I'm part of a trial for Cambridge university at my Diabetic clinic and currently testing an "artificial pancreas" it's all very new and exciting so just thought I'd post this for any who wanted to ask me any questions about it!
Hi, it's good to hear about someone on this trial. I'm aware of a few people that had been looking at these. Is this the one using the Cellnovo pump, the Medtronic 670G, or the Beta Bionics iLet? My understanding was that the 670G doesn't include a phone process?
I've built my own hybrid closed loop system that I've been running since August, and the biggest thing that I find from it is that I don't have to think about diabetes as much. Namely, when you go to bed you wake up in range, and throughout the day, it's doing it's best to keep you there.
The biggest difference between what you have and what I've been using is that the open source systems have moved a step beyond what most of the systems that are being trialled can do and now include features that help around meals (something called Advanced Meal Assist) that can estimate carbs based on glucose level changes and adjust insulin accordingly, and also autodetection of changes in insulin sensitivity, that allows the system to adjust what it needs to give you to get you back in range. I've been working on trying to incorporate that into a bolus calculator, which is interesting stuff.
For those who are interested in the Cambridge trial, you can get details
here. Be aware that you need to have an Hba1C between 7.5% and 10%. You also must not have been using a CGM system in the preceding three months (both things that precluded me from having a go).
Sorry, I asked in an unclear way! Obviously sleepy : D I mean does it correct you by increasing your basal rate for an hour or by giving you a correction bolus? That is, does it correct you gradually using an increased basal rate over an hour or two, or does it basically give you a bolus?
I don't know which system this one is Azure, but the 670G from Medtronic works on a Microbolus basis, delivering a tiny incremental dose as it detects you going higher. This is typically the equivalent of five minutes worth of an hour's TBR.
Most of the systems are triggered by the incoming glucose data, and undertake a comparison between the new value and the previous one to four values to determine a trend, plus a calculation that looks at IOB (so getting your DIA and ISF values right is important) and carbs on board, with a model for whether they are long, medium or short absorbing, which you tell the system when you add the carbs for food. It then uses these to determine a predicted glucose level out into the future and microbolus or reduce basal rate accordingly.
In addition there's typically an "error" function that determines whether the prediction deviated from what the actual value was and adjusts the outputs accordingly.
The commercial systems differ from the open source ones, as they can handle error reporting within the system and put safety features in line.
Hope that explains it a little.