Withdrawal of priming fluid from extracorporeal circuit of hemodialysis machines or the like
First Claim
1. A method of removing a priming fluid from an extracorporeal circuit of a dialysis machine, said extracorporeal circuit comprising arterial and venous lines filled with said priming fluid and a dialyzer connected to said arterial and venous lines, said dialyzer having a membrane separating said extracorporeal circuit from a dialysate circuit and a blood side in said extracorporeal circuit and a dialysate side in said dialysate circuit, the method comprising the steps of:
- transporting at least a portion of said priming fluid from said extracorporeal circuit across said dialyzer membrane into said dialysate circuit; and
simultaneously introducing blood from a patient connected to said arterial and venous lines into at least one of said arterial and venous lines as said priming fluid is being transported across said dialyzer membrane,whereby the introduction of said blood into said arterial and venous lines and withdrawal of said priming fluid from said extracorporeal circuit prevents said portion of priming fluid from being substantially returned to said patient or disposed of in a receptacle externally of the extracorporeal circuit.
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Accused Products
Abstract
A method for withdrawing priming fluid from the extracorporeal circuit of a dialysis machine is described which substantially prevents return of the priming fluid back to the patient. In accordance with the method, priming fluid is drawn from the extracorporeal circuit through the dialyzer membrane and into the dialysate circuit. Blood is introduced into the extracorporeal circuit as the priming fluid is withdrawn through the dialyzer. Withdrawal of the priming fluid may be accomplished by pumping the blood pump in the forward direction at a first rate and operating a pump in the dialysate circuit at a second rate. Valves in the dialysate circuit are operated such that the pump in the dialysate circuit draws priming fluid across the dialyzer membrane into the dialysate circuit, and thereby prevents the priming fluid from being returned to the patient. In a preferred embodiment, the fluid volumes of the arterial and venous portions of the extracorporeal circuit, and the fluid volume of the blood side of the dialyzer, are known in advance. With this information, it is possible to operate the blood and dialysate pumps such that the blood progresses into the arterial and venous lines at different rates such that blood reaches the dialyzer via both lines at about the same time, while at the same time the priming fluid is withdrawn through the dialyzer. Thus, in this embodiment, blood fills the extracorporeal circuit after priming with only a small amount of priming fluid remaining in the blood compartment of the dialyzer being returned to the patient.
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Citations
23 Claims
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1. A method of removing a priming fluid from an extracorporeal circuit of a dialysis machine, said extracorporeal circuit comprising arterial and venous lines filled with said priming fluid and a dialyzer connected to said arterial and venous lines, said dialyzer having a membrane separating said extracorporeal circuit from a dialysate circuit and a blood side in said extracorporeal circuit and a dialysate side in said dialysate circuit, the method comprising the steps of:
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transporting at least a portion of said priming fluid from said extracorporeal circuit across said dialyzer membrane into said dialysate circuit; and simultaneously introducing blood from a patient connected to said arterial and venous lines into at least one of said arterial and venous lines as said priming fluid is being transported across said dialyzer membrane, whereby the introduction of said blood into said arterial and venous lines and withdrawal of said priming fluid from said extracorporeal circuit prevents said portion of priming fluid from being substantially returned to said patient or disposed of in a receptacle externally of the extracorporeal circuit. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 22, 23)
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3. The method of clam 1, wherein said at least a portion of said priming fluid comprises at least 90 percent of the fluid volume of said extracorporeal circuit.
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12. A dialysis machine having an extracorporeal circuit which prevents priming fluid from substantially being returned to a patient connected to said dialysis machine via arterial and venous lines, comprising:
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a blood pump in said extracorporeal circuit for circulating fluid in said extracorporeal circuit; a dialyzer separating said extracorporeal circuit from a dialysate circuit, said dialyzer having a dialyzer membrane with a blood side thereof in said extracorporeal circuit and a dialysate side in said dialysate circuit; a pump in said dialysate circuit in fluid communication with said dialyzer; first and second valves in said dialysate circuit positioned upstream and downstream from said dialyzer, respectively; and a computer control system operative of said blood pump, pump in said dialysate circuit and said first and second valves, wherein when said extracorporeal circuit is filled with said priming fluid and a patient is connected to said arterial and venous lines, said computer control system operates said blood pump so as to pump blood into said extracorporeal circuit and said pump in said dialysate circuit and said first and second valves for a predetermined amount of time so as to transport said priming fluid across said dialyzer membrane into said dialysate circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification