Earlier this year, Medtronic released their new insulin pump/CGM system called the Minimed 670G, the world’s first hybrid closed loop system. The hybrid closed loop system basically means that a CGM communicates with your insulin pump and if it sees your blood sugar rising, it will give small “micro-boluses” every 5 minutes. If it sees your blood sugar going down, it will hold off on the micro-boluses. The system aims to have a blood sugar of 120 mg/dls but will only correct a high blood sugar to 150 mg/dls if it’s correcting a high.
I have been on auto mode for 2 months now. Overall, I LOVE it and would highly recommend the Medtronic 670G! It is a new way of thinking about pumping and it takes some time for the pump to “learn” you.
First Week was ROUGH
The first week on auto mode was ROUGH. I had so many highs and lows it was crazy. I felt like I was on a never ending roller coaster ride. As the pump was learning me, I was also learning how to use the new pump as well. When I would go low, I would have to be patient and know that the pump was making adjustments so I didn’t need to correct with as many carbs as I usually did.
No Correcting Highs
I was also frustrated at not being able to correct a high when I wanted to. On auto mode, you aren’t able to do a correction bolus unless it tells you to. The first week when I was high, I would be frustrated when I couldn’t bolus for a high that sometimes I would do a “phantom carb” entry, meaning I would bolus for about 10 carbs so that it would give me some extra insulin. However, this hinders the pump to learn you so I only did it a couple of times and waited patiently for the pump to learn me.
Need Accurate Carb Counts
In addition to the highs and lows, I was finding it to be a lot more work initially. I had gotten into a funk where I wasn’t carb counting very well. I would just SWAG (Scientific, Wild Assed Guess bolus) and go on with my day, often resulting in higher blood sugars. However, with the 670G auto mode, you can’t just guess at carbs. If you do, the pump will never learn how to accurately give micro-boluses. So I had to start being diligent with my carb counting.
It Gets Better…No Basal Testing!
While I have to work hard at carb counting, one thing that I no longer have to do on the 670G is basal test (where you fast for several hours to see how your hourly rates are working). The new system is constantly working and correcting micro-boluses to keep you at the 120mg/dls number so you no longer need to make changes. In fact, the only two things that you can change while on auto mode are your carb ratios and your active insulin time.
I did run into an issue with a morning spike. I normally eat breakfast at 6:30AM and the way my carb ratio was, it was handling my morning spike instead of letting the basal/micro-boluses handle it. If I would wait to eat breakfast at 8 instead, my blood sugars would rise because normally my carb ratio (incorrectly) would take care of the spike. So I needed more basal and less bolus but on the 670G, you can only change the carb ratio. I had to be patient and let the pump figure it out on its own.
Overnight Looking Good!
Before I got the new pump, I was really struggling with my blood sugars, especially overnight. I would rise overnight to the higher 200’s and I knew I needed to basal test/adjust rates but I just never got around to it. I was so thankful to get the new pump because now it handles it all for me. Often, overnight I am a perfect 120 mg/dls or at least close!
In addition to having good blood sugars overnight, my daytime blood sugars have improved also. In fact, I got my A1C checked about a month into being on auto mode and my A1C was a lot lower than I expected. The two months prior, my blood sugars were much higher so I was expecting an A1C in the high 8’s. I was pleasantly surprised to see my A1C at 7.0. I look forward to seeing my A1C in three months when I will be in auto mode 100%.
While I am LOVING auto mode, I have found a few drawbacks. Back when I was pregnant, I had my average blood sugars in the low 100’s. While my blood sugar story lately has been much different, I worry that the auto mode might prevent me from getting back to that place. The longer that I have diabetes, the more worried I become about long-term complications. The pump aims to get your blood sugar to 120 mg/dls, but I’ve found that I hover in the 130’s/140’s more. I think the pump is great at getting an A1C to around a 6.5 but if you are wanting a lower A1C, I’m not so sure it would help to achieve that. I am hoping over the next few months to really get back in shape, both physically and with my diabetes management so hopefully I can keep you posted on if it’s possible to achieve a lower A1C than a 6.5.
The Dreaded Loop
Another negative to the auto mode is that the pump can get confused easily. It’s like it doesn’t like to receive too much information. The day that I was training on the new pump, I got stuck in the dreaded loop. This is a term I learned from a Facebook group because my trainer had no idea what was wrong. For over an hour (during my training phone call), I entered my blood sugar, it said it was processing my blood sugar then wait to enter blood sugar, then enter blood sugar where I would and repeated over and over! It was so frustrating but I learned that you just can’t enter too much information. Only enter what it asks for. So if you are calibrating, you don’t need to also enter a new blood sugar unless it asks and vice-versa (unless you want to calibrate because your blood sugar is stable).
