Tips & tricks: 670G & 780G

Dear Dani, Grace and Jude,

Note: This page is advice for Grace, Jude and John. For any other reader, it’s information only. No therapeutic relationship is formed – read this.

If you select the Medtronic 670G or 780G, here are the essentials:

  • How the SmartGuard algorithms work
  • Starting settings
  • Tips & tricks
  • Preventing and treating hypos
  • High-fat meals
  • Exercise

The 780G is hands down much better than the 670G. Choose 780G if you have a choice. I have put them together here as the education is similar, just the 780G is better!

How the algorithm works

The Medtronic systems have three components:

  • Medtronic Pump
  • Guardian Sensor 3 or 4
  • The algorithm inside the pump is called SmartGuard

This graphic explains how the 670G algorithm works in a nutshell.

Take homes:

  • The algorithm works by auto calculating basal rates and correction factors
  • Basal increases when the glucose is rising
  • There are no auto corrections
  • Basal decreases and suspends if the glucose is predicted to go low
  • The target level is 6.7mmol/L (120mg/dL)

This graphic explains how the 780G algorithm works in a nutshell.

Take homes:

  • The algorithm works by auto calculating basal rates and correction factors
  • Basal increases when the glucose is rising
  • There are auto corrections given aggressively when the glucose is rising quickly – above 6.7 mmol/L
  • Basal decreases and suspends if the glucose is predicted to go low
  • The target level is 5.5mmol/L (100mg/dL) which can be adjusted higher if required to 6.1 mmol/L or 6.7 mmol/L

Starting settings

Both algorithms need a weight, average total daily insulin dose, carb ratios, and active insulin time. SmartGuard does the rest automatically and updates continually. You have to wear for 48 hours before SmartGuard can be turned on. This makes sure the System has an idea of your insulin sensivity.

Active insulin time is the aggressiveness switch of the SmartGuard algorithm.

For example, how quickly it will tackle after-meal spikes in glucose.

This is a decent guide:

2 hrs = Aggressive

2 ½ hrs = Normal

3 hrs = Safe

On the 780G, you can change the target level. However, it’s best left at 5.5mmol/L (100mg/dL) to get more time in range.

You will have to remember to keep your basal rates and correction factors up to date in case it goes out of SmartGuard

Once the above is set, you will only need to adjust your carb ratios in the future.

Starting an AID system can be broken down into two parts. First, SURVIVE, then, THRIVE. You can download a guide on how to do this.

How to Survive and Thrive – (780G). If you want a more comprehensive onboarding resource (780G)

Tips & tricks

If you want to get 70% or more time in range do not forget the basics:

Other things to be aware of:

  • Always suspend the pump when disconnecting (showers, sports, sex)
  • Update manual mode settings in the case SmartGuard stops:
    • Basal rates
    • Correction factors
    • Target level

Preventing and treating hypos

It would be awesome if hypos were a thing of the past. But this will not be the case.

The algorithm will be able to stop hypos overnight!

However, if you give too much bolus insulin for a meal or exercise without planning, hypos will still happen.

It is likely you will need less hypo treatment than normal because the algorithm will have already slowed or stopped the insulin at least 30 minutes prior.

You may also want to prevent hypos if you see the glucose is 4.0-6.0mmol/L (70-110mg/dL) and trending down.

This is a guide I use based on weight. This example is for a 30kg person and the weight can be changed. Download the Survive and Thrive – (780G) and enter your weight at the top to get a personalised chart.

If you want this hypos guide, download it here.

High-fat meals

We know from the Mealtime Insulin Guide that high-fat meals with carbs, such as pizza and takeaways require additional insulin.

If you set the Active insulin time between 2-3 hours, the SmartGuard algorithm should manage the delayed glucose rise with ease.

For example, you could enter all the 100g for a Pizza upfront and let SmartGuard do the rest.

If you still get a delayed rise, next time, dial in 25-50% extra (e.g. 25-50g in this example) of “fake carbs” 90 minutes after eating.

If you go hypo in the first 2-3 hours, next time only enter 75% of the carbs, 75g in this example.

Exercise

There is the quick and dirty way and the more comprehensive planned method.

The quick and dirty method 

This involves putting on the Exercise mode before starting, ideally 90 minutes before. Then supplement with small amounts of carbohydrates every 20 minutes as required.

Do not shovel loads of carbs in at once as the glucose might shoot high and the algorithm will increase the insulin and hypo risk.

How many carbs every 20 minutes?

Good question.

It depends on how much you weigh. Here is an example for a 50kg person. Download the Survive and Thrive – (780G) and enter your weight at the top to get a personalised chart.

You can download the mmol/L and mg/dL versions if you want to give them a try?

Comprehensive planned method 

To be able to use this method you will need to work your way through the Exercise Guide, so you understand exercise types, bolus reductions, and how to change a plan after trial.

Read it?

Great, you are up to speed with exercise management.

This table should now make complete sense!

Go forth and conquer.