WO2022172926A1 - Device for calculating muscle mass and method for calculating muscle mass - Google Patents

Device for calculating muscle mass and method for calculating muscle mass Download PDF

Info

Publication number
WO2022172926A1
WO2022172926A1 PCT/JP2022/004955 JP2022004955W WO2022172926A1 WO 2022172926 A1 WO2022172926 A1 WO 2022172926A1 JP 2022004955 W JP2022004955 W JP 2022004955W WO 2022172926 A1 WO2022172926 A1 WO 2022172926A1
Authority
WO
WIPO (PCT)
Prior art keywords
dialysis
uric acid
urea
muscle mass
distribution volume
Prior art date
Application number
PCT/JP2022/004955
Other languages
French (fr)
Japanese (ja)
Inventor
徹 新里
真幹 三輪
正富 佐々木
亘 水野
満隆 上田
Original Assignee
ニプロ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ニプロ株式会社 filed Critical ニプロ株式会社
Priority to JP2022580637A priority Critical patent/JPWO2022172926A1/ja
Publication of WO2022172926A1 publication Critical patent/WO2022172926A1/en

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/14—Dialysis systems; Artificial kidneys; Blood oxygenators ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
    • A61M1/16—Dialysis systems; Artificial kidneys; Blood oxygenators ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis with membranes

