Flow estimation in a blood pump
AssigneeHeartWare, Inc.
InventorsHeinrich Schima, Ing Francesco Moscato, Marcus Granegger
Life of this patent
Estimating the term…
Abstract
The flow rate of blood out of a blood pump is determined at least in part based on an acceleration of the pump's rotor and on the blood's viscosity. Considering the rotor acceleration when determining blood flow rate, increases the accuracy of the blood flow measurement thereby permitting the determination of a parameter related to the contractility of a patient's heart. The parameter may include a rate of pressure change of blood across the pump, a ratio of the rate of pressure change and a peak-to-peak value of the blood flow rate, or any other contractility index.
Claims21
A blood pump system comprising:
- a pump including a housing and a rotor disposed within the housing, the rotor being rotatable around an axis;
- and
- a control circuit operatively coupled to the pump, the control circuit being configured to:
- determine a speed of rotation of the rotor;
- determine a derivative of the speed of rotation of the rotor;
- determine a flow rate of blood exiting the pump, the determined blood flow rate having a dynamic frequency range of at least 15 hertz based at least in part on a calculated time-varying parameter which accounts for disturbances in the blood flow rate introduced by the pulsating action of the heart, the time-varying parameter based at least in part on the derivative of the speed of rotation.
A method for determining a flow rate of blood that is used to provide a ventricular assistance to a patient's heart:
- determining a speed of rotation of a rotor of the pump;
- determining a derivative of the speed of rotation of the rotor;
- and
- calculating, by a processor, the flow rate of the blood having a dynamic frequency range of at least 15 hertz based at least in part on a calculated time-varying parameter which accounts for disturbances in the blood flow rate introduced by the pulsating action of the heart, the time-varying parameter based at least in part on the derivative of the speed of rotation.
Dependencies are inferred from the claim text.