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Insulin duration Vs BS reduction

Discussion in 'Type 1 Diabetes' started by Postleneo, Dec 10, 2016.

  1. Postleneo

    Postleneo Type 1 · Well-Known Member

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    Hi you informative kind folks.... yet another question.... but not too sure how to put it accross!:confused:... What i am after seeking advice on is the amount and time it takes NovoRapid to reduce blood sugar... ie if taking 1:10 ratio and have a 60g carb(basic carb little fat) meal i would take 6 units... if my BS was 5.5 before meal and i anticipate a rise of approx 14 mmol (ie a rise of approx .24mmol per gram) and my insulin lasts 4 hours... is is possible to calculate the reduction per hour?.. ie would bs reduce by 70% total rise in 1st hour...reduce by a further 40% of the current mmol the next hour etc..etc... Reason as to why i am asking is i am trying my best to maintain levels at around 5.5 mmol and there have been occasions where 3 hrs after injection i have been say 6.1... and would be interested in knowing how much more of a reduction (mmol wise) would occur in the last hour of IOB just so i can anticipate more accuratly if i may need a few grams of carb to prevent my BS dropping too much lower than 5.5... hope you get that and know where im comming from... would be very interested on your thoughts or am i trying to be too precise trying to control this (often) uncontrolable and very unpredictable beast!!!!
     
  2. catapillar

    catapillar Type 1 · Well-Known Member

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    @Postleneo isnt this just how long does your fast acting act for? If you get 3hours post meal and find you have to eat carbs to stop dropping, that suggests your insulin to carb ratio might be too high. I think working out how much insulin drops you per hour after a meal might be a bit tricky - it's not a straight line equation, the factors going into the calculation are endless, they include how long before eating you bolused, whether the insulin was working when you ate or whether the action is stalled by high blood sugar from the carbs being digested before the insulin starts acting, what did you eat, i.e the carb value and the other macros, what sort of GI the carbs were, what your activity levels are pre and post meal, what your stress levels and health is doing, what the weather is like (seriously, skin temperature can affect insulin action)...

    Is there any particular reason you don't want to drop under 5.5?

    If you are rising by 14mmol after eating you might want to have a look into pre bolusing - http://www.diabetesselfmanagement.c...blood-glucose-management/strike-the-spike-ii/
     
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  3. Postleneo

    Postleneo Type 1 · Well-Known Member

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    Thanks for the responce - seems to be quite complex - dont mids dropping below 5.5 but suppose by not too much more.. think im using 5.5 as a comfort zone - i only ask re how much mmol reduce in lastt hour to try and find an easiaer way re fine tweeking my ratio - ie before today i have taken no action re the above scenario and gone too low... at another time i tried pre-empting and gave myself 6-7 carbs but that took me a little too high...just trying to be as accurate as possible suppose lol :)
     
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  4. col101

    col101 Type 1 · Well-Known Member

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  5. donnellysdogs

    donnellysdogs Type 1 · Master

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    Make it simple..
    Any rise after eating up to 2.7mmol is acceptable after a meal and provding you remain within targets at 5 hours..
     
  6. Blackers183

    Blackers183 Type 1 · Well-Known Member

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  7. Blackers183

    Blackers183 Type 1 · Well-Known Member

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    Novorapid absorption profile is below. So based on how much you have dosed you should be able to work out how this affects your BGL, does this help?
    1 hour 40%
    2 hours 60%
    3 hours 80%
    4 hours 90%
     
  8. tim2000s

    tim2000s Type 1 · Expert
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    The clamp studies that have been undertaken show that Novorapid in a dose of 0.3U/kg produce the following action times:

    [​IMG]
    The solid line is Novorapid. This is a test across multiple people and shows that Insulin Aspart (NovoRapid/NovoLog) typically undertakes most of its action in the first four hours after eating with a peak at about 90-120 mins. It also has a tail that can hang around a lot longer than people realise.

    If you are trying to work out how this all works, it's worth a visit to www.perceptus.org and signing up, then play with the Glucodyn tool. It allows you to see how insulin and carbs affect blood glucose levels.
     
  9. donnellysdogs

    donnellysdogs Type 1 · Master

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    I have said this for 6 years!! On a pump the minimum my novorapud was lasting was 5 hours. Even back on MDI and the same (except when sleeping) or at least a 4aminjectjon only works effectively against my rapidly rising bloods till 7am.

    I set my pump acting time to 5 hours and got a bit of a knock back here of people saying its 4 hours.

    The hospitals say 4 hours too.

    I can prove that if I ever needed a correction that with a 5 hour acting time it worked perfectly... absolutely perfect. The thing I always had to do, which is generalised anyway is give more than normal corrections when over 12.0....

    People do say about going from highs to lows and having swings.... I 100% believe that its because acting time is set to 4hours or even less.

    My consultants previously always stated to be normal at 5 hours.. not before..
     
  10. tim2000s

    tim2000s Type 1 · Expert
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    It's interesting. At 0.3U/kg, we see total duration of about 10 hours. At 0.15U/kg it's about 6 hours. I guess if you are using less, then it would be shorter still.

    A study of 25 men in 1998 showed that at 0.1U/kg, the insulin Aspart was out of the system in around 4 hours. If you dig even further, you'll find that dependent on site, the absorption profiles differ again, with abdomen being much faster than other sites.

    So while it's rather hit and miss, it seems that dosage is the best indicator of how long insulin remains in the body, which makes sense given the physiological mechanisms for the use and breakdown of insulin.
     
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    #10 tim2000s, Dec 12, 2016 at 9:01 AM
    Last edited: Dec 12, 2016
  11. DunePlodder

    DunePlodder Type 1 · Well-Known Member

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    Carb absorption rate also comes into this. 60gm of carbs may well take a couple of hours to absorb. There can also be a long delay before the bolus does anything, we all vary, but I sometimes see no reaction (CGM) for an hour or more, including a lag of course. Pre bolusing or split bolusing may help. A crystal ball would probably be useful as well!
     
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  12. donnellysdogs

    donnellysdogs Type 1 · Master

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    As most people will have to correct at some point, it is worthwhile to not have acting time at 4 hours unless having using the 0. U/kg....Agree with sites too.
    Although, again we are sll different on this.. or at least I am.. my legs are the best.. my stomach worst.. yet only rarely used.

    If I have my blood machines set to 4 hrs for acting time or cgm etc I guarantee I will have an unecessary extra correction suggested and I will go low within 5 hours.

    There is actually one of the books that suggest acting time for pumps etc should be set between 5-6 hours. Don't know which book though.

    To me, sometimes people want to see blood down quicker and cause hypo's. Patients for a 5 hour wait is better if hypo prone...
     
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