Automatic Fluid Container Switching In A Blood Processing System

• US 20130233394A1
• Filed: 09/05/2012
• Published: 09/12/2013
• Est. Priority Date: 09/06/2011
• Status: Active Grant

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Inventors: Prendergast, Jonathan, Case, Brian, Nguyen, Lan, Foley, John
• Granted Patent: US 9,956,141 B2
• Time in Patent Office: Days
• US Class Current: 137/2
• CPC Class Codes: A61J 1/20 Arrangements for transferring or mixing fluids, e.g. from vial to syringe
• CPC Class Codes: A61M 1/342 Adding solutions to the blood, e.g. substitution solutions for preventing coagulation A61M1/3672
• CPC Class Codes: A61M 1/3496 Plasmapheresis; Leucopheresis; Lymphopheresis A61M1/3472 takes precedence
• CPC Class Codes: A61M 2205/3393 by weighing the reservoir
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: Y10T 137/0324 With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/27 Liquid level responsive
• CPC Class Codes: Y10T 137/7313 Control of outflow from tank

Abstract

Systems and methods for determining when a fluid supply container of a blood processing apparatus becomes empty. The system uses a scale to monitor and detect when a fluid supply container is empty based on the rate of change of the container weight and whether the container weight is below a pre-established threshold, and a controller receives a signal from the scale and controls the operation of a pump to stop pumping when the fluid supply container is empty.

Claims

1. A system for determining when a fluid supply container of a fluid processing apparatus becomes empty, the system comprising:

a first fluid supply container;

a first scale for measuring the weight of the first fluid supply container and providing a first output signal indicative of the measured weight of the first fluid supply container;

a pump for pumping fluid from the first fluid supply container;

a controller configured to receive the first output signal from the first scale,

to determine the rate of change in weight of the first fluid supply container, and to determine that the first fluid supply container is empty when the rate of change becomes substantially zero and the first fluid supply container weight is below a first pre-established threshold.

2. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 1 wherein the controller is configured to cause the pump to cease pumping when the controller determines that the first fluid supply container is empty.

3. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 1 further comprising:

a first valve in fluid communication between the first fluid supply container and the pump, the first valve normally in an open condition;

a second fluid supply container;

a second scale for measuring the weight of the second fluid supply container and providing a second output signal indicative of the measured weight of the second fluid supply container;

a second valve in fluid communication between the second fluid supply container and the pump, the second valve normally in a closed condition;

the controller configured to cause the pump to cease pumping upon determining that the first fluid supply container is empty, causing the second valve to move to an open condition and causing the first valve to move to a closed condition, the controller then activating the pump to begin pumping fluid from the second fluid supply container.

4. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 3 wherein the pump operates in a first direction when pumping fluid from the first fluid supply container and the pump operates in a second direction when pumping fluid from the second fluid supply container.

5. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 3 wherein the controller is configured to receive the second output signal from the second scale, to determine the rate of change in weight of the second fluid supply container, and to determine that the second fluid supply container is empty when the rate of change becomes substantially zero.

6. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 1 wherein the first scale measures the weight of the first fluid supply container over pump-unit intervals and compares weight change measured by the first scale for each pump-unit interval to a volume pumped during the pump-unit intervals.

7. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 6 wherein the controller is configured to indicate the first fluid supply container is empty if the ratio of the weight change to the volume pumped is less than a predetermined value for two consecutive pump-unit intervals.

15. The system of claim 7 wherein the controller is further configured to provide notification when the ratio or weight change to the volume pumped is less than a predetermined value and if less than a predetermined time has elapsed after the pump begins pumping fluid from the second fluid supply container.

18. The system of claim 3 wherein an accumulated volume of fluid pumped from the first and second fluid supply containers is tracked based on the change of weight of the fluid supply containers and the accumulated volume is increased by a predetermined amount for each time the pumping switches between the first and second fluid supply containers.

