Blood purification apparatus and method of estimating patient's state of nutrition on blood purification apparatus

Inventors

Hasegawa, Shinya • Kawarabayashi, Satoru • Toyoda, Masahiro • Akita, Kunihiko

Assignees

Nikkiso Co Ltd

Abstract

A blood purification apparatus that accurately calculates the colloid osmotic pressure of a patient's blood. A dialyzer included in the blood purification apparatus has thereinside blood flow routes and dialysate flow routes that are separated from each other by hollow fibers. An ultrafiltration pump draws out water from the blood in the blood flow routes through the hollow fibers into the dialysate flow routes. Four detecting units measure the pressures of liquid flowing into the blood flow routes, the liquid discharged from the blood flow routes, dialysate flowing into the dialysate flow routes, and the dialysate discharged from the dialysate flow routes. The pressures at the four positions, the transmembrane pressure difference can be calculated. The blood flow routes are filled with a priming solution, and the transmembrane pressure difference (TMPa) is measured. Subsequently, the blood flow routes are filled with the patient's blood, and the transmembrane pressure difference (TMPb) is measured. Referencing TMPa and TMPb, the colloid osmotic pressure of the patient's blood can be calculated. Referencing colloid osmotic pressure, the plasma total protein can be calculated. Referencing plasma total protein, the patient's state of nutrition can be estimated.

Core Innovation

The invention provides a blood purification apparatus with a blood circuit for extracorporeal circulation of a patient’s blood through an arterial blood circuit and a venous blood circuit, and a blood purifier between the arterial and venous circuits. The blood purifier includes a blood flow route and a dialysate flow route separated by a blood purification membrane, and an ultrafiltration unit that filters out water from blood and drains the water through the dialysate flow route. A detecting unit detects a transmembrane pressure difference occurring on the membrane under a pressure difference between liquid in the blood flow route and liquid in the dialysate flow route.

The apparatus acquires a colloid osmotic pressure of the patient’s blood in the blood flow route or a correlation value of colloid osmotic pressure, using the transmembrane pressure difference detected under a first condition where a liquid that does not generate colloid osmotic pressure is supplied with filtration by the ultrafiltration unit withheld. The apparatus also acquires a plasma total protein or a correlation value of plasma total protein with reference to the colloid osmotic pressure or the correlation value acquired.

The control unit executes a first step with the non-colloid-osmotic-pressure-generating liquid supplied while ultrafiltration is withheld, and a second step with the patient’s blood supplied while ultrafiltration is withheld, each time calculating the transmembrane pressure difference using the detecting unit. The control unit stops a blood pump and a duplex pump to stop flow or liquid in the blood flow route and the dialysate flow route, and performs the second step while the blood pump and the duplex pump are stopped under a condition that a predetermined time has lapsed since a start of a treatment step.

The plasma total protein or the correlation value of plasma total protein stored in a storage unit or transmitted to a server is linked to pieces of patient information, and the control unit is capable of sequentially executing a priming step and the treatment step. In the priming step, a priming solution is supplied into the blood circuit, and the priming solution is the liquid that does not generate colloid osmotic pressure used in the first step.

Claims Coverage

The partial content includes two independent claims: an apparatus claim and a method claim. Both claims share a common inventive structure based on acquiring colloid osmotic pressure and plasma total protein using transmembrane pressure difference measured while ultrafiltration is withheld, with a two-step sequence using a non-colloid-osmotic-pressure-generating liquid and then the patient’s blood.

Overall, the independent claims cover measuring a transmembrane pressure difference with ultrafiltration withheld in a two-step sequence, acquiring colloid osmotic pressure or a correlation value and then plasma total protein or a correlation value from those measurements, and using the resulting plasma total protein or correlation value for patient nutrition state estimation, with control sequencing including priming, treatment, and pump stopping under a predetermined time condition.

Stated Advantages

Documented Applications