Open To Closed-Loop Transition Schemes For In Vivo Glucose Control.

FABRICIO GARELLI; HERNÁN DE BATTISTA; EMILIA FUSHIMI; NICOLÁS ROSALES

Paris

Conferencia; 10th International Conference on Advanced Technologies & Treatments for Diabetes; 2017

ATTD

Background and AimsContinuous Subcutaneous Insulin Infusion (CSII) treatments for people with type 1 diabetes can combine the use of a smart insulin pump with a Continuous Glucose Monitor (CGM) and a control algorithm to improve the regulation of the insulin delivery. New control algorithms need to be tested in clinical trials under strictly safety conditions for the patients. MethodIn this work, a safety layer called the SAFE loop (Revert et al., IEEE-TBME 2013) is reformulated to be employed during clinical trials in two different ways: the Time Enable mode, which gives a criterion for the transition between open and closed-loop therapy in hybrid configurations, and the Amplitude Enable mode, which diminishes the risk of an hypoglycemic event when testing fully closed-loop algorithms by delimiting the Insulin-On-Board (IOB) profile of the new control algorithm with the IOB profile corresponding to the usual open-loop therapy of the patient (or a factor of it).ResultsIn-silico trials show how using the Time Enable method the transition from open (bolus) to closed-loop is made automatically and gradually, resulting in a bumpless mechanism which improves the controller response. In the case of the Amplitude Enable mode, the results show how the patient is protected from hypoglycemia even when controller gain is disproportionally large, as shown in the figure below.ConclusionTwo IOB constraint profiles are proposed for its use in clinical trials, giving rise to a safe mechanism for in vivo testing both hybrid and fully closed-loop controllers.