Integrated Multivariable AP

By Marcia Faye

This graph depicts part of the data collected during a clinical experiment that lasts about 60 hours, such as the one described in the article “Algorithm for an Improved Quality of Life” in the print edition of IIT Magazine. A six-hour segment is shown in the figure:

  • Top red curve indicates continuous glucose monitoring (CGM) readings
  • Green band indicates the desired glucose range
  • Square symbols indicate accurate blood glucose measurements made infrequently
  • L indicates lunch; J indicates juice; C indicates calibration
  • Middle curve is the insulin infusion rate
  • Bottom curve is the energy expenditure as estimated by the armband
  • Exercise, such as running on a treadmill, is indicated by E on the top graph (within the black rectangle); the bottom curve shows the intensity

A critical advantage of the IIT control system is the use of the exercise information to further adjust the insulin infusion rate. Since exercise increases glucose utilization, the controller does not give high doses of insulin during exercise even if though the glucose concentration is increasing (CGM inside black rectangle in top curve and corresponding insulin in middle curve).