8. A system for determining when a fluid supply container of a fluid processing apparatus becomes empty, the system comprising:

a first fluid supply container;

a first scale for measuring the weight of the first fluid supply container and providing a first output signal indicative of the measured weight of the first fluid supply container;

a pump for pumping fluid from the first fluid supply container;

a controller configured to receive the first output signal from the first scale,

and to determine the rate of change in weight of the first fluid supply container,

means for determining the rate of fluid flow from the pump;

the controller further configured to determine that the first fluid supply container is empty when the ratio of the rate of change in weight of the first fluid supply container to the rate of fluid flow from the pump is less than a predetermined value and the weight of the first fluid supply container is less than a first pre-established threshold.

9. The system for determining when a fluid supply container of a blood processing apparatus becomes empty in accordance with claim 8 wherein the controller is configured to cause the pump to cease pumping when the controller determines that the first fluid supply container is empty.

10. The system for determining when a fluid supply container of a fluid processing apparatus becomes empty in accordance with claim 8 further comprising:

a first valve in fluid communication between the first fluid supply container and the pump, the first valve normally in an open condition;

a second fluid supply container;

a second scale for measuring the weight of the second fluid supply container and providing a second output signal indicative of the measured weight of the second fluid supply container;

a second valve in fluid communication between the second fluid supply container and the pump, the second valve normally in a closed condition;

the controller configured to cause the pump to cease pumping upon determining that the first fluid supply container is empty, to cause the second valve to move to an open condition and to cause the first valve to move to a closed condition, the controller configured to then activate the pump to begin pumping fluid from the second fluid supply container.

16. The system of claim 10 in which the controller is further configured to provide notification when the ratio of the weight change to the volume pumped is less than a predetermined value and if less than a predetermined time has elapsed after the pump begins pumping fluid from the second fluid supply container.

19. The system of claim 10 wherein an accumulated volume of fluid pumped from the first and second fluid supply containers is tracked based on the change of weight of the fluid supply containers and the accumulated volume is increased by a predetermined amount for each time the pumping switches between the first and second fluid supply containers.

11. A method of determining when a fluid supply container of a fluid processing system becomes empty, the method comprising:

providing a first fluid supply container adapted to be in communication with a patient when a first valve is in an open condition;

monitoring the weight of the first fluid supply container while it is being emptied by a pump that is pumping fluid from the first fluid supply container into the patient;

establishing a first threshold weight for the first fluid supply container;

determining a rate of change of the weight of the first fluid supply container;

determining when the rate of change of the weight of the first fluid supply container becomes substantially zero and the weight of the first fluid supply container is less than the first threshold weight; and

stopping the operation of the pump when the rate of change of the weight of the first fluid supply container is determined to be substantially zero and the weight of the first fluid supply container is less than the first threshold weight.

12. The method of claim 11 wherein when upon determining that the rate of change of the weight of the first fluid supply container is substantially zero and the weight of the first fluid supply container is less than the first threshold weight further moving the first valve to a closed condition.

13. The method of claim 12 further comprising:

providing a second fluid supply container adapted to be in communication with a patient when a second valve is in an open condition; and

moving the second valve to an open condition upon determining that the rate of change of the weight of the first fluid supply container is substantially zero and the weight of the first fluid supply container is less than the established threshold weight.

14. The method of claim 12 further comprising:

measuring the weight of the second fluid supply container while it is being emptied by a pump that is pumping fluid from the second fluid supply container into the patient;

establishing a second threshold weight for the second fluid container;

determining a rate of change of the weight of the second fluid supply container;

determining when the rate of change of the weight of the second fluid supply container becomes substantially zero and the weight of the second fluid supply container is less than the second threshold weight; and

stopping the operation of the pump when the rate of change of the weight of the second fluid supply container is determined to be substantially zero and the weight of the second fluid supply container is less than the second threshold weight.

17. The method of claim 13 further comprising providing notification when the ratio of weight change to the volume pumped is less than a predetermined value and if less than a predetermined time has elapsed after the pump begins pumping fluid from the second fluid supply container.

20. The method of claim 12 further comprising:

tracking the accumulated volume of fluid pumped from the first and second fluid supply containers based on the change of weight of the fluid supply containers and the accumulated volume is increased by a predetermined amount for each time the pumping switches between the first and second fluid supply containers.