JP2010155068A - Hemodialysis apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hemodialysis apparatus capable of finding an accurate quantity of bodily fluid by simple work while reducing the cost, and capable of finding a blood flow velocity necessary for achieving a target dialysis quantity by simple work using the quantity of bodily fluid. <P>SOLUTION: The hemodialysis apparatus includes: a hemodialysis executing means 9; a bodily fluid quantity computing means 11 which computes the quantity of bodily fluid as the total sum of the moisture present within the body of a patient by analyzing a mathematical model on the dynamic state of urea; and a blood flow velocity computing means 12 which, before the start of the hemodialysis treatment to be performed after the hemodialysis treatment performed when the quantity of bodily fluid is computed by the bodily fluid quantity computing means 11, computes the blood flow velocity necessary to achieve the target quantity of dialysis, based on the quantity of bodily fluid computed by the bodily fluid quantity computing means, the planned time of dialysis treatment, the planned flow velocity of dialysis solution, the planned total water removal quantity during the dialysis, the overall mass transfer-area coefficient of a dialyzer to be used for the dialysis, and the target quantity of dialysis to be achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dialysis apparatus that can achieve a target dialysis amount.

Dialysis volume is defined as the therapeutic volume of a single hemodialysis treatment performed on a patient. There are two dialysate indicators, urea removal rate and Kt / V. Generally, Kt / V is adopted. Kt / V is usually obtained by substituting the serum urea concentration at the start and end of hemodialysis treatment, the total water removal amount during the hemodialysis treatment, and the treatment time of the hemodialysis treatment into a predetermined arithmetic expression. calculate. Factors that affect the serum urea concentration at the end of hemodialysis treatment include body fluid volume, the total amount of water present in the patient's body, hemodialysis treatment time, total water removal during hemodialysis treatment, and dialyzer used Are general mass transfer area coefficients (so-called K _O A), blood flow velocity, and dialysate flow velocity, which are indicators of the performance of Medical staff usually adjust serum urea concentration at the end of hemodialysis treatment by adjusting blood flow velocity among these factors before starting hemodialysis treatment, thereby increasing Kt / V Or decrease. That is, the medical staff usually adjusts the blood flow velocity in order to increase or decrease Kt / V.

  At present, many statistical research studies have revealed the Kt / V, the so-called optimal Kt / V value, which minimizes mortality. In hemodialysis medical treatment, it is necessary to perform hemodialysis treatment that achieves the optimum Kt / V value that has been clarified by many statistical research studies.

  Therefore, at the present hemodialysis facility, the serum urea concentration at the start and end of hemodialysis treatment in the past hemodialysis treatment, the total water removal amount during the hemodialysis treatment, and the treatment time of the hemodialysis treatment, Substituting it into a predetermined arithmetic expression, the Kt / V value in the past hemodialysis treatment is calculated, and the Kt / V value in the past hemodialysis treatment and the optimum Kt / V value clarified by the statistical research are obtained. In comparison, the Kt / V value of the hemodialysis treatment to be performed from now on matches the optimal Kt / V value, referring to the blood flow velocity in the previous hemodialysis treatment, by trial and error, The blood flow velocity is adjusted in the hemodialysis treatment to be performed from now on.

  However, the total water removal amount during hemodialysis treatment, which is one of the factors that determine the serum urea concentration at the end of hemodialysis and is also one of the substitution items of the calculation formula for calculating Kt / V, The hemodialysis treatment is not necessarily equal to the hemodialysis treatment to be performed. In addition, the relationship between the blood flow velocity in hemodialysis treatment and Kt / V in the hemodialysis treatment also varies from patient to patient and depending on the dialyzer used. Therefore, even if the blood flow velocity in the hemodialysis treatment is adjusted in this way, it is difficult to accurately achieve the target Kt / V value after the hemodialysis treatment is completed. In spite of this, it took a great deal of labor and a long time to determine the blood flow velocity necessary to achieve the target Kt / V value. In addition, since this prior art does not relate to the literature known invention, there is no prior art document information to be described.

  The present invention has been made in view of such circumstances, and the problem to be solved is to obtain an accurate body fluid amount with a simple operation while keeping the cost low, and using this, the start of hemodialysis treatment Before, it is providing the hemodialysis apparatus which makes it possible to obtain | require the blood flow rate required in order to achieve a target dialysis amount by simple operation | work.

