Basal test

Diabetes Technology Insulin Pumps
#1

So, the past two days I skipped breakfast to run a basal test. These are the results I got.

June 12:

3:00 - Basal rate 1.30 u/hr
6:30 - 6.3 (113)
7:30 - 7.2 (130)
8:30 - 7.1 (128)
9:00 - Basal rate 0.85 u/hr
9:30 - 6.4 (115)
10:30 - 6.4 (115)
11:30 - 4.8 (86)
12:30 - 4.9 (88)

July 13:
3:00 - Basal rate 1.30 u/hr
6:30 - 6.5 (117)
7:30 - 6.1 (110)
8:30 - 6.3 (113)
9:00 - Basal rate 0.85 u/hr
9:30 - 5.6 (101)
10:30 - 5.4 (97)
11:30 - 6.3 (113)
12:30 - 6.3 (113)

According to John Walsh, if your BG changes by 1.7 mmol/L or more you should adjust your basal rate. Looking at the first day, my blood sugar dropped by 2.4 mmol/L throughout the morning. So that would lead me to think I need to lower my basal rate. Yet the second day I stayed essentially perfectly flat.

So if I lowered my basal rate it might fix that first day, but it would make me go high the second day. And if I don't lower my basal rate I'd be fine on the second day but would easily go low on the first day. These two mornings were literally identical in that I got up and went to work, and in both cases I hadn't eaten or corrected BG in over eight hours.

From the second test I'd say my basal rate is fine - yet if it can drop (and probably rise) by 2.4 mmol/L on some days, then no wonder I have random highs and lows. I'll probably do another test on the weekend to see what happens.

#2

What did you eat the night before, how late, and how much?

My insulin needs for hours after I wake up (as well as before, with DP) are drastically impacted by the previous evening's mastication party.

If I'm a good boy, eat a healthy, low-carb dinner at, well, dinner time (5-8pm), then quit for the night, I'm real good the next morning.

If I'm really bad and pig out at 10-11 with a bedtime "snack" () then I can count on pouring insulin in my body for hours the next morning. Although I properly account for the carbs with a bolus with the snack, somehow that glucose finds some way to "hide" in my liver and then come out guns-a-blazin' the next morning.

#3

Both prior nights were chicken with 1/4 cup of gluten-free pasta and tomato sauce (about 45g in total). Dinner was around 6:00 PM, and I didn't eat anything after that.

Due to being at risk for acid reflux, and acid reflux risking making my allergic throat issues (EoE) and asthma much worse, I've been instructed to not eat anything for 2-3 hours before bed and to quit caffeine, both of which I do. So I basically never eat after dinner unless I'm low.

#4

So I was thinking back to yesterday morning and this morning and truly the only difference I can think of is that yesterday morning I took a bus from the train station and then walked from the bus stop to work and this morning I took a shuttle from the train station directly to work. The walk from the bus stop takes 10-15 minutes depending on how long I have to wait at intersections. I know you're not supposed to do moderate or intense exercise during a basal test, but this was hardly even exercise (I don't walk fast enough to get my heart rate up), and because I take public transit it's impossible for me not to walk a few blocks at some point during the day. I wonder if this could have been the reason for such a fall.

#5

FYI...A 15 min walk would lower my BG 20-30mg/dL (1.6mmol/L).
I don't see any big swing in your fasting BG...JMHO..

A 10-15 min walk would be a significant factor in calculating my morning basal....I cannot walk around the block without doing a temp basal or eating a small snack when my BG is in target range (90-110).

#6

Interesting. Is this even for leisurely walks? Do you plan ahead for it? I definitely can't walk 15 minutes when I have insulin on board, but didn't think it would have such a big impact with just basal. It's hard because I don't "plan" on walking like I do with exercise - it's just something I do throughout the day. It would be like everyone else having to plan a temporary basal rate each time they jumped in the car to go to work or run an errand. :\

I don't notice any huge swing either, other than the first day drops (equivalent to 43 mg/dl) and the second day doesn't. Trying to make sure my pump settings are right so that I can fix them if they're not and hopefully get my blood sugar better controlled. Even though my blood sugars are lower in general, and food-wise I've been weighing and measuring everything, my standard deviation is still about 3.6 (65) which means I have highs and lows every day that I and my endo can't find any pattern to. If my pump settings are right then I'll probably just settle for what I have, since the only other option would be to eat low-carb which I can't do due to food allergies.

I was going to fast again this morning but I woke up at 11.1 so will do it tomorrow hopefully.

#7

I think the earliest days of a pump reservoir run a shade hotter than the subsequent ones. I have never kept track of it but slight variability caused by zippier insulin might explain the result too.

#8

Hmmm. I did change my cartridge today. The 200u Animas cartridge lasts me 3-4 days (it's really more like 150u after filling tubing such). But I usually have my insulin in the insulin pen I have in my bag, so it's out of the fridge for a while before I put it in the cartridge. Does the cartridge do something to it that makes it's potency fade a bit?

#9

Hey Jen! I think youre on the right track, but Ill add my .02.

First, when do your basal test, it needs to on a night where nothing out of the ordinary happens. No extra or less exercise, for example. Also, you want to start your test 4 hours AFTER your last meal and/or bolus. And make sure your last meal was not overly fatty. In other words, you want ZERO IOB and ZERO undigested food. Also, no caffeine, even decaf. Water, sugar free jello, and sugar free popsicles for the most part only.

Looks like your testing times are OK. I would try for hourly if you can. Its a PITA but very useful.

Also, I would avoid doing the test on the same day you change your set, or on the last day for best results.

I would suggest 3 tests, then average the three to see your differences. I would never make a change based one test.

Hope that helps!

#10

Thanks! I looked up the "rules" before doing this and followed all that I know of - the days prior had no weird highs or lows, it was 8+ hours after any meal or IOB, no overly fatty food, and no caffeine (I don't drink caffeine, even decaf, I only drink herbal teas). I actually didn't eat at all during these tests.

Do you mean you would try for half hourly tests? I tested hourly above, starting from when I woke up.

I change my set every two days (I use metal sets), so unfortunately it's either going to land on a day that I do a site change or on a day that I'm scheduled for a site change. But I would avoid doing a site change during the actual test.

This test was more a test of morning basal rates rather than overnight. I'm pretty sure my overnight basal is fine. I believe in order to do an overnight basal you have to eat an early dinner and then test every two hours or so throughout the night.

I think you are right abut three tests. I'm going to try and do a test on Monday (I'm eating dinner late tonight, plus have had some weird allergic reaction issues today which might mess things up), and then I'll do changes (or not) based on the two that seem the most similar.