Pump delivery?

Hello friends,

I'm at it again. I have a One touch ping pump and have a question;

When you bolus, do you get it all at one time?

I ask because today (like every other day) I was rocking the 119. My I:C for lunch is 1:8. I took 13 units and an hour and half later, dex is freaking out because I am 209 and climbing. I have apidra in the pump and I know I'm getting a good connection (I'm T1)but when I go to bg bolus it tells me theres a ton of IOB. Does that mean it's not giving me all my bolus when I key it in?

I'm still new to pumping and I know if I didn't have dex, this would correct itself as the minutes go past, but I really would like to have a Dex flat line!

Anyone know?

Yes, it is bolused all at once, but I believe the problem might be with absorption. For injections, Dr. Bernstein recommends taking no more than 7 units at a time because above that amount insulin absorbs irregularly into the bloodstream. I can't find any documentation, but I would guess the same might be true with a pump. So I would suggest perhaps two separate boluses.

But perhaps more significant, I just did the math, and if your I:C is 1:8, and you needed 13 units, than that means you ate 104 carbs for lunch. That's a lot of carbs at one time. When I go above 50 carbs at a time my I:C ratio isn't entirely accurate and I can end up going high. You might want to see if you have better results with a bit less carbs.

When you do a "regular" bolus, all the insulin is delivered at once. Once the insulin has entered your body, it takes time to become active and that is what is reflected by the IOB calculation. In general, insulin like Apridra will take 15 minutes before it has any affect and then may last up to 4 or 5 hours. This means that after 1.5 hours, most of your meal bolus has probably still not had a full effect (that is the IOB). When you go to do a correction (altho I am on MDI, I usually wait to correct until like 3 hrs), then your pump should compute a correction bolus and then subtract off for the IOB and you may actually not get any further insulin.

Darn it! I knew someone would correct my math lol. I think lunch is 1:5, I can't check right now...I can, but I have to play "guess the screen" My carb count is 45 breakfast 60lunch 75dinner and I stick to that for the most part. My lunch today was 64.

I will take the above advice of doing 7 at a time to the correct number in hopes that it will work. You're right, when I go to correct a while later, it says I don't need to bolus and it gets frustrating.

Thank you both for your replies.

Oops, I didn't even hear the question about correction, but looks like bsc got it. I can see now, why you wondered if you didn't get all your insulin at once! I just thought it was from being high. Yes, think about it this way, if you have a duration of 3 hours (for round numbers, we all vary a bit and the 3 insulins vary), then at 1 1/2 hours you have only used 1/2 the 13 units and still have 6 1/2 left (This is assuming an even use, but the pump wizard figures it more like it actually happens which is not even). So you should have enough iob to bring you down. (Did you come down at 2 or 3 hours?)

But that still begs the question of why you spiked so high to begin with, so it can't hurt to try and break up your dose and/or reduce your carb intake. My I:C ratio is 1:5 at breakfast (though 1:10 at lunch) so at breakfast I really limit carbs so I don't have to take very large doses of insulin. Large doses can have absorption problems as I mentioned but also lead to weight gain and developing insulin resistance.

Thanks all!

I know it's only been a few days, but I started breaking up delivery into 5u at a time and it seems to work! While my numbers go high 128 fasting to 162 for meal, it's a LOT better than the 200-230+


Way to go, Jigga!

Something else to try: bolus a few minutes earlier. If you are going high even in the face of lots of IOB, you may have the dose correct but just need a few more minutes before the carb rush hits.

Thanks for that! I usually bolus while getting ready to eat, but I'll do it about 5 minutes before starting and still stick to 5's.

I don't know about the Ping. I use the Deltec Cozmo. I use a Dexcom, CGM, too. Pumps calculate IOB in various ways, but the basic idea is this. You have programmed (or the pump default is) say, that a bolus lasts 3-4 hours in your bloodstream. That 3-4 hours is the period of time when you have IOB, meaning that you already have insulin chugging away in your system based on a bolus you gave some time ago.

I don't know your numbers, but let's say you bolused 12 units and that your "duration" factor is 3 hours and that your pump calculation is a rather "straight line." So, at the moment you bolus, you have 12 units IOB. One hour later, you have 8 units IOB (because 1/3 of the insulin is used up); two hours after the bolus you'd have 4 units IOB; and finally, at 3 hours, IOB = 0.

Pumpus use this feature to remind us mere mortals that we DID bolus a while ago and that insulin is still working. Hope this helps a bit.

BTW, I'd love to have a flatline graph on my Dexcom. It doesn't happen often or for long, though ;-)