  In order to solve such a problem, the gist of the invention of claim 1 is to provide a dialyzer for purifying blood and supplying the blood to be purified taken out from the body to the dialyzer. Blood supply circuit, a blood pump provided on the blood supply circuit for sending blood to the dialyzer, and blood connected to the dialyzer and purified by the dialyzer is returned to the body A blood return circuit, a dialysate supply channel connected to the dialyzer for supplying dialysate to the dialyzer, and a dialysate provided on the dialysate supply channel to the dialyzer A dialysate pump for supplying, a dialysate discharge channel for discharging dialysate used to purify blood in the dialyzer, and a unit time of dialysate from the dialyzer Per unit time of dialysate discharged to the dialyzer Hemodialysis means comprising a water removal means that is driven so that the difference from the supply amount of water is equal to the water removal rate from the body, the measured serum urea concentration at the start of hemodialysis treatment, and the hemodialysis Measured serum urea concentration at the end of treatment, dialysis treatment time of the hemodialysis treatment, total water removal amount during the hemodialysis treatment, blood flow velocity during the hemodialysis treatment, dialysate flow during the hemodialysis treatment Body fluid for determining body fluid volume, which is the total amount of water present in the patient's body, by analyzing the mathematical model related to urea dynamics from the velocity and the overall mass transfer area coefficient of the dialyzer used for the hemodialysis treatment An amount calculating means, and a body fluid amount determined by the body fluid amount calculating means before the start of hemodialysis treatment performed after the hemodialysis treatment in which the body fluid amount is determined by the body fluid amount calculating means; From the dialysis treatment time of the hemodialysis treatment, the total water removal amount, the dialysate flow rate, the overall mass transfer area coefficient of the dialyzer used, and the target dialysis amount to be achieved at the end of the hemodialysis treatment, A hemodialysis apparatus comprising: a blood flow velocity calculating means for obtaining a blood flow velocity required to achieve the target dialysis amount by analyzing a mathematical model relating to dynamics.

  In the hemodialysis apparatus according to the invention of claim 2, in the analysis of the mathematical model of the body fluid amount calculation means, the measured serum urea concentration at the start of the hemodialysis treatment and the measured serum urea concentration at the end of the hemodialysis treatment The dialysis amount is calculated from the dialysis amount, the dialysis treatment time of the hemodialysis treatment, the total water removal amount during the hemodialysis treatment, the blood flow velocity during the hemodialysis treatment, and the blood The volume of the body fluid is obtained from the dialysate flow rate in dialysis treatment and the overall mass transfer area coefficient of the dialyzer used in the hemodialysis treatment.

  The hemodialysis apparatus according to the invention of claim 3 has dialysis condition storage means, and the dialysis treatment time, blood flow velocity, and dialysate flow velocity stored in the dialysis condition storage means are the dialysis conditions. It is transmitted online from the condition storage means to the body fluid amount calculation means.

  Furthermore, the hemodialysis apparatus according to the invention of claim 4 has dialysis condition storage means, and the dialysis treatment time and the dialysate flow rate stored in the dialysis condition storage means are obtained from the dialysis condition storage means. The blood flow velocity calculation means is transmitted online.

  According to the first aspect of the present invention, first, the actually measured serum urea concentration at the start of hemodialysis treatment on the day of a periodic blood sampling test performed approximately once a month, and the dialysis treatment time of the hemodialysis treatment Blood flow velocity in the hemodialysis treatment, dialysate flow velocity in the hemodialysis treatment, total water removal amount in the hemodialysis treatment, and overall mass transfer area coefficient of the dialyzer used in the hemodialysis treatment The body fluid volume calculating means determines the body fluid volume so that the calculated serum urea concentration at the end of the hemodialysis treatment matches the measured serum urea concentration by analyzing a mathematical model related to urea dynamics. . And about the hemodialysis treatment performed for about one month after that, before the start of hemodialysis treatment, the scheduled dialysis treatment time of the hemodialysis treatment, the scheduled dialysis fluid flow rate in the hemodialysis treatment, The planned total water removal amount during the hemodialysis treatment, the overall mass transfer area coefficient of the dialyzer to be used, the target dialysis amount, and the body fluid amount calculated by the body fluid amount calculating means on the day of the periodic blood sampling test From the above, the blood flow velocity calculating means calculates a blood flow velocity necessary to achieve the target dialysis amount by analyzing a mathematical model relating to urea dynamics. The medical staff sets the blood flow velocity necessary to achieve the calculated target dialysis amount in the hemodialysis apparatus, and performs hemodialysis treatment with the target dialysis amount.

