Flow balancing devices, methods, and systems
AssigneeNxStage Medical, Inc.
InventorsDennis M. Treu, Jerome James, Jeffrey H. Burbank, Daniel Joseph Rubery, Jr.
Life of this patent
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Abstract
The disclosed subject matter relates to extracorporeal blood processing or other processing of fluids. Volumetric fluid balance, a required element of many such processes, may be achieved with multiple pumps or other proportioning or balancing devices which are to some extent independent of each other. This need may arise in treatments that involve multiple fluids. Safe and secure mechanisms to ensure fluid balance in such systems are described.
Claims20
A method for controlling flow in a fluid circuit, comprising:
- using an extracorporeal fluid treatment system that includes a controller, controlling a balancing component that balances flows to and from a patient to maintain, or restore, a patient's normal fluid balance by regulating speeds of multiple pumps;
- attaching a replaceable disposable fluid circuit through which flows of fluid are balanced to the extracorporeal fluid treatment system;
- attaching bags containing fluids to the replaceable disposable fluid circuit;
- pumping a priming fluid through the replaceable disposable fluid circuit including pumping fluid through pumping tube segments thereof;
- after completion of the pumping of the priming fluid, detecting pressures in portions of the replaceable disposable fluid circuit, with pressure sensors, caused by a hydrostatic head of the fluids in the bags attached to the replaceable disposable fluid circuit;
- determining, over a time interval, a rate of change of said hydrostatic-head pressures;
- and
- based on the determined rate of change of said hydrostatic-head pressures, generating a retry command or a fail command.
A system for controlling flow in a fluid circuit, comprising:
- an extracorporeal fluid treatment system having a controller configured to command a balancing component that is configured to balance flows to and from a patient to maintain, or restore, a normal fluid balance of the patient by regulating speeds of two pumps of the balancing component;
- a replaceable disposable fluid circuit attached to the extracorporeal fluid treatment system and connected to said two pumps and configured to convey fluids to be balanced;
- a source of a priming fluid connected to the replaceable disposable fluid circuit and connected to a third pump that engages a pumping tube segment of the replaceable disposable fluid circuit;
- and
- bags containing fluids attached to the fluid circuit, wherein
- the controller is configured to pump the priming fluid through the replaceable disposable fluid circuit during a priming operation,
- the controller is further configured to, after completion of the priming operation, detect pressures, with pressure sensors, in portions of the replaceable disposable fluid circuit caused by a hydrostatic head of the fluids in the bags,
- the controller is further configured to determine, over a time interval, a rate of change of said hydrostatic-head pressures, and
- the controller is further configured to generate a retry or fail command based on the determined rate of change of said hydrostatic-head pressures.
Dependencies are inferred from the claim text.