Closed-loop blood glucose control using insulin and carbohydrates in front meals and exercise

In patients with type 1 diabetes mellitus (T1DM), physical exercise increases the associated risk of hypoglycemia according to Ertl and Davis (2004). Moreover, exercise is associated with an enhanced insulin sensitivity that may last for several hours, which in turn leads to faster glucose consumption. Thus, exercise is one of the most important perturbations for the tight control of blood glucose (BG). Nevertheless, regular physical exercise has also been related to health benefits by Waden et al. (2008). So, T1DM face the implicit trade-off of exercising for healthy reasons in expenses of an increased risk of hypoglycemia. Particularly, the artificial pancreas (AP) systems that aim to automate the insulin infusion suffer when dealing with exercise. Their main control action, i.e. insulin, cannot directly counteract the lowering glucose effect of exercise, non delivering insulin for large periods of time in most cases. In this work we present an approach to deal with exercise that aims to mimic what T1DM patients are currently doing, i.e. eating carbohydrates (CHO) when exercising to avoid hypoglycemia. Hence, an AP with insulin and a CHO suggestion strategy has been developed and tested 'in silico' against challenging scenarios. The results show that using CHO suggestions can potentially increase the safety of T1DM patients when using an AP in front exercise. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.