  According to the invention of claim 2, dialysis amount, dialysis treatment time of hemodialysis treatment, total water removal amount during hemodialysis treatment, blood flow velocity in hemodialysis treatment, dialysate flow velocity in hemodialysis treatment, The body fluid volume is determined from the overall mass transfer area coefficient of the dialyzer used for hemodialysis treatment, and the blood flow velocity necessary to achieve the target dialysis volume is calculated. The medical staff sets the blood flow velocity necessary to achieve the calculated target dialysis amount in the hemodialysis apparatus, and performs hemodialysis treatment with the target dialysis amount.

  According to a third aspect of the present invention, when the body fluid amount is calculated by the body fluid amount calculating means, the dialysis treatment time, the blood flow velocity, and the dialysate fluid flow velocity stored in the dialysis condition storage means are calculated as follows. Since it is transmitted on-line from the condition storage means to the body fluid volume calculation means, it is possible to save time and effort to manually input these data for each patient and for each hemodialysis treatment. When trying to calculate the amount of body fluid, the required time can be greatly shortened.

  Further, according to the invention of claim 4, when the blood flow velocity calculating means calculates the blood flow velocity necessary to achieve the target dialysis amount, the scheduled dialysis treatment stored in the dialysis condition storage means. Since the time and the scheduled dialysis fluid flow rate are transmitted online from the dialysis condition storage unit to the blood flow rate calculation unit, these data, which are different for each patient and for each hemodialysis treatment, are stored one by one. The time required for manual input can be saved, and the time required for calculating the blood flow velocity necessary to achieve the target dialysis volume can be greatly reduced particularly in a large number of patients.

It is a schematic explanatory drawing regarding the basic structure of a hemodialysis enforcement means. It is a schematic explanatory drawing which shows the connection structure of a bodily fluid amount calculating means. It is a schematic explanatory drawing which shows the connection structure of a blood flow rate calculating means. It is a schematic explanatory drawing which shows the structure of the whole hemodialysis apparatus. It is a schematic explanatory drawing explaining a local blood flow model. It is a graph which shows the relationship between target Kt / V and Kt / V achieved by the plan dialysis apparatus.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic explanatory diagram regarding the basic structure of hemodialysis enforcement means.
As shown in FIG. 1, hemodialysis means 9 includes a dialyzer 10 for purifying blood, a blood supply circuit 1 for supplying blood to be purified that has been removed from the body to the dialyzer 10, A blood pump 2 provided on the blood supply circuit 1 for sending blood to the dialyzer 10 and a blood return connected to the dialyzer 10 for returning blood purified by the dialyzer 10 to the body. Connected to the circuit 3 and the dialyzer 10, the dialysate supply channel 4 for supplying dialysate to the dialyzer 10, and the dialysate provided on the dialysate supply channel 4 to the dialyzer 10. Dialysate pump 5 for delivery, dialysate discharge flow path 6 for discharging dialysate used to purify blood in the dialyzer 10, and dialysate from the dialyzer 10. The amount of discharge per unit time and the unit time of dialysate to the dialyzer 10 The difference between the delivery amount of a water removal means 7 for driving to be equal to the water removal speed from the body, consisting of a dialysis condition storage unit 8 Metropolitan for keeping stores various dialysis conditions.

  As shown in FIG. 2, the body fluid amount calculation means 11 is electrically connected to the input means 15 and the display means 16. Specifically, the input means 15 includes a Kt / V value calculated from a measured serum urea concentration at the start of hemodialysis treatment and a measured serum urea concentration at the end of the hemodialysis treatment by a predetermined arithmetic expression. Dialysis treatment time in hemodialysis treatment, total water removal amount during hemodialysis treatment, blood flow velocity in hemodialysis treatment (drive speed of blood pump 2), dialysate flow velocity in hemodialysis treatment (dialysis fluid pump 5) And the overall mass transfer area coefficient of the dialyzer used for hemodialysis treatment, and the body fluid amount calculation means 11 uses these various parameters to analyze a mathematical model related to urea dynamics. By doing so, it is possible to determine the amount of body fluid that is the total amount of water present in the patient's body. The body fluid amount obtained by the body fluid amount calculating means 11 is configured to be displayed on the display means 16.

  As shown in FIG. 3, the blood flow velocity calculation means 12 is electrically connected to the input means 17, the control means 18, and the display means 19. Specifically, the input means 17 includes the body fluid volume determined by the body fluid volume calculator 11 before the start of hemodialysis treatment performed after the hemodialysis therapy determined by the body fluid volume calculator 11. The scheduled dialysis treatment time of the hemodialysis treatment to be performed, the scheduled dialysis fluid flow rate, the planned total water removal amount during the hemodialysis treatment, the overall mass transfer area coefficient of the dialyzer 10 to be used, The target Kt / V value to be achieved at the end of the hemodialysis treatment can be input, and the blood flow velocity calculation means 12 uses these various parameters to analyze a mathematical model related to urea dynamics, It is possible to determine the blood flow velocity necessary to achieve the Kt / V value. The blood flow velocity obtained by the blood flow velocity calculating means 12 is transmitted to the control means 18 that controls the hemodialysis enforcement means 9 and displayed on the display means 19.

