US Patent 8257300 Safety features for integrated insulin delivery system

Safety features are applied to an integrated insulin delivery system to enhance safety while accounting for glucose sensor bias and calibration errors. One safety feature includes comparisons of calibrations of the sensor to nominal sensitivity and taking action, such as limiting insulin delivery or taking a further calibration of the sensor. In another feature, an automatic resumption of a basal delivery rate is programmed into the delivery device to avoid the possibility of complete loss of delivery of insulin in the event that communication with the delivery device is disrupted. Other features include steps taken to avoid hypoglycemia in the event that the sensor is negatively biased.