Safeguarding techniques for a closed-loop insulin infusion system

摘要

Processor-implemented methods of controlling an insulin infusion device for a user are provided here. A first method obtains and analyzes calibration factors (and corresponding timestamp data) for a continuous glucose sensor, and regulates entry into a closed-loop operating mode of the infusion device based on the calibration factors and timestamp data. A second method obtains a most recent sensor glucose value and a target glucose setpoint value for the user at the outset of the closed-loop mode. The second method adjusts the closed-loop insulin infusion rate over time, in response to the sensor glucose value and the setpoint value. A third method calculates an upper insulin limit that applies to the insulin infusion rate during the closed-loop mode. The insulin limit is calculated based on a fasting blood glucose value of the user, a total daily insulin value of the user, and fasting insulin delivery data for the user.

主权项

1. A processor-implemented method of controlling an insulin infusion device having an insulin reservoir for insulin to be delivered from the insulin infusion device to a body of a user, the method comprising:
operating a processor architecture comprising at least one processor device to obtain sensor calibration data for a continuous glucose sensor that generates a sensor variable indicative of blood glucose of the user; identifying a most recent calibration factor from the sensor calibration data, the most recent calibration factor representing a first conversion value applicable to convert a first value of the sensor variable to a first blood glucose value; identifying a prior calibration factor from the sensor calibration data, the prior calibration factor representing a second conversion value applicable to convert a second value of the sensor variable to a second blood glucose value, and the prior calibration factor corresponding to an earlier time relative to the most recent calibration factor; regulating entry into a closed-loop operating mode of the insulin infusion device, based on the most recent calibration factor and the prior calibration factor; and operating the insulin infusion device in a closed-loop mode to continuously deliver insulin from the insulin reservoir to the body of the user in accordance with the most recent calibration factor and the prior calibration factor, wherein: regulating entry into the closed-loop operating mode comprises permitting entry into the closed-loop operating mode only when t−tRecent≦tR≦t; t is a time when attempting to enter the closed-loop operating mode; tRecent is a predetermined time period; and tR is a time when the most recent calibration factor was obtained.