title: Design of the Glucose Rate Increase Detector: A Meal Detection Module for the Health Monitoring System.
abstract: The Glucose Rate Increase Detector (GRID), a module of the Health Monitoring System (HMS), has been designed to operate in parallel to the glucose controller to detect meal events and safely trigger a meal bolus. The GRID algorithm was tuned on clinical data with 40-70 g CHO meals and tested on simulation data with 50-100 g CHO meals. Active closed- and open-loop protocols were executed in silico with various treatments, including automatic boluses based on a 75 g CHO meal and boluses based on simulated user input of meal size. An optional function was used to reduce the recommended bolus using recent insulin and glucose history. For closed-loop control of a 3-meal scenario (50, 75, and 100 g CHO), the GRID improved median time in the 80-180 mg/dL range by 17% and in the >180 range by 14% over unannounced meals, using an automatic bolus for a 75 g CHO meal at detection. Under open-loop control of a 75 g CHO meal, the GRID shifted the median glucose peak down by 73 mg/dL and earlier by 120 min and reduced the time >180 mg/dL by 57% over a missed-meal bolus scenario, using a full meal bolus at detection. The GRID improved closed-loop control in the presence of large meals, without increasing late postprandial hypoglycemia. Users of basal-bolus therapy could also benefit from GRID as a safety alert for missed meal corrections.
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA Sansum Diabetes Research Institute, Santa Barbara, CA, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Harvey
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA Biomolecular Science & Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, USA Sansum Diabetes Research Institute, Santa Barbara, CA, USA.
authors.forename: Eyal
authors.initials: E
authors.lastname: Dassau
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA Sansum Diabetes Research Institute, Santa Barbara, CA, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Zisser
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA Sansum Diabetes Research Institute, Santa Barbara, CA, USA.
authors.forename: Dale E
authors.initials: DE
authors.lastname: Seborg
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA Biomolecular Science & Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, USA Sansum Diabetes Research Institute, Santa Barbara, CA, USA frank.doyle@icb.ucsb.edu.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Doyle
keywords: Health Monitoring System; artificial pancreas; meal detection; safety