How to correct on a sharp rise?

I was reading some of the training material in dexcom's thecgmsresourcecenter.com website. I came across a powerpoint which had case studies using the dexcom. They mentioned a scenario where after bolusing, the dexcom alerted to a sharp rise and they recommended taking a correction bolus prior to even the first hour.

I'm confused- I thought we weren't supposed to stack boluses? I actually tried this on Friday and it worked, but it was a total SWAG. Can anyone help me figure out a little bit better way of guesitmating how much to bolus based on the trend and rate of rise?

Here's their scenario:

"Let’s take a look at how John started his day
On waking, his BG was 72
He ate breakfast at 8:00 AM and took 4U of H (60g/15=4)
At 9:20 AM the “high alert” alarm (set at 180) went off
He did a fingerstick to confirm his BG level and reviewed the 1- and 3-hour glucose trend graphs

Best answer—meal bolus should maintain glucose values within 50 mg/dL of pre-meal value. Glucose up 100+ points – correction ratio 1:50. One question you might ask is, given that the correction factor is 1:50 and that 2 or 3 units of Novalog would drop the blood glucose 100-150 points, if John is only 182 mg/dL, shouldn’t this amount of insulin cause hypoglycemia? The BIG difference in this situation is that we have TREND information showing the trend is going up and has a high ROC (rising steeply). Helps make the decision to take more insulin to address rapid rise and reduce time spent in hyperglycemia."

I'm wondering if there is a safe guideline to correcting if you've *obviously* underbolsed and you don't feel like spending the next 4+ hours high...

Thanks!

Here's what I do....in this case, there was a likely a mis-estimation of the carb count or hidden carbs in the food, etc. If I normally plan for a rise to at most 150, and I see , say 200 shortly after eating, I know that after 3-4 hours I will not be back down to 90. I will compute a correction factor for the "extra" bg rise, namely 200-150 (my max post prandial target (you may have another target , and I'll say I am not happy with even 150 for me)) = 50 points and compute a correction bolus for that. 50 points/ ISF (in my case 25) = 2 units.

With the dexcom I am more comfortable doing things like this as I will see whether it will get me into trouble.

I do not call this stacking as it is correcting for the extra carbs and will be covered by those carbs.

Yes- this is what I was looking for- thank you!

Is there a time when you won't correct? Do you only correct if you see it shoot up within 30 minutes? 60? 90? I'm thinking only within the first 30-45 minutes, otherwise the insulin and carbs might be too far off. Thoughts?

And yes, this is for when I totally mis-guess what I'm eating...

Thanks you!

Well, I would say experiment. I tend to be very aggressive in stopping highs.

If I am too high at 3 hours later, then most of the meal bolus insulin is already gone and now it is a standard correction bolus. Then I will probably just use the pumps correction bolus calculator and be done with it. (Manually, I would just compute a standard correction bolus).

You can also manually compute the insulin remaining on board and subtract that out, as the books "Using Insulin" , or "Pumping Insulin" describe. A very conservative way to do this is to count 25% of the insulin as used for each hour since you last bolused. In reality, for most people using Humalog/Novolog, it gets used up faster than that. I currently use a duration of 3.5 hours on my pump, but for manual calculations in my head, 25% is safe for me.

Some pump bolus calculators handle all this automatically. The current Omnipod calculator does not factor meal boluses into its IOB calculations... it assumes that all the meal bolus will be covered by the carbs you put in. The new Omnipod PDM is supposed to change this.

I stack insulin all the time; and most of the time I am fine. Every once in a while I over correct; but I have come to rely on my active insulin feature on my pump. I do a similar calculation to the others and based on my total active insulin sometimes I cut my standard corrections in half; so if I would have taken 10 to fix a high sugar then I might take 4 or 5 depending on how long ago I ate my meal and what I am physically doing. Then I try to let it ride for at least an hour.

Just be careful because I have had the dex give me the double up arrows and showing that I am spiking when in reality my numbers were perfect. If I just bolused up intead of spot checking with a finger; I would have put myself in a real tail spin. For me this happens a lot during the morning right around the dawn phenomenon.

Good luck
Ed