Definitions

  • the technology disclosed in this specification relates to a technology for calculating the muscle mass of dialysis patients.
  • Muscle mass is known to be an important indicator of the nutritional status of dialysis patients.
  • Methods for obtaining muscle mass include MRI, DEXA, and CT (for example, Behrang Amini, et al: Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography. Journals of Gerontology: Medical Science, 2019, vol. 74 , No. 10), and a method of measuring muscle mass using the impedance method or the like is known.
  • a method of estimating muscle mass using creatinine production rate is also known.
  • the muscle mass of dialysis patients can be measured by using the MRI method, DEXA method, CT method, and impedance method.
  • the MRI method, DEXA method, and CT method require large-scale equipment for measurement. For this reason, it is costly and time-consuming, and it places a heavy burden on both the medical staff performing the measurement and the dialysis patient.
  • the impedance method can be performed using a relatively simpler device than the MRI method, DEXA method, and CT method, it can only measure an approximate value of muscle mass, and cannot accurately measure muscle mass. do not have.
  • the creatinine production rate is affected by many factors other than muscle mass, muscle mass cannot be accurately estimated.
  • This specification discloses a technique for acquiring the muscle mass of dialysis patients while reducing the burden on dialysis patients and medical staff.
  • the muscle mass calculation device disclosed herein includes a uric acid concentration acquisition unit that acquires the serum uric acid concentration of the dialysis patient before and after dialysis, a urea concentration acquisition unit that acquires the serum urea concentration of the dialysis patient before and after dialysis, and and a calculation unit for calculating the muscle mass based on the serum uric acid concentration of the dialysis patient and the serum urea concentration of the dialysis patient before and after dialysis.
  • the calculation unit calculates the difference between the urea distribution volume and the uric acid content volume based on the serum uric acid concentration before and after dialysis obtained by the uric acid concentration obtaining unit and the serum urea concentration obtained by the urea concentration obtaining unit.
  • the above muscle mass calculator uses the serum uric acid concentration and serum urea concentration before and after dialysis to calculate the difference between the urea distribution volume and the uric acid content volume.
  • the present inventors have found a method capable of calculating muscle mass from the difference between the urea distribution volume and the uric acid content volume.
  • the serum uric acid concentration and serum urea concentration before and after dialysis, which are used to calculate the difference between the urea distribution volume and the uric acid content volume can be easily obtained during dialysis. Therefore, the muscle mass of a dialysis patient can be calculated without using a device for acquiring muscle mass.
  • the muscle mass calculation method disclosed herein includes a urea concentration acquisition step of acquiring the serum urea concentration of the dialysis patient before and after dialysis, a uric acid concentration acquisition step of acquiring the serum uric acid concentration of the dialysis patient before and after dialysis, a calculating step of calculating muscle mass based on the difference between the urea distribution volume calculated from the obtained serum urea concentrations before and after dialysis and the uric acid distribution volume calculated from the obtained serum uric acid concentrations before and after dialysis.
  • the uric acid distribution volume is calculated from the serum uric acid concentrations before and after dialysis in dialysis patients, which can be easily obtained during dialysis, and the urea distribution volume is calculated from the serum urea concentrations before and after dialysis in dialysis patients. Then, the muscle mass is calculated based on the difference between the calculated urea distribution volume and uric acid distribution volume. Therefore, it is possible to achieve the same effect as the muscle mass calculation device described above.
  • FIG. 4 is a flow chart showing an example of processing in which a computing device calculates muscle mass of a dialysis patient; Schematic diagram showing substances distributed in intracellular and extracellular compartments.
  • Fig. 2 shows the correlation between the difference between the urea distribution volume and the uric acid distribution volume, and the muscle mass calculated by multiplying the creatinine production rate by the value of creatinine equivalence.
  • the muscle mass calculation device disclosed in the present specification may further include a correlation formula storage unit that stores a correlation formula between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass.
  • the calculation unit may calculate the muscle mass based on the correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass.
