Method and apparatus for determining a rate of flow of blood for an extracorporeal blood therapy instrument

For use with an extracorporeal blood therapy instrument, apparatus for determining a rate of flow of blood in a channel, comprising:

• said channel having a predetermined volume between first and second predetermined positions therein;
• a first flexibly resilient tube for transporting said blood;
• a second flexibly resilient tube for transporting another fluid;
• a connector connected to said first and second tubes and said channel for inserting a bolus of said other fluid into said blood for producing an interface at said first predetermined position in said channel;
• a clamp unit including an electric motor under control of a processor and a roller eccentrically connected to said motor for selectively occluding said flow of said blood and a flow of said other fluid in said first and second tubes for producing said bolus of said other fluid;
• a laser for directing an optical signal having a predetermined intensity into said channel at said second predetermined position;
• a first photodetector responsive to said optical signal transmitted through said channel at said second predetermined position for producing a first output signal indicative of when said interface is thereat and a second output signal indicative of bubbles in said blood;
• a second photodetector responsive to said optical signal reflected from said channel for producing a third output signal indicative of particles in said blood and a fourth output signal indicative of a pulsating flow of said blood;
• a timer circuit for determining a time period initiated by an indication of when said interface is produced and terminated by said first output signal;
• a processor utilizing a predetermined algorithm and an indication of said volume and responsive to said time period for calculating said blood flow rate;
• said processor being further responsive to said second through fourth output signals for determining a quantity for said bubbles, said particles, and said pulsating blood flow, respectively;
• and
• a display unit for visually displaying said blood flow rate and said quantity of said bubbles, said particles, and said pulsating blood flow.

For use with an extracorporeal blood therapy instrument, method for determining a rate of flow of blood in a channel, comprising:

• producing a trailing interface of another fluid and between said blood and said another fluid at a first predetermined position in said channel and a first indication of a production of said trailing interface;
• producing a second indication of when said trailing interface is at a second predetermine position in said channel, said channel having a predetermined volume between said first and second positions;
• and
• calculating said rate of said flow of said blood in said channel utilizing a predetermine algorithm, said first and second indications, and an indication of said predetermined volume.

For use with an extracorporeal blood therapy instrument, apparatus for determining a rate of flow of blood through a channel, comprising:

• first means for transporting said blood, second means for transporting another fluid, and connector means for inserting a bolus of said other fluid into said blood for producing an interface between said blood and said other fluid at a first predetermined position in said channel;
• sensor means for producing an output signal indicative of when said interface is at a second predetermined position in said channel, said channel having a predetermine volume between said first and second predetermined positions;
• control means utilizing a predetermined algorithm and an indication of said volume and responsive to said output signal and an indication of when said interface is produced for calculating said blood flow rate through said channel;
• and
• clamp means under control of said control means for selectively occluding said flow of said blood and a flow of said other fluid in said first and second means, respectively.

For use with an extracorporeal blood therapy instrument, apparatus for determining a rate of flow of blood through a channel, comprising:

• delivery means for producing an interface between said blood and another fluid at a first predetermined position in said channel;
• sensor means for producing an output signal indicative of when said interface is at a second predetermined position in said channel, said channel having a predetermined volume between said first and second predetermined positions;
• control means utilizing a predetermine algorithm and an indication of said volume and responsive to said output signal and an indication of when said interface is produced for calculating said blood flow rate through said channel;
• and
• means for determining the amount of said other fluid delivered to said channel.

For use with an extracorporeal blood therapy instrument, method for determining a rate of flow of blood in a channel, comprising:

• producing an interface between said blood and another fluid at a first predetermined position in said channel and a first indication of a production of said interface, said producing including transporting said blood in a first resilient flexible tube and said other fluid in a second resiliently flexible tube interconnecting said first and second tubes with said channel, and selectively occluding said blood flow and a flow of said other fluid in said first and second tubes, respectively;
• producing a second indication of when said interface is at a second predetermine position in said channel, said channel having a predetermined volume between said first and second positions;
• and
• calculating said rate of said flow of said blood in said channel utilizing a predetermined algorithm, said first and second indications, and an indication of said predetermined volume.