with another fresh q-tip). If you use an adhesive remover pad or liquid, even mastisol won’t work there for many hours-- and the whole rest of the Dexcom Sensor pad will probably fail too, with the entire Sensor falling off into your hands.
(Fortunately, I learned THAT lesson on one of the old $35 STS Sensors, not one of the current $60 ones.)
When you finally remove the Sensor completely, THEN use an adhesive removal pad to tkae off the mastisol sludge. Smith and Nephew “remove” pads are perfect for this.
On a slightly related note: Before you put a Dexcom Sensor down, I think that you should scrub the target area quite hard with a soapy washcloth (until the skin actually goes a bit red). Removing all of the loose derma stuff before putting down the alcohol wipe really helps Sensor adhesion, at least for me personally. It’s also extremely helpful from a disinfectant point of view-- the effectiveness of HARD soap scrubbing followed by a clean washcloth rinse, air dry, followed by 70% IPA twice (and completely air-dried both times) is comparable to PVP-I (the red stuff they use in hospitals for major surgery.) If you don’t use expensive little alcohol pads, and work from plastic bottled stuff as I do, 90% IPA is even better.
I don’t use any “prep” pad under my Dexcom Sensors anymore, I just don’t need them. But before I was scrubbing hard enough, and before I tried mastisol, I found that both of the S&N “prep” products helped a bit, and didn’t have any effect on Dexcom performance. But “I.V. Prep” didn’t help pad adhesion anywhere near as much as “Skin-Prep”-- if you want to try one, that’s the one to get. Again, you don’t have to pain around the wire location; you can just do the entire area, shoot the Dexcom wire right through the thin layer of skin-wipe, and it performs just as well as it would shot through totally bare skin.
That’s NOT true with Minimed or Abbott – don’t dare shoot those Sensors into skin-prep, you’ll ruin them. Users of those devices need to leave a little “donut-hole” at the area which the wire goes through.