Categories
Auto Mode

Final Post – 2 Years Later on Medtronic MiniMed 670G and AutoMode

Considering that Medtronic plans to release the MiniMed 780G this year, I have decided I might as well wind up my blog on my experience with the MiniMed 670G and Auto Mode.

I have compiled a set of final tips/observation for those planning to get the 670G and use Auto Mode based on my 2 year experience with the pump and Auto Mode.

Auto Mode does not adjust for diurnal trends such as dawn phenomenon.

Despite being adaptive, Auto Mode will not adjust for diurnal trends. Medtronic explicitly recommends manual correction for fasting BG numbers related to dawn phenomenon or somogyi effects.

Auto Mode does not work as well for foods high carb or high-fat foods.

Because of the conservative nature of Auto Mode, expect a spike in BG when you eat high glycemic index (GI) foods. Timing is a little tricky with this pump since there is a period of no basal insulin delivery right after bolusing.

Unless my BGs are low or dropping, I typically wait for 30 minutes after bolusing to eat high GI foods.

For high-fat foods like Pizza, you might need an additional bolus after 1 or 2 hours.

Balance between Bolus and Basal is important

Auto Mode works on input from your historical daily total daily dose (TDD). So the dispensing of bolus and basal will be a balancing act, but in relation to the TDD. So if you set your carb ratio to be so aggressive, expect the Auto Mode to cut back on the basal delivered and vice versa.

I think the jury is still out on whether the 50:50 basal bolus ratio is s needed for Auto Mode. According to my Medtronic Educator, a 55:45 bolus-to-basal ratio is the recommended starting point.

Consistency is Key.

Since Auto Mode depends on TDD history, I have found that it is important to keep my daily carb intake consistent. If you miss a meal or two the previous couple days, Auto Mode will scale down the basal to reflect the changes in your TDD.

Too much snacking will get you into trouble.

Although Auto Mode can handle small BG changes, too much snacking will get you in trouble since the system is very conservative in nature. Too much snacking also might require too much bolusing, which will force the pump to scale back on basal to meet the daily TDD limits.

Bolusing for Ghost Carbs will come back to haunt you.

Although it might seem a good idea to inject for “ghost carbs” or fake carbs to adjust for high BG, it is not. Auto Mode assumes that a meal accompanied the ghost carbs. So expect a precipitous drop in BG a couple hours later since Auto Mode does not account for ghost carbs as part of its BG correction process.

Auto Mode is only as good as the accuracy of your sensor.

Make sure that your sensor is as accurate as possible by identifying which sites give you the most accurate readings. Upper Thigh sites work best for me as compared to belly sites.

Change your infusion sites often.

Just as sensor sites, make sure that the site you are using for your infusion sites deliver insulin consistently. Rotate your sites as recommended. If your BG rises for unexplained reasons, the major culprit is normally a bad or overused infusion site.

Also remember Medtronic offers a wide variety of infusion sets. So talk to your Doctor to see whether you can test different infusion sets to see which one is best for you.

Know when to change your sensor.

Do not wait for the sensor to expire before changing your site. Remember that:

  • It takes nearly an hour to charge your transmitter.
  • It takes two hours for the sensor to warm up.
  • It takes 30 minutes for you to reenter Auto Mode after the first calibration.
  • The pump will require a mandatory calibration in 6 hours.

So if you start the sensor change-out at 7 pm, you will be up all night.

It also helps to “marinate” the new sensor about 24 hours in advance, but remember this might cut short the sensor life by a day.

Optimize your manual basal rates often for a rainy day.

There are days when you might not enter or stay in Auto Mode. So it is prudent to make sure your manual basals are good for such a time.

It also seems as if Auto Mode will “reset” if you run manual mode for a couple days. This has seemed to help where Auto Mode was delivering very little basal insulin.

Do not be too hard on yourself when on Auto Mode.

Auto Mode will test your patience on some days, but do not give up. Work with your doctor and Medtronic educator to optimize your settings. Also, be realistic on your BG targets when using Auto Mode. Auto Mode might not be for you if you are looking for tight control of your BGs.

I would say a realistic HbA1c when using Auto Mode is between 6.5 and 7.0.

Categories
Auto Mode Guardian Sensor Medtronic MiniMed 670G

A year Later – Success with Auto Mode

Exactly a year ago on this day, I met with my diabetes educator for my Medtronic MiniMed 670G training. Two weeks later I started using Auto Mode.

Along the way, I started documenting my journey on ButDoISay, nearly gave up on Auto Mode and certainly drove my endocrinologist crazy by constantly changing my delivery settings.

Her very words during our last appointment were: “Why change something if it ain’t broken”

Since we have a good rapport my answer was “You know, the scientist in me pushes me to fiddle with the settings. Right?!” And she just laughed.

Finally 100%. I took a year but I think am getting there
Time in Range is 91% in the last 7 days

Fittingly, yesterday for the first time I was 100% in Auto Mode and 100% in Target Range. Woohoo! I just can’t believe how the algorithm has learned my sugar basal rhythms in the last one year.

But seriously, the last year was also a very stressful year for me. Our youngest daughter was diagnosed with Autism at the start of 2018 and my life was completely changed. All of a sudden I started noticing all the missed milestones and my schedule was now filled with Autism parent training, speech therapy, and occupational therapy appointments.

