System and method for adaptive drug delivery
The present invention provides a system and method for determining and maintaining a concentration level of medication in a patient sufficient to achieve and maintain a desired effect on that patient. Generally speaking, in accordance with one embodiment of the invention, a medication delivery controller uses a patient response profile to determine a concentration of medication in the patient that will achieve the desired effect on the patient. The patient response profile is a graphical, tabular or analytical expression of the relationship between the concentration of a medication and the effect of the medication at the specific concentration. Using this information, the medication delivery controller provides instructions to a medication delivery unit such as, for example, an infusion pump or inhalation device, to deliver the medication to the patient at a rate that will achieve the desired concentration level of the medication in the patient.
1. A method of controlling delivery of medication with an electronic medication delivery controller, comprising the steps of:
sampling, using at least one physiological sensor, data from a patient during the delivery of medication to the patient by a medication delivery unit;
establishing, using said electronic medication delivery controller, a medication response profile;
repeatedly updating, using said electronic medication delivery controller, in a closed loop process, the medication response profile using said data sampled from the patient by adapting parameters of said medication response profile, said medication response profile being indicative of a relationship between a concentration of the medication and an effect of the medication;
minimizing, using said electronic medication delivery controller, the error between said updated medication response profile and the said sampled data; and
adjusting, using said electronic medication delivery controller, the delivery of medication to the patient by the medication delivery unit based on the updated medication response profile.
2. The method of controlling the delivery of medication of claim 1 , wherein an initial medication response profile is a population-derived medication response profile.
3. The method of controlling the delivery of medication of claim 1 , wherein an initial medication response profile is a patient-specific medication response profile calculated from data sampled during an initial administration of the medication.
4. The method of controlling the delivery of medication of claim 2 wherein said parameters of said medication response profile are adapted to the patient in a controlled manner by a weighted combination of said sampled data and said initial medication response profile.
5. The method of controlling the delivery of medication of claim 3 wherein said parameters of said medication response profile are adapted to the patient in a controlled manner by a weighted combination of said sampled data and said initial medication response profile.
6. The method of controlling the delivery of medication of claim 1 wherein each parameter of the medication response profile is individually adapted.
7. The method of controlling the delivery of medication of claim 1 wherein the minimizing the error step further comprises using a minimization technique on a single merit function.
8. The method of controlling the delivery of medication of claim 7 , wherein the extent to which the sampled data is used to update said medication response profile to changes in patient response is weighted based on an age of said data.
9. The method of controlling the delivery of medication of claim 8 wherein said age-weighted sample data is converted to an equivalent single-sample value to improve an objective weighing of all contributing factors in a merit function, irrespective of the number of samples.
10. The method of controlling the delivery of medication of claim 7 further comprising the step of calculating, using said electronic medication delivery controller, an estimate of a goodness-of-fit of the obtained medication response profile.
11. The method of controlling the delivery of medication of claim 10 further comprising the step of determining, using said electronic medication delivery controller, whether to use the calculated medication profile in the closed-loop operation based on said estimate of said goodness-of-fit.
12. The method of controlling the delivery of medication of claim 10 further comprising the step of setting, using said electronic medication delivery controller, a new medication response profile as an initial medication response profile during medication administration based on the calculated goodness-of-fit.
13. The method of controlling the delivery of medication of claim 1 further comprising the steps of:
continuing to sample data using said at least one physiological sensor; and
updating, using said electronic medication delivery controller, the medication response profile if the process operates in a temporary open-loop state.
14. The method of controlling the delivery of medication of claim 1 , wherein the medication response profile is established prior to operating in the closed loop process.
15. A medication delivery system comprising:
at least one physiological sensor for sampling data from a patient during delivery of medication to the patient by a medication delivery unit; and
a medication delivery controller comprising a processor that is configured to:
establish a medication response profile;
update said medication response profile using said data sampled from the patient by adapting parameters of said medication response profile, said medication response profile indicative of a relationship between a concentration of the medication and an effect of the medication;
minimize an error between said sampled data and said updated medication response profile; and
adjust the delivery of medication to the patient by the medication delivery unit based on the updated medication response profile.