Variable flow infusion pump system

Abstract

An implantable infusion pump system is disclosed. The pump system preferably includes an implantable pump and a removable module. The module may provide for varying flow rates of fluid being dispensed from the pump or may provide for a constant flow rate of such fluid. In the case of varying flow rate capabilities, the module preferably includes one or more sensors to determine information relating to the flow rate, electronics for analyzing the flow rate information, and a mechanism for physically altering the flow rate. Methods of dispensing a medicament to a patient are also disclosed, as are variations of the pump system.

1 . A method of monitoring the amount of medicament dispensed from an implantable infusion pump, the method comprising the steps of:
 providing a pump having the medicament disposed housed therein;   dispensing at least some of the medicament from the pump at varying actual flow rates;   measuring the actual flow rate of the medicament from the pump at least two different times;   storing information relating to the actual flow rate; and   calculating the overall amount of medicament dispensed based upon the information relating to the actual flow rate.   
     
     
         2 . The method of  claim 1 , wherein the providing step includes providing a pump housing and a module connected to the pump housing. 
     
     
         3 . The method of  claim 1 , wherein the measuring step includes taking pressure measurements indicative of the actual flow rate. 
     
     
         4 . The method of  claim 3 , wherein pressure measurements are taken at two different locations within the pump. 
     
     
         5 . The method of  claim 4 , wherein the pressure measurements are taken on either side of a fixed flow restrictor included in the pump. 
     
     
         6 . The method of  claim 4 , wherein the pump includes a pump housing and a module attached to the pump housing, the pressure measurements taken within the module. 
     
     
         7 . The method of  claim 6 , wherein the pressure measurements are taken on either side of a fixed flow restrictor. 
     
     
         8 . The method of  claim 1 , wherein storing step includes transmitting the information relating to the actual flow rate to an external device. 
     
     
         9 . The method of  claim 8 , wherein the external device is a PC. 
     
     
         10 . The method of  claim 8 , wherein the external device is a handheld. 
     
     
         11 . The method of  claim 1 , wherein the storing step includes storing the information relating to the actual flow rate in a memory module associated with the pump. 
     
     
         12 . The method of  claim 1 , wherein the calculating step is performed external to the pump. 
     
     
         13 . The method of  claim 1 , wherein the dispensing step includes dispensing the medicament at a desired flow rate. 
     
     
         14 . The method of  claim 13 , wherein the measuring step includes comparing the desired flow rate to the actual flow rate. 
     
     
         15 . The method of  claim 14 , wherein the actual flow rate is varied when the actual flow rate deviates from the desired flow rate by a first amount. 
     
     
         16 . The method of  claim 15 , wherein the first amount is ten percent of the desired flow rate. 
     
     
         17 . The method of  claim 15 , wherein the actual flow rate is increased when the actual flow rate is a first amount less than the desired flow rate. 
     
     
         18 . The method of  claim 15 , wherein the actual flow rate is decreased when the actual flow rate is a first amount greater than the desired flow rate. 
     
     
         19 . The method of  claim 1 , wherein the calculating step includes determining a first average flow rate for a first period based upon the measuring step, and determining a second average flow rate for a second period based upon the measuring step. 
     
     
         20 . The method of  claim 19 , wherein the calculating step includes determining the first amount of medicament dispensed for the first period and the second amount of medicament dispensed for the second period. 
     
     
         21 . The method of  claim 20 , wherein an overall amount of medicament dispensed from the pump includes adding the first and second amounts.