Correction doses

[samantha13]

Can anyone tell me how I properly calculate how much insulin I need to bring me down with a correction dose and how many carbs i need to bring me up from a hypo?

Can it be precise or is it just a rough guess? I usually take 4u if im over 10. And take 30g carbs for a hypo but when talking to my dsn today I got the feeling she wanted me to be more precise?

 

[tim2000s]

Hi @samantha13 - there are a couple of ways of doing it. Mathematically, by estimation followed by fine tuning and experimentally.

Experimentally, you make sure your blood glucose level is at about 9mmol/l and running steady, with no carbs on board, then you administer 0.5 or 1u, depending on which you feel safest with. You give the insulin 5 hours to see how much you come down by.

Mathematically, you can estimate using the rule of 100. To do this you take your total daily dose, which includes basal and boluses, add them up to create your TDD, then calculate 100 divided by this number. That is the estimate of what one unit will drop you.

e.g. Basal = 20u, breakfast =7u, l;unch = 8u and dinner = 10u, gives you a TDD of 45u.

The correction factor (also known as Insulin Sensitivity Factor) is 1u: (100/45), which equals 1u:2.2mmol/l

In theory, you'd see a drop of 2.2mmol for each 1u of insulin.

This is an estimate, and you should always try and check it, as you'll probably find that it is not exactly that number as it assumes that you have your doses set up correctly. Likewise, as your levels get higher (typically above about 12mmol/l) most people find that their correction factors are out and they need more insulin to achieve the same drop.

www.bertieonline.org.uk can take you through the process on this page: http://www.bertieonline.org.uk/listing.asp?SctID=1&ModID=8

Hope that helps?

 

[samantha13]

Fantastic @tim2000s thank you so much!

 

[delmcp]

@Samantha to work out your correction dose if you work out your total daily insulin(Both Basal and Bolus) Then divide 94 by your total daily insulin figure the answer will be the amount in mmol/l that one unit of insulin will reduce your BS. This information is taken from the book "Think like a Pancreas".
As a rough guide for treating hypos it is different for every individual. It is based on your body weight.
48-76 Kg requires 14g of carbs to correct a hypo in the 3.3-3.9 range.
77-105 Kg requires 18g of carbs to carbs to correct a hypo in the 3.3-3.9 range.
> 105 Kg requires 28g of carbs to carbs to correct a hypo in the 3.3-3.9 range.
Again these figures are taken from the same book as above. I hope this helps.

 

[tigger]

Also factor in that at different times of day you may be more insulin resistant than others so will need more/less insulin to correct.

 

[Bassiette]

I'm confused now

 

[samantha13]

So I take on average 60u total a day between levimer and novorapid so 1u should bring me down 1.6mmol. How long should it take to work if no food in the system? Or I guess that's an individual response?

Also does my carb/insulin ratio have an effect? What I mean is in the morning I take 2u to 10g and all other times 1.5u to 10g so would this be true for the correction dose? Would I have to increase/decrease accordingly?

 

[tim2000s]

So I take on average 60u total a day between levimer and novorapid so 1u should bring me down 1.6mmol. How long should it take to work if no food in the system? Or I guess that's an individual response?

Yup. 100/60=1.667, so you'd expect between 1.6mmol/l and 1.7 mmol/l drop with 1u. How long before you see an deffect? Dependent on how high you were, anywhere between 20 mins and 45 mins for me.

Also does my carb/insulin ratio have an effect? What I mean is in the morning I take 2u to 10g and all other times 1.5u to 10g so would this be true for the correction dose? Would I have to increase/decrease accordingly?

If you think about it, your I:C ratio is kind of an inverse of ISF. When your I:C ratio is 1u to 5g, it means that 5g of carbs will raise your bg level about the same amount as 1u of insulin will drop it. When it's 1.5u:10g it means that 6.67g will raise your glucose level by the same amount as 1u will drop it.

So you effectively have different sensitivity factors and therefore corrections doses throughout the day, if you have different I:C ratios.

 

[samantha13]

@tim2000s thanks for taking the time to explain that. Really appreciate it!