Outpatient Automated Blood Glucose Control With a Bi-hormonal Bionic Endocrine Pancreas

The study population will be volunteers with type 1 diabetes who are 21 years of age or older. The setting will be an outpatient environment in a three square-mile area on the Boston Peninsula (see Appendix A). Volunteers will stay in a hotel adjacent to the MGH campus at night and will have free activity during the day within the specified geographic area. They will determine the timing and nature of their meals from local restaurants, with food brought from home, or food kept in their hotel room, which will have a small refrigerator. They will have the opportunity to exercise as they wish in their choice of two gyms. There will be minimal scheduling constraints, limited only by an 11:00 PM curfew and morning departure time from the hotel of no earlier than 7:00 AM. They will be able to work if they wish as long as that can be done within the geographical constraints (e.g. if they work in the downtown Boston area or can "work from home" or have meetings at a conference room in the hotel or at a restaurant). During the entire experiment they will be closely monitored by study staff (RN, NP, or MD) around the clock. They will remain within direct line of sight and no more than a short distance away from study staff during the daytime for safety. During the night they will be continuously monitored via BG telemetry from a nearby hotel room and study staff will be able to enter their rooms quickly, should that become necessary. During the night, when volunteers will remain in their rooms, one study staff member will monitor up to two volunteers at a time. Capillary BG will be tested every two hours during the day using a highly accurate, laboratory equivalent meter (HemoCue, selected for maximum data integrity) and venous BG will be tested every 30 minutes overnight using an autosampling device (GlucoScout). Continuous glucose monitoring (Dexcom G4) will be done throughout the study period. Photos and menu information, if available, will be documented for each meal and snack by the escort and estimates of carbohydrate intake will be estimated later from this information by a nutritionist. The type and level of activity being performed by the volunteers (e.g. lying, sitting, standing, walking, running) will be documented in 15 minute intervals by the study staff escort. Additional data will be collected using an accelerometer. During exercise, the type and duration of exercise, and, depending on the kind of activity, the heart rate (recorded using a Polar heart rate monitor) will be documented every 15 minutes and point-of-care blood glucose will be documented every 30 minutes.