Baxter International Inc.

Andros Incorporated

World Heart Corporation

Novacor Medical Corporation

Jassawalla, Jal

Laforge, David H.

Miller, Phillip J.

David H LaForge

Peer M Portner

Jal S Jassawalla

Phillip J Miller

Tofy Mussivand

James Lee

Jal Jassawalla

A pumping system for assisting either or both ventricles of the heart. In one embodiment, separate devices are provided for each ventricle. In another embodiment, one device provides both right and left pumping. The pumping system is small, efficient, atraumatic, and fully implantable. In addition, the pumping system can provide pulsatile flow during systole. The ventricular assist device includes an actuator plate between a pair of serially connected pumping chambers that operate in a two-stroke mode, specifically a power stroke and a transfer stroke. The ventricular assist device also includes an electromagnetic drive system that provides adjustment to the pump pressure according to the current through an electromagnet. For the pumping system, springs provide a 'spring force' on the actuator plate that is towards the high-pressure pump chamber. The bias force allows the springs to store and deliver energy from the electromagnetic drive system to provide better utilization of the pump components, and to reduce the pump size and consumption of electricity.

Miniature, pulsatile implantable ventricular assist devices and methods of controlling ventricular assist devices

An implantable ventricular assist device (VAD) has a small size to provide full-implantable capabilities. The VAD has two variable-volume chambers and an actuator for expelling blood from the chambers in sequence and to a common outlet, thus operating as a positive-displacement pump. The variable-volume chambers may be flexible sacs and the pump is operable at a substantially continuous flow, such as during the systolic phase of the assisted ventricle. A method of operation includes operating the pump at a first frequency during systole and a second lower frequency during diastole. The VAD pump includes a pair of coils housed within a frame and disposed in a spaced relationship to generate a coil flux through a pair of poles. A plate including an armature and a magnet is disposed within the frame such that the armature is between the poles and the magnet is between the coils. Gaps are defined between the armature and each of the poles and the coil flux displaces the armature across the gap. The coil flux follows a donut-shaped path including the frame, one of the poles, one of the gaps, the armature, the other the gap, and the other the pole, and no coil flux passes through the magnet. The magnet is not subject to depolarization and may be made substantially smaller than those of conventional devices. The magnet generates a bias flux that offsets a portion of the coil flux around the frame. A spring may be provided to counteract the unstable action of the bias magnet. The volume of the chambers is a fraction of the ventricular volume, and may be about 20 ml. To pump a typical 80-ml volume of a left ventricle, the controller may activate the coils four times during systole, or once every 40 msec.

Implantable ventricular assist device

A cell monitoring and control circuit for a multicell battery comprises a cell access switch coupled to the cells of the battery for electronically accessing individual cells of the battery and a monitoring and control circuit coupled to the cell access switch for electronic communication with the cells. The circuit is coupled to the battery for providing electric power and constitutes an insignificant current drain on the battery. The circuit senses the voltage state of each cell and controls the charging of each cell and provides End-of-Discharge and End-of-Charge signals.

Cell monitor and control unit for multicell battery

The present invention is an apparatus and a method for determining the state of charge of a rechargeable battery. It comprises a means for charging the batter, current sensors, heat detectors for detecting the heat emanating from the battery during charging, with the heat being the complement of the charge acceptance percentage, and a processor for storing a mathematical charge acceptance model for providing the relationship between the charge acceptance percentage and the state of charge of the battery, and for calculating the state of charge of the battery from the heat detected by the heat detectors and the charge acceptance model. An accurate measure of battery charge state is produced while the battery is being charged. This provides information concerning the operability of the battery and also allows efficient charging to avoid energy waste. The present invention is adaptable to existing battery power systems without the need for significant additional components and is applicable to any system utilizing rechargeable batteries.

Apparatus and method for calorimetrically determining battery charge

An implanted blood pump system is described wherein power for driving the pump is provided by a transcutaneous transformer having an external primary winding and an implanted secondary winding. Control of the driving voltage to the pump is provided by an implanted shunt regulator. Voltage applied to the primary winding is controlled in accordance with the power factor sensed in the primary winding.

Power supply for body implant and method of use

Real time servo control in a nonlinear, cyclical dynamic system adjusts the energy applied to a prime mover from a source of the energy as a linear function of an error between the measured load characteristics and modeled load characteristics. The modeled load characteristics are linearized as a function of the initial conditions of the load at the beginning of each cycle.

Real time servo control apparatus and method

A power supply system to operate an implanted electric-powered device such as a blood pump. A secondary coil having a biocompatible covering is implanted to subcutaneously encircle either the abdomen or the thigh at a location close to the exterior skin. The secondary coil is electrically interconnected with an implanted storage battery and the blood pump. A primary coil of overlapping width is worn by the patient at a location radially outward of the secondary coil. An external battery plus an inverter circuit in a pack is attached to a belt having a detachable buckle connector which is conventionally worn about the waist. Efficient magnetic coupling is achieved through the use of two air-core windings of relatively large diameter.

Power supply for body implant and method for operation

A method and apparatus for analyzing pulmonary function including diffusing capacity and cardiac output or local pulmonary blood flow while necessarily determining alveolar volume in order to complete the above-noted analysis. In order to provide a rapid response in each of the abovenoted analyses or determinations, appropriate gases are caused to be inhaled and exhaled through a sample cell wherein a percentage of each gas may be constantly monitored during inhalation and exhalation by means of non-dispersive infrared absorption techniques, the sample cell and associated components of the pulmonary function analyzing device including additional features to facilitate the abovenoted analyses and determinations, the combination of gases employed for monitoring the pulmonary functions being selected to permit accurate detection by infrared absorption techniques.

Growing community of inventors

Kensington, CA, United States of America

David H LaForge