The CGM: Insertion Change

Every Sunday afternoon, we change out Michael's Continuous Glucose Monitor (or CGM).  This device monitors the glucose level in his tissue cells.  It is not as accurate as the glucose level in his blood, so finger-pricks are still a necessity in order to get a true idea of what his blood sugar is before meals and bedtime.  Also, we have to calibrate the CGM at least once every 12 hours by doing a finger-prick and then entering that number into the CGM hand-held receiver.

Some people don't consider CGMs to be worth it since you still have to do finger-pricks before meals and bedtime.  However, in our minds, we think "Well, if we have to do finger-pricks anyway, we might as well use those opportunities to calibrate the CGM."  The more calibrations, the more accurate the CGM readings. 

The CGM is made up of several parts.  First, we have a hand-held receiver.   This looks like of like an iPod Nano tilted on its side-- though not as slim.  It has a screen where we can see the trend graph showing Michael's tissue-glucose.  This screen shows us a number (ie, 214) to indicate his tissue sugar, and it will also show an arrow (either straight out to the side, gradual up, gradual down, single arrow straight-up, single arrow straight-down, double arrow straight-up, or double arrow straight-down).  We have set alarms on the receiver to alert us to high blood sugars, low blood sugars, and we have set a customized alarm to alert us if his blood sugar is rapidly dropping.  We were able to customize these alarms to go off when his blood sugar reaches a certain level.  For example, Michael's daytime blood sugars are supposed to be between 90-180.  Therefore, we set his low blood sugar alarm to go off at 100 in order for us to do a finger-prick before his sugar drops too low. 

The second part of the CGM is a sensor.  This is the actual part that we insert under Michael's skin into his fatty tissue.  For the pediatric version of this CGM, we must insert the sensor into his upper buttocks or his tummy about two inches to the side of his belly button.  Since Michael is a rough and tumble kind of boy and slides off the couch tummy first, we only insert his CGM into his upper buttocks.  We switch buttock cheeks for each site change.  The sensor is attached to an adhesive pad that hold it in place.  We insert the tiny wire under Michael's skin via a plastic piece that looks like a pen.  We stick the adhesive in place, then we unlock the "inserter pen" and push down on the top of it to stick a needle under Michael's skin and the needle leaves the tiny wire behind.  We then pull up on a collar piece and it retracts the needle from the skin.  We then push the pen part forward and it unhooks from the adhesive base. 

The third part of the CGM is the transmitter.  This is a tiny electronic piece that attaches to the sensor.  We snap it into place once the sensor is under Michael's skin.  Every week, we change out the sensor, and we then remove the transmitter from the sensor.  We use the same transmitter each week.  The sensor pieces are disposable.  The transmitter is not. 

Every five minutes, the tiny wire under Michael's skin sends a signal to the transmitter and the transmitter then sends that signal to our hand-held receiver which displays the data on the trend graph.  I love love love this technology.

Sometimes the CGM is a bit off from Michael's actual blood sugar. This is why it's so important to do a finger-prick before taking corrective action. The monitor should show tissue-glucose levels that are within 20% of Michael's blood sugar levels. One night, the CGM beeped at us to indicate that Michael was low. I checked his blood sugar and he was 161. Therefore, we did not give Michael a spoonful of jelly, because he was not actually low. We calibrated the CGM and it then showed a more accurate number. So, there are instances where the CGM will be off, but that's technology and we expect that to happen. The benefits that the CGM provides, and the peace of mind that it brings, far far far outweighs the little nuances that occur.

When we are ready for a site change, we use an adhesive remover pad to get the adhesive base of the sensor wet.  We then pull it off of Michael's skin and the tiny wire comes with it.  We then detach the transmitter and we wipe the underside with an alcohol swab.

To prep the other buttock cheek for the new site change, we use an alcohol swab or a "Skin-Prep" wipe to cleanse the area where the wire will be inserted.  Then we use a Skin Tac wipe and we rub it in a doughnut shape around where the alcohol was wiped.  Using a Skin-Tac wipe makes the skin extra sticky and allows the adhesive to stick to Michael for the full week.  We cut a hole in the middle of an "IV-Prep" pad and we attach that to Michael's skin, leaving the circle we cut out to be where the alcohol was rubbed-- which will be where the wire is inserted.  The "IV-Prep" pad puts an adhesive barrier between Michael's skin and the adhesive pad of the sensor, since the sensor adhesive can irritate sensitive skin.

We then remove the "inserter pen" from the sterile packaging.  We pull off the white tabs of the adhesive backing and attach the adhesive to Michael's skin on the "IV-Prep pad."  We then insert it using the method described above.

Then, we snap on the transmitter, and Michael gets to pick a prize from the Prize Bag!

Ta-da!  He is always so proud of himself, and words will never be able to describe the emotions I feel during this process.  It's heart-wrenching to cause pain on your own child in order to provide him with the best care.  And it's incredible, the welling of joy in my heart to see how strong this little two-year old boy is.  I love him so. 

Here you can see the sterile packaging that the inserter pen is in, along with a Skin-Tac wipe and a Skin-Prep wipe that I have set on top of the packaging.

Here is the transmitter.  You can see how small it really is. 

This is a side view of the inserter pen.  The piece I am holding onto is the lock that we remove once the adhesive is in place on Michael's skin. 

The Prize Bag!  I fill this with little toys, or cups, or coloring books, etc and Michael gets to pick something each week for being so brave. 

This week, he chose a pail and shovel!

Here is my "sweetie boy" saying Cheese!

This is where the sensor is placed on Michael's upper buttocks-- the right cheek.  Next week, this will be on the left side of his buttocks.

Thank-you for taking the time to read this post about what a CGM insertion change involves.

Thanks for keeping us in your prayers!  We surely appreciate it.  Every single day.


Until Next Time!

Much love, Reba