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US 11,964,130 B2Granted
Implantable medical device with drug reservoir volume measurement system
AssigneeMedtronic, Inc.
InventorsErik J. Peterson, Jerel K. Mueller
Life of this patent
Estimating the term…
Abstract
An implantable medical device (IMD) including a housing defining a propellant chamber, a drug reservoir located within the propellant chamber of the housing configured to receive a therapeutic fluid, a propellant gas within the propellant chamber; and a volume measurement system that includes a temperature sensor configured to measure a temperature of the propellant gas within in the propellant chamber and a pressure sensor configured to measure a pressure of the propellant gas within the propellant chamber. The volume measurement system is configured to measure the pressure and the temperature of the propellant gas to provide current volume information of the therapeutic fluid in the drug reservoir.
Claims23
An implantable medical device comprising:
- a housing defining a propellant chamber therein;
- a drug reservoir located within the propellant chamber of the housing configured to receive a therapeutic fluid therein;
- a propellant gas within the propellant chamber;
- and
- a volume measurement system comprising:
- a temperature sensor configured to measure a temperature of the propellant gas within the propellant chamber;
- a pressure sensor configured to measure a pressure of the propellant gas within the propellant chamber, wherein the volume measurement system is configured to measure the pressure and the temperature of the propellant gas to provide current volume information of the therapeutic fluid in the drug reservoir, and without requiring direct contact of the therapeutic fluid with the temperature sensor.
4 more elements
An implantable medical device comprising:
- a housing defining a propellant chamber therein;
- a drug reservoir located within the propellant chamber of the housing configured to receive a therapeutic fluid therein;
- a propellant gas within the propellant chamber;
- and
- a volume measurement system comprising:
- a temperature sensor configured to measure a temperature of the propellant gas within the propellant chamber;
- a pressure sensor configured to measure a pressure of the propellant gas within the propellant chamber, wherein the volume measurement system is configured to measure the pressure and the temperature of the propellant gas to provide current volume information of the therapeutic fluid in the drug reservoir, and is configured to measure the current volume of the therapeutic fluid based on Equation 4 below:
- V
- Dr
- =
- V
- T
- -
- A
-
- T
- P
- Equation
-
-
- 4
- wherein VDr is the current volume of the therapeutic fluid having SI units of m3, T is the temperature of propellant gas measured by the temperature sensor having SI units of K, P is the pressure of propellant gas measured by the pressure sensor having SI units of J·m−3, VT is a volume constant of the propellant chamber having SI units of m3, and A is a gas constant of having SI units of J·K−1.
19 more elements
A method of producing an implantable medical device comprising a volume measurement system, 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;
- installing a volume measurement system in the implantable medical device, the volume measurement system comprising a temperature sensor configured to measure a temperature of a propellant gas within the propellant chamber and a pressure sensor configured to measure a pressure of the propellant gas within the propellant chamber;
- charging the propellant chamber with a positive gauge pressure of the propellant gas;
- and
- calibrating the volume measurement system so that the volume measurement system is configured to measure the pressure and the temperature of the propellant gas to provide current volume information of the therapeutic fluid in the drug reservoir, and without requiring direct contact of the therapeutic fluid with the temperature sensor.
2 more elements
A method of producing an implantable medical device comprising a volume measurement system, 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;
- installing a volume measurement system in the implantable medical device, the volume measurement system comprising a temperature sensor configured to measure a temperature of a propellant gas within the propellant chamber and a pressure sensor configured to measure a pressure of the propellant gas within the propellant chamber;
- charging the propellant chamber with a positive gauge pressure of the propellant gas;
- and
- calibrating the volume measurement system so that the volume measurement system is configured to measure the pressure and the temperature of the propellant gas to provide current volume information of the therapeutic fluid in the drug reservoir;
- wherein the volume measurement system is configured to measure the current volume of the therapeutic fluid based on the current volume of the propellant gas using the temperature and the pressure measured by the temperature sensor and the pressure sensor, wherein the current volume of the propellant gas is determined based on an ideal gas law;
- wherein the volume measurement system is configured to measure the current volume of the therapeutic fluid based on Equation 4 below:
- V
- Dr
- =
- V
- T
- -
- A
-
- T
- P
- Equation
-
-
- 4
- wherein VDr is the current volume of the therapeutic fluid having SI units of m3, T is the temperature of propellant gas measured by the temperature sensor having SI units of K, P is the pressure of propellant gas measured by the pressure sensor having SI units of J·m−3, VT is a volume constant of the propellant chamber having SI units of m3, and A is a gas constant of having SI units of J·K−1;
- and
- wherein the volume measurement system is also configured to empirically determine at least A for calibrating the volume measurement system.
21 more elements
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.
2 more elements
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 a temperature sensor and 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;
- wherein the volume measurement system is configured to measure a current volume of the therapeutic fluid based on Equation 4 below:
- V
- Dr
- =
- V
- T
- -
- A
-
- T
- P
- Equation
-
-
- 4
- wherein VDr is the current volume of the therapeutic fluid having SI units of m3, T is the temperature of propellant gas measured by the temperature sensor having SI units of K, P is the pressure of propellant gas measured by the pressure sensor having SI units of J·m−3, VT is a volume constant of the propellant chamber having SI units of m3, and A is a gas constant of having SI units of J·K−1.
18 more elements
Dependencies are inferred from the claim text.