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 T-Slimx2 with Control-IQ, here are the essentials:
- How the algorithm works
- Starting settings
- Tips & tricks
- Preventing and treating hypos
- High-fat meals
How the algorithm works
The T-Slimx2 has three components:
- T-Slimx2 pump
- Dexcom G6 sensor
- The algorithm inside the pump is called Control-IQ
This graphic explains how Control-IQ works, in a nutshell.
- The algorithm works from manually set basal rates and correction factors
- Basal increases when the glucose is rising but not over 10.0mmol/L (180mg/dL)
- Auto-correction bolus’s if the glucose predicted to go above 10.0mmol/L (180mg/dL)
- Basal decreases and suspends if the glucose is predicted to go low
- Control-IQ is targeting the glucose level to be between 6.3-8.9mmol/L (113-160mg/dL)
The Control-IQ algorithm calculates insulin adjustments from the manually set basal rates and correction factors. Therefore, it is advisable to get your time in range (3.9-10.0mmol/L or 180mg/dL) above 50% before turning it on. This will mean your basal rates and correction factors will unlikely be dangerous. This will also give you a chance to tune your carb ratios and carb counting.
Once you have at least 50% in range, use your current settings to create an insulin profile that has your different basal rates, correction factors, and carb ratios.
Remember, you cannot adjust the Target level or Active insulin time. That’s why the algorithm is not very aggressive at tackling after-meal glucose spikes.
I would advise working on the settings of the first insulin profile. Get time in range of at least 70%. Then you can think about trying a second profile for weekends or other days if your insulin sensitivity is drastically different.
Tips & tricks
If you want to get 70% or more time in range do not forget the basics:
- Three balanced meals
- Accurate carb counting
- Bolus insulin 10-20 minutes before eating
- Be active for 10-15 minutes after eating
- Rotate cannula sites
Other things to be aware of:
- Always suspend the pump when disconnecting (showers, sports, sex)
- Set the sleep schedule during usual sleep times so the algorithm targets waking up at 6.1mmol/L (110mg/dL)
- Update basal rates, correction factors, and carb ratios when insulin sensitivity changes:
- Weight loss
- New exercise regime
- Every three months at a young person
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.
If you want this hypos guide, download it here.
We know from the Mealtime Insulin Guide that high-fat meals with carbs, such as pizza and takeaways, require additional insulin. Unfortunately, Control-IQ’s Active insulin time fixed at 5 hours poses a real problem here. The algorithm thinks that’s there’s too much insulin on board and is very sluggish at responding to the delayed rise in glucose from high-fat meals.
Control-IQ cannot keep up with high-fat meals with lots of carbs. I have experienced this several times and seen it countless times in others.
One solution is to increase the carbs entered by 25-50% and use an extended wave for 50% now and 50% over 2 hours.
For example, for a 100g carbohydrate pizza, dial in 125g and set an extended wave of 50% now and 50% over 2 hours. If the delayed glucose rise still happens, enter 150g (50% extra) next time.
A process of trial and error is required.
There is the quick and dirty way and the more comprehensive planned method.
The quick and dirty method
This involves putting on the Activity mode before starting exercise, 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.
You can use a sneaky tip to prevent this!
If you five a 0.1unit bolus just before starting the exercise, Control-IQ will not be able to put an auto-correction bolus in for the next 60 minutes!
How many carbs every 20 minutes?
It depends on how much you weigh. Here is an example for a 50kg person.
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. You need to understand exercise types, bolus reductions, and how to change a plan after trial.
Great, you are up to speed with exercise management.
This table should now make complete sense!
Go forth and conquer Control-IQ.