Sensorless flow estimation for implanted ventricle assist device

摘要

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.

主权项

1. A method of measuring a rate of change in the rotational speed of a rotating impeller within a blood pump and determining blood viscosity comprising the steps of:
applying electrical power to rotate the impeller; monitoring the rotational speed of the impeller; monitoring back EMF signals created by the rotational speed of the impeller; determining a transient rate of change in rotational speed of the impeller from at least the back EMF signals created by a change of rotational speed of the impeller during a predetermined time period; and using the transient rate of change in rotational speed of the impeller to determine the viscosity of the blood in the pump, wherein viscosity of the blood is determined when the pump is implanted in a subject.