System for monitoring safety in medication delivery for diabetes management
An integrated diabetes management (IDM) system includes a safety layer which, in one configuration has two components, one located between a glucose sensor and a controller and a second component located between a controller and a pump, to monitor various aspects of signals and modify those signals for compatibility and safety purposes. In one application, the safety layer receives output control signals from a controller and modifies those control signals as a function of an actual amount of insulin delivered to the user. The safety layer allows for an increased level of safety in the IDM system and permits development of separate hardware and software upgrades with the safety layer assuring that compatibility between components will continue.
1. An integrated diabetes management system, comprising:
a glucose sensor configured to provide sensor glucose data representative of sensed glucose;
a delivery device configured to deliver medication in response to a delivery control signal;
a controller programmed to receive the sensor glucose data and to provide a first output control signal as a function of the received sensor glucose data; and
a safety layer programmed to receive the first output control signal, to modify the received first output control signal to generate a second output control signal that is a modified version of the first output control signal, and to provide the second output control signal as the delivery control signal.
2. The integrated diabetes management system of claim 1 , wherein the safety layer is further programmed to monitor an amount of medication delivered and to modify the received first output control signal at least partially as a function of the monitored amount of medication delivered.
3. The integrated diabetes management system of claim 2 , wherein the monitored amount of medication delivered comprises insulin on board.
4. The integrated diabetes management system of claim 1 , wherein the safety layer is further programmed to modify the received first output control signal in accordance with a characteristic of at least one of the glucose sensor and the delivery device.
5. The integrated diabetes management system of claim 1 , wherein the safety layer is further programmed to modify the received first output control signal as a function of delivery device output.
6. The integrated diabetes management system of claim 1 , further comprising: a communication module;
wherein the controller comprises a controller calculation software module configured to provide the first output control signal;
wherein the communication module is configured to provide the delivery control signal to the delivery device; and
wherein the safety layer is further programmed to intercept the received first output control signal and substitute the received first output control signal with the second output control signal without any reconfiguration of the communication module or the controller calculation software module.
7. The integrated diabetes management system of claim 1 , wherein: the controller comprises a controller calculation software module configured to receive the sensor glucose data; and
the safety layer is further programmed to intercept the received sensor glucose data from the glucose sensor and cause the modified sensor glucose data instead of the received sensor glucose data to be provided to the controller calculation software module without any reconfiguration of the glucose sensor or the controller calculation software module.
8. The integrated diabetes management system of claim 1 , wherein the safety layer is further programmed to:
determine a maximum medication delivery rate of the delivery device;
determine an amount of medication the first output control signal is configured to cause to be delivered; and
generate, if the first output control signal is configured to cause the delivery device to deliver medication at a higher medication delivery rate than the maximum medication delivery rate of the delivery device, the second output control signal such that the second output control is configured to cause the amount of medication to be delivered according to a modified medication delivery rate that does not exceed the maximum delivery rate of the delivery device.
9. The integrated diabetes management system of claim 8 , further comprising a visual display,
wherein the safety layer is further programmed to cause the modified medication delivery rate to be displayed on the visual display.
10. The integrated diabetes management system of claim 1 , wherein:
the glucose sensor includes an output having a first range representative of glucose levels;
the controller has an input having a second range representative of glucose levels;
the second range is different from the first range; and
the safety layer is further programmed to receive the sensor glucose data from the glucose sensor, modify the received sensor glucose data for compatibility with the second range, and cause the modified sensor glucose data to be provided to the input of the controller.
11. The integrated diabetes management system of claim 1 , wherein:
the glucose sensor is configured to provide sensor glucose data having a first format; and
the safety layer is further programmed to:
determine if the first format is equivalent to a second format; and
modify, if the first and second data formats are not equivalent, the sensor glucose data having the first format to have the second format, wherein the controller is configured to receive the sensor glucose data having the second format instead of the first format.
12. The integrated diabetes management system of claim 1 , wherein the safety layer further comprises:
an input safety module operably connected to the glucose sensor; and
an output safety module operably connected to the delivery device.
13. The integrated diabetes management system of claim 12 , wherein the output safety module provides feedback to the input safety module.
14. A method of diabetes management, comprising:
sensing glucose and providing sensor glucose data representative of sensed glucose;
delivering medication in response to a delivery control signal;
receiving the sensor glucose data and providing a first output control signal as a function of the received sensor glucose data;
modifying the received first output control signal to generate a second output control signal that is a modified version of the first output control signal; and
providing the second output control signal as the delivery control signal.
15. The method of diabetes management of claim 14 , further comprising:
intercepting the received first output control signal; and
substituting the received first output control signal with the second output control signal.
16. The method of diabetes management of claim 14 , further comprising:
safety monitoring the received sensor glucose data between the steps of receiving the sensor glucose data and providing the received first output control signal; and
separately safety monitoring the received first output control signal.
17. The method of diabetes management of claim 16 , wherein the step of separately safety monitoring the received first output control signal comprises providing feedback.
18. The method of diabetes management of claim 17 ,
wherein the step of providing feedback comprises providing feedback as a function of a limit on the delivery of medication and the second output control signal; and
further comprising modifying the received sensor glucose data at least partially as a function of the feedback.
19. The integrated diabetes management system of claim 1 , wherein the safety layer is further programmed to modify the received sensor glucose data to generate modified sensor glucose data.
20. The integrated diabetes management system of claim 1 , wherein the safety layer comprises linear conditioning.