  • the muscle mass calculator 10 is used to calculate the muscle mass of a dialysis patient. As shown in FIG. 1 , the muscle mass calculation device 10 is composed of an arithmetic device 12 and an interface device 30 .
  • the computing device 12 can be configured by a computer including, for example, a CPU, a ROM, a RAM, and the like. By the computer executing the program, the arithmetic unit 12 functions as the calculation unit 20 shown in FIG.
  • the patient information storage unit 14 stores various information regarding dialysis patients.
  • the patient information storage unit 14 stores information on dialysis patients input via the interface device 30 and information on dialysis patients calculated by the calculation unit 20 .
  • the dialysis patient's information input via the interface device 30 is, for example, the uric acid concentration before and after dialysis, the urea concentration before and after dialysis, the creatinine concentration before and after dialysis, etc. of the dialysis patient.
  • the information about the dialysis patient calculated by the calculator 20 is the uric acid distribution volume, the urea distribution volume, and the muscle mass of the dialysis patient calculated based on the information input via the interface device 30 .
  • the dialysis information storage unit 16 stores various information related to dialysis.
  • the dialysis information storage unit 16 stores dialysis-related information input via the interface device 30 and dialysis-related information calculated by the calculation unit 20 .
  • the dialysis-related information calculated by the calculator 20 is, for example, the amount of urea removed, the amount of uric acid removed, and the like.
  • the correlation formula storage unit 18 stores a correlation formula between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. The correlation formula will be detailed later.
  • the computing device 12 acquires various kinds of information used to calculate the muscle mass of the dialysis patient (S12).
  • the various information used to calculate the muscle mass of the dialysis patient are the urea concentration of the dialysis patient before and after dialysis, the uric acid concentration of the dialysis patient before and after dialysis, the amount of urea removed by dialysis of the dialysis patient, This is the amount of uric acid removed by dialysis in dialysis patients.
  • the uric acid and urea concentrations before and after dialysis can be obtained as actual measurements.
  • uric acid concentrations before and after dialysis are obtained by the following procedure. First, blood is collected from dialysis patients before and after dialysis. Then, the collected blood before dialysis is centrifuged into blood cells and plasma, and the uric acid concentration in the separated plasma is measured. The method for measuring the uric acid concentration in plasma is not particularly limited. The operator inputs the measured plasma uric acid concentrations before and after dialysis into the interface device 30 . The input pre- and post-dialysis plasma uric acid concentrations are output from the interface device 30 to the computing device 12 and stored in the patient information storage unit 14 .
  • the amount of uric acid removed and the amount of urea removed by dialysis can be calculated from various information obtained by dialysis.
  • the amount of uric acid removed by dialysis can be calculated by measuring the concentration of uric acid in the effluent dialysate after dialysis and multiplying the measured uric acid concentration by the amount of effluent dialysate.
  • it can be calculated using other information obtainable by dialysis.
  • a method for calculating the amount of uric acid removed and the amount of urea removed using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. WO 2019/138917, and detailed description thereof will be omitted.
  • the calculator 20 calculates the urea distribution volume using the various information acquired in step S12 (S14).
  • An example of a method for calculating the urea distribution volume will be described below.
  • the urea distribution volume can be calculated by dividing the amount of urea removed by the urea concentration difference before and after dialysis. Therefore, the formula represented by Equation 1 below is established.
  • urea V indicates urea distribution volume
  • urea E indicates urea removal amount
  • urea Cs indicates urea concentration before dialysis
  • urea Ce indicates urea concentration after dialysis.
  • the calculation unit 20 substitutes the pre-dialysis urea concentration urea Cs, the post-dialysis urea concentration urea Ce, and the urea removal amount urea E obtained in step S12 into the above equation (1) to obtain the urea distribution volume Calculate urea V.
  • the urea distribution volume was calculated from the urea concentration urea Cs before dialysis, the urea concentration urea Ce after dialysis, and the urea removal amount urea E, but the configuration is not limited to this.
  • the urea distribution volume may be calculated using other information obtainable by dialysis.
