Tweak the basal or the carb ratio?

Please help me think this through. I’ll call the endo Monday, but I need to puzzle this stuff out for myself first.

My son (13 next week) has been on the pump for almost 2 weeks. His basal rate currently is the same all day & night. He’s staying pretty stable, but he’s stable at a little higher than I think he should be. The endo is happy with his numbers, because he is always “in range”. I’d like him to settle in around 100 most of the time, and he’s been closer to 110-115 before meals. At bedtime, if he’s below 100, he has a small snack; if he’s over 100, he doesn’t snack. He’s been pretty consistently waking up around 115 snack or not. When he was on shots, he was waking up around 95-100 most of the time.

So, if his basal is keeping him steady, should we tweak his I:C ratio a bit to bring his numbers down a smidge and then the basal will hold him steady at that slightly lower level or do we need to turn up the basal a little?


The basal.

I agree with Gerri, tweak the basal. You should have that set at the levels you want to be (or your son to be) without food or bolus insulin working.

Basal without a doubt. Aside from bringing down his fasting BG levels, it will tend to smooth out the postprandial curve some by mimicking some of the background insulin production that occurs when non-diabetic people eat (it involves some neural signaling mechanisms that my endocrinologist attempted to explain when I asked him about basal and I:C interplay).

I’ve been yutzing w/ mine of for a while and it my BG drifts down when I’m at .85U/ hr and up when I’m at .80/ hour. For a while I had little “bumps” when I’d eat that would put “tails” on a lot of boluses and then I got the rates to .85 or .80 and it seems to be that neither way is quite as precise as I’d like. I’d love to get a .825 capable model to see what would happen but I recall you were something like .3U/ hour or so so that may be a bit dicier, since the “bump” up would be a bigger %age of each hourly dose than adjustments for me? It sounds like you guys are watching it closely.

First of all, you’re doing an awesome job, especially for only 2 weeks on the pump!

His basal rates should keep his bg where you want it without food. If he’s a little higher than you’d like, raise the basal a little. He may also need different basal rates for different times of day. I think you said you have a Ping? If you aren’t already, download the data from the pump and you’ll be able to see patterns for different times of day. Just don’t tweak too much at a time, go slowly :slight_smile:

What is his target BG? If you want him around 100, his target in the pump should be set at 100.

Thanks - basal is what I was thinking, and you all confirmed that. His current basal is .325/hr, so he can go to .350 which is less than a 10% increase. I think we’ll try that for a few days, at least during daytime hours, and see what happens. His basal rate was derived from taking his daily lantus number (10 units), reducing that by 20% (to 8 units), then dividing by 24 hours. That resulted in .3375, which the pump can’t do, so the endo rounded down to .325. I’m thinking going up to .350 shouldn’t be too crazy of a move.

Jrtpup - thanks for your kind words - we’re trying our best! To answer your question, the target on his pump is set at 100 during the day and 120 overnight. I have mixed feelings about the overnight number (the endo picked it, not us). I think it’s a little higher than it should be, but I can sleep at night knowing there’s a little larger margin before he would go low. I have downloaded the pump and the only real pattern I can detect is that he seems to rise a bit (10-15 points) after being asleep for 3-4 hours and stays close to that level until he wakes up. He hasn’t been eating right away, and he tends to drop back down to around 100 within an hour or so of waking up. I guess that would argue for raising his basal overnight, but he is in that 120 range (generally 110-125 at 3am & 6am), so really, given that number, his basal is fine. I guess we need to determine whether 120 overnight is really where we want him to be.

Thanks for your input!

What you don’t say is what his numbers are like two hours after meals. You would want to tweak his I:C ratio only if those postprandials are high. You wouldn’t tweak his I:C ratio to control other times of day. His numbers sound very good to me (especially for an adolescent!), but if you wanted him to wake up a bit lower in the morning, you would want to tweak the period of time a couple hours before he gets up, or whenever you perceive it as rising. Most of us have varied basal rates, because we experience highs or lows at specific time periods, but whatever works! Again, his numbers sound good! Many of us would kill for that kind of stability. My guess, though is he is still in his honeymoon period so it may start to vary after awhile.

