Hi all! I have a Tandem T-Slim pump now, and I have questions about Control IQ for all you CGM pros out there.
Does anyone know what it uses to determine how much to increase basal specifically? Is it a percentage of your normal rate? They tell you how it determines the bolus, but not how it figures out how much to up the basal.
I see that it won’t give a correction bolus automatically if you’ve given a bolus within the last 60 minutes, supposedly. I get that, and I see the logic. But, does this also apply if you are currently using an extended bolus? Not sure how the recent update might impact this, since it changed something with extended bolus options, right?
If I turn off Control IQ, would I still be able to view my current CGM readings on the Tandem T Slim screen until I turn it back on? Or do you just use the phone app for the CGM in the meantime?
The algorithm is sort of secret. It does a calculation based on sensitivity factor or correction factor, your glucose trend and your actual glucose value.
It is attempting to pull you into your target whatever you have set.
It will also bolus if you are way out of range, but yes not if you just bolused. Thats to prevent insulin stacking.
There are 2 systems at play during the day if you are in regular mode. The algorithm takes your basal rate and makes micro adjustments based on your readings.
But a separate mechanism delivers automatic bolus.
The extended bolus is new so I can only assume it takes that into account.
The pump uses a standard 4 hour active insulin time limit, so if you have 5 units still onboard, it will reduce its auto bolus accordingly.
Of course if you switch to sleep mode your target is lowered and also it will not give you automatic bolus. It will only give small basal corrections.
If you switch to manual, then the pump won’t correct at all and just use what is programmed.
Thank you for the explanation. Is it different in exercise mode?
Darn, of course it’s proprietary. They say that your automatic bolus will be 60% of your calculated dose based on your correction factor, I think. So, I was hoping it was that simple with basal rate adjustments and I’d just missed it somewhere. Something like, oh, a 25% basal increase for every 50 points out of range or some such thing. I wish they’d say. I wonder, does it ignore max basal rates when on Control IQ and adjusting basal rates for high blood sugar?
It will limit basal rate if you have that set. But I would set my rates in my pump to be pretty close to my needs. So the algorithm never really made much of an adjustment most of the time
Exercise mode just keeps your target higher. I can’t remember if it does not do automatic bolus.
There are automatic boluses in exercise mode. Partly for that reason, when I’m actually exercising I turn CIQ off and set a lower temporary basal. For me, exercise mode is good for light exercise like walking and hiking but not so much for anything vigorous.
I see. I think I saw somewhere that it ignores your max basal setting, which worried me.
I use extended boluses every day, so I’m very curious to see how it handles those. I’m wondering if it just doesn’t give any automatic boluses until one hour after the end of the extended bolus as well. I can’t figure it out from the manual. Maybe they’ll release a new version due to the update.
