I’m using my pump with saline now to get used to the settings. I’ve been quite confused by the EZcarb suggestions. I know I can override it and bolus what I want, but I do want to understand the suggestions. I didn’t get the recommendation so I made up a round number example. I input that my current BG was 120. My target blood glucose is also 120. My dinner I:C ratio is 1:18 so I input that I was eating 36 carbs. It recommended I bolus 2.0 units. I don’t get that. If my I:C ratio is correct does that mean I would end up exactly where I started? For two years of MDIs I’ve thought of my I:C ratio as meaning I would rise a nominal amount, say 30 points and stay under my target goal. Have I been misunderstanding it all along?
No . . . you haven’t been missing it. . . as your blood sugar can still rise after meals on a pump . . . but it is easier to fine tune and adjust your basal and bolus with tiny increments of insulin that help decrease the amplitude of blood glucose excursions.
Your example sounds right to me. What were you expecting? On both shots and the pump I want the pump to give me 100% of the calculated dose for all carbs unless my bg is markedly below my target. I have my target set to 100+/- 10. Any correction the pump gives is calculated to return bg to 100 but only gets triggered at bgs less than 90 or over 110. If my bg is say 82 the pump will subtract a little from the carb bolus to bring sugar up to 100. I will often over ride this to get a full dose for carbs though. If I’m over 110 then the pump will calculate a dose that brings the sugar back to 100.
I expect blood sugars to rise after a meal peaking in an hour or two (unless its pizza) but returning back to baseline after 3 or 4 hours. If that happens then I assume my I:C is correct.
Like Diana said, your example sounds right. Since your target is 120, it won’t offer you a correction bolus. If you put your BS in at 150, it would do a calculation to bring your BS back down to 120. If you want it lower than 120, you would either have to change your target range or do the calculation manually.
When I first got my pump this summer, Cheri told me about Danny’s TAGger’s group. You can get tips how to use the extended bolus for protein & fat. It has really been a big help for me. You can check that out here http://www.tudiabetes.org/group/tagers
Ok, I’m still a little confused. What Diana said is that blood sugars rise and peak in an hour or two and return to baseline after 3 or 4 hours. Doing shots I test my blood sugar at the two hour point and that is what I think of as my target time - I aimed for below 140 at 2 hours because I don’t want peaks higher than that. When the pump responds to the target goal is that for 3 or 4 hours later? The “Duration of Insulin”? That would make sense, because that is when it should return to normal. But I still plan to test at 2 hours. And that is how I determine if my I:C ratios are working well (and if the foods I eat are ok). Do you think of it differently with the pump? (And I can also see setting the number lower if it is not for the two hour mark)
Like just now before breakfast: My I:C is 1:7. I have 28 carbs. My BG before is 82. Doing shots I bolused 4 units. Than I checked the pump and it said 4 units minus some for " bg" and advised 2.75. I would be high at the 2 hour mark if I only used 2.75. So I need to reduce my targets??
It will really depend on what your goals are and what you have your insulin duration set for – that can vary depending on what kind of insulin you use and how your body work with that insulin. I use Apidra and have mine set for 2.5 hours but I know someone else that uses Apidra and he has his duration set for 4 hours because that is what works for him.
I am a little “anal” (and I am sure some people will say that is more than a little!) and check my BS every hour. If I put my BS into the pump after 1 hour, it will take in account how much IOB I have. If there is more IOB than what would be needed to get me back to my target, it won’t recommend a correction. If my BS is high enough to need a correction bigger than how much IOB I have left, then it will come back with a recommended correction. Since I have my duration set at 2.5 hours, my insulin gets used up faster than someone that has their set for 4 or 5 hours.
Ok, so let me see if I understand: My duration is set for 3 hours (I also use Apidra). So I was at 82 when I sat down for my 28 carb breakfast. At a ratio of 1:7 I know from experience that if I take 4 units I will be in range (under 140) by 2 hours later when I test. I set my blood glucose target for 120 because I’m hoping to tighten up my numbers with the pump. So when the pump suggested only 2.75 units it was looking at my being under 120 at 3 hours, rather than the 2 I look for. Am I understanding that? If I only bolused 2.75 units I would be too high at the two hour mark.
