Month: March 2018

Exploring other sensors that could be used with #OpenAPS and for diabetes in general

by Dana Lewis

Nobody appeared to notice the other day when I tweeted about going through airport security with 13 pieces of adhesive on my body. Which is amusing to me, because normally I sport two: my insulin pump site, and my continuous glucose monitor (CGM) sensor. That particular day, I added another diabetes-related piece of adhesive (I was giving the Freestyle Libre, a flash aka not quite continuous glucose monitor, a try), and 10 pieces of adhesive not directly related to diabetes. Or maybe, it will be in the future – and that’s what I’m trying to figure out!

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Last fall, my program officer from RWJF (for my role as PI on this RWJF-funded grant – read more about it here if you don’t know about my research work) made an introduction to a series of people who may know other people that I should speak to about our project’s work. One of these introductions was to a researcher at UCSD, Todd Coleman. I happened to be in San Diego for a meeting, so my co-PI Eric Hekler and I stopped by to meet Todd. He shared about his lab’s work to develop an ambulatory GI sensor to measure gastric (stomach) activity and my brain immediately started drooling over the idea of having a sensor to better help assess our methods in the DIY closed looping community for articulating dynamic carb absorption, aka how slow or fast carbs are absorbing and therefore impacting blood glucose levels. I took over part of the white board in his office, and started drawing him examples of the different data elements that we have #OpenAPS (my DIY hybrid closed loop “artificial pancreas”) calculate every 5 minutes, and how it would be fantastic to wear the GI sensor and graph the gastric activity data alongside this detailed level of diabetes data.

I immediately was envisioning a number of things:

  • Assessing basic digestion patterns and figuring out if the dynamic carb absorption models in OpenAPS were reasonable. (Right now, we’re going off of observations and tweaking the model based on BG data and manual carb entry data from humans. Finding ways to validate these models would be awesome.)
  • Seeing if we can quantify, or use the data to better predict, how post-meal activity like walking home after dinner impacts carb absorption. (I notice a lot of slowed digestion when walking home from dinner, which obviously impacts how insulin can and should be dosed if I know I’ll be walking home from dinner or not. But this is something I’ve learned from a lot of observation and trial and error, and I would love to have a more scientific assessment of this impact).
  • Seeing if this could be used as a tool to help people with T1D and gastroparesis, since slowed digestion impacts insulin dosing, and can be unpredictable and frustrating. (I knew gastroparesis was “common”, but have since learned that 40-50% of PWDs may experience gastroparesis or slowed digestion, and it’s flabbergasting how little is talked about in the diabetes community and how few resources are focused on coming up with new strategies and methods to help!)
  • Learning exactly what happens to digestion when you have celiac disease and get glutened.
  • Etc.

Fast forward a few months, where Todd and his post-doctoral fellow Armen Gharibans, got on a video call to discuss potentially letting me use one of their GI sensors. I still don’t know what I said to convince them to say yes, but I’m thrilled they did! Armen shipped me one of the devices, some electrodes, and a set of lipo batteries.

Here’s what the device looks like – it’s a 3D printed gray box that holds an open source circuit board with connectors to wearable electrodes. (With American chapstick and unicorn for scale, of course.)

DanaMLewis EGG for scale

And here’s what it looked like on me:

DanaMLewis wearing an ambulatory EGG

The device stores data on an SD card, so I had many flash backs to my first OpenAPS rig and how I managed to bork the SD cards pretty easily. Turns out, that’s not just a Pi thing, because I managed to bork one of my first EGG SD cards, too. Go figure!

Sticky notes with data scratched out and a USB stick with data from non-diabetes science experiments

And this device is why I went through airport security the other day with 10 electrodes on. (I disconnected the device, put it in my bag alongside my OpenAPS rigs, and they all went through the x-ray just fine, as always.)

Just like OpenAPS, this device is obviously not waterproof, and neither are the electrodes, so there are limitations to when I can wear it. Generally, I’ve been showering at night as usual, then applying a fresh set of electrodes and wearing the device after that, until the next evening when I take a shower. Right now, hard core activity (e.g. running or situps) generates too much noise in the stomach for the data to be usable during those times, so I’ve been wearing it on days when I’ve not been running and when I’ve not been traveling so Scott can help me apply and connect the right electrodes in the right places.

This device is straight from a lab, too, so like with #OpenAPS I’ve been an interesting guinea pig for the research team, and have found even low-level activity like bending over to put shoes on can trigger the device’s reset button. That means I’ve had to pay attention to “is the light still on and blinking” (which is hard since it’s on my abdomen under my shirt), so thankfully Armen just shipped me another version of the board with the reset button removed to see if that makes it less likely to reset. (Resetting is a problem because then it stops recording data, unless I notice it and hit the “start recording” button again, which drives me bonkers to have to keep looking at it periodically to see if it’s recording.) I just got the new board in the mail, so I’m excited to wear it and see if that resolves the reset problem!

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Data-wise, it’s been fascinating to get a peek into my stomach activity and compare it to the data I have from OpenAPS around net insulin activity levels, dynamic carb absorption activity, expectations on what my BG *should* be doing, and what actually ended up happening BG-wise. I wore it one night after a 4 mile run followed by a big dinner, and I had ongoing digestion throughout the night, paired with increased sensitivity from the run so I needed less insulin overall despite still having plenty of digestion happening (and picture-perfect BGs that night, which I wasn’t expecting). I only have a few days worth of data, but I’m excited to wear it more and see if there are differences based on daily activity patterns, the influences of running, and the impact of different types of meals (size, makeup of meal, etc).

