PostGrad Terminology

As an addendum to my post on the latest ADA conference, I’d like to add that I learned some new Scholar_1 terms. Or clarified their meaning for myself, at last:

  • Dual Wave vs. Square Wave Bolus – literally, bolus doses administered by an insulin pump in these patterns. MiniMed explains: “The Square Wave Bolus allows patients to easily select an amount and duration (from 30 min to 8 hrs) over which time a meal bolus is to be delivered. The Dual Wave Bolus simply combines a Square Wave Bolus with a Normal bolus and delivers them at the same time.”
    • Insulin on Board (aka Bolus on Board) – a measure of how many units of rapid-acting insulin are still working in the body. Now why do I seem to hear so much confusion about this apparently simple concept?

    • Rule of 1500 – used to estimate blood glucose decrease per unit of insulin, and looks like this:

    Total Daily Use = Blood GLUCOSE DECREASE PER 1.0 unit of Insulin

    • Calibration – the act of coding your glucose monitor (or other device) to make sure readings are correct. Usually this means setting the numbers on the meter to match your current test strip vial, although some newer meters — including Ascensia’s Contour — can now boast “no calibration required”; it’s automatic.

    • Cleo 90 infusion set – new product being launched by Smiths Medical featuring an automatic needle retraction system, which I’m told is less painful and stays put better than many traditional infusion sets.

    And just to illuminate the subtle distinction:

    • Physical activity – “body movement produced by the contraction of skeletal muscles that requires energy expiration in excess of resting expenditure.”
    • Exercise – “a subset of physical activity; planned, structured and repetitive bodily movements performed to improve or maintain fitness.”

    • Resistance exercise – “trying to lift a weight you can barely lift.”

    Darn! I may have come away a little smarter, but surely not fitter, because spending the weekend at the conference meant my bodily movement this week’s been limited to “resting expenditure.”

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    9 Responses

    1. Kassie
      Kassie February 16, 2006 at 6:59 am | | Reply

      Here’s what confuses me about IOB: If I eat x g cho and bolus y units of insulin, then an hour later, snack again, IOB will show insulin still around, right? But to me, that insulin is ‘spoken for’ with the carbs I ate earlier. So I don’t grasp the utility of it.

      I’m meeting a Cozmo rep in an hour, I’ll be sure to ask him!

    2. Sandra Miller
      Sandra Miller February 16, 2006 at 10:41 am | | Reply

      Kassie, my understanding of IOB is that, if you go into a snack with IOB, it shouldn’t affect how much insulin is given to cover those snack carbs.

      The utility of IOB comes into play if you’re bolusing a correction for a high (meaning that IOB is still at work, thus depending on how much insulin is still in your system, a correction may be unnecessary).

      Soooo, if you’re bolusing for that snack and you’ve added your bg, the pump should tell you how much insulin you have remaining from the previous bolus. Then it will only subtract that amount from the correction part of your bolus if your bg is above target.

      And Amy, I think some further confusion surrounding IOB stems from the fact that each pump manufacturer appears to use a slightly different insulin “action curve” to calculate IOB.

    3. Kassie
      Kassie February 16, 2006 at 12:58 pm | | Reply

      sounds about like what the pump rep told me. And you can overide the IOB. I noticed that you can set the window of the IOB function based on how long insulin acts in your own system. I can’t wait to try to figure that out!

    4. Shannon Lewis
      Shannon Lewis February 16, 2006 at 1:35 pm | | Reply

      The way Sandra explained IOB is how I’ve always understood it to be.

    5. Felix Kasza
      Felix Kasza February 16, 2006 at 9:06 pm | | Reply

      Please do yourself and all other diabetics a favour and forget about the 1500 and 450 rules. They only apply if you consume a set amount of carbs per day, as they conflate the correction factor and the insulin/carb ratio.


    6. Caro
      Caro February 17, 2006 at 2:52 am | | Reply

      Some of the confusion with IOB stems from the fact that every pump does it slightly differently, and every insulin acts in a slightly different way in each person!

      A major glitch with the IOB on the Animas IR1200 (the only pump I can really speak for, as my previous pumps did not have IOB) is that if you enter a blood sugar that is at or below your target when you are eating, it will not subtract any ‘correction’ insulin still on board from the CarbSmart bolus (food bolus it calculates.) Even though you no longer need that insulin to bring your bg down, because it is already where it needs to be, the pump assumes you do!

      Fortunately the IR1200 lays out the bolus calculations on screen, so you can see how it reached the answer and manually adjust. Don’t get me wrong – it is a minor glitch on a great pump!

    7. Kirk
      Kirk February 17, 2006 at 6:24 am | | Reply

      It seems they are overcomplicating the whole subject.

    8. Tyler Wolf
      Tyler Wolf February 20, 2006 at 10:41 pm | | Reply

      Should one really forget about the rule of 1500? This is the first that I’ve heard about it, but it seems valuable. I take about the same amount of insulin each day (according to my MiniMed 515 pump’s “Daily Totals”), and I generally try to stick to a routine. I think the rule could help me be more precise with correction boluses.

    9. Tiffany
      Tiffany February 20, 2006 at 11:17 pm | | Reply

      The 1500 rule is a baseline; more of a starting point than anything. It’s one major flaw is that it is unable to calculate individuality.

      And something to note is that the 1500 Rule was developed in the early 1990′s and intended for Regular insulins; the accepted rule when using the new fast-acting insulins (Novolog/Humalog) is 1800.

      1800 divided by TDD = ISF

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