Extracorporeal circulation apparatus

Apparatus for filtering whole blood to selectively remove designated components thereof comprising:

• a filter for filtering the whole blood through a porous membrane to separate the designated components from the filtrate resulting from the filtration, the whole blood flowing interiorly of said filter on one side of said porous membrane at an interior pressure and the designated components flowing through said porous membrane to another side of said porous membrane at substantially atmospheric pressure to remove the designated components from the whole blood as the filtrate passes through said filter, the volume of said filtrate varying depending upon the amount of designated components removed and being substantially less than the volume of the whole blood;
• a first pump operating at a first speed for pumping the volume of whole blood through the interior on said one side of said filter at a first flow rate;
• a pressure monitoring means for sensing a first pressure of the whole blood between said first pump and said filter;
• a second pump operating at a second speed for regulating the flow rate of the reduced volume of the filtrate from the outlet of said filter;
• a second pressure monitoring means for sensing a second pressure of the reduced volume of the filtrate between said filter and said second pump;
• control means for reading said first and second pressures and speeds to determine said interior pressure and flow rates of the whole blood and filtrate and regulating said speeds of first and second pumps to maintain a predetermined interior pressure of said filter and flow rates of the whole blood and filtrate;
• fluid connecting means for providing a blood flow path from said first pump to said filter to said second pump;
• and
• said first and second pumps fully occluding said fluid connecting means to act as flowmeters to measure and regulate said flow rates as the volumes vary during filtration.

Apparatus for filtering whole blood to selectively remove designated components thereof and return the filtrate to the patient, comprising:

• a filter for filtering the whole blood through a porous membrane to remove the designated components from the whole blood and produce the resulting filtrate with the whole blood flowing interiorly of said filter on one side of said porous membrane at a predetermined interior pressure and the designated components flowing through said porous membrane to the other side of said porous membrane to remove the designated components as the whole blood passes through said filter, the volume of the filtrate varying depending upon the amount of designated components removed and being substantially less than the volume of the whole blood, said membrane having a given filter permeability;
• a first peristaltic pump operating at a first speed for pumping the volume of whole blood through the interior of said filter at a first flow rate;
• a pressure monitoring means for sensing the inlet pressure of the whole blood between said first pump and said filter;
• a second peristaltic pump operating at a second speed for pumping the reduced volume of the filtrate from the outlet of said filter at a second flow rate to the patient's bloodstream having a higher pressure than the outlet pressure of said filter;
• control means for reading said inlet pressure and said first flow rate to determine said interior pressure from said given filter permeability and regulating said speeds and flow rates of said first pump and said second pump to maintain said predetermined interior pressure;
• fluid connecting means for providing a blood flow path from said first pump to said filter to said second pump;
• and
• said second pump having rollers fully occluding said fluid connectig means to force the filtrate into the patient's bloodstream against the higher pressure.

Apparatus for receiving whole blood from a patient, treating the whole blood, and returning the treated blood to the patient, comprising:

• treatment means forming a first and second compartment having pores therebetween for treating the patient's whole blood to remove blood components therefrom by passing the damaged blood cells from said first compartment through said pores into said second compartment as the blood flows through said first compartment;
• said second compartment having an exit to the ambient for the disposal of the damaged blood cells;
• said first compartment having an inlet for the whole blood and an outlet for the treated blood, said treated blood having a reduced volume which varies according to the amount of blood components removed from the whole blood by said treatment means;
• tubing means for receiving the patient's whole blood, circulating the whole blood to said inlet of said treatment means, and returning the treated blood from said outlet to the patient;
• arterial pump means connected to said tubing means having a plurality of rollers fully occluding said tubing means to force the whole blood to flow to said inlet of said treatment means;
• venous pump means connected to said tubing means and independent of said arterial pump means also having a plurality of rollers fully occluding said tubing means to force the treated blood from said treatment means back to the patient's bloodstream, the pressure of the treated blood downstream of said venous pump being greater than the pressure of the treated blood upstream of said venous pump;
• and
• control means for controlling said arterial pump means at a first rate and said venous pumpp at a second rate to regulate independently the treatment of the blood by said treatment means and the return of the treated blood to the patient.

