# Insulin On Board/Active Insulin quandary



## everydayupsanddowns (May 31, 2013)

Here's a thing. 

One of the 'clever' things I read people talking about with insulin pumps is that they take into account 'insulin on board' when calculating meal doses.

But do any of them *actually* do that? Has anyone experienced a pump reducing a meal bolus in the light of IOB? From what i can see the only part of a dose that ever gets affected is the bit added on for correction.

I'm wondering whether this might be an Animas thing - because from what I can see of the Accu-chek Expert (that only ever tracks active *correction* but calls it active _insulin_) and the Medtronic Veo (which does track IOB, but assumes you got your carb count right for any previous meal) no device quite does what I want.

My situation is this. At breakfast and lunch I give the bolus a good 30-40 minutes head start in order to help post-meal readings. This is less practical at eve meal time though for various reasons too boring to list, so I've been experimenting with a 2-4u manual bolus 20-30 mins before I expect to eat, then doing the whole test BG/calculate thing immediately before eating. It's working OK, but I have to manually reduce the meal bolus by my 'pre-bolus' each time, because Artoo completely ignores the fact that I have all that IOB set against no carbs. 

Do other pumps handle this situation differently?


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## Phil65 (May 31, 2013)

everydayupsanddowns said:


> Here's a thing.
> 
> One of the 'clever' things I read people talking about with insulin pumps is that they take into account 'insulin on board' when calculating meal doses.
> 
> ...



....for me Mike, clear as mud and simply... I choose to ignore the whole IOB thing, don't trust or believe it! I kind of know how much I have on board depending on the time of day.


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## Pumper_Sue (May 31, 2013)

I have the animas and the IOB thingy, works a treat as it did on the Cozmo


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## Redkite (May 31, 2013)

We have the Veo too.  When doing a pre-bolus like you describe, we put a carb amount in as a "deposit" before bolusing the "final balance" when we know how many carbs he'll be having.  The risk is that he or I will forget about the deposit and bolus the whole lot, thus doubling up on part of it.  Do other pumps knock this off then?

The other situation that sometimes arises is when he's had a snack with insulin mid-morning and there's still active insulin sloshing about when it's time for his lunch bolus.  In most cases if his BG is in range he's better deducting the remaining IOB from his lunch bolus, but he doesn't remember this if left to his own devices and can end up hypo.  The Veo does rely on the user thinking it through and having a good memory!


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## randomange (May 31, 2013)

The Animas will take off IOB for carbs, but only if you're below target when you're calculating the dose - so if you put in your 2U pre-bolus, but then tested and were e.g. 7, but your target is set at 6, then it wouldn't take it off.  You can, however, change your targets in the dosing screen, so you could always adjust it (a one-off for that single dose) to be higher than your BG, and it would then take off the IOB. 

Clear as mud?


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## everydayupsanddowns (May 31, 2013)

Redkite said:


> The Veo does rely on the user thinking it through and having a good memory!



Yup. That's pretty much where I'm at.

Sounds like the Animas has a more logical approach to that function. I quite like the idea of being able to tweak ranges on a per-dose basis too!


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## Redkite (May 31, 2013)

everydayupsanddowns said:


> Sounds like the Animas has a more logical approach to that function. I quite like the idea of being able to tweak ranges on a per-dose basis too!



So you'd still have to do some thinking!   The trouble with the Animas and Accu-Chek pumps knocking off IOB for carbs is that sometimes that IOB is there to cover carbs which are still digesting, in which case you want an additional bolus to cover ALL the additional carbs.


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## everydayupsanddowns (May 31, 2013)

Redkite said:


> So you'd still have to do some thinking!   The trouble with the Animas and Accu-Chek pumps knocking off IOB for carbs is that sometimes that IOB is there to cover carbs which are still digesting, in which case you want an additional bolus to cover ALL the additional carbs.



I imagine that's why they have taken the decision to assume all carb calculations are always correct. Still a bit mad though - when you can get bolus advice that completely ignores a virtually unlimited amount of iob recorded against no carbs at all on the Veo


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## Redkite (May 31, 2013)

everydayupsanddowns said:


> I imagine that's why they have taken the decision to assume all carb calculations are always correct. Still a bit mad though - when you can get bolus advice that completely ignores a virtually unlimited amount of iob recorded against no carbs at all on the Veo



Well yes but.....this is because it allows the user to put in a manual bolus, override the bolus wizard as and when you want to, and generally be in control.  I would hate a pump that didn't let me have the final say!!! Maybe the Veo could be improved if it flagged up the IOB as an advisory message under the calculated bolus figure.


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## everydayupsanddowns (May 31, 2013)

Redkite said:


> Maybe the Veo could be improved if it flagged up the IOB as an advisory message under the calculated bolus figure.



I guess it kinda does that already, with the (very useful) 'how I came up with this figure' screen before the bolus is confirmed. As you say though, it would be nice if it flagged it up a little more enthusiastically!


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## Dory (Jun 4, 2013)

Hi Mike, I remember we were discussing this annoying issue a while back, where we worked out that the 'active insulin' is actually the 'active correctional' on the Accu-chek meter.

HOWEVER.............................

I was sans meter the other day, so used the pump direct to input a food bolus amount.

When I used the meter a short while later, guess what appeared in my 'active insulin' field??  Yep, the remainder of the food bolus shot I had given myself (I know it wasn't any earlier corectional as I had not had any food, tests or doses prior to the bolus I input directly into pump.

Just to make things even more confusing???!!!!!!!

On a separate note, I have to admit, I've never 'pre-bolused' with my pump as I was always told it starts working the minute you pump it, so you can eat food there and then (although I accepted this resignedly given I'd have 20 years of MDIs and 'inject then wait' management).

Do people on pumps tend to do the 'bolus then wait' approach?  Be interested in hearing others' experiences......


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## m1dnc (Jun 4, 2013)

Dory said:


> Do people on pumps tend to do the 'bolus then wait' approach?  Be interested in hearing others' experiences......



I confess to be a 'bolus and eat' person, rather than 'bolus and wait'.


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## Phil65 (Jun 4, 2013)

Dory said:


> Hi Mike, I remember we were discussing this annoying issue a while back, where we worked out that the 'active insulin' is actually the 'active correctional' on the Accu-chek meter.
> 
> HOWEVER.............................
> 
> ...



....generally I now bolus 15-20 mins before I eat (....if I remember... or if my wife remembers to tell me!! ) I have found that my 2 hour post prandials are much better!


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## pgcity (Jun 4, 2013)

I pre bolus. About 10 or 15 mind depending on what I am eating


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## Dory (Jun 4, 2013)

well indeed!  I didn't know this!  I have to admit, when I'm eating fruit I do pre-bolus but that's been because the fruit gets into my system too quickly otherwise.  never done it for other foods, athough may reconsider.....

thanks guys!


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## Pumper_Sue (Jun 4, 2013)

I always pre bolus by 30 mins.


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