Bolus & IOB on the vibe

Isn't it because according to the algorithims in the pump and your acting time and carbs entered that it just thinks that you still need that 1 unit to return you to your target level.

It isn't just a case of 10 carbs - 1 unit.. 1 unit still active..

@Topher........I know exactly what you mean. Confusing isnt it. If yr bg is at its target level within 3hrs, then any remaining IOB will make you go lower unless you eat something to use up the IOB. If yr basal rates are more or less correct, then have a look at yr acting time and also yr carb ratio. The alternative is to eat whatever and using the carb wizard see how much insulin it prompts you to take with deducting any IOB and then bg test 2hrs later to see if the pumps calculation was correct or wrong.

iHs said:

@Topher........I know exactly what you mean. Confusing isnt it. If yr bg is at its target level within 3hrs, then any remaining IOB will make you go lower unless you eat something to use up the IOB. If yr basal rates are more or less correct, then have a look at yr acting time and also yr carb ratio. The alternative is to eat whatever and using the carb wizard see how much insulin it prompts you to take with deducting any IOB and then bg test 2hrs later to see if the pumps calculation was correct or wrong.

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It depends upon the acting time set up... You need to know how long insulin is acting in your body...it is vital thst this is correct otherwise it also affects corrections given...

The reason for this is because the Vibe computer associates that 1 unit on board to already be 'in use' and should be taking care of the carbs you ate 3 hours ago. When you add more carbs it adds more insulin as it is supposed too.

The reason for this is not the Vibes fault, but the users fault. If you return to normal after 3 hours and still have insulin in your system it has to be assumed that you either under ate, over estimated, have your ratio is incorrect, or that your insulin is fully used in <4 hours (the default is 4 hours and can be changed by the user). Had you changed the usage to 3 hours, it wouldn't have said that you had any IOB at all.

The target zones on a pump are only for corrections, where as that 1 unit left in your system is seen as in use and so not counted in the new dose.

@Topher, not sure if you can do this on all pumps like the Vibe which you are using but some pumps allow you to adjust the time in which the insulin is active in the body, the profile for most fast-acting insulins is 4-5 hours but some people find from personal experience its a lot less, so by adjusting the action time of the insulin you can get it to best suit your own needs, on the Omnipod Pump it comes under Settings, then ratios/factors/targets and then you select Insulin Action where you can adjust the duration of the insulin.

So the opinion seems to be from all of us is that acting time may need a tweak amongst other more day today ratios/basals etc

Topher said:

Hi, I'll try my best to explain this, and can anyone tell me the reason for it

You have bolused for carbs taken
3 hours later you check your bloods snd they are in range
But you still have say 1 unit of insulin on board
Now let's say you take a further 10 g carbs ( ratio 1:10)
The vibe will tell you to take 1 unit of insulin, although you still have 1 unit in your system based on the insulin on board,
So strictly speaking you should have enough insulin to cover that 10g of carbs - so why does the vibe tell you to take another 1 unit ??

Any answers would be helpful - thanks

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Read page 69 of your manual Also look in the index for insulin on board as it's all in the manual.