Closing the loop
I’ve been using tools and mathematical models to establish my insulin requirements for a while. I keep the links to these calculators on my pump pages and thank my lucky stars for first wifi and then 3 and then 4G mobile networks.
Most of them I have produced myself while allowing them to be tailored for any other insulin user.
The most useful one, IMO, is the basal rate estimator. By fasting (and testing) you can tweak your basal rate in the tool until you get a smooth line. It’s a beautiful piece of code. It’s also why I use my Roche pump as it has a basal programme that sets the amount of insulin I have each hour.
I use a simple spreadsheet to record my basal and the blood sugar results and do the comparison.
But it is not closing the loop.
For me, using interstitial readings with a subcutaneous pump is not closing the loop because the insulin I had 3 hours and 57 minutes ago, whether by basal or by bolus, is having an impact now. If I stop my pump, it is going to hurt me in an hour’s time and that impact will last for four hours.
That’s if the interstitial readings are correct. The sensor is not meant to be used for clinical decisions. Indeed, if I get an unexpected result, I do a capillary blood test to see what is actually happening now rather than 10 minutes ago.
Time is the killer?
Exactly. I would be happy if my pump were not a constant subcutaneous insulin infusion (CSII) pump but a CIPII (continous IntraPeritoneal insulin infusion) could allow the loop to be properly closed. The Accu-Chek Diaport looks really interesting for that – with the insulin going straight into the stomach wall rather than subcutaneously. The action of the insulin is sharpened considerably because the insulin isn’t going into fat.
It’s not quite as good as IV, but it would be enough to close the loop easily.
Posted: November 13th, 2018 under Diabetes.