GUESS THE CARBS IN THIS

[pm133]

IOB is definitely relevant for boluses. If before eating the sandwich your bg is say 5 with 3u IOB, you’re not going to then bolus for the full sandwich as the bolus advisor subtracts the 3u IOB from the calculation, so you’d reduce the chance of going low. If doing it in your head without the advisor, it is harder to keep track of IOB and to calculate how much to subtract.

You need make adjustments to the final dose yourself for the aspects that aren’t programmed into the advisor, just as you would without one.

Hi Lucyr,

I'm not sure I understand your example.
There are 2 points I'd raise.

Firstly, if someone has blood glucose at 5 and they still have an estimated 3 units of insulin then I'd say the problem is that they over-bolused at the previous meal.

Secondly, there is no way of knowing at all how much insulin they still have in your body. Not even a finger in the air estimate would be possible.

@Inka also raises a good point that in reality, a lot of people are going to assume the bolus calcuator is correct and blindly do what it tells them. It won't be everyone but it will be a lot of people.

 

[Inka]

It depends when I’m eating the sandwich. If, if I’ve got 3u of IOB because I just ate half a sandwich and then decide I want another sandwich or whatever because I’m still hungry, that IOB is no more relevant than if I decided to eat a lunch requiring 6 units of insulin, but for some reason decided to inject 3 units in each arm.

That’s what I’ve always understood intuitively, but a few years ago I’d seen lots of mention of stacking so I was worried I was missing something. I specifically asked my consultant and she agreed that the concern about stacking is for corrections.

If people like to know or find it useful in some way, then that’s fine. We all deal with things in different ways, so whatever makes you feel happiest.

 

[Sally71]

We’ve always used the bolus advisor on pumps because that’s what you are expected to do. On the Roche ones the IOB shown is only the correction part of any bolus, because it assumes that any bolus for carbs will be used up by the carbs. Not sure how the T-Slim does it, other than the calculation seems to be different! When we first got the T-slim pump daughter decided to have a snack one day having already eaten less than 4 hours ago. Pump decided to only give her 0.01 unit (yes that is the correct number of 0s!), er might as well not bother then, and given the size of the snack and whatever and when she’d eaten previously we decided that we didn’t agree, she’ll go high, so we added a unit or two on. Can’t remember the exact details. And then she promptly went low, which leads me to believe that the pump knows what it’s doing better than we do!

Nothing is perfect, whatever algorithm the bolus advisor uses won’t work in all cases, and neither will the human brain. And not everyone can cope with doing loads of calculations, I tried to learn about high and low GI foods and factor that in but found it one step too much for my brain to cope with, so other than a couple of specific foods like porridge, which we know will cause problems unless we deal with them in a particular way, I just ignore that bit now and we seem to get on perfectly well most of the time. I know my mum wouldn’t like doing things the way we do, she thinks we test far too often and don’t need to do corrections at every meal, and is just happy injecting her fixed doses and eating similar meals all the time. Her attitude is “it’s impossible to get it right all the time so why bother trying”. Which I don’t agree with at all, and I know my daughter’s consultant would go up the wall if we thought like that, but mum is still here after nearly 54 years of diabetes so who am I to tell her what to do!

 

[Lucyr]

Hi Lucyr,

I'm not sure I understand your example.
There are 2 points I'd raise.

Firstly, if someone has blood glucose at 5 and they still have an estimated 3 units of insulin then I'd say the problem is that they over-bolused at the previous meal.

Secondly, there is no way of knowing at all how much insulin they still have in your body. Not even a finger in the air estimate would be possible.

@Inka also raises a good point that in reality, a lot of people are going to assume the bolus calcuator is correct and blindly do what it tells them. It won't be everyone but it will be a lot of people.

So in my example I would say “oh I should have done a smaller correction as I’m 5 with 3u iob”(maybe i went for a walk after correcting that I hadn’t accounted for) and i can learn for next time but I can’t go back in time to take less when I did the earlier correction. So taking the 3u IOB off the next dose makes sense to reduce the risk of hypos.

You say there is no way of even making a finger in the air estimate of how much insulin is active in your body but there is. Bolus advisors track this. They know what time you took insulin, how much you took, you program in the length of time the insulin works for you, and they track the amount active from corrections and adjust your doses for this.

 

[pm133]

You say there is no way of even making a finger in the air estimate of how much insulin is active in your body but there is. Bolus advisors track this. They know what time you took insulin, how much you took, you program in the length of time the insulin works for you, and they track the amount active from corrections and adjust your doses for this.

Personally, I wouldn't touch these calculations with a bargepole but these are decisions for each person to make.