Is an Automatic Pump Suspension Feature Safe for Children with Type 1 Diabetes? An Exploratory Analysis with a Closed-Loop System

Objectives: It has been proposed that the first step towards a closed-loop artificial pancreas might be to use a continuous glucose sensor to automatically suspend the basal insulin delivery based on projected low sensor glucose values. Methods: We reviewed our recent experience with an artificial pancreas system, utilizing a proportional-integrative-derivative (PID) algorithm, in 17 adolescents with type 1 diabetes (T1D) to assess the safety and efficacy of this maneuver. Results: During 34 h of closed-loop automated insulin delivery, 18 pump suspensions >= 60 min (90 +/- 18 min) occurred in eight subjects. Sensor glucose levels fell from 159 +/- 42mg/dL to a nadir of 72 +/- 13mg/dL. Corresponding plasma glucose levels fell from 168 +/- 51 to 72 +/- 16mg/dL, with values <60mg/dL recorded in only four of the 18 events. Conclusions: These data suggest that automatic pump suspension using the PID algorithm may be an effective means to prevent hypoglycemia in youth with T1D.