In FIG. 4, the structure of the whole hemodialysis apparatus in embodiment of this invention is shown.
The hemodialysis apparatus according to the embodiment of the present invention includes a hemodialysis enforcement unit 9, a body fluid amount calculation unit 11, and a blood flow rate calculation unit 12. Between the dialysis condition storage means 8 and the body fluid amount calculation means 11 of the hemodialysis enforcement means 9, the dialysis treatment time, the total water removal amount, the blood flow rate, and the dialysate flow rate stored in the dialysis condition storage unit 8. Are communicated by a transmission line 13 so as to be transmitted online from the dialysis condition storage means 8 to the body fluid amount calculation means 11. On the other hand, between the dialysis condition storage means 8 and the blood flow rate calculation means 12 of the hemodialysis enforcement means 9, the scheduled dialysis treatment time, the planned total water removal amount, and the planned dialysate flow rate stored in the dialysis condition storage means 8. Is communicated by a transmission line 14 so that it is transmitted online from the dialysis condition storage means 8 to the blood flow velocity calculation means 12.

  Now, in the hemodialysis apparatus in the embodiment, when the hemodialysis treatment for achieving the target Kt / V value is to be performed, first, on the day of the regular blood sampling test performed once a month, After the hemodialysis treatment is completed, the dialysis treatment time of the hemodialysis treatment stored in the dialysis condition storage means 8, the blood flow velocity in the hemodialysis treatment, and the dialysate flow velocity in the hemodialysis treatment , The total water removal amount during the hemodialysis treatment is transmitted online from the dialysis condition storage means 8 to the body fluid amount calculation means 11, and the overall mass transfer area coefficient of the dialyzer used in the hemodialysis treatment, The Kt / V value calculated by the following equation 1 from the measured serum urea concentration at the start and end of the hemodialysis treatment is manually input, and the body fluid amount calculation means 11 relates to the urea kinetics described later. By analyzing the mathematical models to calculate the fluid volume. The volume of body fluid in dialysis patients usually does not change significantly for at least one month. Therefore, the body fluid volume of the patient calculated by the body fluid volume calculating means 11 can be used effectively for at least one month. In the calculation formula, R is the ratio of the serum urea concentration at the end of dialysis treatment to the serum urea concentration at the start of dialysis treatment, TD is the dialysis time in hr, TF is the total water removal amount (L), and BW is the end of dialysis treatment. The weight (kg) at the time is shown.

  Next, the current hemodialysis treatment stored in the dialysis condition storage means 8 before the start of hemodialysis treatment performed after the hemodialysis treatment when the body fluid amount is calculated by the body fluid amount calculation means 11 The scheduled dialysis treatment time, the scheduled total water removal amount during the current hemodialysis treatment, and the scheduled dialysis fluid flow velocity in the current hemodialysis treatment are transmitted from the dialysis condition storage means 8 to the blood flow velocity calculation means 12 online. Further, manually input the body fluid volume obtained by the body fluid volume calculation means 11 in the past, the overall mass transfer area coefficient of the dialyzer used this time, and the target Kt / V value to be achieved at the end of the current hemodialysis treatment Then, the blood flow velocity calculating means 12 calculates a blood flow velocity necessary to achieve the target Kt / V value by analyzing a mathematical model related to urea dynamics described later. The blood flow velocity necessary to achieve the target Kt / V value calculated in this way is transmitted to the control means 18 and displayed on the display means 19. If the medical staff confirms the blood flow velocity necessary to achieve the target Kt / V value displayed on the display means 19, the hemodialysis enforcement means 9 is activated. Thus, hemodialysis treatment that achieves the target Kt / V value is performed.

  Here, a mathematical model relating to urea dynamics used for calculation of the body fluid volume by the body fluid volume calculation means 11 and calculation of the blood flow speed necessary for achieving the target Kt / V by the blood flow speed calculation means 12; The analysis method is described.

