Feedback control and ventricular assist devices

• US 7,520,850 B2
• Filed: 11/19/2004
• Issued: 04/21/2009
• Est. Priority Date: 11/19/2003
• Status: Expired due to Fees

• Current Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Original Assignee: Transoma Medical, Inc.
• Inventors: Brockway, Brian P.
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Oropeza; Frances P
• Application Number:
  US10/993,826
• Publication Number:
  US 20050107658A1
• Time in Patent Office: 1,614 Days
• Field of Search: 600/509, 600/513, 600/16, 600/17, 607/16, 607/17, 623/3.1
• US Class Current: 600/17
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/8243 by induction
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/523 using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors

Abstract

Various devices, systems and methods for providing effective, long term and reliable use of pressure feedback in VADs. Exemplary embodiments are described which provide for direct LV pressure measurement, non-invasive calibration techniques to detect ventricular collapse and recalibrate the feedback mechanism, improved pressure sensor designs with reduced drift, and barometric pressure correction schemes. These devices and methods may be used alone or in combination with each other, and may also be combined with other feedback mechanisms.

Claims

1. A method of calibrating a pressure sensor that measures left ventricular pressure and is associated with a ventricular assist device (VAD) implanted in a patient, comprising:

observing, using a non-invasive imaging technique, a ventricular geometry of the patient for an indication of ventricular collapse or onset of ventricular collapse of the patient'"'"'s left ventricle;

gradually increasing flow rate of the VAD until an initial indication of ventricular collapse is observed; and

calibrating the pressure sensor that measures left ventricular pressure based upon the initial indication of ventricular collapse.

2. A method of calibrating a pressure sensor that measures left ventricular pressure as in claim 1, wherein observing the ventricular geometry of the patient comprises a non-surgical diagnostic technique.

3. A method of calibrating a pressure sensor that measures left ventricular pressure as in claim 1, wherein the non-invasive imaging technique comprises ultrasonic imaging.

4. A method of calibrating a pressure sensor that measures left ventricular pressure as in claim 1, wherein the pressure sensor provides a pressure feedback signal to the VAD for use in controlling a motor speed of the VAD.

5. A method of calibrating a pressure sensor that measures left ventricular pressure as in claim 1, wherein the pressure sensor is disposed on a left ventricle free wall.