Generally, he’s around 120-150 two hours after he eats, which varies a bit depending on what he ate. When he was on shots, he was taking his shot after his meal (per the doctor), but now that he has the pump, I’m having him bolus before he eats then “top off” if he eats more than he bolused for. I can’t tell that it’s made a big difference in his numbers, though, but that might be because his basal isn’t quite right. I felt like we had the lantus dialed in pretty well, but it sounds like his basal on the pump needs some minor adjusting. He’s definitely running a bit higher overall than he was on shots.

He is definitely still honeymooning, and his numbers are usually very good and pretty easy to manage. He and I tweaked all his dosages and ratios for his shots and got him in a good groove, but I’m a little less confident about changing his settings on the pump. I’ll get there, and I’ll hopefully come up the learning curve quickly, but it’s tough to manage someone else’s body! I really feel for parents who have tiny ones with this disease. At least my son is old enough and mature enough to be part of the process.

Thanks for chiming in!

It definitely takes awhile after the switch from shots to pump to get all the numbers right. Some people do formal basal testing which is recommended first before changing I:C ratios. I didn’t feel the need to do that, but I could see patterns where I was low at some times and high at others and so kept tweaking the basals and the “time zones” until it was perfect. Since you can change by such small increments it really felt much more precise than with long-acting insulin where I’d go up one unit and then I’d be low, then down one unit and be high. You can also see the results more quickly. It felt like a puzzle to me and when it fell into place it was just right. I kept careful records of when I tweaked up or down and the new “time zones” I created. For me the main adjustment going from shots to pump was the basal, my I:C ratios didn’t change. (until recently when I got on Symlin and cut them in half, that is!)

As for the timing, I have found 15-20 minutes pre-bolusing before I eat gave me the best results because the insulin had time to start working before the food hit.

Yes, I can only imagine how much more complicated it is doing it for another person, but easier if they are old enough to participate. Unless they were like me as a teenager…if my mother had told me to take more insulin I’d rebel and take less…lol. Sounds like you both are doing a great job.

I also found the MM Carelink Charts very useful in figuring out which little numbers need to be tweaked? The breakdown by time isn’t 100% accurate, particularly when I was involved in stuff until 8:00 and later several nights/ week but it offers an objective perspective that washes out some of the eek numbers and highlights the trends.

My bet is that the endo is going to tell you not to bump either the basal or the carb ratio. As jrtp and Zoe have said, your son’s numbers are very, very good for a teen just starting on the pump and your endo is likely to be more than satisfied. If you son is honeymooning, the whole process is probably going to get much tougher very soon. You might want to save your efforts for that next battle.

Whatever you do, take pleasure in how well your son is doing with your help.


Physical activity can use up glucose quickly. So you presumably don’t want your son having lots of hypoglycemic episodes when he suddenly decides to go out and play some ball. All just to keep his numbers 10 points lower when they are already superb. I agree with Maurie. I would hold off changes until you see the endo but that is me. I hope he carries glucose tabs or some hypo treatment at all times, just in case.

As you say it has only been two weeks and these things take time to get used to. It sounds to me (and the endo) as if he is doing reasonably well, and if he is in range then all well and good.

To set a target that YOU want him to be at is unrealistic. Blood sugars go up and down throughout the day, and remember he is a growing child with growth, angsts, hormones, diabetes to deal with and it is hardly surprising that he might go up and down a bit. Cut him some slack and give him lots of praise and encouragement, but do NOT go “You should be (such and such) number and if you are not you have failed!” This is not only discouraging for the child, but likely in later life to cause rebellion. I am a true believer in celebrating a child’s successes and playing down the not such good numbers. It is a fickle illness and sometimes it will go up for no known reason at all.