Closed loop systems have been used to optimise insulin delivery in children with diabetes, but they have not been tested in neonatal intensive care. Extremely preterm infants are prone to life-threating hyperglycaemia and hypoglycaemia; both of which have been associated with adverse outcomes. Insulin delivery is notoriously variable in these babies and time-consuming, with management requiring frequent changes of dextrose-containing fluids and careful monitoring. We aimed to evaluate the feasibility of closed loop management of glucose control in preterm infants in a single centre feasibility study with a randomised parallel design. Eligibility criteria included birth weight <1200g and <48hours of age. All infants had subcutaneous continuous glucose monitoring for the first week of life, with those in the intervention group receiving closed loop insulin delivery between 48 and 72hours of age. The primary outcome was percentage of time in target (sensor glucose 4-8mmol/l). The mean (SD) gestational age and birth weight of intervention and control study arms were 27.0(2.4) weeks, 962(164) g and 27.5(2.8) weeks, 823(282) g respectively. The time in target was dramatically increased from median (IQR) 26%(6, 64) with paper guidance to 91%(78, 99) during closed loop (p<0.001), without increasing hypoglycaemia. There were no serious adverse events and no difference in total insulin infused. Closed loop glucose control based on subcutaneous glucose measurements is feasible and appears to provide an efficacious means of optimising glucose control in extremely preterm infants.

Feasibility of automated insulin delivery guided by continuous glucose monitoring in extremely preterm infants