Magnetically suspended fluid pump and control system

• US 6,179,773 B1
• Filed: 04/08/1999
• Issued: 01/30/2001
• Est. Priority Date: 11/26/1997
• Status: Expired due to Fees

• Current Assignee: Vascor, Inc.
• Original Assignee: Vascor, Inc.
• Inventors: Prem, Edward K., Kolenik, Steve A.
• Primary Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US09/288,413
• Time in Patent Office: 663 Days
• Field of Search: 600/16-18, 600/438, 600/439, 600/459, 600/587, 600/508, 607/4, 607/5, 607/3, 607/6, 623/3
• US Class Current: 600/17
• 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 60/196 replacing the entire heart, e.g. total artificial hearts [TAH]
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: A61M 60/812 Vanes or blades, e.g. static flow guides
• CPC Class Codes: A61M 60/814 Volutes
• CPC Class Codes: A61M 60/822 specially adapted for being actively controlled
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: A61M 60/833 Occluders for preventing backflow
• CPC Class Codes: A61M 60/892 Active valves, i.e. actuated by an external force
• CPC Class Codes: F04D 13/0646 the hollow pump or motor shaft being the conduit for the working fluid
• CPC Class Codes: F04D 29/048 magnetic; electromagnetic
• CPC Class Codes: F16C 2316/18 Pumps for pumping blood
• CPC Class Codes: F16C 2360/44 Centrifugal pumps
• CPC Class Codes: F16C 32/0444 Details of devices to control the actuation of the electromagnets
• CPC Class Codes: F16C 32/047 Details of housings; Mounting of active magnetic bearings

Abstract

A blood pump for assisting a heart is provided having a stator and a rotor. The rotor is magnetically radially supported creating a suspension gap between the stator and the rotor. The rotor can be supported axially by a Lorentz force bearing and can be magnetically rotated. The stator can have a single or double volute pump chamber and the rotor can have an impeller portion for pumping blood. The rotor can have a center bore as a primary blood flowpath. The suspension gap can be a secondary blood flowpath. The blood pump can also have an axial position controller and a flow rate controller. The axial position controller can cause the axial bearing to adjust the position of the rotor. The flow rate controller can have a member for measuring a dimension of a heart ventricle to control the flow rate to avoid overly distending or contracting the ventricle. A method of operating the flow rate controller to create a pulsatile flow rate is also provided. Additionally, the blood pump can be part of a cardiac assist and arrhythmia control system. Moreover, a method of operating the flow rate controller can be provided which reduces the amount of energy needed to treat fibrillation. The method can include operating the flow rate controller to reduce a radial dimension of the ventricle prior to delivering defibrillation energy such that the ventricle contains less blood which absorbs less energy so that a larger fraction of the energy is delivered to the heart.

Claims

1. A system for cardiac assist and arrhythmia treatment comprising:

a. an implantable defibrillator operatively connected to a heart and said defibrillator having means for administering a therapeutic treatment to the heart responsive to the occurrence of said arrhythmia;

b. at least one implantable blood pump operatively connected between a circulatory system and a ventricle of a heart said implantable blood pump having;

i. a stator member;

ii. a rotor member disposed in said stator member for rotation therein;

iii. a magnetic suspension having a stator magnet portion carried by said stator member and a rotor magnet portion carried by said rotor member, said stator member and rotor magnet portions cooperating to magnetically support said rotor member radially in said stator member such that an annular magnetic suspension gap is created between said stator member and said rotor member;

iv. a magnetic drive having a stator motor portion carried by said stator member and a rotor motor portion carried by said rotor member, said stator motor portion and said rotor motor portion cooperating to magnetically rotate said rotor member relative to said stator member to pump blood through said blood pump; and

v. a Lorentz-force axial bearing having a stator axial bearing portion carried by said stator member and a rotor axial bearing portion carried by said rotor member, said stator axial bearing portion and said rotor axial bearing portion cooperating to magnetically support said rotor member axially in said stator member; and

c. an implantable blood pump flow rate controller operable to reduce a volume of blood in said ventricle prior to said defibrillator administering said therapeutic treatment.

2. The system of claim 1, wherein said flow rate controller further comprises:

a. a heart measurement member attachable to a heart ventricle which is assisted by said blood pump;

b. said heart measurement member measuring at least one of distention and contraction of said ventricle; and

c. said flow rate controller utilizing said dimensions to control said flow rate of said blood pump.

3. The system of claim 2, wherein said flow rate is a pulsatile flow rate.

4. The system of claim 2, wherein said heart measurement member comprises:

a. a heart caliper having a pair of arms pivotable relative to each other;

b. each of said pair of arms having one end attachable to an outer surface of said ventricle and an opposite end connected at a pivot point; and

c. an angular measurement device measuring changes in angular position between each of said pair of arms.

5. The system of claim 4, wherein said angular measurement device comprises an electronic eddy current position sensor measuring said changes in angular position between said pair of arms.

6. The system of claim 2, wherein said heart measurement member comprises a pair of ultrasonic transducers positioned at generally opposing sides of said ventricle measuring a radial dimension of said ventricle based upon an elapsed time for an ultrasonic pulse to travel between said pair of transducers.