  • a method of calculating the urea distribution volume using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. 2019/138917.
  • urea passes through both the cell membrane 42 and the capillary membrane 56, so it is distributed throughout the body's water compartments (the combined range of the intracellular compartment 40 and the extracellular compartment 50).
  • the urea distribution volume therefore corresponds to the total body fluid volume. Therefore, for example, the urea distribution volume can also be calculated by using the method for calculating the total body fluid volume disclosed in International Publication No. 2019/138917.
  • the calculator 20 calculates the uric acid distribution volume using the various information acquired in step S12 (S16).
  • the uric acid distribution volume can be calculated by dividing the uric acid removal amount by the uric acid concentration difference before and after dialysis. Therefore, the following formula (2) is established.
  • Acid V indicates the uric acid distribution volume
  • acid E indicates the amount of uric acid removed
  • acid Cs indicates the uric acid concentration before dialysis
  • acid Ce indicates the uric acid concentration after dialysis.
  • the calculation unit 20 substitutes the pre-dialysis uric acid concentration acid Cs, the post-dialysis uric acid concentration acid Ce, and the uric acid removal amount acid E obtained in step S12 into the above equation (2) to obtain the uric acid distribution volume Calculate acid V.
  • the uric acid distribution volume was calculated from the uric acid concentration acid Cs before dialysis, the uric acid concentration acid Ce after dialysis, and the uric acid removal amount acid E, but the configuration is not limited to this.
  • the uric acid distribution volume may be calculated using other information obtainable by dialysis.
  • a method of calculating the uric acid distribution volume using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. 2019/138917.
  • uric acid does not pass through the cell membrane 42 but passes through the capillary membrane 56, so it is distributed only in the extracellular compartment 50 among the water compartments in the body, and is not distributed in the intracellular compartment 40. . Therefore, the uric acid distribution volume corresponds to the extracellular fluid volume. Therefore, for example, the uric acid distribution volume can also be calculated by using the extracellular fluid amount calculation method disclosed in International Publication No. 2019/138917.
  • the calculation unit 20 stores the urea distribution volume calculated in step S14, the uric acid distribution volume calculated in step S16, and the correlation formula storage.
  • the muscle mass is calculated using the correlation formula stored in the unit 18 (S20).
  • the correlation formulas stored in the correlation formula storage unit 18 will be described.
  • the correlation formula stored in the correlation formula storage unit 18 is a formula showing the correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass.
  • the urea distribution volume corresponds to the total body fluid volume
  • the uric acid distribution volume corresponds to the extracellular fluid volume. Therefore, the value obtained by subtracting the uric acid distribution volume from the urea distribution volume agrees with the value obtained by subtracting the extracellular fluid volume from the total body fluid volume, ie, the permeable intracellular fluid volume.
  • Intracellular fluid volume is known to correlate with muscle mass. Therefore, it can be said that there is a correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. A method of calculating the correlation formula will be described below.
  • the muscle mass in the correlation formula is calculated.
  • About 98% of creatine in the body is distributed in muscle. Creatine is irreversibly non-enzymatically converted to creatinine at approximately 2% per day. Therefore, the amount of creatine converted to creatinine per day (ie, creatinine production rate) is proportional to the amount of creatine in the body. That is, the rate of creatinine production is proportional to the muscle mass in the body.
  • the ratio between the amount of creatinine produced per day (creatinine production rate) and muscle mass is called creatinine equivalence.
  • the creatinine equivalence is reported to be 0.0186 when the unit of weight is kg. That is, multiplying the creatinine production rate in mg/day by the creatinine equivalence value (0.0186) yields muscle mass in kg. Therefore, if the creatinine production rate can be obtained, the muscle mass can be calculated.
  • a kinetic model of creatinine is analyzed to calculate the creatinine production rate.
  • the total amount of creatinine removed by dialysis three times a week corresponds to the total amount of creatinine produced in one week. Therefore, the amount of creatinine produced per day (that is, the creatinine production rate) is calculated from the total amount of creatinine removed by dialysis three times a week.
  • the amount of creatinine removed by one dialysis is equal to the amount of creatinine present in the body before dialysis minus the amount of creatinine present in the body after dialysis.
