Page 458 - Handbook of Biomechatronics

452 Graham Brooker

Closed-loop
Real-time control State update Data filtering User interface
control algorithm (meal info etc.)
module
Recommended
basal rate
differential
Safety
Continuous User interface
safety supervision State estimation Data filtering (bolus approval etc.)
module algorithm
Delivered insulin CGM data Basal rate
Approved
total
insulin
Data logging
Interface Actuation and outcome Data handling User interface
module measures (patient info etc.)

Continuous
Insulin
pump glucose
monitor
Fig. 30 The MPC prediction scheme relies on past inputs and outputs with future
outputs predicted as a function of future inputs within the control horizon. (Based on
Cobelli, C., DallaMan, C., Sparacino, G., Magni, L., DeNicolao, G., Kovatchev, B., 2009.
Diabetes: models, signals and control. IEEE Rev. Biomed. Eng. 2: 54–96.)

which improvements in accuracy have little effect on clinical outcomes. To
date only one system CGM system meets this criterion (Castle et al., 2017).
There is a drive toward producing CGM systems that are accurate
enough without finger-prick calibrations for both control and insulin shut
off. Commercial systems developed by Dexcom and Medtronic obtained
FDA approval for both of these functions in 2016. Novel CGM systems
include implantable types discussed earlier, and flash glucose monitoring
(CGM on demand). The latter can replace finger-prick measurements
completely in some cases.
One of the issues surrounding the incorporation of sophisticated control,
safety, and multihormonal delivery into the insulin pump is that it compli-
cates what would otherwise be a comparatively simple device into a complex
power-hungry computer with a pump attachment. An alternative is to keep
both the CGM and the pump as simple as possible and provide wireless com-
munication to a smart phone as shown in Fig. 31. This approach leverages a
powerful, yet cheap computing platform with performance driven by a mas-
sive user base beyond diabetics. This allows for new and improved