  In the embodiment, a local blood flow model that is considered to be most approximate to a living body of a dialysis patient is employed among the urea kinetic models. A diagram for explaining the local blood flow model is schematically shown in FIG. The local blood flow model is a region (hereinafter referred to as a low blood flow organ B) composed of organs (muscles, skin, etc .; low blood flow organs) with low blood flow even though the living body has a high water content. Urea based on the theory that it is divided into areas (hereinafter referred to as high blood flow organ A) consisting of organs with low water content and high blood flow (digestive organs such as liver and intestine; high blood flow organs). It is a dynamic model. In the local blood flow model, 15% of the cardiac output minus the extracorporeal blood flow returns to the low blood flow organ B, and the remaining 85% returns to the high blood flow organ A, while 80% of the body fluid volume. Is distributed in the low blood flow organ B, and the remaining 20% is distributed in the high blood flow organ A.

When the local blood flow model is rewritten in the form of a mathematical model, it is as follows.
_{d M H (t) / dt} + d M L (t) / dt = -K × C A (t) (1)
M _H (t) = C _H (t) × V _H (t) (2)
_{M L (t) = C L} (t) × V L (t) (3)
d _MH (t) / dt = [C _A (t) −C _H (t)] × Q _H (4)
d M _L (t) / dt = [C _A (t) −C _L (t)] × Q _L (5)
However, M _H (t) represents the amount of urea present in the high blood flow organ A at time t, and M _L (t) represents the amount of urea present in the low blood flow organ B at time t.
_{d V T (t) / dt} = -F (6)
V _H (t) = 0.2 V _T (t) (7)
V _L (t) = 0.8 V _T (t) (8)
_{Q H = 0.85 (Q A -Q} B) (9)
Q _L = 0.15 (Q _A -Q _B ) (10)
However, F shows the water removal rate, V _T (t) shows the volume of body fluid at time t, and Q _A shows the cardiac output.

Now, in analyzing the mathematical local blood flow model in order to obtain the amount of body fluid in the body fluid amount calculation means 11, first, at the start of hemodialysis treatment (t = 0), urea dynamics in the body is in an equilibrium state. Therefore, it is assumed that the urea concentration in the low blood flow organ B and the urea concentration in the high blood flow organ A are both equal to the urea concentration in arterial blood. That is, the measured serum urea concentration at the start of hemodialysis treatment is set to the initial value [C _A (0)] of the arterial blood urea concentration in the mathematical local blood flow model, and at the same time, the urea concentration of the low blood flow organ B [ C _L (0)] and the initial value of urea concentration [C _B (0)] of the high blood flow organ A are also used. Next, the urea clearance in the dialyzer is calculated from the blood flow velocity that circulates outside the body, the dialysate flow velocity, and the overall mass transfer area coefficient of the dialyzer according to the following calculation formula 2. _However, Q B (mL / min) blood _velocity, Q D (mL / min) the dialysate flow rate, _{K O} A is overall mass transfer area coefficient of the dialyzer 10 (mL / min), and K (mL / Min) indicates the urea clearance of the dialyzer 10.

The urea clearance (K) and the water removal rate (F) obtained by dividing the total water removal amount by the dialysis treatment time are treated as constants, and 4000 mL, which is an average value for cardiac output, is further obtained. / Min and a provisional value for the body fluid volume [V _T (0)], and by analyzing the mathematical local blood flow model, the arterial blood urea concentration at the end of dialysis treatment [C _A (Td) ] Is calculated. Here, Td represents dialysis treatment time.

When the calculated arterial blood urea concentration [C _A (Td)] at the end of dialysis treatment in the provisional body fluid amount is different from the actually measured serum urea concentration at the end of dialysis treatment, the provisional body fluid amount slightly changed, calculates the arterial urea concentration at dialysis treatment ends in a body fluid of a new temporary [C _{a (Td)].} The same operation is repeated until the calculated arterial blood urea concentration [C _A (Td)] at the end of the dialysis treatment matches the measured serum urea concentration at the end of the permeabilization analysis, and finally the calculated dialysis treatment is completed. When the arterial blood urea concentration [C _A (Td)] at the time coincides with the actually measured serum urea concentration at the end of the permeabilization analysis, the fluid volume at that time is adopted as the true fluid volume.

