Two Way Crossover Closed Loop Study MPC vs FMPD
Condition: Type 1 Diabetes
MeSH terms: Diabetes Mellitus, Type 1
Study type: Interventional

Summary: 
      An artificial pancreas (AP) is a control system for automatic insulin delivery. Our group has
      implemented a fading memory proportional derivative controller (FMPD) for use within an AP
      control system which has been evaluated in clinical studies. However, the long action of
      insulin (90 minutes for peak action) makes it challenging to control insulin with a classical
      proportional derivative system. The study described within this protocol is designed to test
      the effectiveness of a new model-predictive control (MPC) AP that modulates insulin delivery
      based on estimated activity level. The potential benefit of this type of AP is that it
      handles exercise not as a discrete event, but it automatically adjusts insulin delivery based
      on estimated activity level calculated at every 5 minute cycle. This type of algorithm may
      significantly improve glucose control over our FMPD AP, which is designed only to detect
      exercise when activity level goes above a threshold for a specific duration of 45 minutes.
    

Detailed description: 
      Participants will undergo two approximately 76 hour studies. During each of these
      intervention visits, participants will wear an Omnipod to deliver insulin and a Dexcom G6 CGM
      to measure glucose. The CGM system will provide sensed glucose data every 5 minutes. Sensed
      glucose data will be wirelessly transmitted via Bluetooth Low Energy (BTLE) from the Dexcom
      G6 transmitter to the Samsung master controller every five minutes. The smart phone will
      wirelessly communicate via BTLE to an Omnipod through an Omnipod PDM. During one of the
      studies, glucose will be controlled using the MPC AP. During another study, glucose will be
      controlled using the FMPD AP. The AP system will receive activity data through a Polar M600
      watch worn by the participant.

      Participants will arrive at the clinic at approximately 7am for the inpatient visits.
      Participants will eat breakfast, lunch and dinner in the clinic. Participants will perform
      activities of daily living and exercise using an aerobic exercise video. Participants will
      discharge at 7pm to go home for the remainder of the study visit and perform one exercise
      video session at home. Participants will return to OHSU on Day 4 for removal of all devices.
      The exception to this is for the first 8 participants using the MPC AP. These participants
      will stay at the research clinic during the day and go home to sleep each night (7pm-7am).
    

Intervention name(s): FMPD AP algorithm; MPC AP system; Dexcom G6 Continuous Glucose Monitoring (CGM) System
Intervention type(s): Device; Device; Device
Intervention description(s): The Fading Memory Proportional Derivative (FMPD) insulin infusion algorithm determines insulin delivery rates based on proportional error, defined as the difference between the current CGM level and the target CGM level, and the derivative error, defined as the rate of change of the CGM. The FMPD algorithm utilizes derivative and proportional glucose errors to determine delivery rates of insulin.; The Model Predictive Control (MPC) insulin infusion algorithm contains a model within the controller that takes as an input the aerobic metabolic expenditure in addition to the CGM and meal inputs. The algorithm uses heart rate and accelerometer data collected on the patient's body to calculate metabolic expenditure. The metabolic expenditure then acts on the model for the insulin dynamics, whereby more energy expenditure and longer duration exercise can lead to a more substantial effect of insulin on the CGM.; The Dexcom G6 CGM measures interstitial glucose through a sensor transmitter. This glucose value is reported to the MPC algorithm during this intervention.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: glucose sensor; automated insulin delivery systems