Insulin can be delivered by injections or pump:
1-injections contain certain amount of insulin to be injected according calculations (manual dosing)
2- pumps deliver insulin continuously under the skin-actually mimicking the response of healthy pancreas leads to optimum glycemic control :
pumps could batch pump or traditional pump:
glucose sensing and giving insulin accordingly is called closed loop system where CGM talks to pump and provide with glucose updates.
previously-open loop system was developed where pump -completely-programmed by the users and according to blood glucose level measured by a glucometer or CGM . (there is a separate sensor for monitoring)
Recently,closed loop appeared where a pump is connected to a CGM and both are talking to each other (glucose sensed is the output which will be considered as a feedback in order to adjust the initial input: this is the main difference between open loop and closed loop control system: closed loop vs open loop
however, sub optimal accuracy of available sensors remains an obstacle towards developing of a complete closed loop system where insulin (basal or bolus )is administered automatically
Till now a hybrid closed loop (HCL)system is the only developed and approved where a a basal insulin only can be delivered according to CGM readings while bolus is not . (manual intervention is still needed )
HCL is the initial outcome of artificial pancreas research where a bright future of diabetes management is about to be realized.
at the end, TOP needs to be highlighted which (DIY) project (not approved by any organization still under trial)
TOP is a fully closed loop system depends on auto piloting where a continuous review of previous days are performed to double check the impact of insulin dosing in addition to certain tactics of supervised machine learning . see :