For reasons not under our control (PM me to ask what happened in more detail), we have stopped using openAPS for the past week and are back to manually pumping and giving corrections (essentially, using sugar surfing) instead of looping. I thought this would be a disaster but surprisingly, his blood sugar has actually been MUCH better and I’ve enjoyed a ton about it. The past 7 days his average BG was 116 with an SD of 40; the prior week with openAPS running it was 139 with an SD of 55 – so same number of lows basically but with many more highs.
Here are some of the unexpected benefits of manual-mode pumping:
a) Without seeing his IOB and without the potential to give him remote boluses, I am simply less tempted to make lots of little tweaks during the day, meaning I’m paying a little less attention to his BG (I still get low alerts, but that’s it). This has been so good for my mental state; just feeling like my brain was less cluttered.
b) Without openAPS (and in particular, autotune and autosens) running, I can see very very clearly which parameters are off. Before, with so many factors changing all the time it was really difficult to deduce which things were wrong or would make the most difference. We also had certain parameters that we knew were not optimal for manual mode ,but we kept them because they seemed to work best with looping.
- For instance, we had his basal rate set to about 5 units per day, knowing this was too high most days but trusting that openAPS could ramp down from this higher rate when it was not needed and then ramp up on the days when his insulin resistance went way up. But this was more of a hack to get openAPS to work best for things like covering meals. For instance, openAPS will not issue microboluses for meals if your max basal rate in the day is lower than 0.3 units per hour, so we had periods with this rate.
But it’s become glaringly obvious that this basal rate is simply too high. My guess is that he’ll settle in around a basal rate of about 4 units per day; right now it’s at 4.3 units per day. Once we truly isolate a better basal rate, we can work on tweaking factors like sensitivity and carb factors. My hope is that we can somehow find a set of parameters that both work in manual mode AND for openAPS
c) THE BIGGIE: openAPS allowed us to be sloppy when bolusing for food because it did a good job of preventing spikes into the 300s. Instead of just bolusing for a whole meal upfront, we would bolus for half knowing that openAPS could pick up the slack by issuing super-microboluses. But often times this led to persistent highs or highs followed by lows. Now that we know we can’t go back and “revise” our meal boluses, we have become much more attentive. And not surprisingly the results have been much better!!! This also gives us confidence that our carb ratios aren’t totally off.
d) TEMP BASALS. openAPS issues temp basals to moderate insulin levels, and the algorithm updates every minute or two. So, you can’t manually set a temp basal for foods that are slow digesting, because openAPS would simply overwrite that temp basal a minute later.
But some foods really do need a slow, sustained, higher basal rate over a period of hours. The hacks that openAPS uses to mimic temp basals never worked well for us. For instance, you are told to set a temporary low target (such as 80 mg/DL) or log extra “phantom” carbs for foods like pizza 2, 4 or 5 hours after eating, and that should prompt the algorithm to pile on extra insulin. But it usually didn’t ramp up quite enough or at the right times; we needed to log something ridiculous like 300 g of carbs to get the desired effect! Now, I can just set a temp basal for 0.6 units per hour for 6 hours, and Samson’s BGs have been perfectly flat or with just a slight rise after eating 130 g of carbs!! The constant temp basals just seem to work better for pizza, cake and other fatty foods.
Which brings me to my last benefit
e) Flatter profiles with less swings. When openAPS predicts a low, it often “zero temps” a person for an hour or two after meals, effectively turning most boluses into super boluses. But we often had a problem with Samson being flat after a meal, only to rise an hour or two later. I now suspect hat is because openAPS was subtracting some of his meal insulin soon after he ate, predicting a low. Now we have much flatter landings to normal. Also, when he got low treatments, it was usually after he’d been zero temped for a while… meaning that after he ate the low treatment he usually spiked much higher… which meant openAPS predicted a high… which meant he got a pile of insulin after a low treatment. Unfortunately, fast-acting carbs are fast-in, fast-out for him and take less insulin than the equivalent number of carbs in a solid meal, so those quick spikes led to yo-yoing highs and lows with tons of low treatments. Without the zero temping before a low, he isn’t spiking as high. And without the automating high temping after the spike, he isn’t yo-yoing.
In general, it seems like Samson’s BGs have seen a lot less wandering – even without the highs and lows, when he’s flat he’s flatter than he was with openAPS. I think all the turning on and off of temp basals had some unpredictable effectsin him because he uses such low basal rates, and so it was creating a less flat insulin delivery profile than was optimal for him… At least, that’s my impression
The downsides:
NIGHTTIME: We currently have Samson’s night profile set to 0.075 units/hour, and last night I had to give him 3 carb treatments to keep him in range. But a nighttime rate of 0.05 units/hr has him rising steadily. Other nights he’s been high for several hours and there is nothing gently bringing him down. openAPS really did well at nights at keeping him in range. I suspect the optimal nighttime dose is something like 0.065 units/hr, which is not attainable on the pump but which openAPS can pretty naturally accomplish.
SICK DAYS: So far, Samson has not been sick so his daily use of insulin is on the lower end of his habitual use - maybe 7 to 9 units. But I have no idea how manual mode will fare when he all of a sudden starts needing more insulin. When he’s sick he can use 14 units easily. I suspect I’ll have to go to daycare a lot more when he comes down with a cold.
MEAL SPIKES: Right now Samson’s basal rate is clearly too high, which means that there’s always something pulling his BG down if we, say, bolus for his food after a meal. But I wonder if we’ll have to start doing things like pre-bolusing or risk seeing much higher spikes once his basal rate is dialed in properly. It also means that when we miscalculate in a restaurant, we have to step in much sooner to prevent that 300 mg/DL spike that lasts for hours.
I’m not sure if the problems I noted with openAPS are truly intractable, or are due to the fact that Samson uses so little insulin each day and so the openAPS safety settings, etc. just don’t work well (in which case, it might make sense to dilute insulin). Or it may be that openAPS simply exacerbated poor tendencies on our part (like sloppy bolusing).
in any case, we will probably set up a new rig for him in a few days…but I’m feeling a bit ambivalent. I’d love to get my nighttime sleep back but other than that, life has been a lot simpler without all the extra fiddling with knobs on openAPS. If we do get another rig up and running, perhaps I should create a thread about reevaluating all his settings and troubleshooting it anew…
. Well, not exactly every hour; we are doing two to three hour stretches oscillating between 0.05 mg/DL and 0.075 mg/DL, based on when he is likeliest to crash. But the same idea as you describe. He was pretty flat last night but it’s hard to say if the new settings are right: His sensor is also on the fritz. For instance he was 73 last night and I tested and he was 171 and 148 mg/DL on two different finger sticks. So it’s still a little too early to see if that works.