These are chat archives for nightscout/beta

Apr 2016
Apr 26 2016 13:50
Sorry for the long post, but want to run by a concept. I recently installed nightscout and the cob-iop module and bwp. I understand it has not been kept up with people moving on to Open APS and I have only just started reviewing that work. In looking at my daughter's cgm tracings over the last month, and also knowing something about endocrinology and metabolism (i am a doc), I wonder if instead of worrying about carb absorption rates, which are tricky and primarily related to glycemic index, we model it differently. If she eats and doesn't take insulin, it is not like the glucose goes up and down, it goes up, stays up and comes down very slowly. Probably related to residual pancreatic function slowly dealing with the carbs or glucosuria (peeing it out) if it is very high. I notice that the bwp is pretty accurate for predicted blood glucose if all the carbs are dealt with, but it does not work so well if you try to use the carbs on board to mentally adjust. Instead what if we define a concept called residual insulin activity (ria) which is the amount of insulin left (based on carb factor) after the carbs are "dealt with" at whatever rate the insulin and carbs actually absorb. the ria is then used to calculate the eventual glucose result (egr) and that is displayed. Would then change the bwp to continue to list units if over the target and Gs of carbohydrates if under the target. Thoughts?
Apr 26 2016 14:01
@ddaniels1, that the BG very slowly comes down again (too slowly to be healthy) when no prandial insulin is given but there is no lack of basal insulin also works without pancreatic function and even below renal threshold.
The gradient is so high, that more glucose than usually will go through the glucose transporters opened by the basal rate. This is just slightly more than the liver produces so the drift downwards is very slow (and may even start after fat/protein is through) and will get slower the more normal the bg level is.
Apr 26 2016 14:10
Your Ideas might be good to be presented in the artificial pancreas channels.
Matthias Granberry
Apr 26 2016 14:16
@ddaniels1 yes, that is what you see with well-set basal rates. I use that as a proxy signal for when I need to adjust my basal rate somewhere. It is difficult to know exactly how and when carbohydrates (and don't forget the other macronutrients) will absorb. There is a great deal of variability between people and even meals there, so any calculations based on a simple assertion will be problematic. I still use it as a finger-in-the-breeze measurement because it's better than nothing, but like everything else, judgement is required for tight control. The simple rules all break down in various situations.