After 8 years of continuous use of my Medtronic Paradigm 722, I have replaced it with the new Medtronic 670G. This is the latest insulin pump technology from Medtronic. It provides a hybrid closed loop system that promises better management of blood glucose levels. Below I will detail my experience (both good and bad) using this system. Before using this new device, Medtronic offers a 2 hour group training class. I attended the training and the 2 hour session lasted over 3 1/2 hours. The class did give me some additional information that was not included in the manuals.
The first thing I learned was the Medtronic CGM sensor that is part of the 670G hybrid system is NOT covered by Medicare. I asked the trainer how long before Medtronic would get it approved. She said it was up to the FDA and didn’t know how far the approval process had progressed. Interesting that the other CGM suppliers (Dexcom and Abbott’s FreeStyle Libre) are already approved by Medicare. Also, both Dexcom and Abbott CGMs are FDA certified to provide BG reads that can be used for insulin dosing. The Medtronic CGM is NOT certified so you still always need to do a finger poke prior giving a bolus insulin dose.
After using the Medtronic CGM for 2 weeks I can understand why it cannot be used to determine how much insulin to dose. The CGM can be used continuously for up to 7 days before the sensor must be replaced. I found it takes about 3 days of calibrating the sensor to get the reads to correspond to my BG meter. Also, you cannot just insert the CGM sensor like an infusion set. Instead you need a large hand held device to do the insertion. You must follow a very intricate set of instructions to make sure the device works properly.
One thing I do like about the 670G is the backlight color display screen. You can see it well in both bright sunlight and total darkness. My old pump needed an onboard light turned on to view the screen when only limited lighting was available.
The Medtronic SmartGuard(tm) technology used in the 670G has what they call an Auto Mode. This will automatically adjust your basal (background) insulin every five minutes based on your CGM reading. There is a 9 point check list of requirements the must occur BEFORE auto mode can start functioning. The main item is the requirement for constant BG meter readings.
After you insert the CGM, there is a warm up period that may last up to 2 hours before you get a prompt to enter a BG meter reading. The BG read is used to calibrate the CGM. After that you must enter a BG meter read at least every 12 hours. Since the CGM BG reads are not accurate for insulin dosing, every time you do a bolus (like before breakfast, lunch, dinner and bedtime) you must also enter a BG meter read. Medtronic recommends you use the breakfast, dinner and bedtime BG meter reads to calibrate the CGM. Also, once Auto Mode is activated it will constantly ask you for even more BG meter reads.
In fact, after Auto Mode is functioning you may have to do BG meter reads 10 t0 12 times per day. I found out from Medtronic tech support that you should NEVER use the BG meter readings prompted by Auto Mode to do CGM calibrations. They told me that this overloads the calculation of BG levels by the CGM.
It seems obvious to me that the weakest part of the Medtronic 670G system is the CGM. You would think that Medtronic would want the best available CGM to working with the 670G. This would certainly make it better for all the type 1 diabetics that use Medtronic insulin pumps. I guess they just want to maximize the profits they make from selling their own CGM consumables like sensors and transmitters. What do you think?