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A huge thanks to Todd, Armen (who’s been phenomenal about getting me the translated GI data back in super fast turnaround time), and the rest of the group that developed the sensor. They just put out a press release about a publication with data from one of their GI studies, and this press release is a great read if you’re curious to learn more about the GI sensor, or this news piece. I’m excited to see what I can learn from it, and how we can potentially apply some of these learnings and maybe other non-diabetes sensors to help us potentially  improve daily diabetes management!

RIP, original looping pump

by Dana Lewis

In 2014, a lightbulb went off. We could use Ben’s code to read and write to a particular version of an old pump. We had built an algorithm to take is input carb, BG, and insulin dosing data, and to output recommendations for action. If we hooked those together, we could close the loop. We could close the loop? Cool! We should try that. But wait – I didn’t have a compatible pump..

This is another place social media played a role in the story that is #OpenAPS. I posted on Facebook asking if anyone had one of these older model pumps sitting around unused, because we wanted to use it for research and try to close the loop. Would anyone dust off the dust bunnies on one and share? The answer turned out to be yes. A very kind person sent me the pump, we put it into play, and we closed the loop. I put the pump on, and the rest is history. Yay!

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A year ago, I noticed a broken piece of blue plastic on the carpet of a hotel room. “Hey, that looks like my pump color…” “!!!! A piece of my pump broke off!”. Luckily, it was the upper edge of the reservoir; it did not impact usability of the pump; I taped it back on and continued to tape it over time. I thought eventually this, or other cracks or other physical broken pieces, would be what eventually would be the cause of failure of this beloved, well-used second-generation pump.

The edge of my pump's reservoir section broke off and I tried to tape it back on.

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Some history for those who don’t know the backstory: we’re talking about using older generation pumps because it was discovered that someone (if in range, and with the right equipment) could remotely command the dosing of the pump. This was discovered by a security researcher, and the FDA had the manufacturer fix this in a future version. Thus, more modern pumps you couldn’t remotely set temp basals on, or remotely bolus. Turns out, that “hole” is what enabled us to close the loop: the ability to remotely set temporary basal rates. That is a risk. Some people don’t like that risk, and choose not to DIY closed loop because they don’t want to accept that risk. That’s fine. Other people decide that the reduction in the baseline risks of diabetes due to DIY closed looping outweigh any additional risk, and with appropriate safety guards like backup alarms, hardware and software dosing limits, etc. decide to use these pumps regardless. “YDMV” (your diabetes may vary) applies to what devices and systems you choose to help you with your diabetes, too. I personally choose to use these devices to close the loop, but acknowledge not everyone wants to – and that it shouldn’t have to be this choice that drives (for some people) whether or not to DIY loop. That is why I’ve had active conversations with every pump manufacturer for going on 4 years now about the need to have secure but documented communication protocols: I would love for people (including myself) to be able to have a secure, safe in-warranty pump with which to close the loop. Now: I’m only one person. I haven’t been able to move the needle on this myself. I’ve asked and encouraged (see this visual in the OpenAPS docs) members of the community to also take up and advocate for this. And people have. But I think it’s going to take the resources of something like the JDRF Open Protocol Initiative to really get companies to finally focus on this. And hopefully this will make the infrastructure changes needed to make it possible to achieve the vision of having a secure, in-warranty modern pump (and one that comes with the ability to choose your preferred CGM and preferred closed loop algorithm, too!).

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I’ve continued to cut and apply sensor tape “pump bandaids” over the last year. But something changed about a month ago: suddenly, with normal AAA battery changes of the pump, the pump started losing the time settings with every battery change. (And battery changes happen more frequently with DIY closed looping because we communicate so frequently with the pump; mine go around ~6+ days). At first I thought I was just too slow in changing the battery. But even with a lightning quick battery change, the pump would lose the settings. No big deal…except that every time it required me to reset the clock, rewind, and reprime. Which meant drops of lost insulin (ugh), and a hassle overall.

I lasted about a month before I decided to give up. Not only was the change and reset process a pain, but because the internal battery that maintains settings when you change the AAA is apparently dying, it also means that some of the history gets wiped from the pump. Again – not a big deal because I’m uploading everything from the pump to multiple places every 5 minutes, but it is still annoying. It makes it hard to skim back through the last month on the pump to analyze how much insulin I’m using on average, when every 6 days two days get blotted off the pump’s record.

@DanaMLewis switches pumpsAnd so, I threw in the towel (sadly) last night on this beautiful, long-lasting work horse of a pump that I’ve been using for 3.5+ years. I have such an emotional tie to it because it’s what enabled me to close the loop. It’s what led us to be able to share DIY closed looping with the world. And because of the reality of using (mostly*) second hand pumps for DIY closed looping, throwing the towel on a partially busted but still-kind-of-usable loopable pump feels wrong when there are lots of people who are desperately looking for pumps so they can close the loop for themselves.

* I say mostly, because there are in fact other kinds of DIY-compatible looping pumps – they’re just not approved or available in the U.S. where I live. The DANA*R or DANA*RS pumps (made by SOOIL, they have nothing to do with me!) have bluetooth capabilities built in, so they can communicate with an Android phone. They’re very popular and usable in places like Europe & Asia, where they’re in-warranty and on the market. They can be used with AndroidAPS (which uses OpenAPS’s oref0 algorithms for looping). Because of the bluetooth comms, no extra device is needed, and the phone with AndroidAPS can communicate to the pump directly. Additionally, the AndroidAPS dev team has also been working hard on evaluating other pumps, and the Roche Combo was recently established as another pump that would be compatible with AndroidAPS; again due to built-in bluetooth capabilities.

Sadly, the DANA*R(S) is not FDA approved in the US and thus not available; and the Combo pump is no longer being actively distributed by Roche in the US (even though it’s approved) – so there are fewer pump options in the U.S. right now. But again, I’m hopeful for more change and more options in the future as the pump companies begin to leverage resources from the Open Protocol Initiative.