Non-invasive diagnostics for ventricle assist device
A circulatory assist system has a pump with a motor coupled to rotate the pump at a selectable speed. A controller drives the motor at a target speed and collects blood flow measurements during operation of the pump. An impaired flow condition is identified when a plurality of successive blood flow measurements are between an expected minimum flow and a low flow threshold, such that the low flow would necessitate issuing an alert. During the impaired flow condition, it is detected whether an inflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined increase in the blood flow measurements. If the inflow obstruction is detected, then the speed of the pump is further reduced to further increase the blood flow measurements.
1. A method of controlling blood flow delivered to a patient by a left ventricle assist device including a pump, comprising the steps of:
collecting blood flow measurements during operation of the pump;
identifying an impaired flow condition when a plurality of successive blood flow measurements are between an expected flow and a low flow, wherein the low flow would necessitate issuing an alert;
during the impaired flow condition, detecting whether an inflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined increase in the blood flow measurements; and
if the inflow obstruction is detected, then further reducing the speed of the pump to further increase the blood flow measurements.
2. A method of controlling blood flow delivered to a patient by a left ventricle assist device including a pump, comprising the steps of:
collecting blood flow measurements during operation of the pump;
identifying an impaired flow condition when a plurality of successive blood flow measurements are between an expected flow and a low flow, wherein the low flow would necessitate issuing an alert;
during the impaired flow condition, detecting whether an inflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined increase in the blood flow measurements;
if the inflow obstruction is detected, then further reducing the speed of the pump to further increase the blood flow measurements;
during the impaired flow condition and if the inflow obstruction is not detected, then detecting whether an outflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined decrease in the blood flow measurements; and
if the outflow obstruction is detected, then increasing the speed of the pump to increase the blood flow measurements.
3. A system for coupling to a patient to assist blood flow in the patient, comprising:
a pump adapted to receive an inflow of blood from the patient and to provide an outflow of blood back to the patient;
a motor coupled to rotate the pump at a selectable speed;
a controller coupled to the motor and adapted to drive the motor at a target speed via a driver signal generated by the controller, wherein the controller is configured for:
collecting blood flow measurements during operation of the pump;
identifying an impaired flow condition when a plurality of successive blood flow measurements are between an expected flow and a low flow, wherein the low flow would necessitate issuing an alert;
during the impaired flow condition, detecting whether an inflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined increase in the blood flow measurements; and
if the inflow obstruction is detected, then further reducing the speed of the pump to further increase the blood flow measurements.
4. A system for coupling to a patient to assist blood flow in the patient, comprising:
a pump adapted to receive an inflow of blood from the patient and to provide an outflow of blood back to the patient;
a motor coupled to rotate the pump at a selectable speed;
a controller coupled to the motor and adapted to drive the motor at a target speed via a driver signal generated by the controller, wherein the controller is configured for:
collecting blood flow measurements during operation of the pump;
identifying an impaired flow condition when a plurality of successive blood flow measurements are between an expected flow and a low flow, wherein the low flow would necessitate issuing an alert;
during the impaired flow condition, detecting whether an inflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined increase in the blood flow measurements;
if the inflow obstruction is detected, then further reducing the speed of the pump to further increase the blood flow measurements;
during the impaired flow condition and if the inflow obstruction is not detected, then detecting whether an outflow obstruction exists by determining whether a reduction in speed of the pump is correlated with a predetermined decrease in the blood flow measurements; and
if the outflow obstruction is detected, then increasing the speed of the pump to increase the blood flow measurements.