So if, in fact, I want to be let’s say under 120 at 2 hours I need to set my target lower (like maybe 100) because the pump is referring to target as the 3 hour duration mark?
Sigh. I need to go back and read more Pumping Insulin. This is really a paradigm shift! Thanks for helping me understand!
When you went to eat breakfast, you most likely did not have IOB. One thing I don’t like about Animas is that it subtracts insulin from what you need for your carbs if you are under your target. It is not looking at what you will be in a couple hours but what you are right now. It is kind of saying that if you take less insulin for the carbs, that will bring you up to 120. Most likely, you just want to stay even and no go low or high. I am like you and I know that I need x amount for a certain meal or I will go high.
The IOB would come into play if you need to make a correction bolus for what your BS is. You can do that thru the BG bolus or when you go to enter carbs. The IOB won’t come off any actual carb boluses.
Here is a link that Gary Scheiner explains the IOB features of different pumps (he is the Think Like a Pancreas guy). He can explain it better than I can!
You’re on the right track. Here’s how I think of it. The pump has no way of knowing if that blood sugar is premeal or post meal even though you can flag them pre/post in the ping. If your target is set to 120 then the pump will want to do a correction to 120 all of the time whether you just ate or are fasting or 2 hours after or 3 hours after eating. The pump can’t know that.
What the duration does is determine how long your previous bolus is active. So if you have it set for three hours and you check your insulin on board at 2 hours you’ll have a little bit insulin still working. Animas does a curve linear calculation so it’s not 1/3, 1/3, 1/3 but to make it easier to explain I’ll use a straight calculation as an example. Let’s say you give a 3 unit bolus at 8 am. At 9 am your insulin on board will be 2 units, at 10 am it will be 1 unit, at 10:30 it will be 0.5 units and the bolus will be all gone at 3 hours. That’s all the duration does. If you need a correction any time a previous bolus is active then the pump will subtract insulin on board from a correction only.
I find it easier to set my pump target to a premeal target bg and to manually adjust for post meal corrections on the fly. You can either do it in your head or on the bolus details screen you can arrow up and change the target and get a precise calculation for what you want your 2 hour post meal target to be.
If your target is set too high the pump will tend to shave off too much from carb boluses when your bg is lower. If you set it too low you’ll get really aggressive corrections for highs. Setting a target with a range will help reduce some of that though. That’s why I have my target at 100 with +/- 10 points. I’ve been thinking about changing that to +/- 20 to reduce negative corrections even more.
Thanks, Diana and Kelly. I think I understand it better now. It was the first thing that feels sort of counter-intuitive to me and is a shift from how I am used to thinking about things with shots. I was assuming the pump knew I was pre-meal since I was inputting carbs. It does still sound like it is looking at the Duration of Action, when it tells me to take less for my carbs, because then I will be at my target after the insulin is done working. But I will spike before that if I take less insulin. It seems like that subtraction or addition of insulin would be important if I were really low before eating or really high, but not when I am at a good number. So I will just ignore it then.
I think I’m more familiar with the IOB concept as I always computed that for shots. But I’ll not assume I know how it works with the pump and will read the link you sent, Kelly. Thanks a lot you two. I’ll not go and sit quietly in the back until the next thing that boggles my poor brain!
Another thing need to understand is that a Target BG set for +/- 10 (as the preset Targets are set) tells the pump not to calculate a correction if BG is within 10 mg/dl above or below your target BG . . . So if your target is set at 100 mg/dl +/- 10, the pump will not calculate a correction if BG is between 90 and 110 mg/dl.
Also, you cannot know how your body will respond to insulin from a pump until you start using rapid acting insulin to replace your long acting basal insulin. Believe me . . . everything you know about your body and the way it responds to insulin will change once you begin using basal insulin in your pump! And the degree of “insulinization” you have from your basal insulin, prior to a meal, greatly impacts the way your body responds to bolus insulin. Fine tuning basal rates to your bodies’ circadian pattern is therefore an essential element of controlling post meal spikes.
Thanks, Leilani. I hadn’t really thought of the impact that the change in form of basal insulin could have. I do understand how important it is to make sure my basal rates are correct. They are starting me at a lower dose than I now use, so I’ll see where that puts me. Thanks for your input!