  In the embodiment, the mathematical local blood flow model is analyzed by using the measured serum urea concentration at the start of hemodialysis treatment as the arterial blood urea concentration at the start of hemodialysis treatment in the mathematical local blood flow model. Calculating the arterial blood urea concentration at the end of the hemodialysis treatment, and when the arterial blood urea concentration at the end of the hemodialysis treatment matches the serum urea concentration at the end of the actual hemodialysis treatment, the body fluid given at that time The amount is the true body fluid amount. As is apparent from Equation 1, if the hemodialysis treatment time and the total water removal amount during hemodialysis treatment are equal, Kt / V is the serum at the end of hemodialysis treatment relative to the serum urea concentration at the start of hemodialysis treatment. Determined by the ratio of urea concentrations. Therefore, in this embodiment, the hemodialysis obtained by analyzing the mathematical local blood flow model after using the serum urea concentration at the start of the actual hemodialysis treatment as the arterial blood urea concentration at the start of the hemodialysis treatment. It is obtained by analyzing the mathematical local blood flow model that the body fluid volume when the arterial blood urea concentration at the end of treatment matches the serum urea concentration at the end of the actual hemodialysis treatment is the true body fluid volume. The body fluid volume when the Kt / V is equal to the Kt / V calculated from the measured serum urea concentration at the start of hemodialysis treatment and the serum urea concentration at the end of the actual hemodialysis treatment, Same thing.

Further, the body fluid volume calculation means 11 uses the body fluid volume obtained by analyzing the mathematical local blood flow model, and the blood flow velocity calculation means 12 analyzes the mathematical local blood flow model to obtain the target Kt. In order to determine the blood flow velocity necessary to achieve / V, first, the initial value [C _A (0)] of urea concentration in arterial blood at the start of hemodialysis treatment (t = 0) the initial value of the urea concentration in blood flow organs B and _[C L (0)], the initial value of the urea concentration of the high blood flow organs a a _[C H (0)], assumed as 1 mg / mL.

Next, a temporary value is given to the blood flow velocity, and the urea clearance in the dialyzer 10 is calculated from the temporary blood flow velocity, the actual dialysate flow velocity, and the overall mass transfer area coefficient of the dialyzer 10 by the above equation 2. Is calculated. From the urea clearance under the temporary blood flow velocity calculated in this way, the body fluid amount obtained by analyzing the mathematical local model, the total water removal amount, and the hemodialysis treatment time, By analyzing the local blood flow model, the arterial blood urea concentration [C _A (Td)] at the end of dialysis treatment is calculated. Then, from the ratio of the calculated arterial blood urea concentration [C _A (Td)] at the end of dialysis treatment and the initial value of the arterial urea concentration [C _A (0) = 1 mg / mL], the above calculation formula 1 To calculate the Kt / V value.

When the calculated Kt / V value is different from the target Kt / V value, the temporary blood flow velocity is slightly changed, and the new temporary blood flow velocity, the actual dialysate flow velocity, and the overall mass transfer of the dialyzer From the area coefficient, the urea clearance in the dialyzer 10 is calculated by the above equation 2. Next, the mathematical local blood flow model is calculated from the urea clearance thus calculated, the body fluid amount obtained by analyzing the mathematical local blood flow model, the total water removal amount, and the hemodialysis treatment time. by analyzing, calculating the arterial urea concentration at dialysis treatment ends [C _{a (Td)].} Then, from the ratio of the calculated arterial blood urea concentration [C _A (Td)] at the end of dialysis treatment and the initial value of the arterial urea concentration [C _A (0) = 1 mg / mL], the above calculation formula 1 To calculate the Kt / V value. The same operation is repeated until the calculated Kt / V value at the end of dialysis treatment matches the target Kt / V value. Finally, the calculated Kt / V value becomes the target Kt / V value. When they coincide, the blood flow velocity at that time is set as the blood flow velocity necessary to achieve the target Kt / V value.

  In the embodiment, the body fluid volume was calculated by the body fluid volume calculation means 11 on the day of the periodic blood sampling test in 10 dialysis patients. The blood flow velocity at which the target Kt / V value is achieved by the blood flow velocity calculation means 12 using the respective body fluid amounts before the start of the total 27 hemodialysis treatments performed thereafter. Furthermore, blood dialysis treatment was performed by setting the blood flow velocity at which the target Kt / V value calculated in this way was achieved in the hemodialysis apparatus.

  FIG. 6 shows the relationship between Kt / V and target Kt / V achieved in hemodialysis treatment performed with the dialysate flow rate set in the hemodialyzer. The achieved Kt / V is the Kt / V calculated by the arithmetic expression 1 from the actually measured serum urea concentration at the start of the hemodialysis treatment and the actually measured serum urea concentration at the end of the hemodialysis. Means. As is apparent from FIG. 6, the correlation coefficient is 0.984 between the target Kt / V and the Kt / V achieved by the hemodialysis apparatus, and the regression equation is Y = 1.0533X−0.063. There was a strong linear correlation. This indicates that the Kt / V achieved by the hemodialyzer matches the target Kt / V.

  According to this embodiment, after completion of hemodialysis treatment performed on the day of a periodic blood sampling test performed approximately once a month, the dialysis treatment time of the hemodialysis treatment, and the hemodialysis treatment Blood flow rate, dialysate flow rate in the hemodialysis treatment, total water removal amount during the hemodialysis treatment, overall mass transfer area coefficient of the dialyzer used in the hemodialysis treatment, and start of the hemodialysis treatment If the body fluid volume is calculated by analyzing the mathematical model related to urea dynamics in the body fluid volume calculating means 11 from the Kt / V calculated by the calculation formula 1 using the actually measured serum urea concentration at the time and the end, For hemodialysis treatments to be performed for approximately one month thereafter, the scheduled dialysis treatment time of the hemodialysis treatment and the scheduled dialysate flow rate in the hemodialysis treatment before the start of hemodialysis treatment From the planned total water removal amount during the hemodialysis treatment, the overall mass transfer area coefficient of the dialyzer 10, the target Kt / V, and the body fluid volume calculated by the body fluid volume computing means on the day of the periodic blood sampling test, The blood flow velocity calculation means 12 calculates a blood flow velocity necessary to achieve the target Kt / V by analyzing a mathematical model related to urea dynamics. If the medical staff sets the blood flow velocity necessary to achieve the calculated target Kt / V in the hemodialysis apparatus, the target Kt / V hemodialysis treatment is performed. .

  When the body fluid amount is calculated by the body fluid amount calculating means 11, the dialysis treatment time, the total water removal amount, the blood flow rate, and the dialysate flow rate stored in the dialysis condition storage unit 8 are transferred from the dialysis condition storage unit 8 to the body fluid. Since it is transmitted to the volume calculation means 11 online, it is possible to save the labor of inputting these data one by one, which is different for each patient and for each hemodialysis treatment. In this case, the required time can be greatly shortened. Further, when the blood flow velocity calculation means 12 calculates the blood flow velocity necessary to achieve the target Kt / V, the scheduled dialysis treatment time, the planned total water removal amount and the schedule stored in the dialysis condition storage means 8. Since the dialysate flow rate is transmitted online from the dialysis condition storage unit 8 to the blood flow rate calculation unit 12, these data, which differ for each patient and for each hemodialysis treatment, are manually input. The time required can be greatly shortened in the case where it is possible to save time and calculate the blood flow velocity necessary to achieve the target Kt / V, particularly in a large number of patients.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the embodiment, a local blood flow model is used as a model related to urea dynamics. However, the model related to urea dynamics used in the present invention is not limited to the local blood flow model. Any model can be used as long as it can mathematically express the dynamics of urea in the living body, such as a pool model. In the embodiment, Kt / V is used as an index of the dialysis amount. However, the index of dialysis used in the present invention is not limited to Kt / V, and the dialysis treatment is started and ended. Any index can be used as long as it is an index calculated from the serum urea concentration.

  In the present embodiment, in the analysis of the mathematical model of the body fluid amount calculation means 11, dialysis is performed using a predetermined arithmetic expression from the measured serum urea concentration at the start of hemodialysis treatment and the measured serum urea concentration at the end of the hemodialysis treatment. Although the amount is calculated, the measured serum urea concentration at the start of hemodialysis treatment and the measured serum urea concentration at the end of the hemodialysis treatment may be simply used as parameters without obtaining the dialysis amount. . That is, in the body fluid amount calculation means 11, the actual measured serum urea concentration at the start of hemodialysis treatment, the actual measured serum urea concentration at the end of the hemodialysis treatment, the dialysis treatment time of hemodialysis treatment, and the total during hemodialysis treatment By analyzing the mathematical model of urea dynamics from the amount of water removed, blood flow velocity in hemodialysis treatment, dialysate flow velocity in hemodialysis treatment, and overall mass transfer area coefficient of the dialyzer used for hemodialysis treatment The body fluid amount that is the total amount of water present in the patient's body may be obtained.

  Furthermore, in the embodiment, when the body fluid amount calculating means 11 tries to calculate the body fluid amount, the overall mass transfer area coefficient of the dialyzer 10 used, and the measured serum urea concentration at the start and end of the hemodialysis treatment are used. The Kt / V value calculated from the above was manually input. However, in the present invention, it is not always necessary to manually input these data. The dialyzer used is transferred from the storage mechanism storing the overall mass transfer area coefficient of the dialyzer used to the body fluid amount calculation means 11. The overall mass transfer area coefficient may be transmitted online. In addition, the Kt / V value calculated from the measured serum urea concentration at the start and end of hemodialysis treatment does not necessarily have to be manually input, but the body fluid amount is calculated from the calculation means for calculating the Kt / V value. The calculated Kt / V value may be transmitted to the means 11 online.

