Patent ID: 7442294

Claim:
A hemodialysis apparatus, comprising: a blood measuring means that measures a blood parameter, converts the blood parameter into a blood index value and conveys to a control member; and an actual working member that performs a blood treatment, wherein the control member sets up a target control line which consists of target blood index values determined previously at each measurement point of a lapsed time of hemodialysis processing, controls a water removal speed of the working member by a following formula (a): BV 0 {−(% Δ BV n−1′ −% Δ BV n′ )+(% Δ BV n′ −% Δ BV n+1 )}/ T+UFR n =UFR n+1 (a) and the target control line, until a blood volume decreases to a preset patient's standard blood volume in a former part of the hemodialysis, and controls the water removal speed of the working member to maintain the preset patient's standard blood volume in a latter part of the hemodialysis wherein B V 0 is the blood volume at a time of initiation of the hemodialysis; %ΔBV n′ is a ratio of the blood volume change at an optional selected measurement point (n) in the former part of the hemodialysis; %ΔBV n−1′ is the ratio of the blood volume change at the previous measurement point of the selected measurement point (n) in the former part of the hemodialysis; %ΔBV n+1 is the ratio of the blood volume change determined by the target control line at a measurement point (n+1), a next measurement point of the selected measurement point (n); T is a measurement time; UFR n is the water removal speed at the selected measurement point (n) in the former part of the hemodialysis; and UFR n+1 is the water removal speed defined when control toward the working member is carried out, to attain a target blood indication level at the measurement point (n+1); and a distance of each measurement point is defined to be short so that a patient's plasma refilling rate (PRR) at each measurement point does not change substantively; wherein the PRR is a speed of blood plasma that is refilled from a patient's body to a blood vessel using the following formula (b): PRRn−UFRn=ΔBVn′/Tn (b) wherein PRRn is the plasma refilling rate at an optional measurement point (n), UFRn is the water removal speed at the optional measurement point (n), ΔBVn′ is the blood volume change at the optional measurement point (n), and Tn is the elapsed time until the optional measurement point (n).