An apparatus for receiving whole blood from a patient, filtering the whole blood to selectively remove designated components thereof, and returning the filtrate to the patient comprising:

• receiver means for receiving the patient's whole blood;
• filter means having a porous membrane dividing said filter means into first and second chambers for filtering the whole blood and selectively passing the designated components from said first chamber through the pores of said porous membrane into said second chamber to remove the designated components as the whole blood passes through said first chamber of said filter means at a predetermined pressure;
• said second chamber having an exit to the ambient for the disposal of the designated components;
• said first chamber having an inlet for the whole blood and an outlet for the filtrate, said filtrate having a reduced volume which varies according to the amount of designated components removed from the whole blood;
• return means for returning the filtrate to the patient;
• tubing for circulating the blood among said receiver means, filter means and return means;
• an arterial pump connected to said tubing and having a plurality of rollers fully occluding said tubing and operating at a first speed for pumping the blood from said receiver means to said inlet of said filter means at a first flow rate;
• first pressure monitoring means for monitoring the inlet pressure of the whole blood between said arterial pump and the inlet of said filter means;
• a venous pump connected to said tubing and having a plurality of rollers fully occluding said tubing and independently operating at a second speed for pumping the filtrate of reduced volume from the outlet of said filter means to said return means to the patient's bloodstream having a higher pressure than the outlet pressure of said filter at a second flow rate;
• second pressure monitoring means for monitoring the outlet pressure of the reduced volume of the filtrate between said venous pump and the outlet of said filter means;
• said venous pump being a positive displacement pump which displaces a predetermined volume of filtrate independent of the pressure of the whole blood, said pumps acting as flowmeters to regulate said flow rates as the volumes vary during filtration;
• and
• control means for reading said inlet and outlet pressures of said first and second pressure monitoring means and said speeds of said pumps for regulating said first and second flow rates to maintain said predetermined pressure of said filter means.

An apparatus for receiving a patient's whole blood, filtering the whole blood to selectively remove designated components thereof, and returning the filtered blood to the patient, comprising:

• an accumulator for accumulating the patient's whole blood;
• receiver means for receiving the patient's whole blood from said accumulator, including a cardiotomy for collecting the patient's whole blood and releasing air from the whole blood;
• filter means for filtering the whole blood through a porous membrane to separate the designated components from the filtrate as the whole blood passes through said filter means at a predetermined pressure to remove the designated components by flowing the designated components through said membrane to the other side of said membrane at atmospheric pressure;
• return means for returning the filtered blood to the patient, the filtered blood having a reduced volume which varies according to the amount of designated components removed from the whole blood;
• an arterial pump operating at a speed for pumping the whole blood from said receiver means to said filter means;
• first pressure monitoring means for continually monitoring inlet pressure of the whole blood between said arterial pump and the inlet of said filter means;
• a venous pump for pumping the filtered blood from said filter means to said return means at a constant flow rate;
• second pressure monitoring means for continually monitoring the outlet pressure of the filtered blood between said venous pump and the outlet of said filter means;
• tubing means for circulating the blood among said receiver means, treatment means, arterial and venous pumps, and return means;
• said pumps having a plurality of rollers fully occluding said tubing means to act as flowmeters to measure and regulate said flow rates as the volumes vary during filtration, said venous pump forcing the filtered blood downstream into the patient's bloodstream at a pressure higher than the outlet pressure;
• control means, having pump controllers for independently regulating the speed of said arterial and venous pumps, and having a central processor for reading said inlet and outlet pressures of said first and second pressure monitoring means and regulating said speed of said arterial pump to maintain said predetermined pressure of said filter means;
• said control means including an input device connected to said central processor for input of predetermined operational parameters;
• and
• a display device connected to said central processor for displaying operational parameters.

A method of filtering whole blood to selectively remove designated components thereof, comprising the steps of:

• removing whole blood from a patient utilizing tubing extending to a filter;
• pumping blood through the tubing using a pump having a plurality of rollers which fully occlude the tubing as the rollers rotate at a first speed;
• passing the whole blood into a first chamber of the filter;
• filtering the designated components through a porous membrane at a predetermined pressure into a second chamber at atmospheric pressure;
• passing the filtrate having a reduced volume from the filter into a tubing extending to the patient;
• pumping the filtrate through the tubing utilizing a second pump having a plurality of rollers which fully occlude the tubing at a second flow rate;
• sensing said filter pressure and said second flow rate;
• regulating said first flow and said second flow rates to maintain a predetermined filter pressure;
• and
• pumping the filtrate into the patient's bloodstream at a pressure higher than the outlet pressure of the filter.