  Furthermore, in the embodiment, when the blood flow velocity calculating means 12 tries to calculate the blood flow velocity necessary to achieve the target Kt / V value, the body fluid amount obtained by the body fluid amount calculating means 11 in the past is used. In addition, the overall mass transfer area coefficient of the dialyzer used this time and the target Kt / V value to be achieved at the end of the current hemodialysis treatment were manually input. However, in the present invention, it is not always necessary to manually input these data, the body fluid amount obtained by the body fluid amount calculating means 11 in the past, the overall mass transfer area coefficient of the dialyzer to be used, These data may be transmitted online from the storage mechanism storing the target Kt / V value to the blood flow velocity calculation means 12.

DESCRIPTION OF SYMBOLS 1 Blood supply circuit 2 Blood pump 3 Blood return circuit 4 Dialysate supply flow path 5 Dialysate pump 6 Dialysate discharge flow path 7 Water removal means 8 Dialysis condition storage means 9 Hemodialysis enforcement means 10 Dialyzer 11 Body fluid amount calculation means 12 Blood flow velocity calculation means 13, 14 Transmission line 15 Input means 16 Display means 17 Input means 18 Control means 19 Display means

Claims (4)

A dialyzer for purifying blood, a blood supply circuit for supplying blood to be purified taken out from the body to the dialyzer, and blood provided on the blood supply circuit to the dialyzer A blood pump for delivery, a blood return circuit connected to the dialyzer and returning blood purified by the dialyzer to the body, and connected to the dialyzer to supply dialysate to the dialyzer Used to purify blood with the dialyzer, and a dialysate pump provided on the dialysate supply channel for supplying dialysate to the dialyzer. The dialysate discharge flow path for discharging dialysate from the dialyzer, and the difference between the amount of dialysate discharged from the dialyzer per unit time and the amount of dialysate supplied to the dialyzer per unit time Dewatering hand that is driven to be equal to the dewatering rate from the body And blood dialysis means composed of a,
Measured serum urea concentration at the start of hemodialysis treatment, measured serum urea concentration at the end of the hemodialysis treatment, dialysis treatment time of the hemodialysis treatment, total water removal amount during the hemodialysis treatment, and hemodialysis By analyzing a mathematical model related to urea dynamics from the blood flow velocity in the treatment, the dialysate flow velocity in the hemodialysis treatment, and the overall mass transfer area coefficient of the dialyzer used in the hemodialysis treatment, A body fluid amount calculating means for obtaining a body fluid amount that is the total amount of water present in
Before the start of hemodialysis treatment performed after the hemodialysis treatment in which the body fluid amount is determined by the body fluid amount calculation means, the body fluid amount determined by the body fluid amount calculation means, the dialysis treatment time of the hemodialysis treatment, By analyzing a mathematical model for urea dynamics from the total water removal rate, dialysate flow rate, overall mass transfer area coefficient of the dialyzer used, and the target dialysis volume to be achieved at the end of hemodialysis treatment A blood flow velocity calculating means for obtaining a blood flow velocity necessary to achieve the target dialysis amount;
A hemodialysis apparatus comprising:   In the analysis of the mathematical model of the body fluid amount calculating means, the dialysis amount is calculated by a predetermined arithmetic expression from the measured serum urea concentration at the start of the hemodialysis treatment and the measured serum urea concentration at the end of the hemodialysis treatment, The dialysis amount, the dialysis treatment time of the hemodialysis treatment, the total water removal amount during the hemodialysis treatment, the blood flow velocity in the hemodialysis treatment, the dialysate flow velocity in the hemodialysis treatment, and the hemodialysis 2. The hemodialysis apparatus according to claim 1, wherein the amount of the body fluid is obtained from an overall mass transfer area coefficient of a dialyzer used for treatment.   A dialysis condition storage unit is provided, and the dialysis treatment time, the blood flow rate, and the dialysate flow rate stored in the dialysis condition storage unit are transmitted online from the dialysis condition storage unit to the body fluid amount calculation unit. The hemodialysis apparatus according to claim 1 or 2, wherein the hemodialysis apparatus is configured.   A dialysis condition storage means, and the dialysis treatment time and dialysate flow rate stored in the dialysis condition storage means are transmitted on-line from the dialysis condition storage means to the blood flow rate calculation means; The hemodialysis apparatus according to any one of claims 1 to 3, wherein the hemodialysis apparatus is configured.

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