Patent ID: 8597274

Claim:
A method of determining an insulin delivery rate when a closed loop insulin delivery system delivering insulin to a user at a pre-programmed basal delivery rate terminates unexpectedly, comprising: a) providing a glucose level and predicting a future glucose level in order to determine an appropriate insulin bolus value for a latest control command, and assuming that this command is immediately followed by open loop control where the pre-programmed basal delivery rate will be in effect thereafter; b) analyzing the predicted future glucose level using the insulin bolus value of the latest control command plus a future basal rate to determine if the predicted future glucose level is acceptable, and if so, waiting for a selected period of time and repeating step a); c) if the predicted future glucose level of step b) is not acceptable, computing an alternate temporary basal delivery amount that is lower than the previously assumed future basal rate, and, if the predicted future glucose level is acceptable, providing a temporary basal command at a computed basal rate and duration, waiting for a selected period of time and repeating step a); d) if the predicted future glucose level in step c) is unacceptable, decreasing the alternate temporary basal delivery amount by an amount determined by a minimum bolus resolution provided by the insulin delivery system, projecting the predicted future glucose level, and, if the predicted future glucose level is acceptable, providing a temporary basal command including a rate and duration and then waiting for a selected period of time and repeating step a); and e) if the predicted future glucose level in step d) is unacceptable, reducing the alternate temporary basal rate delivery amount by a selected amount, projecting the predicted future glucose level, and if the predicted future glucose level is acceptable, providing a temporary basal command including a rate and duration and then wait for a selected period of time and repeating step a); and f) if the predicted future glucose level in step e) is unacceptable, repeating steps d) and e) until an acceptable predicted glucose profile achieved.