  • the amount of creatinine present in the body before dialysis is equal to the product of the creatinine distribution volume and the serum creatinine concentration before dialysis
  • the amount of creatinine present in the body after dialysis is the creatinine distribution volume and the serum creatinine concentration after dialysis equal to the product of Therefore, the following formula (3) holds.
  • R indicates the amount of creatinine removed by one dialysis
  • V indicates the creatinine distribution volume
  • Cpre indicates the serum creatinine concentration before dialysis
  • Cpost indicates the serum creatinine concentration after dialysis.
  • the creatinine volume of distribution can be estimated by multiplying the post-dialysis body weight by 0.49. From the above, the amount of creatinine removed by one dialysis can be calculated from the serum creatinine concentration before dialysis, the serum creatinine concentration after dialysis, and the body weight after dialysis. Then, the amount of creatinine removed three times a week is calculated, and the calculated amounts of creatinine removed are totaled to calculate the amount of creatinine removed for one week. By dividing this by 7, the amount of creatinine removed per day, that is, the creatinine production rate can be calculated.
  • muscle mass can be calculated by multiplying the creatinine production rate by the creatinine equivalence value.
  • creatinine production rate is also affected by many factors other than muscle mass. For example, the amount of creatinine excreted into the urine, which indicates the rate of creatinine production, fluctuates by 4-8% even under normal circumstances, and increases by 5-10% with vigorous exercise. increased by 10-30% when switched to Therefore, the muscle mass calculated by multiplying the creatinine production rate by the creatinine equivalence value fluctuates greatly from day to day.
  • muscle cells are the only cells in the body that can expand or shrink. This suggests that there is a proportional relationship between intracellular fluid and muscle mass.
  • the urea distribution volume corresponds to the total water content in the body
  • the uric acid distribution volume corresponds to the extracellular fluid content. Therefore, the value obtained by subtracting the uric acid distribution volume from the urea distribution volume is considered to match the intracellular fluid volume. This suggests that the value obtained by subtracting the uric acid distribution volume from the urea distribution volume correlates with muscle mass.
  • the inventors calculated the urea distribution volume and the uric acid distribution volume for 74 patients, and then calculated the difference between the urea distribution volume and the uric acid distribution volume. Also, for 74 patients, the creatinine production rate was calculated, and then the muscle mass was calculated by multiplying the creatinine production rate by the value of creatinine equivalence. As shown in FIG.
  • the muscle mass calculated by multiplying the creatinine production rate by the creatinine equivalence value is distributed above and below the regression line so that the total deviation (residual error) is minimized.
  • the calculated creatinine production rate includes creatinine contained in meat and fish ingested in meals and creatinine leaked from muscles during exercise. Therefore, this deviation is due not only to measurement errors in the creatinine production rate, but also to fluctuations in the creatinine production rate due to diet and exercise, and fluctuations in the natural creatinine production rate.
  • the values on the regression line are values obtained by averaging variations in dietary protein intake and exercise amounts. That is, when using this regression line to calculate the muscle mass from the difference between the urea distribution volume and the uric acid distribution volume, the muscle mass is calculated without errors due to diet and exercise.
  • step S18 the calculation unit 20 substitutes the value obtained by subtracting the uric acid distribution volume calculated in step S16 from the urea distribution volume calculated in step S14 into the correlation expression stored in the correlation expression storage unit 18. Thereby, the muscle mass can be calculated with high accuracy.
  • a correlation formula was created using the value of creatinine equivalence reported by Picou et al.
  • the value of creative equivalence is not limited to this.
  • a correlation may be created using creatinine equivalence values reported by other researchers.
  • the computing device 12 may have an analysis function for obtaining the above correlation formula. Since the arithmetic unit 12 has such an analysis function, the error in the correlation between the difference D between the urea distribution volume and the uric acid distribution volume and the muscle mass is reduced, and the difference between the urea distribution volume and the uric acid distribution volume is reduced. The accuracy of calculating the muscle mass from the difference D can be improved.

