Blood purification apparatus and method of acquiring plasma flow rate on blood purification apparatus
Inventors
Hasegawa, Shinya • Kawarabayashi, Satoru • Toyoda, Masahiro • Akita, Kunihiko
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12383664-B2
Publication Date
2025-08-12
Expiration Date
Abstract
A blood purification apparatus includes a blood circuit that allows a patient's blood to extracorporeally circulate; a blood purifier between the arterial blood circuit and the venous blood circuit having a blood flow route through which the blood extracorporeally 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; an ultrafiltration unit that filters out water from the blood in the blood flow route through the blood purification membrane and drains the water through the dialysate flow route; and a substitution-fluid supply unit that supplies substitution fluid. The blood purification apparatus includes 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 a plasma total protein detected from the blood.
Core Innovation
The invention relates to a blood purification apparatus and a method for acquiring a plasma flow rate (Qpw) in extracorporeally circulating a patient's blood from an arterial blood circuit to a venous blood circuit through a blood purifier. The blood purifier includes a blood flow route and a dialysate flow route separated from each other by a blood purification membrane, with an ultrafiltration unit performing ultrafiltration by filtering out water from the patient's blood and draining the water through the dialysate flow route. A substitution-fluid supply unit supplies substitution fluid into the blood circuit, while a detecting unit 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.
A colloid-osmotic-pressure-acquiring unit acquires 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 when liquid that does not generate colloid osmotic pressure is supplied into the blood flow route and filtration by the ultrafiltration unit is withheld. The colloid-osmotic-pressure-acquiring unit further uses a 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 acquires plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value acquired.
A plasma-flow-rate-acquiring unit acquires plasma flow rate or a correlation value of plasma flow rate with reference to blood concentration detected from the patient's blood and the plasma total protein or the correlation value acquired. The control unit controls the colloid-osmotic-pressure-acquiring unit, the plasma-total-protein-acquiring unit, and the plasma-flow-rate-acquiring unit, and 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. The plasma flow rate (Qpw) is determined using a formula comprising Qpw=Qb*(1−Ht)*(1−0.0107*TP), and colloid osmotic pressure (CP) is determined with a formula comprising CP=TMPa−TMPb. CP is further used to determine plasma total protein and the substitution rate, including a substitution rate formula Qs=Qpw*FF/100−Quf.
Claims Coverage
The independent claims are clm-00001, clm-00008, clm-00013, clm-00014, clm-00015, and clm-00016. Across these independent claims, the inventive features consist of four main features: using a transmembrane pressure difference with ultrafiltration withheld to acquire colloid osmotic pressure, converting colloid osmotic pressure into plasma total protein (or correlations), acquiring plasma flow rate from blood concentration and plasma total protein (or correlations), and calculating and using a substitution rate based on plasma flow rate together with filtration fraction and ultrafiltration flow rate (or related quantities).
Ultrafiltration-withheld transmembrane pressure difference sensing
A detecting unit 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 colloid-osmotic-pressure-acquiring unit acquires 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.
Plasma total protein acquisition from colloid osmotic pressure
A plasma-total-protein-acquiring unit 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.
Plasma flow rate acquisition from blood concentration and plasma total protein
A plasma-flow-rate-acquiring unit 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.
Substitution rate calculation based on plasma flow rate
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.
Plasma flow rate formula using blood flow rate, hematocrit, and plasma total protein
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.
Colloid osmotic pressure formula using two transmembrane pressure differences
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.
Substitution rate formula using plasma flow rate, filtration fraction, and ultrafiltration flow rate
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.
Across the independent claims, the core coverage is for determining plasma flow rate during a blood purification apparatus using transmembrane pressure difference sensing with ultrafiltration withheld to acquire colloid osmotic pressure, mapping it to plasma total protein (or correlations), and then acquiring plasma flow rate from detected blood concentration and plasma total protein (or correlations). The claims further cover calculating a substitution rate for the substitution-fluid supply unit based on the acquired plasma flow rate, with explicit formula relationships including Qpw and CP=TMPa−TMPb, and optionally Qs=Qpw*FF/100−Quf.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
Interested in licensing this patent?