Extended/Duel Wave Bolus with Tslim Basal IQ

I would like to hear others hints and experiences using extended and/or duel wave bolus. I use a Tandem Tslim X2 with G6 Basal IQ. I use extended bolus usually due to gastroparesis and also for specific foods. So any information on others experience with timing, percentages and Basal IQ would be great! Thank you!


I like extended bolus to combat high BG.

I pick how many units up front and then how many units per hour. I don’t really worry about how many hours as I figure the Basal-IQ will terminate it when it starts going down but generally start it running for 2 or 3 hours.

6 units, 33% up front over 2 hours ==> 2 units now plus 2 units per hour for the next 2 hours.
6 units, 25% up front over 3 hours ==> 1.5 units now plus 1.5 units per hour for the next 3 hours
9 units, 33% up front over 3 hours ==> 3 units now plus 2 units per hour for the next 3 hours

Something like that. How high is the BG right now. How effective the insulin seemed during the day. How much IOB is already on board. When carbs were eaten. What time of the day. How long until bed.

I find that for us, a bolus any larger than 4 or 5 just does not have the impact one would expect. I find a smaller bolus coupled with an extended to keep delivering small (mostly) continous doses to be much more effective.

And with the Basal-IQ, it will eventually kick in (unless a site issue or something like that) and just terminate the remaining extended.

For anybody not familiar, when Basal-IQ kicks in and suspends insulin delivery, any extended bolus that is running gets permanently cancelled. The remaining extended bolus does NOT resume when the Basal-IQ subsequently allows insulin deliver to resume. This is as opposed to any temp basal setting which WILL resume at the previously set temp rate assuming the temp counter has not run down.


We also use extended bolus for food - didn’t want to imply we did not.

The impact from Basal-IQ in terms of food is that if starting at a good BG then it is quite possible for a little tiny dip in BG what would cause Basal-IQ to kick in for a short time but that would be enough to cancel the extended bolus intended for any slow absorbing carbs.

In this case, we would turn off the Basal-IQ, turn on an alarm clock on a cell phone (reminder to turn Basal-IQ back on) and then do the extended bolus for the food as we typically would.


Thank you @Thomas I knew I could depend on you to cover it for me and others! It’s such a useful tool

This is so true and happens for me too. Another benefit to IQ. I’m going to start using it more for high BG as opposed to temp basals. Both have their benefits. Thank you for laying it out so clearly!

Good idea!