System and method for providing closed loop infusion formulation delivery
A system and method for providing closed loop infusion formulation delivery which accurately calculates a delivery amount based on a sensed biological state by adjusting an algorithm's programmable control parameters. The algorithm calculates a delivery amount having proportional, derivative, and basal rate components. The control parameters may be adjusted in real time to compensate for changes in a sensed biological state that may result from daily events. Safety limits on the delivery amount may be included in the algorithm. The algorithm may be executed by a computing element within a process controller for controlling closed loop infusion formulation delivery. The biological state is sensed by a sensing device which provides a signal to the controller. The controller calculates an infusion formulation delivery amount based on the signal and sends commands to an infusion formulation delivery device which delivers an amount of infusion formulation determined by the commands.
1. A method for delivering an insulin formulation, the method comprising:
taking a plurality of samples of a blood glucose level over a period of time;
filtering out high frequency components of the blood glucose level of each of the plurality of samples;
comparing the filtered blood glucose level of each of the plurality of samples to a predefined blood glucose level threshold; and
disabling a delivery of an amount of insulin formulation if the filtered blood glucose level of the plurality of samples is less than the predefined blood glucose level threshold;
wherein filtering comprises filtering with a finite impulse response filter; and
wherein filtering with the finite impulse response filter comprises determining an order of the finite impulse response filter based on whether the blood glucose level of the plurality of samples is falling over the period of time.
2. The method recited in claim 1 , wherein an order of the finite impulse response filter is selectively changeable.
3. The method of claim 1 , wherein determining the order of the finite impulse response filter comprises:
increasing the order of the finite impulse response filter in response to the blood glucose level of the plurality of samples falling over the period of time; and
maintaining the order of the finite impulse response filter in response to the blood glucose level of the plurality of samples rising over the period of time.
4. The method recited in claim 3 , wherein determining whether the blood glucose level of the plurality of samples is falling or rising is based on a derivative of the blood glucose level of the plurality of samples as a function of time.
5. The method recited in claim 1 , further comprising:
disabling the delivery of the amount of insulin formulation if an amount of insulin formulation that has been delivered in a predefined time period is more than a predefined insulin formulation amount threshold.
6. The method recited in claim 1 , further comprising:
detecting a biological state;
wherein the delivery of the amount of insulin formulation is adjusted based on the biological state.
7. The method recited in claim 6 , wherein the detected biological state comprises sleeping, being awake, temperature, exercising, or blood oxygen level.
8. A system for delivering an insulin formulation comprising:
a data acquisition unit for taking a plurality of samples of a blood glucose level over a period of time;
a filter for filtering out high frequency components of the blood glucose level of each of the plurality of samples;
a comparator for comparing the filtered blood glucose level of each of the plurality of samples to a predefined blood glucose level threshold; and
a controller for disabling a delivery of an amount of insulin formulation if the filtered blood glucose level of the plurality of samples crosses the predefined blood glucose level threshold;
wherein the filter is a finite impulse response filter; and
wherein the controller is configured to determine an order of the finite impulse response filter based on whether the blood glucose level of the plurality of samples is falling over the period of time.
9. The system of claim 8 , wherein the filter is a low pass filter.
10. The method recited in claim 8 , wherein an order of the finite impulse response filter is selectively changeable.
11. The system of claim 8 , wherein the controller is further configured to increase the order of the finite impulse response filter in response to the blood glucose level of the plurality of samples falling over the period of time and to maintain the order of the finite impulse response filter in response to the blood glucose level of the plurality of samples rising over the period of time.
12. The system recited in claim 11 , wherein determining whether the blood glucose level of the plurality of samples is falling or rising is based on a derivative of the blood glucose level of the plurality of samples as a function of time.
13. The system recited in claim 8 , wherein the controller is further configured to disable the delivery of the amount of insulin formulation if an amount of insulin formulation that has been delivered in a predefined time period is more than a predefined insulin formulation amount threshold.
14. The system recited in claim 8 :
wherein the data acquisition unit is further configured to detect a biological state;
wherein the controller is further configured to adjust the delivery of the amount of insulin formulation based on the biological state.
15. The system recited in claim 14 , wherein the biological state detected by the data acquisition unit comprises sleeping, being awake, temperature, exercising, or blood oxygen level.