Abstract: Methods for determining a viscosity of a fluid passing through a fluid pump are disclosed. An amount of energy associated with axially moving a rotor may be determined and correlated to a viscosity of fluid interacting therewith. For example, energy associated with a response of a suspended rotor may be determined. The amount of energy may be correlated with a viscosity of the fluid interacting with the rotor. The rotor may be initially unsuspended and an amount of energy associated with suspending the rotor may be determined and correlated with a viscosity of fluid interacting with the rotor. In another method, subsequent to suspending a rotor, the rotor may be unsuspended and an energy response of the rotor may be quantified to determine a viscosity of fluid passing through the pump. Systems for determining a viscosity of a fluid are also disclosed.

Abstract: A method and apparatus for controlling a ventricular assist device are disclosed. The method includes the step of providing a ventricular assist device which can be defined in terms of operational parameters such as pump speed or current. Measuring at least one physiological parameter reflecting a physiological state corresponding to a patient. Correlating at least one physiological parameter measured from the patient to at least one operational parameter using an estimation method. Selecting a physiological state definable by desired values of the physiological parameters. Monitoring at least one operational parameter. Controlling input values of the operational parameter based on output from the monitoring step. The apparatus includes a pump driven by a motive drive and having an impeller. A sensor detects the value of an operational parameter of the pump.

Abstract: A method and apparatus for controlling a ventricular assist device are disclosed. The method includes the step of providing a ventricular assist device which can be defined in terms of operational parameters such as pump speed or current. Measuring at least one physiological parameter reflecting a physiological state corresponding to a patient. Correlating at least one physiological parameter measured from the patient to at least one operational parameter using an estimation method. Selecting a physiological state definable by desired values of the physiological parameters. Monitoring at least one operational parameter. Controlling input values of the operational parameter based on output from the monitoring step. The apparatus includes a pump driven by a motive drive and having an impeller. A sensor detects the value of an operational parameter of the pump.

Abstract: The present invention relates to a hydrophone and to a virtual array of hydrophones for sensing the amplitude, frequency, and in arrays, the direction of sonic waves in water. The hydrophone employs a laser beam which is focused upon a small "focal" volume of water in which natural light scattering matter is suspended and which matter vibrates in synchronism with any sonic waves present. The vibration produces a phase modulation of the scattered light which may be recovered by optical heterodyne and sensitive phase detection techniques. The sonic waves are sensed at locations displaced from the focusing lenses. Because of this remote sensing capability, the physical hardware of an array of hydrophones may be confined to a small area comparable to the dimensions of the lenses themselves while the sensing of the sonic waves virtually occurs at widely spaced, remote focal volumes.