Medical fluid compounding systems with coordinated flow control
A system for compounding precise amounts of fluid from one or more source containers into at least one target container is described. The fluid can be drawn from the one or more source containers via an intermediate measuring container such as a syringe pump actuated by a stepper motor or other electronic motor. A system controller can use a measured back EMF value of the motor to determine a pressure within a syringe pump, and control the operation of the motor based at least in part on the determined pressure. The determined pressures of a plurality of syringe pumps can be used to optimize the speed at which the syringe pumps dispense fluid from the source containers while avoiding an overpressure condition which can compromise a compounding process and damage one-way valves within the system.
1. An electronically controlled compounding system configured to transfer fluids from a plurality of source containers to a target container, the system comprising:
a plurality of fluid transfer stations, each of the plurality of fluid transfer stations comprising:
an electric motor; and
a pump functionally connected to the electric motor, the pump actuatable via the electric motor to transfer fluid between a source container and an outlet line in fluid communication with the pump;
a mixing manifold in fluid communication with the outlet lines of each of the plurality of fluid transfer stations, the mixing manifold comprising an outlet connector configured to be placed in fluid communication with a target container; and
an electronic controller configured to receive information from each of the plurality of electric motors indicative of a measured back electromotive force (EMF) voltage during operation of the electric motors and to control the operation of the plurality of electric motors based at least in part on the received information indicative of the measured back EMF voltages.
2. The system of claim 1 , wherein one or more pumps of the plurality of fluid transfer stations is a syringe pump.
3. The system of claim 2 , wherein the electronic controller is configured to determine a pressure within the syringe pumps of each of the plurality of fluid transfer stations based at least in part on the received information indicative of the measured back EMF voltage of the electric motor of the fluid transfer station.
4. The system of claim 3 , wherein the electronic controller is configured to control the operation of an electronic motor based at least in part on the determined pressure within the syringe pump functionally connected to the electric motor.
5. The system of claim 3 , wherein the electronic controller is configured to estimate a pressure at the outlet connector of the mixing manifold based at least in part on the determined pressures within the plurality of syringe pumps.
6. The system of claim 1 , wherein one or more pumps of the plurality of fluid transfer stations is a peristaltic pump.
7. The system of claim 1 , wherein the electric motor comprises control circuity configured to measure the back EMF voltage during operation of the electric motor and transmit an output signal indicative of the back EMF voltage.
8. The system of claim 1 , wherein each of the plurality of fluid transfer stations additionally comprises:
a source check valve disposed between the pump of the fluid transfer station and a source inlet configured to be placed in fluid communication with a source container; and
a target check valve disposed between the pump of the fluid transfer station and the outlet line.
9. The system of claim 8 , wherein each of the plurality of fluid transfer stations additionally comprises a connector configured to place the pump of the fluid transfer station in fluid communication with the outlet line and the source container, and wherein each of the source check valve and the target check valve are disposed within the connector.
10. The system of claim 3 , wherein the electronic controller is configured to compare the determined pressure within the syringe pumps of each of the plurality of fluid transfer stations to a threshold pressure in order to identify an overpressure condition.
11. An electronically controlled compounding system configured to compound fluids drawn from a plurality of source containers in desired proportions in a destination container, the system comprising:
a plurality of syringe pumps, each syringe pump of the plurality of syringe pumps comprising a plunger movable relative to a body of the syringe pump;
a plurality of motors, each of the plurality of motors being configured to control the position of a linear actuator mechanism configured to be connected to one of the plurality of syringe pumps to control the position of the plunger of the syringe pump; and
an electronic controller configured to control the operation of each of the plurality of motors to cause the plurality of syringe pumps to dispense fluids drawn from a plurality of source containers in desired proportions into a destination container, the electronic controller configured to receive information from each of the plurality of motors regarding a back electromotive force (EMF) voltage of the motor and control the operation of each of the plurality of motors based at least in part on the received information regarding the back EMF voltages of the plurality of motors.
12. The system of claim 11 , wherein the system further comprises:
a plurality of outlet lines, each of the plurality of outlet lines in fluid communication with one of the plurality of syringe pumps via a destination check valve; and
a manifold connector in fluid communication with each of the plurality of outlet lines, wherein the controller is configured to estimate a pressure at the manifold connector based at least in part on the received information regarding the back EMF voltages of the plurality of motors.
13. The system of claim 12 , wherein the electronic controller is configured to:
determine the pressure in each of the syringe pumps based at least in part on the information regarding the back EMF voltages of the plurality of motors; and
estimate the pressure at the manifold connector based at least in part on the determined pressure in each of the syringe pumps.
14. The system of claim 12 , wherein the electronic controller is configured to control the operation of the plurality of motors based on a set of dispensing parameters, and wherein the electronic controller is configured to update the set of dispensing parameters based at least in part on the estimated pressure at the manifold connector.
15. The system of claim 14 , wherein the electronic controller is configured to update the set of dispensing parameters to reduce a completion time of a compounding process while maintaining the estimated pressure at the manifold connector below a threshold pressure.
16. A method of adjusting dispensing parameters of a multichannel compounder, the method comprising:
beginning a compounding process to combine fluids dispensed from a plurality of source containers into a single target container using a plurality of syringe pumps, each syringe pump in fluid communication with a mixing manifold and one of the plurality of source containers, each of the plurality of syringe pumps comprising a driving motor, the driving motors being controlled according to an initial set of driving parameters;
during the compounding process, determining pressures within each of the plurality of syringe pumps based on a measured back electromotive force (EMF) voltage; and
during the compounding process, updating the initial set of driving parameters based at least in part on the determined pressure within each of the plurality of syringe pumps.
17. The method of claim 16 , wherein updating the initial set of driving parameters comprises reducing a driving speed of at least one of the plurality of syringe pumps.
18. The method of claim 17 , wherein reducing a driving speed of at least one of the plurality of syringe pumps comprises reducing a driving speed of a syringe pump having the highest determined pressure of the plurality of syringe pumps.
19. The method of claim 16 , wherein updating the initial set of driving parameters comprises increasing a driving speed of at least one of the plurality of syringe pumps.
20. The method of claim 19 , wherein increasing a driving speed of at least one of the plurality of syringe pumps comprises increasing a driving speed of a syringe pump having the largest remaining amount of fluid to be dispensed.