Method and apparatus for ultrafiltration measurement in a two pump dialysis system

Claim 2

In a dual pump blood processing system for a patient wherein an arterial pump fills blood processing means with blood from the patient and a venous pump removes a known volume of blood from said blood processing means between said arterial and venous pumps and returns said blood to the patient, said arterial and venous pumps being alternately operated to fill and remove blood in response to control means, apparatus for performing ultrafiltration measurements comprising: (a) first means associated with said arterial pump for providing first signals responsive to the volume pumped by said arterial pump; (b) second means associated with said venous pump for providing second signals responsive to the volume pumped by said venous pump; (c) first and second signal connecting means for communicating said first and second signals to said control means and wherein said control means calculates the ultrafiltration volume in response to said first and second signals.

Claim 3

The apparatus as set forth in claim 1 wherein said control means further calculates the ultrafiltration rate based on the ultrafiltration volume and the elapsed time.

Claim 4

The apparatus as set forth in claim 1 wherein said first and second means comprises a slot encoder and said control means comprises a microprocessor with display means.

Claim 5

A low pressure blood processing system for a patient comprising: means for withdrawing blood from said patient; a first arterial blood pump having an input coupled to said withdrawing means and an output at which a flow of blood is provided when said pump is activated; means for processing blood having an input coupled to the output of said arterial blood pump and an output at which a flow of processed blood is produced; a second venous blood pump having an input coupled to the output of said blood processing system, and an output; means, coupled to the output of said venous blood pump, for returning processed blood to said patient, wherein said blood processing system exhibits a given blood capacity when full; a monitor coupled to said blood processing system for detecting the attainment of said given blood capacity; blood pump control means, coupled to said pumps and said monitor, for activating said venous blood pump upon detection of said given blood capacity, and for activating said arterial blood pump after said venous blood pump has been activated for a given number of operating cycles; first means associated with said arterial blood pump and connected to said control means for providing to said control means first signals responsive to the volume of blood pumped by said arterial pump; second means associated with said venous blood pump and connected to said control means for providing to said control means second signals responsive to the volume of blood pumped by said venous pump; and wherein said control means displays ultrafiltration information in response to said first and second signals.

Claim 6

A low pressure blood processing system for a patient comprising: means for withdrawing blood from said patient; a first arterial blood pump having an input coupled to said withdrawing means and an output at which a flow of blood is provided when said pump is activated; means for processing blood having an input coupled to the output of said arterial blood pump and an output at which a flow of processed blood is produced; a second venous blood pump having an input coupled to the output of said blood processing system, and an output; means, coupled to the output of said venous blood pump, for returning processed blood to said patient, wherein said blood processing system exhibits a given blood capacity when full; a monitor coupled to said blood processing system for detecting the attainment of said given blood capacity; blood pump control means, coupled to said pumps and said monitor, for activating said venous blood pump upon detection of said given blood capacity, and for activating said arterial blood pump after said venous blood pump has been activated for a given number of operating cycles; first means associated with said arterial blood pump and connected to said control means for providing to said control means first signals responsive to the volume of blood pumped by said arterial pump; second means associated with said venous blood pump and connected to said control means for providing to said control means second signals responsive to the volume of blood pumped by said venous pump; and wherein said control means displays ultrafiltration information in response to said first and second signals.

Claim 7

A low pressure blood processing system for a patient comprising: means for withdrawing blood from said patient; a first arterial blood pump having an input coupled to said withdrawing means and an output at which a flow of blood is provided when said pump is activated; means for processing blood having an input coupled to the output of said arterial blood pump and an output at which a flow of processed blood is produced; a second venous blood pump having an input coupled to the output of said blood processing system, and an output; means, coupled to the output of said venous blood pump, for returning processed blood to said patient; a pressure monitor coupled to said blood processing system for detecting the blood pressure therein; blood pump control means, coupled to said pumps and said monitor, for activating said venous blood pump when said detected blood pressure of said blood processing system attains a given threshold, and for activating said arterial blood pump after said venous blood pump has been activated for a given number of operating cycles; first means associated with said arterial blood pump and connected to said control means for providing to said control means first signals responsive to the volume of blood pumped by said arterial pump; second means associated with said means blood pump and connected to said control means for providing to said control means second signals responsive to the volume of blood pumped by said venous pump; and wherein said control means displays ultrafiltration information in response to said first and second signals.

Claim 8

A low pressure blood processing system for a patient comprising: means for withdrawing blood from said patient; a first arterial blood pump having an input coupled to said withdrawing means and an output at which a flow of blood is provided when said pump is activated; means for processing blood having an input coupled to the output of said arterial blood pump and an output at which a flow of processed blood is produced; a second venous blood pump having an input coupled to the output of said blood processing system, and an output; means, coupled to the output of said venous blood pump, for returning processed blood to said patient; a pressure monitor coupled to said blood processing system for detecting the blood pressure therein; blood pump control means, coupled to said pumps and said monitor, for activating said venous blood pump when said detected blood pressure of said blood processing system attains a given threshold, and for activating said arterial blood pump after said venous blood pump has been activated for a given number of operating cycles; first means associated with said arterial blood pump and connected to said control means for providing to said control means first signals responsive to the volume of blood pumped by said arterial pump; second means associated with said means blood pump and connected to said control means for providing to said control means second signals responsive to the volume of blood pumped by said venous pump; and wherein said control means displays ultrafiltration information in response to said first and second signals.

Claim 9

The blood processing system of claim 4, wherein said processing means comprises a dialyzer for performing hemodialysis, and said system further comprises a flexible blood accumulator coupled between said dialyzer and said second venous blood pump, said accumulator exhibiting a known blood capacity when full, and said first and second means include a slot encoder and said ultrafiltration information includes ultrafiltration volume and ultrafiltration rate.

Claim 10

The blood processing system of claim 5, wherein said processing means comprises a dialyzer for performing hemodialysis, and said system further comprises a flexible blood accumulator coupled between said dialyzer and said second venous blood pump, said accumulator exhibiting a known blood capacity when full, and said first and second means include a slot encoder and said ultrafiltration information includes ultrafiltration volume and ultrafiltration rate.

Claim 11

The blood processing system of claim 6, wherein said monitor comprises a pressure transducer coupled between said dialyzer and said venous blood pump for measuring venous blood pressure.

Claim 12

The blood processing system of claim 7, wherein said monitor comprises a pressure transducer coupled between said dialyzer and said venous blood pump for measuring venous blood pressure.

Claim 13

The blood processing system of claim 6, wherein said first and second means detect operating cycles of said arterial and venous blood pumps respectively, and communicate said operating cycle information to said control means which calculates volume of blood pumped by each pump based on each pump's known volume per cycle pumping characteristics.

Claim 14

The blood processing system of claim 7, wherein said first and second means detect operating cycles of said arterial and venous blood pumps respectively and communicate said operating cycle information to said control means which calculates volume of blood pumped by each pump based on each pump's known volume per cycle pumping characteristics.