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correction doses of insulin - how do i work out?

weeezer

Well-Known Member
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272
Location
bristol
hopefully a quick question...i will phone DSN monday but i want to get more of a handle on this subject. am 'starting again' with learning about how to accurately calculate my insulin. been t1 for 12 years, have always kinda guessed, this works out ok but i want to be better than ok (am 9 weeks pregnant so am seeking better than average control right now)!

am seeing a dietician but she's started me off by just getting me to fill in food diary...just the carbs so i can prove i can do this accurately (which i can, not finding it hard). saw DSN thurs and she wanted to move me along by using those carb calcs to find the correct dose of insulin (coz losing hypo awareness due to few hypo's a day). we surmised that my 'ratio' is 2u for 10g for breakfast and 1u for 10g lunch/tea/snack. but i didn't ask about corrections...i.e. if i'm not in the 3.5-5.9 before meals (i'm 9 weeks pregnant so guidelines are strict) how do i work out how much extra to add to the calculation? i've been guessing and adding on an extra unit for every 1 mmol over 5.9 i am (so if my BS 8mmol i add 2u on the the 6u i would've calculated for 30g of carbs???). it's kinda working but just wanted to know if anyone has a list???

do the units per day we use have any affect on the calculations? i'm using around 50 (30am/20pm) long acting (insulatard) per day and between 8-12 of humalog per meal, so around 30u on average. that amounts to 80u per day, higher than average from what i gather. part of this is due to being 2.5 stone overweight and part of this due to pregnancy (was using 5-9 per meal before and 24am/18pm long acting so 60ish a day which is still higher than average i think).

grateful for any pointers/advice/guidelines
 
Hi,

I have also recently started carb counting after just guessing for years! From what i've been told 1 unit of fast-acting insulin should decrease your blood sugar by about 3mmol. But it varies from around 1 - 5mmol depending on the individual. So maybe adding 1 unit per 1 mmol is right for you!

This website might help you
http://dtc.ucsf.edu/types-of-diabetes/t ... ulin-dose/ - just be aware its american so the blood sugars are measured in mg/dl not mmol

Your last question 'do the units per day we use have any affect on the calculations?', no i don't think they do, as the number of units we use changes every day!

I hope this was a little helpful!!
 
There's what called the 100 rule for calculating your correction dose..

Where you dividing 100 by your TDD.. This will give you the amount that 1 unit of insulin will drop your BG by...

So if your TTD (Total Daily dose (including both background and quick acting insulin)

it would be 100/80 so works out 1 unit of insulin = 1.3 mmol/l drop

But remember this is only a guideline, so you will need to be careful and insure that you keep a very tight eye on how it actually effects your BG, I suggest if you'll in a position that you going to be attempting to bring you BG down by using a couple of units, I would give the full amount, so say it looks like you need 2 units to correct, try 1 and see what effect it gives..

A good book to invest in, is 'Using Insulin' by John Walsh, this goes through the Basal/bolus regime for carb counting, I also suggest contacting your DSN, and asking if they can provide you with the Roche Expert meter as this has the ability for you not only to enter your carb amounts and insulin, but also has a bolus wizard on it, so it will calculate your bolus from your BG reading (once you've got all your corrections factor etc set up_.... They are pricey though £80 if you have to pay for it, but worth trying to blag one out of your DSN..

But do remember has you are pregnant your insulin needs are going to change throughout the different trimesters, so things like your correction factor and perhaps your carb-insulin ratio's will change so will need constant reviewing, and recalculating as needs be..
 
The 100 rule as jopar suggests is a good starting point...

also be aware that as your blood glucose increases so the effectiveness of insulin reduces... this not only has an effect on the dose you are using to correct but also the background insulin in effect... this is often why when people give themselves a 'normal' amount to correct it doesn't have the desired effect.. you need to be quite aggressive with corrections but remember to keep testing to make sure you don't go hypo.
 
Hello,

That 100 rule doesn't work for everyone. I'll be needing more as I'm normally BG around 8 but at the minute I'm on 5-6 units per day. Pretty sure it wouldn't take 20 off my reading when I take the 6th unit!

Paul
 
Paul

You've only been diagnosed for a month, so you will be in the honey period, where you still got some functioning pancreas still going.. Some your insulin needs now is probably going to be a lot different than 6-12 months time...

Pene is right about the higher your BG the more insulin resistance you normally are... Some people will add 15-20% onto their correction when dealing with higher number, but at what point your insulin resistance kicks in is really individual, some people find this at around 10mmol/l others might find it hits at 14mmol/l...

Another thing to consider when correcting, is Insulin Stacking this is where you've either eaten and/or corrected in quick session and the various injections of insulin overlap each other, so stacks up you get a whack of insulin which plummets your blood glucose..

So how do you avoid it...

Quick acting insulin last between 4-5 hours in your system, (you do need to work this out really) But for ease I use the 4 hour figure.. (as this is the average for people)

The quick acting insulin profile, give the main action of your insulin peaking at the 2 hour mark, at this point you've adsorbed about 80% of the insulin injected... The remaining insulin will take a further 2 hours to adsorb, it will still impact on your BG, but will only lower your BG one 1 or 2 mmol/l's

Example you inject 10 units at 2 hours you've used 8 units, and you have 2 units of insulin still on board (IOB). which will lower your BG 2mmol/l over the next 2 hours..

So if you eat or do a correction, you have to take a look at your BG work out the correction/bolus of that then deduct the 2 units off the figure..
 
Hi

To keep track of everything, I use an app called RapidCalc. You can set up all your ratios etc in settings and then the app does the rest. Input your current BG reading and how many carbs (if any) and it gives you a total dose to take helpfully split into 3 sections - amount needed for meal, amount needed for correction and amount on board (to avoid the stacking problem). The app obviously needs a basic amount of data to begin with but once you are up and running, it can then be easily tweaked to provide more accurate dose suggestions. You can also tell it when you are going to exercise and it will lower your suggested dose by the percentage you have entered in settings. It also copes with alcohol, gives a handy stats page with predicted HbA1c results, a graph showing you how you have been doing over up to 90 days and you can email the whole file to yourself (or your DSN) so that you don't have to keep other records elsewhere. Costs £5.49 but I wouldn't be without it!

Tracy
 
Hello all. Thanks for the advice. I am the mother of a 9-year old boy, with type 1 for two years. He seems to have come out of his honeymoon period 6 months ago (or so says his DSN). we are struggling with his correction doses, as his sugar is very sensitive to temperature changes, now that we are warmly tucked in at home on school holiday, his sugar is all over the place. The 100 rule is not working consistently. Does any one know if the app is validated? thanks.
 

The 100 rule is only a guide, it could be possible that your lad needs more insulin as he's less active in the school holidays, I would get in touch with his DSN and ask about adjusting his insulin doses.
 
I would not want to answer this as doses and strength of effects can vary greatly from person to person and mistakes likewise can be very harmful I'd suggest contact your own doctors and nurses for this advice.
 
Unfortunately, there is no correction dose rule that works for everyone. It's trial and error really. All part of the fun with diabetes lol !
 
mo1905 said:
Unfortunately, there is no correction dose rule that works for everyone. It's trial and error really. All part of the fun with diabetes lol !
Click to expand...
My nurse told me if my bloods were high I had to deduct 7, as this was the normal reading and for every 3 over the 7 give myself 1 extra unit of insulin.
Hope this makes sense.
 
My sons correction is 1 unit brings down 10mmol, they haven't changed this for a while although the they've changed his slow and fast acting insulin doses, does this sound about right ?? Also he is 8 and been diagnosed for 18months, could he still be in the honeymoon period nobody as mentioned this to me yet, they said when he was first diagnosed his pancreas would still be working but haven't mentioned anything since x
 
The easiest way I found was shown to me by my DSN. Add all of your doses of insulin together for the day to get the daily average. Do this for 7 days and then add them all together. Divide by 7 to get you weekly average. Take the weekly average and divide by 100. For example:

+ 50 + 40 + 30 + 20 + 60 + 40 = 270u for the the week.

270 / 7 = 38.57 daily average for the week.

100 / 38.57 = 2.59

So 1u of Insulin will reduce your blood sugar by 2.59mmol.

Hope this helps,

Mike
 
Sadly, correction doses are a trial and error thing beyond the suggested starting points. Take me for example. After I've eaten a meal and while my bg remains below 13, 1u reduces me about 3mmol/l.

Before eating, early in the day, 1u knocks me down between 5&6 mmol/l. If my bg level is very high (>13), 1u is good for about 1.5mmol/l.

Then there are the days post exercise where I have muscle inflammation and I require 3-5u to reduce by 1mmol/l.

So while there are starting places, it can get really complex. And don't even look at Pizza...
 
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