Blood purification apparatus and method of acquiring plasma flow rate on blood purification apparatus

A method of acquiring a plasma flow rate on a blood purification apparatus, the blood purification apparatus comprising:

• extracorporeally circulating a patient's blood from a distal end of an arterial blood circuit to a distal end of a venous blood circuit of a blood circuit;
• purifying the patient's blood through a blood purifier provided between the arterial blood circuit and the venous blood circuit, the blood purifier having a blood flow route through which the patient's blood extracorporeally circulating through the blood circuit flows and a dialysate flow route through which dialysate flows, the blood flow route and the dialysate flow route being separated from each other by a blood purification membrane for purifying the patient's blood;
• performing ultrafiltration with an ultrafiltration unit that filters out water from the patient's blood in the blood flow route through the blood purification membrane and draining the water through the dialysate flow route;
• supplying substitution fluid with a substitution-fluid supply unit that supplies the substitution fluid into the blood circuit,
• detecting, with a detecting unit, a transmembrane pressure difference occurring on the blood purification membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route;
• acquiring a colloid osmotic pressure of the patient's blood, with a colloid-osmotic-pressure-acquiring unit, in the blood flow route or a correlation value of colloid osmotic pressure with reference to the transmembrane pressure difference occurring when liquid in the blood flow route that does not generate colloid osmotic pressure is supplied into the blood flow route with filtration by the ultrafiltration unit withheld and the transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by the ultrafiltration unit withheld;
• acquiring, with a plasma-total-protein-acquiring unit, a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value of colloid osmotic pressure acquired by the colloid-osmotic-pressure-acquiring unit;
• acquiring, with a plasma-flow-rate-acquiring unit, the plasma flow rate or a correlation value of plasma flow rate with reference to a blood concentration detected from the patient's blood and the plasma total protein or the correlation value of the plasma total protein acquired by the plasma-total-protein-acquiring unit;
• calculating, with reference to the plasma flow rate or the correlation value of plasma flow rate acquired by a plasma-flow-rate-acquiring unit, a substitution rate to be achieved by the substitution-fluid supply unit;
• and
• controlling the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit with a control unit;
• wherein the plasma flow rate (Qpw) is determined with a formula comprising:
• Qpw=Qb*(1−Ht)*(1−0.0107*TP) where Qb is a blood flow rate in mL/min, Ht denotes a hematocrit percentage and TP is the plasma total protein.

A blood purification apparatus comprising:

• a blood circuit including an arterial blood circuit and a venous blood circuit and that allows a patient's blood to extracorporeally circulate from a distal end of the arterial blood circuit to a distal end of the venous blood circuit;
• a blood purifier provided between the arterial blood circuit and the venous blood circuit and that purifies the patient's blood flowing through the blood circuit, the blood purifier having a blood flow route through which the patient's blood extracorporeally circulating through the blood circuit flows and a dialysate flow route through which dialysate flows, the blood flow route and the dialysate flow route being separated from each other by a blood purification membrane for purifying the patient's blood;
• an ultrafiltration unit that performs ultrafiltration by filtering out water from the patient's blood in the blood flow route through the blood purification membrane and draining the water through the dialysate flow route;
• and
• a substitution-fluid supply unit that supplies substitution fluid into the blood circuit, and
• a detecting unit that detects a transmembrane pressure difference occurring on the blood purification membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route;
• the blood purification apparatus comprising:
• a colloid-osmotic-pressure-acquiring unit that acquires a colloid osmotic pressure of the patient's blood in the blood flow route or a correlation value of colloid osmotic pressure with reference to the transmembrane pressure difference occurring when liquid that does not generate colloid osmotic pressure is supplied into the blood flow route with filtration by the ultrafiltration unit withheld and the transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by the ultrafiltration unit withheld;
• a plasma-total-protein-acquiring unit that acquires a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value of colloid osmotic pressure acquired by the colloid-osmotic-pressure-acquiring unit,
• a plasma-flow-rate-acquiring unit that acquires a plasma flow rate or a correlation value of plasma flow rate with reference to a blood concentration detected from the patient's blood and the plasma total protein or the correlation value of the plasma total protein acquired by the plasma total protein acquiring unit;
• and
• a control unit in communication with and controlling the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit;
• wherein a substitution rate to be achieved by the substitution-fluid supply unit is calculated with reference to the plasma flow rate or the correlation value of plasma flow rate acquired by the plasma-flow-rate-acquiring unit;
• wherein the colloid osmotic pressure (CP) is determined with a formula comprising:
• CP=TMPa−TMPb, wherein TMPa is a transmembrane pressure difference occurring when the liquid does not generate colloid osmotic pressure and TMPb is transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by an ultrafiltration pump.