However, the most stressful thing for me was not being ready to accept that my daughter was fine in her world and I am the one who needed to change to make sure I gave her the love and support that she needed to navigate around my world.

One thing though I did not have to worry so much about was: Do I have the correct basals set to deal with the stress and emotional roller coaster that came with our daughter’s diagnosis? This is quite liberating and freeing.

AUTO MODE TO THE RESCUE

Through this time, Auto Mode worked like a champ and I can undoubtedly say it has done a better job of adapting to all the stressful events of 2018 than I would have done if it was left to me in Manual Mode.

I no longer have to worry so much about lows when taking my daughters to two separate schools or doing yard work. (I had been diagnosed with uncontrolled severe hypoglycemia in 2013 when I got my first pump. I am also a late onset Type 1)

Despite Auto Mode’s many shortcomings that could keep you awake all night, I am glad that I never gave up.

WITH AUTO MODE PATIENCE IS KEY

This is my advice: If you are thinking of giving up on Auto Mode because of all those highs that you can’t seem to control, just give it time. For me it has taken close to a year to finally get to where I am comfortable with my numbers.

The Auto Mode algorithm seems to be more adaptive than I even thought. And the more data you feed it, the better it will become.

 

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Guardian Sensor Infusion Sets Medtronic Contour next Link 2.4 meter Medtronic MiniMed 670G

The perfect storm – pizza, sensor change, and a kinked infusion set canula = readings out of this world!

 

The Perfect storm. New infusion set, sensor, and pizza.

Lesson I learned: At the beginning of sensor life, it might not be a good idea to only depend on sensor readings only.  Also, probably not a good idea to change the Guardian sensor, infusion set and eat pizza close together!


Last night, I had what I would call a perfect storm where I replaced my sensor and infusion set and then ate pizza. Unfortunately, my sensor did not catch up with a sharp rise in blood sugar since it had not stabilized. I only caught the high sugar readings when I checked my meter Blood Glucose (BG) reading.

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Auto Mode Basal Settings PUMP REVIEW Pump Settings

Shortcomings of the Medtronic MiniMed 670g, Auto Mode and Guardian 3 sensors

From the onset let me say I think the Medtronic MiniMed 670G and the Auto Mode setting are a big leap forward in glucose control for Type 1 diabetes. Closed loop insulin pump technology is the technology of the future. Personally I foresee the insulin pump becoming an install-and-forget type of medical device in the near-future. While in no way perfect, the first iteration of the MiniMed 670G was a great step forward in this direction.

Categories
Guardian Sensor

“Marinating” the Guardian 3 Sensor – Does it Work?

Some people using the Minimed 670G pump and Guardian sensor have recommended inserting a new sensor a couple hours beforehand prior to the expiry of their sensor they are using (a process they call “marinating” the sensor). In this way the sensor stabilizes well before you have to exchange it out with an old sensor.

I have tried this technique but with mixed results. It has worked beautifully lately but initially a couple sensors completely failed prior to the warm up period. As soon as I inserted the sensors into the transmitter, the green transmitter light did not blink as expected. Neither could the pump find the sensor. Maybe a bad batch?

Marinating helps the sensor signal stabilize quicker after the warm up period, although you still have to pay attention to upper thigh sites (they take longer to stabilize and can lead to major lows once the sensor stabilizes).

Categories
Auto Mode CGM Sensors Pump Settings

Morning Meter Fasting Glucose is much higher than Sensor Glucose

As you can see my morning fasting glucose numbers are running higher than I would like them. I feel well rested in the morning if my numbers are below 120. Above that I wake up feeling tired. I have also noticed that it is in the morning that I get the biggest differences in reading between the Minimed 670G pump Guardian sensor and my BG meter (during other times the readings are within 10 mg/dL of each other but in the morning closer to 20 mg/dL ). Not sure why the sensor consistently under-reports my BG readings, but it is at this time that I would love my sensor to be the most accurate! Most probably it might have to do with the fact that the Auto Mode algorithm is likely most conservative at night.

Categories
Auto Mode CGM Sensors

Upper Thigh Sensor Insertion Sites are More Accurate than Belly Sites

Bottom-line: For accuracy and fewer calibration errors I have found upper thigh sensor insertion sites better than belly sites. These sites take longer to stabilize (about 12-24 hours) but always give me very good accuracy and fewer calibration errors over the life of the sensor. Sensor values seem to match better with meter values for the upper thigh sites over the belly sites.


During my pump training, I was told that Medtronic now officially recognizes the outer side of the upper thigh as an FDA approved insertion site for the Guardian sensor. This was not the case for the Enlite sensor.

To shorten the time it will take the sensor to stabilize and enter Auto Mode, some people suggest inserting a new sensor and leave it in place a couple of hours prior to replacing the current sensor. I have had mixed results with this approach.

Categories
Auto Mode CGM Sensors Pump Settings

Kicked Out of Auto Mode….Again!

Guardian Sensor Stability and Auto Mode

I have been trying to get back to Auto Mode for the better part of the day today.

As you can see my readings in manual mode were not so bad and I would say those were stable sensor readings. I am not sure what reading variance the Auto Mode algorithm considers acceptable to enter Auto Mode.

Variance does not look too shabby but Auto Mode did not like it.