Apparatus and method for monitoring and controlling extracorporeal blood flow relative to patient fluid status
A system and method for controlling extracorporeal blood flow in a patient. The system includes a blood pump having a rotor, a plurality of rollers carried by the rotor and a pump chamber extended in tension about the rollers. A sensor measures an operating parameter of the blood pump and a controller, coupled to the sensor, calculates the flow efficiency of the blood pump based on the measured operating parameter. The controller is further configured to display the flow efficiency on the display device, and the operation of the blood pump is adjusted based on the flow efficiency when necessary.
1. A system for controlling extracorporeal blood flow in a patient, the system comprising:
a blood pump comprising a rotor, a plurality of rollers carried by the rotor, and a pump chamber extended in tension about the rollers;
a sensor configured to measure an operating parameter of the blood pump;
a controller coupled to the sensor, the controller calculating flow efficiency of the blood pump based on the operating parameter measured by the sensor and according to the equation
FLOW EFFICIENCY=((( Q ÷RPM)×(1+ROLLERS))÷ SV max )×100
wherein:
SV max =the maximum stroke volume under maximum filling pressure;
Q=output flow rate in volume per minute;
RPM=the rotor speed in revolutions per minute; and
ROLLERS=the number of rollers on the rotor; and
a display device coupled to the controller, the controller being configured to display on the display device the flow efficiency as determined by the controller.
2. The system of claim 1 wherein the controller is configured to graphically display the flow efficiency on the display device.
3. The system of claim 1 wherein the system comprises a user input coupled to the controller and configured to adjust at least one additional operating parameter of the blood pump.
4. The system of claim 1 wherein the blood pump comprises three rollers.
5. The system of claim 1 wherein the pump chamber is occluded in a free condition where the pressure acting on the interior of the pump chamber is equal to or less than the pressure acting on the exterior of the pump chamber.
6. The system of claim 1 wherein the pump chamber is defined by a pair of flexible side walls joined at lateral edges thereof and defining a passageway therebetween from a pump inlet to a pump outlet.
7. The system of claim 1 further comprising a pump enclosure defining an interior compartment, the interior compartment housing the rotor, rollers and pump chamber therein.
8. The system of claim 7 wherein the pump enclosure is substantially airtight and the interior compartment is coupled to a vacuum source.
9. The system of claim 1 further comprising a motor coupled to the rotor for rotation thereof, the controller being configured to control rotation of the rotor via the motor, the motor being a DC brushless motor.
10. The system of claim 1 wherein the controller is configured to display the rotational speed of the rotor on the display device.