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RE: [IP] Bolus Dummy



Hi!

I see we are discussing bolus calculations again:

 > I got to the wizard, and told it my BG
 > was 41, and it warned me not to bolus
 > unitl my BG was normal, but I bypassed
 > that screen (as usual), and told it I
 > was eating 40 g CHO [...]. The next screen
 > was to do a normal (immediate) bolus of
 > 1.4 units, even while I had 1.9 units of
 > active insulin.

Remember: Active insulin ("IOB") is supposed to cover food that
you have already eaten, even when you are low. Therefore,
additional food results in an additional bolus.

Besides, consider the following scenario: You eat 100g of
slow-acting carbs, but give the insulin to cover it as a normal
bolus. Your BG may drop at first, but the IOB _still_ is needed to
cover the carbs sitting in your stomach and waiting for their 15
minutes of fame.

 > the way MM handles this situation is deeply
 > flawed. When my BG is above target, it
 > removes the option to do a square wave bolus
 > (extended bolus). Why in the world don't
 > they remove the option to do a normal bolus
 > when my BG is below target?

You misunderstand the behaviour of the pump software. The square
wave bolus is not removed when your BG is above target, it is
removed when the pump suggests a correction bolus. Why? If you
need a correction bolus, the glucose is _already_ coursing through
your veins; delaying the bolus makes limited sense, as the
appropriate insulin dose is best given right away. (You do get the
option of a dual wave bolus, likely for those who must limit the
amount of insulin infused at once -- they can split the dose into
whatever is tolerated right now, plus the rest as soon as
possible.)

Conversely, if you are low and then bolus for food, it makes no
sense to remove the normal bolus option, as you suggest. Again, an
example: I am low. I need 15g carbs to compensate. I eat 15 jelly
beans ... and the other 185 in the bag. Given how fast jelly beans
affect my BG, I certainly do not want the extra insulin to be
given as a square wave bolus.

 > If I had just unconsciously been pressing
 > buttons at that point, I would have been
 > in real trouble.

Yes. Any time you press buttons, you may get yourself into
trouble. If you were to drive your car unconsciously, the
consequences might be even worse. An even easier way to shed one's
mortal coil is to buy a phial of Regular and inject it all in one
go -- $35, and no pump required.

 > It just seems to me like the wizard should
 > take at least some of the active insulin
 > into account, and not let me do a normal
 > bolus (without effort).

How much of the IOB should be subtracted from the suggested bolus?
Why, all that is not needed to cover undigested food, right?

Alas, the pump only knows about IOB, insulin on board. It does not
know about FOB, food on board (food waiting to be digested and to
raise your BG). The only option is to assume that you have a
reasonable idea of what you are doing -- if your food estimates
cannot be trusted, the whole bolus wizard (and every other method
of dosing insulin ever invented) might as well be replaced with a
pair of dice.

Anyway, if you can convince MM to give you a choice and to make
the pump's behaviour configurable, that's fine with me -- but it
works well as it is, and _I_ want it to remain this way.
Subtracting IOB from a food bolus would be plain wrong, incorrect,
in error, as surely as 2+2=5 is incorrect.

Cheers,
Felix.
.
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