Artificial pancreas software state transition requirements

The software requirements for the state machine transition logic will depend upon a list of logical conditions that are constituents of the transition logic, and then an itemized list of the transition logic itself.

Transition Logic

 * T1: Severe hypo detected: if the blood sugar is less than 55 counts continuously for 5 seconds, or is less than 65 counts continuously for 30 minutes, then transition to the "Emergency Halt" state.


 * T2: CGMS sensor fault: If GCMS data = min or max continuously for 5 seconds, or if CGMS data /= valid BG test +/- 30 counts, or if CGMS diagnostics = fault, then transition to "Control basal insulin open loop."


 * T3: CGMS Data Valid: When a CGMS sensor is replaced and its data has stabilized, then transition to "Deliver Correction Bolus" state.


 * T4: Correction bolus needed: If a correction bolus is started manually, or if the present BG is greater than the target value plus 70 counts continuously for 5 seconds, then transition to "Deliver Correction Bolus" state.


 * T5: Manual bolus 15 minutes before a meal: If a manual bolus was started, then transition to "Deliver Pre-bolus" state.


 * T6: Missed Bolus identified by a BG spike: When in the closed-loop mode and a large rapid rise in blood sugar was detected, then transition to "Deliver Missed Bolus" state.


 * T7: After bolus delivered and IOB<50%:  If IOB<50% continuously for 2 seconds, then transition to "Monitor Pre-bolus" state.


 * T8: Bolus Complete: If IOB <5% continuously for 2 seconds, then transition to "Deliver Basal Insulin with Closed Loop" state.

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