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How fast will BG rise without basal?

Discussion in 'Parents of Children with Type 1' started by Theo's dad Joe, Nov 28, 2015.

  1. Theo's dad Joe

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    How fast does blood sugar go up when basal is off? I am trying to make sense of the numbers. If someone gets 1.35 units an hour then wouldn't they rise by about the amount that 1.35 units usually covers? I am curious because I have seen a lot of people post that they end up over 300 with a disconnection, but I have also read about people who don't even use insulin for a couple of days at the end of a month because they run out and can't afford it. If you take 1 unit of basal an hour, and 1 unit corrects say 50 points then wouldn't you expect to rise 50 points an hour without basal if you were fasting, or does it just not work that way?
     
  2. sugarmonkey

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    It would definitely depend on the individual. Everyone's need for insulin is different. Also, with my son it can totally vary all the time. We've had times when his pump has stopped delivering at night for some reason and he's only ended up about 15, other times he's been high, and even very odd times when he hasn't gone up at all.
     
  3. msschiel

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    I agree, I really think it could vary due to any number of variables.
     
  4. mamattorney

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    Honestly, it never makes any sense to me. For my daughter, it doesn't even necessarily happen immediately.

    With a bad pump site, she can easily rise 100+ points in under an hour. Her basal is around 1 - 1.5 units/hour, but her correction factor is 1 unit for a 25 point reduction - the two are definitely not equatable.

    But then, take a day at the beach - numbers are great the entire time pump is off. Put pump back on, numbers are fine, numbers are fine. 5 hours later - numbers are through the roof. This is with basal back and running for hours.

    The whole thing is a mystery to me.
     
  5. jenm999

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    There are no rules. I can't even figure out the optimal time to change his rate to affect his BG X hours later - sometimes it's 1 hour, sometimes it's 3. Once he forgot to put his pump back on after a shower and his BG didn't move for 3 hours, but maybe he would have dropped with basal on board - who knows. Site failures look like a 45 degree rise for us, but sometimes an underbolus or fried food can appear that way too, so we usually agonize over that and lose a good amount of sleep.

    I do know that a deficit of .05 basal per hour for, say, 3-4 hours may require a unit or more correction later, which seems mathematically incongruous. I like to think of adjusting BG like moving a big heavy rock. Takes more energy to get it rolling than to keep it rolling, and a slight change in the incline can make a HUGE difference in the energy required to move it either direction. Another analogy is turning up a thermostat. How much are you trying to change the temperature, how efficient is the furnace, how well are the windows insulated, how cold is it outside, how clean is the ductwork... there are too many variables to do much more than make an educated guess.

    I will say that we almost never do temp basals for corrections in either direction. Insulin or carbs only. If he's at 300 and I correct and add a temp basal it's all but guaranteed that I'll be fighting a low in 4 hours. So I just add an extra unit and watch like a hawk. I do use temp basals for predictable things like exercise or long car rides, but they always bite me in the butt for corrections.

    The only mathematical correlation that even comes close to working (as I've observed it in my test group of n=1) is the relationship between carbs raising BG and correction dose, but even that can be fishy if the basal is not 100% correct.

    mamattorney, we have the same problem at the beach/pool. BGs are great even when disconnected but the lack of basal for hours sends him through the roof later. He hates Omnipod alas, but that does the trick. We may insist upon it for our February vacation in Florida as my mom has a pool and he'll be in and out of it all day.
     
  6. Theo's dad Joe

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    I have been talking recently to an old friend who is a medicinal chemist and he has been explaining to me that basal insulin doesn't just hold glucose in the liver, but it also shuts down a lot of things that make insulin itself not work as well, for example, basal insulin shuts off gluconeogenesis, holds amino acids in muscles so muscle doesn't break down to make glucose, and shuts down enzymes that would otherwise pump fatty acids into the bloodstream from fat cells, as well as of course preventing the production of ketones. So while we usually think of it as "holding in" glycogen in the liver, it also clears out other things that tend to make mealtime insulin not work as well like excess fatty acids and amino acids and ketones from the blood, and enzymes that put fats into the blood that have to be cleared out for insulin to work optimally.

    This seems to be similar to jenm's analogies.

    I have also been told that the "rule of 1500" was based on the premise that you need enough insulin in general to manage about 1500 blood sugar points a day, half from food and half from the liver/basal. That would suggest that someone who uses half basal and half bolus would rise about 750 points in a day without basal, but that is only about 30 points an hour. I mean if you rise 100 points in an hour are you going to rise 2400 points in a day? Not! because your liver has a limited supply of glycogen so eventually you just literally wont have a source to provide for higher and higher blood sugar in the short term, though in the long term, low insulin is going to trigger a breakdown of body proteins to make more glucose.

