Active insulin (Veo)

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Redkite

Redkite

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Does anyone know how the Veo spreads a bolus over the active duration time? I didn't think it was supposed to be linear, I thought more than half would be "used up" by two hours post bolus.

My son's insulin duration is set to 4 hours (this works for larger boluses, but I think is too long for smaller ones, but you can only have one setting!). Last night I did a correction bolus of 1.2U at 4.45am. When we got up at 6.45am I wanted to check the active insulin (so as to not end up with too much in addition to breakfast bolus), and there was 0.6U remaining. I thought it should be less than half?
 
Yes I have found the insulin duration to be a bit of a hobson's choice too. I've intentionally set it too short to cover *most* situations, but I did get caught out last night and overcorrected myself into the upper 3's. 🙄

I did see a graph of the activity curve at a Medtronic event a few weeks after starting with Artoo and from memory it is kind of diagonally 's' shaped (in reverse!).

Perhaps you could call the lovely folks at medtronic and see if someone could send you that graph - they must have it squirreled away somewhere! I really wish I had a copy myself 🙂
 
Thanks Mike. I've found some "active insulin curves" graphs at the back of the Veo manual (page 209) - are these the ones you saw? I don't think they tally with what I see happening in real life! For four hours insulin duration, it reckons only about 20% is used within the first hour, another 30% in the second hour, 35% in the third and 15% in the last hour. Whereas what actually seems to happen is more like 75% by the end of 2 hours, another 22% in the 3rd, and just 3% in the 4th. Usually! Am I right in thinking this means he'd be better off on a 3 hour duration?
 
That's the very chap! THANK YOU!

Though disappointing to hear that what you observe does not fit with the graph :(

Co-incidentally it was 3hrs that I ended up with. I believe it is shorter than the insulin actually lasts for me, but is has largely improved the correction/active insulin estimations in my case.
 
My Veo is set to 4 hours and I've noticed that it shows more active insulin than I think there should be. From 3 to 4 hours after a bolus, I don't see much change in blood glucose but the pump shows quite a few units of insulin remaining active.

Maybe I should try turning the duration down to 3 hours too?
 
chandler said:
My Veo is set to 4 hours and I've noticed that it shows more active insulin than I think there should be. From 3 to 4 hours after a bolus, I don't see much change in blood glucose but the pump shows quite a few units of insulin remaining active.

Maybe I should try turning the duration down to 3 hours too?
Click to expand...

That's pretty much the reason I made the change Chandler. More often than not I seem to get better advice now, though once or twice the short DIA has caused me to stack insulin a little and dropped me low. Having said that those times could probably have been carb-estimation/basal errors just as easily!
 
Hi both, very interesting discussion! I'm on a Vibe but have had traumas over the past 16months I've been pumping as the pump, however it calculates IOB, shows incorrect amounts - I have 4.5 hours set in and it consistently shows IOB up to over 6 hours later! I've sent 2 back over the past year but the replacements all do the same. I've had countless discussions with the tech team (in USA) who deny there's a systemic problem and promise me error reports and calls back which don't materialise. I'm now not prepared to go through the palaver of setting up and exchanging my 3rd pump with this problem, but learn to live with it. I have also come to realise like you that your own use of insulin does not necessarily correlate with their model anyway, and it also depends on other factors like what sort of meal you ate, whether it's still actively being metabolised several hours' later in which case hopefully any IOB will be mopping that up rather than lowering your BG etc. etc. And other factors.

Thanks for the discussion!
 
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Hi Ingrid, that's a bit of a mystery! Do you often use dual wave boluses (extended boluses)? Just wondering if that could be the cause of your pump registering active insulin so long after you did the bolus?

There are SO MANY variables aren't there. I wonder how an artificial pancreas could ever have an algorithm that would cater for all the variables....
 
Hi Redkite (love your name!), nope. I mean yes I do use combo/extended bolus now & again but this anomaly occurs with either! IOB shows up to about 6 hours 10 mins with my preset duration of 4.5 hours, and with extended bolus of 2 hours, it still shows IOB beyond the 6.5 hours, not very much but then the experiments I've done were with smallish amounts - still shouldn't've been showing anything after 6.5 hours though! And each time there has not been any other bolus still active to interfere (I have really extensively tested all this....and read out various data to Animas....and found a few other Vibe users who have noticed the same - unfortunately I think a lot of folk aren't really clocking whether their IOB is accurately cutting out at the set in duration time, partly depends on the gaps between your boluses...). I did study maths..does it show ;-) But seriously, although there are lots of variables, and we always have to use our over-riding common sense with boluses & basals, it still should not be the case that the programming or algorithm is wrong as your starting point. I just wish Animas would take it seriously!

I have a new DSN who said she'd bring it up with the Animas rep, but I'm not holding my breath.
 
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Something definitely wrong with the programming then! I like maths too - don't want to rely entirely on a machine working it out, especially when they are flawed!

I chose "Redkite" as a username because we are lucky enough to have lots of them staging a comeback around here (Chilterns) - I quite often see one or more circling over the garden (sometimes mobbed and chased off by crows!) - beautiful birds 🙂
 
I wonder - if you set the 'duration' to a lot less than that, it would catch on?

Or has it just decided you are lying so it reverts to whatever factory settings are, like 5 hours or whatever?
 
Yup, beautiful birds 🙂

Yes, I think it's important never to rely 100% on technology, but always have a good understanding of manual control and over-ride. It must be hard for diabetics who struggle with maths, at least there are aids to help with everything now, like calculators/mobile phone apps, but still...when these inevitably let you down, you still need to be able to calculate and function manually.
 
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