Adaptive speed control for blood pump
AssigneeThoratec Corporation
InventorsDavid J. Burke, Douglas C. Thomas
Life of this patent
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Abstract
A blood pump may be adapted to sense the onset of left ventricular collapse by monitoring a pulsatility index, and may adjust the pump speed to maintain the index at a setpoint. The pulsatility index may be measured by the amount of difference between the maximum and the minimum volume of flow through the pump during a particular time period. The setpoint may be increased when the onset of ventricular collapse is detected, for example, when the pulsatility index falls suddenly. The setpoint may be decreased incrementally when the onset of ventricular collapse has not been detected for a period of time, such as for a particular period of time since the last detection of the onset of ventricular collapse.
Claims17
A method of controlling the speed of an implantable blood pump, comprising:
- monitoring a blood flow flowrate through the pump;
- calculating a pulsatility index for the blood flow over a control interval;
- modifying a pulsatility index set point if the pulsatility index indicates that ventricular collapse is imminent or occurring;
- and
- modifying the pump speed to maintain a pulsatility index substantially equal to the pulsatility index setpoint.
A variable speed blood pump system, comprising:
- a blood pump having a variable blood pump speed;
- a blood pump flow sensing system to measure the flow rate of blood through the blood pump;
- a pulsatility setpoint controller that establishes a pulsatility setpoint for the blood pump, and modifies the pulsatility setpoint in response to changes in volumetric flowrate through the pump that signify the onset or imminence of a ventricular collapse;
- and
- a pump speed controller responsive to the blood pump volume flow sensing system that adjusts the blood pump speed to maintain a pulsatility index at a level approximately the same as the pulsatility setpoint.
Dependencies are inferred from the claim text.