Patent ID: 11964130
Assignee: MEDTRONIC, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 20:
21. A method of determining a reservoir volume information of an implantable medical device, the method comprising:
providing an implantable medical device comprising a housing that defines a propellant chamber, and a drug reservoir positioned within the propellant chamber, a propellant gas within the propellant chamber, a volume measurement system comprising (i) a temperature sensor within the propellant chamber and not in direct contact with the therapeutic fluid and (ii) a pressure sensor, and processing circuitry connected to the volume measurement system;
measuring, using the processing circuitry, a current temperature of the propellant gas in the propellant chamber with the temperature sensor;
measuring, using the processing circuitry, a current pressure of the propellant gas in the propellant chamber with the pressure sensor; and
determining, using the processing circuitry, current volume information of a therapeutic fluid in the drug reservoir based on the current temperature and the current pressure of the propellant gas in the propellant chamber.