Do you do corrections sooner than your DIA ends?

In regards to my diabetic child:

We always run into trouble when we correct before the 3-4hrs after a bolus is up. Depending on what was previously eaten, of course, and if you 'think' you are still digesting or if it's done. The bolus calculator doesn't know really what's going on, it's just doing math.

Often, I'll see a >300 number on the CGM around 2hrs post-prandial. Sometimes, if I correct at that time, we end up crashing hard-core! Other times, I think to myself, "don't do it yet! It WILL go down, just be patient!" just to be wrong and have a high number at the next BG (after 3-4 hours), wishing I would have corrected earlier.

Sometimes if we have a day where the BG just won't go down, I panic and give lots of corrections before the first one is even done working. Ugh, it's so psychological.

-I have the IOB set at 4 hrs.
-Recently done basal rate tests and ISF correction tests. Determined they are good (for now).
-Use Animas Ping and Dexcom.

I always hear things like, "you should shoot for a BG in the range of 15-200 2 hours post meal." Well that's impossible 75% of the time.

Would love to hear what others do! Thanks!

If you spike high, but end up at an appropriate level 3-4 hours after the bolus, maybe it's an issue of bolus timing rather than bolus amount?


I've heard there is a time of effectiveness, a peak time, and a "tail." I just check if I'm in doubt, or if I feel weird.

I agree with Elena, pre-bolusing for meals that you expect will spike you is the best way to go about it. An example is my breakfast, I tend to eat fast acting carbs(love my oatmeal and chocolate protein drink!). These can easily spike me to 200+, so I pre bolus at least 15 minutes before and as much as 40 minutes if I remember.
Most basic meals I shoot for 10-15 minute pre-bolus.

Thank you everyone! So, I know we are supposed to pre-bolus. I try to do 10 min if >100, 20 min if >200, and 30 min if >300....etc. But it's so impractical a lot of times with a small child! I'm not going to make her wait for dinner that long. I try to check ahead of time so I know if we need to pre-bolus long before dinner or not, so we aren't all waiting for the meal, letting it over-cook or get cold. Yesterday she came home from her activity and it was late, just time to eat a snack before bed, brush teeth and get to bed! I basically said to hell with the pre-bolus lol!

So are you all saying that if you DON'T pre-bolus, other than having a spike post-prandial, does it also mean that the insulin is not fully working properly? Or is all the pre-bolus doing is eliminating the spike.

If the insulin to carb ratio is set correctly, then the purpose of the pre-bolus is just to eliminate the spike. But yeah, that would be hard to do with a kid!

If it were me, and I found that the Dexcom was generally running accurately, I would prebolus based on the Dexcom reading, and do the fingerstick just prior to the meal. I know you aren't SUPPOSED to do that, just saying, but that is probably what I would do.

I could be way off, but I’m wondering if your I:Cs (or maybe just one, if your daughter spikes that high after one meal in particular) need adjusting if she is having post-prandial spikes into the 300s…

I was wondering that too, but then the tail end of insulin action will drop her too low. We recently did basal rate check and it was steady. At breakfast we use 1:14. We tried 1:13 and she ended up at 66 for a BG at lunch. I don't know!! Wish we could use 13.5! lol!

Here's another thing that happens ALL the time at night when she's sleeping. I give a correction and check 3 hours later and her BG is the EXACT same number. So, I'm thinking our ISF is off. But if it doesn't budge AT ALL, how do you calculate how much more to give? BG isn't going up, but it's not moving at all. If there were something wrong with the pump/insulin BG would keep going up. I have her ISF at 1:70 at night. A year ago it was 1:165...seems so drastic to give her more! She's only 8, she hasn't started puberty. Again, we had her not eat after dinner and her nighttime basal rates seemed steady.

WHY WHY WHY!? What do I do?

If I knew the answer to WHY WHY WHY? my daughter wouldn’t continue to have icky post-prandial spikes and those pesky lows anymore… :confused:

I still run tests and calculations on paper. This is what the math looks like for adults, I recognize that kids can be different. 2 hour window of active insulin for meals, 4 hr window of active insulin for correction. Check with Doc about how to built your spreadsheet. I was confused about this, on a pump, for a long time. This is how it ended up working, for me. The trick is to not let these testing windows overlap and to run the test more than just once. If you don’t get the same results, then keep running the tests until it becomes apparent, what to do.

P.S. You dont have to test all the dosages all at once, but you do have to start with a solid basal, so I would testing the basal more than once a day, for three days, then making minor adjustments and seeing if if makes things better. Once the basal is solid, test the meal bolus. Once that is solid, test the correction. THe correction is the hardest because it is soooo slow to play out - a full 4 hr window.

snippet.pdf (47.7 KB)

Thanks! I like the spreadsheet! I have never heard that insulin lasts for 2 hours for meals and 4hrs for correction. Why is it different? Insulin is insulin?

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The duration of insulin action (DIA) is what it is no matter whether you bolus for a meal or correct. The only difference may come from where and how you inject and your activity levels. Most experts would tell you that the DIA for modern rapid insulin is 5 hours. After two hours you will still have significant insulin still on board (IOB). Most pumps will calculate your remaining IOB and subtract it off a 2 hour after meal correction sometimes resulting in no actually corrective insulin being injected. Simply being high at 2 hours doesn’t mean that you insulin wasn’t matched to cover your meal. A proper matched insulin dose will result in restoring your blood sugar at 3-5 hours back to baseline. Particularly with a child I would be fairly conservative about things.

