SYSTEMS AND METHODS FOR DETECTING VASCULAR ACCESS DISCONNECTION
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Accused Products
Abstract
A system for detecting whether a vascular access has been interrupted in an arrangement in which two catheters or needles are present in a blood vessel, fistula or graft. A fluid line leading to a pump is connected via a first connector to a first indwelling catheter, and a fluid line leading from a pump is connected via a second connector to a second indwelling catheter. Each connector is equipped with an electrode in contact with the lumen of the connector, the electrodes electrically connected to an electronic circuit that measures the impedance or conductivity of fluid between the first connector and second connectors via a fluid path through the blood vessel, fistula or graft. An electronic controller receives the impedance or conductivity data and processes the data to determine whether a vascular access disconnection has occurred. The processing may involve filtering the signal received by the controller, and/or setting provisional flags for a disconnection event that may be cleared if the signal changes before the expiration of a counter.
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Citations
35 Claims
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1-34. -34. (canceled)
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35. A system for detecting replacement of blood by dialysate solution in a blood tubing set of a hemodialysis apparatus in which dialysate is pumped from a dialysate side to a blood side of a dialyzer, the system comprising:
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a first fluid line fluidly connecting a first catheter or needle in a blood vessel, fistula or graft to an inlet of a blood pump; a second fluid line fluidly connecting a second catheter or needle in the blood vessel, fistula or graft to an outlet of the blood pump; a first connector connecting the first fluid line to the first catheter or needle, and a second connector connecting the second fluid line to the second catheter or needle, the first connector having a first electrode in fluid communication with a fluid carrying lumen of said first connector, and the second connector having a second electrode in fluid communication with a fluid carrying lumen of said second connector; an electronic circuit having a first terminal electrically connected to the first electrode and a second terminal electrically connected to the second electrode, and configured to measure electrical impedance of fluid between the first connector and the second connector via a conductive path through the blood vessel, fistula or graft; a controller configured to receive a series of sampled electrical impedance values from the electronic circuit, and to process the electrical impedance values as a signal; wherein the controller is configured to; measure the signal or a filtered form of the signal as dialysate is pumped through the dialyzer to the blood tubing set; determine whether the signal or a filtered form of the signal has a first value approximately equal to an expected value of the signal for blood in the first and second fluid lines, or has a second value approximately equal to an expected value of the signal for dialysate solution in the first and second fluid lines; determine a point in time when the signal or a filtered form of the signal changes from the first value to the second value; and provide a first notification to a user if the controller detects a change from the first value to the second value, or provide a second notification to the user if the controller detects a change from the first value that is less than approximately the second value within a pre-determined period of time.
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Specification