Did you ever wonder how the biohacked device works? You know, the one I discussed yesterday. 

Besides technology, the key part of the puzzle is the algorithm needed to deliver the proper insulin doses.   Most of us don’t realize that it’s the model- the definition of the system and how it interacts within the environment- that spells out the difference between success and failure.

In this case, the algorithm  is part of the “Loop”, the model that works on the iPhone- and the RileyLink (a computer with a Bluetooth connection.)  The RileyLink was invented by a dad (Pete Schwamb for his daughter Riley.)  But, now his invention can be purchased directly from a firm in Kentucky without having to make it oneself.

But, as I said, the real trick is to understand the effect food has on insulin needs- in particular, what is termed the carbohydrate absorption rate.  Basically,  this is knowing how long it takes food (carbohydrates) to become immersed in the subject’s bloodstream after ingestion- as well as how long it takes the subject  to utilize (and, therefore, remove those) carbohydrates from within the bloodstream.

How do we do that?  We make sure the subject has not had an injection of insulin for  a while and has abstained from food.  (Basically, we are trying to ascertain the “resting state” of the subject.)

Then, a carbohydrate source (most folks use juice boxes) lacking protein and fats [which contains about 15 to 30 grams of carbohydrates] is drunk. (I am deliberately skipping the determination of the blood glucose to carbohydrate ratio determination; it’s simple, but involved- and necessary for this test.)   After drinking the juice box, the subject’s blood glucose level is tested and recorded (using a blood glucose meter) every five minutes.   Note that  there is a lag period (about 15 minutes) before any results are seen, which is then followed by a steady rise, until the level has reached the one predicted by the carbohydrate:blood glucose ratio. Now, one can compute the CAR (carbohydrate absorption rate).

From this value, we can tell how much unabsorbed carbohydrates may remain in our bodies after a meal.  In particular, we can tell if we have the right amount of insulin in our bodies to keep our blood sugar in line.  If not, we know we must inject more insulin to keep us in the “safe” range.  (By now, the subject knows the carb to insulin ratio (aka, the meal bolus ratio); a typical value would be about  10 g of carbs per unit of insulin.   This lets us administer the proper dosage of insulin to our bodies.)

(After I wrote this two pieces- but before they saw the light of day, Dexcom, a manufacturer of one of the better glucose monitoring systems, acquired TypeZero Technologies.   Why should you care?  TypeZero has a sophisticated algorithm that helps manage diabetes, working with smart insulin pens and smartphones.  Something may be on the market as early as 2019!)

Progress!

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