    What I am really trying to determine is whether my son's carb ratios would become larger (less insulin) if I raised his basal insulin. Is it maybe more efficient to have smaller, slower pulses than sharp spikes? Maybe there is a rebound effect from real fast acting insulin. I have seen that non-Ds will have a blood sugar rebound about 4 hours AFTER dinner after their blood sugar has returned to normal usually. Maybe there is a desensitization to large fast acting amounts all at once.
     
  7. wilf

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    Seems to me that you're overthinking this..

    Overall, regimens which have higher proportions of basal will be "smoother" than those with less. On MDI, you always want to go with the highest amount of basal (Lantus or Levemir) that is possible without causing night-time lows. Let the nights be your guide, and get the Lantus as high as is consistent with good nights. Only then do you worry about fine-tuning the carb ratios. But they will of course be "larger" (i.e. you'll need less insulin to cover carbs as basals go up).

    Good luck. :cwds:
     
  8. jenm999

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    I understand your question better now. I don't know the answer. I can tell you that I have found that my son tends to be more level and have fewer spikes - and therefore a lower TDD - when his basal is on the low side, around 35-40%. He is growing like a weed and eats constantly so it's hard to get a good read on what his exact basal needs are. In the past I had him on too much basal but didn't realize it because he had overall good numbers and a good A1c (low 6s) but lots of spikes because he needed more at meals. I think trial and error might be the only way to answer your question. And if you find the answer, it may not apply in a week. :)
     
  9. jenm999

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    Ha! My experience has been the opposite. That just shows to go ya.
     
  10. wilf

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    No way - how come?
     
  11. jenm999

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    I have no idea. My hypothesis is that he metabolizes food pretty fast so needs a large bolus in conjunction with the food rather than spread over hours as basal, but really I don't know. It could be that I had too many basal rates. But since I've lowered basal and increased carb ratios things have evened out quite a bit.
     
  12. Sarah Maddie's Mom

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    We're about to mark 13 years, here's what I've learned. No "facts" about your child's Type 1 can be conveyed by others, be they other parents or endos or chemists. Regarding your specific kid there are no transferable "facts", there's just how your individual kid responds in that particular and unique phase in their disease progression and their individual physiology at that moment. What you observe is the, "fact", everything else is meaningless.
     
  13. Michelle'sMom

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    ^^^This^^^


    Dd runs basals around 30-35% of TDD. Anything higher results in a rollercoaster. Always has, but it's gotten worse the last 2 yrs.
     
  14. Dad_in_Canada

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    Huh. We're quite the opposite. If I see lots of big swings & roller-coasters, it's usually a sign that basals are too low. Corrections that don't work is another clue to basals being too low.

    Tuning up those basals just a pinch makes things much smoother for us. Our optimal basals are 45-50% of TDD. And when they're dialed in correctly, the overnight Dexcom graph is a beautiful thing :). Just wish it would last more than a week :(.
     
  15. Michelle'sMom

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    Which is why there are no real "rules." What works for one doesn't necessarily work for all.
     
  16. mom24grlz

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    i agree it depends on the individual. My nephew who is type 1 could be 400+ with ketones within 2-3 hours of no pump basal. Yet Ashleigh has gone all night 8+ hours (twice) with no basal and the highest she has risen is 275 and had no ketones
     
  17. Mimikins

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    I see the exact same thing with my basal. I have a 40-60 basal-bolus ratio currently -if I get closer to 50-50 by raising my basal I start seeing a ton more lows, while reducing my bolus to get the 50-50 balance will cause a ton more meal spikes (I bolus for about 160g carbs or carb equivalents a day, though I eat about 120-130g of net carbs).

    If I'm without basal insulin, I notice that I often chill out around 200-350 and enter ketosis really quickly (like having a 230BG and already having moderate urine ketones after 3 hours of no insulin). There's some foods that cause me to spike that high also, so it gets pretty interesting trying to figure out if I'm having a post-meal high or pump issues.
     
  18. Theo's dad Joe

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    That is interesting. Do you have pretty high bolus to carb ratios (low carb ratios). I guess what I am asking is, how much total bolus do you take a day?
     
  19. Mimikins

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    My IC is 1:12-1:16, and my TDD is around 17-17.5 units (bolus about 10-10.5 units). I eat fairly high protein, and I occasionally need to take additional insulin for it (especially if I'm eating it with something lower in net carbs). Most of the time, I get lazy and simply bolus for my fiber and use that extra insulin to account for any protein/fat that may spike my BG.
     
  20. Mimikins

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    My SF is 1:60, though it and my IC haven't changed in close to a year (despite my basal being cut by about 50-65% by pumping and losing extra weight). YDMV though.
     

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