Implantable medical device with time for therapeutic output replenishment determination and method therefore

Abstract

An implantable medical device for producing a variable therapeutic output to a patient. A therapeutic output delivery module requires replenishment following delivery of a predetermined amount of the therapeutic output. A calculator is responsive to a measure of an amount of the therapeutic output actually delivered to the patient for determining a parameter representative of a time at which the therapeutic output delivery module of the implantable medical device should be replenished with the therapeutic substance based at least in part upon the amount obtained from the measure. A method determines a parameter representative of a time at which a therapeutic output module of an implantable medical device should be replenished following delivery of a predetermined amount of therapeutic output. An amount of the therapeutic output actually delivered to the patient is measured. The parameter is calculated based at least in part upon the amount obtained in the measuring step.

1 . A device-implemented method of determining a parameter representative of a time in the future at which a therapeutic output module of an implantable medical device implanted in a patient should be replenished following delivery of a predetermined amount of therapeutic output, comprising the steps of:
 measuring an amount of said therapeutic output actually delivered to said patient; and   calculating said parameter based at least in part upon said amount obtained in said measuring step.   
     
     
         2 . A method as in  claim 1  further comprising the step of communicating said parameter to an external device. 
     
     
         3 . A method as in  claim 1  wherein said therapeutic output delivery module comprises a reservoir for holding a therapeutic substance and a pump operatively coupled to said reservoir for delivering said therapeutic substance to said patient. 
     
     
         4 . A method as in  claim 3  wherein said measuring step comprises measuring an amount of delivery of said pump. 
     
     
         5 . A method as in  claim 3  wherein said measuring step comprises measuring a volume of said therapeutic substance. 
     
     
         6 . A method as in  claim 1  wherein said therapeutic output is delivered to said patient at a variable rate. 
     
     
         7 . A method as in  claim 6  wherein said variable rate is at least partially controlled by said patient. 
     
     
         8 . A method as in  claim 7  wherein said variable rate is at least partially determined by a patient-controlled bolus. 
     
     
         9 . A device-implemented method of determining an adjusted parameter representative of a time in the future at which a reservoir of an implantable drug pump implanted in a patient should be replenished with a therapeutic substance, comprising the steps of:
 determining an initial parameter representative of an initially estimated time at which said reservoir of said implantable drug pump should be replenished with said therapeutic substance based at least in part upon a predicted delivery rate of said therapeutic substance to said patient;   measure an amount based at least in part on a quantity of said therapeutic substance actually delivered to said patient;   comparing said amount with an amount of said therapeutic substance expected to have been delivered to said patient based upon said predicted delivery rate;   determining said adjusted parameter based at least in part upon a result of said comparing step; and   communicating said adjusted parameter to an external device.   
     
     
         10 . A method as in  claim 9  further comprising the step of communicating said parameter to an external device. 
     
     
         11 . A method as in  claim 9  wherein said measuring step comprises measuring an amount of delivery of said pump. 
     
     
         12 . A method as in  claim 9  wherein said measuring step comprises measuring a volume of said therapeutic substance. 
     
     
         13 . A method as in  claim 9  wherein said calculating step uses simple arithmetic. 
     
     
         14 . A method as in  claim 13  wherein said simple arithmetic comprises addition and subtraction. 
     
     
         15 . A method as in  claim 9  wherein said adjusted parameter is determined by subtracting an amount from said adjusted parameter based at least in part on said result. 
     
     
         16 . A method as in  claim 15  wherein said subtracting decrements said adjusted parameter. 
     
     
         17 . A method as in  claim 9  wherein said therapeutic output is delivered to said patient at a variable rate. 
     
     
         18 . A method as in  claim 17  wherein said variable rate is at least partially controlled by said patient. 
     
     
         19 . A method as in  claim 18  wherein said variable rate is at least partially determined by a patient-controlled bolus.