While the pump is learning you, I received way too many alerts at first. If I was high, it would give continuous micro-boluses to the point where I would get an alert for auto mode max delivery, meaning I had been getting continuous micro-boluses for 4 plus hours. Or I might get the auto mode min delivery alarm, meaning I wasn’t getting any micro-boluses for 2 and half hours. Then when you get those alarms, they are quickly followed by a Enter BG alarm because the pump wants to make sure everything is correct. In the beginning, I was also going high and low a lot as the auto mode was learning what I needed so I was getting a lot of high and low alarms as well. And I got stuck in the loop a few too many times as I was learning the pump’s quirks (Note to future users, don’t enter too much information to the pump. Let the pump tell you what it needs and be patient so you don’t get stuck in the loop too often). Note: for those that don’t know about the micro-boluses, the pump takes 288 samples of your blood glucose per day and has an algorithm that divides those with your total daily dose (TDD) and uses 6 days worth of data to figure out how much of a micro-bolus you might need.
Also in those first few weeks, I would often have to calibrate in the middle of the night. It’s like the pump didn’t believe that my blood glucose was doing as well as it was. I was super frustrated those first few weeks because I would make sure to calibrate before bed but then it would still wake me up at 3AM to calibrate (when you first put your sensor in you have to calibrate the first time, then 6 hours after and then every 12 hours after) even though I wasn’t technically due. Now that I’ve been on for about 2 months, I rarely get woken up to calibrate.
I am still learning how the pump handles unusual situations. Right now, I’m not exercising. I went for a long walk last week and my blood sugar tanked. If I were to do this more regularly, I’m not sure how the pump will handle it. If I do it every day, maybe it would learn it but what happens on a day I don’t work out? I also don’t know how the pump handles things like illness or stress. I was sick the last two weeks of December, while on auto mode, but the pump was still learning me so it wasn’t as perfect as things are becoming. Right now, things have been fairly stable (not sick, not working out, etc) so I’m a little nervous to see how it handles things once a variable changes. I guess it will be a fun experiment in the future. I have noticed that when Flo comes to town, I tend to run lower the day before and the day of and I have gotten a couple of minimum delivery alerts. I’m sure that is affecting the algorithm but hopefully not too dramatically.
Back to the Positives…
Now that the pump and I know each other, I think about diabetes a LOT less. I’m checking my blood sugar less (the CGM sensor is very accurate and I no longer need to correct for highs so only test at meals). I’m not getting high alerts as often. In fact, I can almost go a full day without hearing a high alert. I often have to check my CGM to see what my blood sugar is because I’m shocked that I haven’t heard a high alert. As time moves on, it’s really doing a good job of knowing how much insulin I need.
One interesting thing is that my basal/bolus ratio is closer to the 50/50 mark. Most of my pumping life, I’ve been around 30/70 or 40/60. I figured it was always because I ate pretty high carb but I think in actuality it was because I wasn’t getting enough basal and I was constantly correcting highs (which count as bolus).
A final plus to the new system is that I get a pretty little pie chart graph in my pump that shows me how I’m doing and most of the time I’m in range 80% of the time or more. This would never have been the case before auto mode so I really enjoy seeing this from time to time. I am hoping I can one day get that to say 100% in range but I have a feeling I need to try a little bit harder.
Definitely Recommend 670G Auto Mode!
I realize I did write a lot of negatives on the auto mode, but it was really just the first few weeks as we were both getting to know each other. Now that I’ve been on the pump for two months, things are going much more smoothly. Most of what was bothersome in the beginning (lots of alerts, the loop, not correcting highs) has worked itself out and I’m loving it so much. In fact, I hate when it’s time for a new sensor and I have to go a few hours without my auto mode. I actually still had a few boxes of sensors for my old pump and figured I would go back to the old pump after I was set up and working on the new pump (I was part of the Priority Access Group so received this pump for free essentially after upgrading to the 630G last year but needed to complete some surveys for the first month of use). However, I don’t think I could ever go back to the old pump anymore, which sucks because those sensors are expensive! If you are debating on getting the Minimed 670G, I highly recommend it. Just make sure to give it a good month to really get the best experience. I also covered my initial thoughts on the new pump, not on auto mode if you haven’t checked it out yet.