Dual bolusing and IOB: what has worked for you?

i have asked everyone i know how the square part of a dual bolus actually delivers the insulin. if, for example, i give myself a dual bolus of 60% up front, and 40% over the next 2 hours, how long do i have IOB for if my insulin takes approximately 4 hours to finish its full effect? after the 40% is delivered (in the 2 hours programed) do i then still have IOB until that last drop of insulin wears out?

i feel that, all too often, i have to be a chemist to bolus for all the different types of foods i would like to enjoy. i am not talking about indulging in frosted deserts, just regular human food like a slice of pizza or a burger w/ a bun, ketchup and cheese. not that i would eat like that every day; but i want to have the option, and being on the MM pump, i should be able to get some BGs close to a healthy range, shouldn’t i?

please help. all suggestions appreciated!!!

You betcha!

keep a log of what you do and the results. that will help you better than all the questions and answers you will get on the internet.

The short answer is, Yes!

The longer more involved answer is all of your insulin whether basal or bolus is going to have the same duration of action, but you want to know from a bolus perspective how to calculate your IOB for the extended part of the bolus, right? I’m going to think out loud for a moment …

I think the way I might do this practically is take the midpoint of your extended bolus and use that as the time to calculate the IOB. In your example, if you took a 5U Dual wave bolus split 60/40, 3U would be delivered immediately, 2U would be delivered over the next 2 hours as an extended bolus. The initial 3U would be finished in 4 hours. I would calculate the remaining 2U as being finished 5 hours from the initial bolus.

Why are you guys trying to calculate the IOB? The pump shows us the IOB.

thanks, phoenix bound. i did my first experiment last night at dinner. i did a 60/40% split over 2 hours. it went just fine. good calculating on my part, which was no more than a spirited guess.

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thanks YogaO. very appreciated. your answer made complete sense to me. thank god for all you guys w/ all your practical knowledge. the “professionals” don’t seem as informative as us. TuD has really been a compassionate and helpful answer to so many of my questions.