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US 8,506,470 B2Granted
Sensorless flow estimation for implanted ventricle assist device
AssigneeHeartWare, Inc.
InventorsJeffrey A. LaRose, Udai Singh
Life of this patent
Estimating the term…
Abstract
A method of estimating the blood flow rate of a heart ventricle assist device which is positioned externally of, or implanted in, a patient. The assist device comprises a blood pump having a rapidly rotating, electrically powered impeller, and comprises briefly interrupting power to the impeller to cause its rotation to slow. From this, blood viscosity can be estimated, which viscosity is used to obtain real time, estimated blood flow rates and pressure heads. Apparatus for accomplishing this is disclosed.
Claims9
A heart ventricle assist system comprising:
- a blood pump having a magnetically rotatable impeller;
- a plurality of stator drive coils magnetically coupled to said impeller to enable it to rotate;
- a motor control circuit adapted to provide motor control signals to said drive coils thereby magnetically to rotate said impeller within said blood pump to establish a predetermined steady state blood flow rate, said motor control circuit continuously monitoring the rotational speed of said impeller;
- and
- a controller adapted to interrupt said motor control signals at predetermined intervals, each interval consisting of a predetermined period of time, thereby to permit a decay in rotational speed of said impeller during each predetermined period of time, said controller adapted to measure values and time between minimum and maximum back EMF signals generated within said stator coils during each predetermined period and to determine therefrom a transient viscosity value of blood in said blood pump, said motor control circuit establishing a rotational speed of said impeller sufficient to create a steady state blood flow rate which is a function of said transient viscosity value between each of said predetermined intervals.
2 more elements
Dependencies are inferred from the claim text.