Replies to This Discussion

Permalink Reply by MI_Dad on May 5, 2011 at 9:31am

Hi Jen.

We're still rookies... having only been on the pump for about a month... but I'll still offer a thought.

When you follow the recommendations... are they generally successful?

As I understand it, the bolus formula that will take into account your current bg number, the bg target, the IOB (controlled by the duration), the carbs, and I:C ratio, and the Insulin Sensitivity factor.

So, I would think that if it's not telling you to bolus or not, it's not necessarily because of the IOB.

For example, when we started, they had set our target very high, which would impact the amount of bolus (reducing it).

Or, setting a high insulin sensitivity factor would also cause the pump to recommend less insulin.

What is a scenario where it is doing this?

==> Mike.

Permalink Reply by Sindhilicious on May 5, 2011 at 10:54am

Can you give an example? Even if I have some IOB, if I add more carbs to the mix, it will recommend more insulin.
Sometimes IOB can compensate for carbs depending on how much you have on board and how much you're eating.
If the ping doesn't recommend a bolus I tend to wait a half hour to check again once the IOB has reached the bloodstream.

Permalink Reply by gw on May 5, 2011 at 11:09am

The big pieces of this puzzle are stated rather precisely as MI_Dad was suggesting. Perhaps these may be innacurate if the insulin recommendations are causing unusual BG? After all, if the BG is not being affected negatively, then I would hope the problem for you is mostly just a matter of being familiar and getting more comfortable with the different system of the Ping.

I was wondering the same thing as you early on; it took me a while to get familiar with it, but I realized there were several instances when there would be either no insulin bolus suggested or less than I thought. At mealtime there are a couple things: if there is already IOB , your I:C ratio, insulin sensitivity, bg value and target as said above. Also the I:C and sensitivity can change throughout the day. For me I am much less sensitive after waking and much more sensitive before dinner. I am not yet an expert on I:C ratio, but I have that one reasonably well under control.

Also for correction boluses, when there is already insulin on board, it recommends an amount based on your sensitivity, IOB and target, which may at times be little or no insulin. If your BG was not coming down to target for instance, perhaps the sensitivity is not as accurate as it should be.

Btw, I am glad I chose the Ping and not the Cosmo, as it has since been discontinued! I thought the Ping was simpler and easier to use, built better and more like a tank... What are your thoughts on this? Any comparisons? Good luck sorting this out. :)

Permalink Reply by Krist Rosenberg-Mads & Cam's Mom on May 5, 2011 at 11:17am

HI Jen:
The IOB is calculated by algorithems within the pump setup. If you do a normal bolus (versus a combo bolus), the insulin is acting for approximately 2 hours. This IOB is a way to prevent the pump user from "doubledipping" the dose. For instance,( assuming it has been at least 2 hours since your last normal bolus) if you test your bg and result is 300 and you are having snack with 15 carbs. The pump calculates a correction for your high BG plus the snack. You complete the bolus and you are done. However, 5 minutes later, you decide to have another snack. if you were to add your BG again it would subtract out that original correction you completed 5 minutes earlier. It will only suggest insulin to cover the snack.
I hope this helps.
Clear as mud, right?
My son, 5 1/2, has been on an insulin pump for 1.5 years. WE learn something knew everyday! It does get easier.
Kristi Rosenberg (a.k.a Maddie and Cam's MOM)

Permalink Reply by Laura S. on May 5, 2011 at 12:22pm

The best thing to do really (though Kristi's right on) is to take everything as a suggestion and make your own educated decisions. I have to personally rethink everything the pump might 'suggest' because my circumstances are so unpredictable. That may be from being a type I for 40 years......

Btw, I just had to call Deltec today to get the official date my pump would have gone out of warranty. They were helpful, but sounded like the Maytag repairman. Not much to do around there.
Glad I bailed the pump. I liked some features, but the bulk of it with the meter on back made it very heavy.

Permalink Reply by Zoe on May 5, 2011 at 12:53pm

Actually, the pump bases its Duration of Action not on any arbitrary number (such as 2 hours), but whatever you set it for. Most people use somewhere between 3 and 5 hours for their Duration of action.

I do the same as Laura, I always consider the suggestions as a baseline and then make alterations as I know will work best for me. One example has been that if you are low (or even just lower than your "target") it recommends less insulin. For me, if I were decrease my insulin by that much, I'd be high later. I generally take the insulin based on my I:C ratio, only wait to bolus until right before eating or even after I've started if I'm significantly low. Sometimes I'll treat first and then retest and bolus but I prefer not to do that.

Back to the original question: There was a discussion on here a little while back about this very thing. I seem to remember someone explaining that the IOB is not always taken into account in the same way. I don't remember exactly, but I think it was different for corrections and carb boluses? (which would make sense given what I mentioned above about going high if I don't bolus for carbs). Whoever posted before hopefully will chime in and calarify. It's not just you, Jen.

Permalink Reply by t.clayton on May 5, 2011 at 6:19pm

I believe it will only show IOB with the advanced bolus features, EZCarb or EZBG features, if your using the regular or audio bolus function I do not believe it will.

It also needs to be turned on under the advanced setup menu with a duration of action set.

Permalink Reply by Leilani on May 5, 2011 at 6:36pm

I have used the Deltec Cozmo and am now on the PING, and the algorithm that is used to calculate the IOB is different . . . perhaps calculating more active insulin than the Cozmo towards the end of insulin duration. With the PING I often override the IOB suggestion during the last hour of insulin duration because I know there is not that much insulin left to act. I figure that if the PING allowed a 2.75 hour option for IOB it would be closer to accurate for me.

One other thing about the PING is the +/- which is allowable with the ISF. If you use +/- 10 the pump will not calculate a correction or reverse correction if BG is within that range. . . but will correct to target if BG is outside of that given range. So if your target is 100 mg/dl the PING will not calculate a correction if your BG is between 90 and 110 mg/dl, but if your BG is 111 mg/dl it will calculate a correction to 100 mg/dl. If you set the pump to +/- 0 it will always calculate your correction to target.

Permalink Reply by Kelly WPA on May 5, 2011 at 6:51pm

Here is a write up Gary Scheiner did explaining different pumps calculations for IOB.

http://www.diatribe.us/issues/22/thinking-like-a-pancreas.php

Permalink Reply by Zoe on May 6, 2011 at 8:52am

Thanks, Kelly. I usually don't click on links, but that one is a good reference (and explains why it's not easy to answer this question!). For me, the best advice is to always look at the recommendations and then to make your own decision based on trial and error (experience).

Permalink Reply by Kelly WPA on May 6, 2011 at 9:43am

I have a feeling that people that switch from one brand of pump to another have the hardest adjustment because they were used to doing it one way and now they have a new pump that does it differently.