A blood purification apparatus comprising:

• a blood circuit including an arterial blood circuit and a venous blood circuit and that allows a patient's blood to extracorporeally circulate from a distal end of the arterial blood circuit to a distal end of the venous blood circuit;
• a blood purifier provided between the arterial blood circuit and the venous blood circuit and that purifies the patient's blood flowing through the blood circuit, the blood purifier having a blood flow route through which the patient's blood extracorporeally circulating through the blood circuit flows and a dialysate flow route through which dialysate flows, the blood flow route and the dialysate flow route being separated from each other by a blood purification membrane for purifying the patient's blood;
• an ultrafiltration unit that performs ultrafiltration by filtering out water from the patient's blood in the blood flow route through the blood purification membrane and draining the water through the dialysate flow route;
• and
• a substitution-fluid supply unit that supplies substitution fluid into the blood circuit, and
• a detecting unit that detects a transmembrane pressure difference occurring on the blood purification membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route;
• the blood purification apparatus comprising:
• a colloid-osmotic-pressure-acquiring unit that acquires a colloid osmotic pressure of the patient's blood in the blood flow route or a correlation value of colloid osmotic pressure with reference to the transmembrane pressure difference occurring when liquid that does not generate colloid osmotic pressure is supplied into the blood flow route with filtration by the ultrafiltration unit withheld and the transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by the ultrafiltration unit withheld;
• a plasma-total-protein-acquiring unit that acquires a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value of colloid osmotic pressure acquired by the colloid-osmotic-pressure-acquiring unit,
• a plasma-flow-rate-acquiring unit that acquires a plasma flow rate or a correlation value of plasma flow rate with reference to a blood concentration detected from the patient's blood and the plasma total protein or the correlation value of the plasma total protein acquired by the plasma total protein acquiring unit;
• and
• a control unit in communication with and controlling the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit;
• wherein a substitution rate to be achieved by the substitution-fluid supply unit is calculated with reference to the plasma flow rate or the correlation value of plasma flow rate acquired by the plasma-flow-rate-acquiring unit;
• wherein the substitution rate (Qs) is determined with a formula comprising:
• Qs=Qpw*FF/100−Quf where Qpw is plasma flow rate, FF is a filtration fraction and Quf is an ultrafiltration flow rate.

A method of acquiring a plasma flow rate on a blood purification apparatus, the blood purification apparatus comprising:

• extracorporeally circulating a patient's blood from a distal end of an arterial blood circuit to a distal end of a venous blood circuit of a blood circuit;
• purifying the patient's blood through a blood purifier provided between the arterial blood circuit and the venous blood circuit, the blood purifier having a blood flow route through which the patient's blood extracorporeally circulating through the blood circuit flows and a dialysate flow route through which dialysate flows, the blood flow route and the dialysate flow route being separated from each other by a blood purification membrane for purifying the patient's blood;
• performing ultrafiltration with an ultrafiltration unit that filters out water from the patient's blood in the blood flow route through the blood purification membrane and draining the water through the dialysate flow route;
• supplying substitution fluid with a substitution-fluid supply unit that supplies the substitution fluid into the blood circuit,
• detecting, with a detecting unit, a transmembrane pressure difference occurring on the blood purification membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route;
• acquiring a colloid osmotic pressure of the patient's blood, with a colloid-osmotic-pressure-acquiring unit, in the blood flow route or a correlation value of colloid osmotic pressure with reference to the transmembrane pressure difference occurring when liquid in the blood flow route that does not generate colloid osmotic pressure is supplied into the blood flow route with filtration by the ultrafiltration unit withheld and the transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by the ultrafiltration unit withheld;
• acquiring, with a plasma-total-protein-acquiring unit, a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value of colloid osmotic pressure acquired by the colloid-osmotic-pressure-acquiring unit;
• acquiring, with a plasma-flow-rate-acquiring unit, the plasma flow rate or a correlation value of plasma flow rate with reference to a blood concentration detected from the patient's blood and the plasma total protein or the correlation value of the plasma total protein acquired by the plasma-total-protein-acquiring unit;
• calculating, with reference to the plasma flow rate or the correlation value of plasma flow rate acquired by a plasma-flow-rate-acquiring unit, a substitution rate to be achieved by the substitution-fluid supply unit;
• and
• controlling the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit with a control unit,
• wherein the colloid osmotic pressure (CP) is determined with a formula comprising:
• CP=TMPa−TMPb, wherein TMPa is a transmembrane pressure difference occurring when the liquid does not generate colloid osmotic pressure and TMPb is transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by an ultrafiltration pump.

A method of acquiring a plasma flow rate on a blood purification apparatus, the blood purification apparatus comprising:

• extracorporeally circulating a patient's blood from a distal end of an arterial blood circuit to a distal end of a venous blood circuit of a blood circuit;
• purifying the patient's blood through a blood purifier provided between the arterial blood circuit and the venous blood circuit, the blood purifier having a blood flow route through which the patient's blood extracorporeally circulating through the blood circuit flows and a dialysate flow route through which dialysate flows, the blood flow route and the dialysate flow route being separated from each other by a blood purification membrane for purifying the patient's blood;
• performing ultrafiltration with an ultrafiltration unit that filters out water from the patient's blood in the blood flow route through the blood purification membrane and draining the water through the dialysate flow route;
• supplying substitution fluid with a substitution-fluid supply unit that supplies the substitution fluid into the blood circuit,
• detecting, with a detecting unit, a transmembrane pressure difference occurring on the blood purification membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route;
• acquiring a colloid osmotic pressure of the patient's blood, with a colloid-osmotic-pressure-acquiring unit, in the blood flow route or a correlation value of colloid osmotic pressure with reference to the transmembrane pressure difference occurring when liquid in the blood flow route that does not generate colloid osmotic pressure is supplied into the blood flow route with filtration by the ultrafiltration unit withheld and the transmembrane pressure difference occurring when the patient's blood is supplied into the blood flow route with the filtration by the ultrafiltration unit withheld;
• acquiring, with a plasma-total-protein-acquiring unit, a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value of colloid osmotic pressure acquired by the colloid-osmotic-pressure-acquiring unit;
• acquiring, with a plasma-flow-rate-acquiring unit, the plasma flow rate or a correlation value of plasma flow rate with reference to a blood concentration detected from the patient's blood and the plasma total protein or the correlation value of the plasma total protein acquired by the plasma-total-protein-acquiring unit;
• calculating, with reference to the plasma flow rate or the correlation value of plasma flow rate acquired by a plasma-flow-rate-acquiring unit, a substitution rate to be achieved by the substitution-fluid supply unit;
• and
• controlling the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit with a control unit,
• wherein the substitution rate (Qs) is determined with a formula comprising:
• Qs=Qpw*FF/100−Quf where Qpw is plasma flow rate, FF is a filtration fraction and Quf is an ultrafiltration flow rate.