If you are experiencing issues with what the insulin pump is calculating and better question to ask is whether the input to the pump may be off. For instance the pump makes certain assumptions about “timing.” Are you bolusing at the right time? And are you counting accurately? And while you may have done ISF tests have you actually done tests for your ICR?

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I have no idea why they told me 4 hrs Vs 2 hrs, I’ve always wondered that. But, often my correction doesn’t even start to bring my BG down for at least 2 hours, and it tends to run a little longer than 4 hrs. I also think there will be some differences depends on the type of insulin. Calculating ICR would be an easier calculation. How does she calculate ICR, Brian? Wait for ‘flatline’ data and then feed the kid 12g, and then wait an hour, and evaluate the result? Do that a number of times, at different times of day?

Some authors argue that if you know you can infer your ICR from other variables. I think self experimentation is best. Start with a normal fasting (I like 80-100) having not eaten or bolused for 5 hours. You must have basal set spot on. Then ingest a known and fixed amount of glucose (like smarties). It is easiest to do a larger amount 25 grams or so. Then start with a “guess” of your ICR which is about half of what you think it is. Then you should be slightly high at 3-4 hours. The amount that you are high is roughly the error. Then adjust your ICR slightly to reduce the error. You can note the extra insulin needed is roughly how high you were divided by your ISF. Make an adjustment to your ICR based on that. You basically want your ICR to be the minimum insulin required to cover a fixed set of carbs. Hope that helps.

On shots I calculate DIA; on the pump I was always trying to figure out how accurate the pump’s was.
But the answer is yes, I do, if it’s clear that the DIA won’t cut it. At least on the minimed pump if you put a number to correct and no carbs, it just says 0.0 for the correction amount. And on shots- if it’s close to a meal were I took enough insulin to correct a bg of a thousand (my I:C is around 10 but ISF is around 80; and yes I have 100+ grams of carb meals) then I’m not doing a correction anytime soon.
OTOH if my DIA is from a small snack or earlier correction, especially an earlier correction, it often happens that I take another shot (and would have done another bolus when I was pumping) before the DIA is up.

Many of the issues we adults deal with in trying to manage insulin are even worse with children because so many of their physiologic processes are turbocharged.

For example, all parents have noticed (and marveled at) how quickly children heal – especially babies. A minor scrape that drew blood can be virtually completely healed and gone the next day.

Similarly, children digest a bit faster too. Time to first sugar in the blood is sooner; all the carbs finish digesting and absorbing more quickly as well.

Unfortunately, subcutaneous injections/infusions diffuse into the tissue at the same rate in little guys as big ones. That’s (mostly) not a physiologic process, but simply a physical one.

What the point of all this? Strategies like pre-bolusing will be harder to develop/tune for a child, and will be less effective. The insulin absorbs, peaks, and fades off the same. But the sugar spike comes on sooner, bigger, and drops off sooner.

Pre-bolusing children as a care-giver also is fraught with all sorts of other landmines that must be constantly dodged.

The good news is, kids are far far more tolerant of transient BG spikes, in terms of how they feel and negative impact to their health and tissues, than old fogies like the rest of us. Hitting being over 200 for 2-3 hours and hitting 300 at the peak is not anything to worry too much about. As long as most of the time your child is down in the healthy zone (<140 or so, <120 even better) from everything I’ve gathered over my 15 years as a diabetic – they’ll be just fine.

I don’t know what a DIA is but, as an adult, let’s take your example of the high cgm reading post prandial. Of course, if you treated perfectly, then you don’t need help, right?

What I do, if I am still high at 2 hours post-pran is to use the meter which enters the BG number into my pump. Then I hit bolus wizard and let it use the BG along with my IOB and it calculates the additional insulin bolus I need. Voila, I hit the buttons and get the bolus that takes into account my remaining IOB. If it is one of those times when it is hard to get my BG down, I just keep using the bolus wizard and my meter number. FWIW.

A few thoughts…
Is the basal correct, If it is, then meal boluses are easy. I think your child’s are incorrect, even with the testing–I pretty much think basal testing is a waste of time, Look at your pump readings and make decisions. You may be compensating for incorrect basals with meal boluses, especially if they contain correction factors. Concentrate for a while on the basal accuracy. The corrections may be the problem.

In my 53 years of T1, I have never prebolused. I do use prolonged basals for higher fat meal with great success.

A 2 hour after meal BG finger stick should be below 180. Confused by the 15-200 comment. If I was 15, bring in the paramedics.

A BG > then 300 scares the h e double hockey sticks out of me. I takes days to resettle my BGs after a reading like that. It is a scary time. I have been over 300 maybe 4 times in 53 years. If happening a lot, even with possible hormone craziness, reassess treatment and talk to the doc.

It is a hard and crazy disease–changes all the time, causes a variety of weirdnesses. You are doing great and being here is a great resource. Lots of opinions, but also mind opening to new ideas.

Do you have a CGM? Trying to prebolus without a CGM was for me like poking around in the dark with a stick. Sometimes you hit your target, but more often you are way off to one side or the other without even knowing which side, let alone by how much you are off by.

In my case, I simply have no hope of staying under 180 after a meal unless I prebolus. The glucose from the meal arrives way before the insulin diffuses.

And going above 300 is not at all foreign to me. Some people are apparently wired differently. If I tried to live my life trying to achieve the “after 2 hours” targets others seem to go by, my life would be filled mostly with failure and disappointment. So I don’t. :disappointed_relieved:

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really! I do that when I’m a bit higher than I want to be at meal time. It beats chasing a high later.