Landscapes

  • Health & Medical Sciences (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Urology & Nephrology (AREA)
  • Anesthesiology (AREA)
  • Vascular Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Emergency Medicine (AREA)
  • Biomedical Technology (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Investigating Or Analysing Biological Materials (AREA)

Abstract

The present invention is provided with: a urea concentration acquisition unit for acquiring the serum urea concentrations of a dialysis patient before and after dialysis; a uric acid concentration acquisition unit for acquiring the serum uric acid concentrations of a dialysis patient before and after dialysis; and a calculation unit for calculating muscle mass on the basis of the difference between the urea distribution volume calculated from the acquired serum urea concentrations before and after dialysis and the uric acid distribution volume calculated from the acquired serum uric acid concentrations before and after dialysis.

Description

筋肉量算出装置及び筋肉量算出方法Muscle mass calculation device and muscle mass calculation method
　本明細書に開示する技術は、透析患者の筋肉量を算出する技術に関する。 The technology disclosed in this specification relates to a technology for calculating the muscle mass of dialysis patients.
　筋肉量は透析患者の栄養状態の重要に指標であることが知られている。筋肉量を取得する方法としては、ＭＲＩ法、ＤＥＸＡ法、ＣＴ法（例えば、Behrang Amini, et al: Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography. Journals of Gerontology: Medical Science, 2019, vol. 74, No. 10）、インピーダンス法等を用いて筋肉量を測定する方法が知られている。また、クレアチニン産生速度を用いて筋肉量を推定する方法も知られている。 　Muscle mass is known to be an important indicator of the nutritional status of dialysis patients. Methods for obtaining muscle mass include MRI, DEXA, and CT (for example, Behrang Amini, et al: Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography. Journals of Gerontology: Medical Science, 2019, vol. 74 , No. 10), and a method of measuring muscle mass using the impedance method or the like is known. A method of estimating muscle mass using creatinine production rate is also known.
　上述したように、ＭＲＩ法、ＤＥＸＡ法、ＣＴ法、インピーダンス法を用いることによって、透析患者の筋肉量が測定可能となる。しかしながら、ＭＲＩ法やＤＥＸＡ法、ＣＴ法は、測定のために大掛かりな装置が必要となる。このため、費用や手間がかかり、測定する医療従事者も透析患者も負担が大きい。また、インピーダンス法は、ＭＲＩ法やＤＥＸＡ法、ＣＴ法より比較的簡易な装置を用いて実行できるものの、筋肉量の概算値を測定可能であるに過ぎず、筋肉量を正確に測定できるものではない。また、クレアチニン産生速度は、筋肉量以外の多くの因子の影響も受けるので、筋肉量を正確に推定できるものではない。 As described above, the muscle mass of dialysis patients can be measured by using the MRI method, DEXA method, CT method, and impedance method. However, the MRI method, DEXA method, and CT method require large-scale equipment for measurement. For this reason, it is costly and time-consuming, and it places a heavy burden on both the medical staff performing the measurement and the dialysis patient. In addition, although the impedance method can be performed using a relatively simpler device than the MRI method, DEXA method, and CT method, it can only measure an approximate value of muscle mass, and cannot accurately measure muscle mass. do not have. In addition, since the creatinine production rate is affected by many factors other than muscle mass, muscle mass cannot be accurately estimated.
　本明細書は、透析患者や医療従事者の負担を軽減しながら、透析患者の筋肉量を取得する技術を開示する。 This specification discloses a technique for acquiring the muscle mass of dialysis patients while reducing the burden on dialysis patients and medical staff.
　本明細書に開示する筋肉量算出装置は、透析患者の透析前後の血清尿酸濃度を取得する尿酸濃度取得部と、透析患者の透析前後の血清尿素濃度を取得する尿素濃度取得部と、透析前後の血清尿酸濃度と透析患者の透析前後の血清尿素濃度とに基づいて筋肉量を算出する演算部と、を備えている。演算部は、尿酸濃度取得部で取得した透析前後の血清尿酸濃度と尿素濃度取得部で取得した血清尿素濃度とに基づいて、尿素分布容積と尿酸分容積の差を算出する。 The muscle mass calculation device disclosed herein includes a uric acid concentration acquisition unit that acquires the serum uric acid concentration of the dialysis patient before and after dialysis, a urea concentration acquisition unit that acquires the serum urea concentration of the dialysis patient before and after dialysis, and and a calculation unit for calculating the muscle mass based on the serum uric acid concentration of the dialysis patient and the serum urea concentration of the dialysis patient before and after dialysis. The calculation unit calculates the difference between the urea distribution volume and the uric acid content volume based on the serum uric acid concentration before and after dialysis obtained by the uric acid concentration obtaining unit and the serum urea concentration obtained by the urea concentration obtaining unit.
　上記の筋肉量算出装置では、透析前後の血清尿酸濃度と血清尿素濃度を用いて、尿素分布容積と尿酸分容積の差を算出する。本発明者らは、尿素分布容積と尿酸分容積の差から筋肉量を算出できる方法を見出した。尿素分布容積と尿酸分容積の差を算出する際に用いる透析前後の血清尿酸濃度と血清尿素濃度は、透析の際に容易に取得可能である。このため、筋肉量を取得するための装置を用いることなく、透析患者の筋肉量を算出することができる。 The above muscle mass calculator uses the serum uric acid concentration and serum urea concentration before and after dialysis to calculate the difference between the urea distribution volume and the uric acid content volume. The present inventors have found a method capable of calculating muscle mass from the difference between the urea distribution volume and the uric acid content volume. The serum uric acid concentration and serum urea concentration before and after dialysis, which are used to calculate the difference between the urea distribution volume and the uric acid content volume, can be easily obtained during dialysis. Therefore, the muscle mass of a dialysis patient can be calculated without using a device for acquiring muscle mass.
　また、本明細書に開示する筋肉量算出方法は、透析患者の透析前後の血清尿素濃度を取得する尿素濃度取得工程と、透析患者の透析前後の血清尿酸濃度を取得する尿酸濃度取得工程と、取得した透析前後の血清尿素濃度から算出される尿素分布容積と取得した透析前後の血清尿酸濃度から算出される尿酸分布容積の差に基づいて筋肉量を算出する算出工程と、を備えている Further, the muscle mass calculation method disclosed herein includes a urea concentration acquisition step of acquiring the serum urea concentration of the dialysis patient before and after dialysis, a uric acid concentration acquisition step of acquiring the serum uric acid concentration of the dialysis patient before and after dialysis, a calculating step of calculating muscle mass based on the difference between the urea distribution volume calculated from the obtained serum urea concentrations before and after dialysis and the uric acid distribution volume calculated from the obtained serum uric acid concentrations before and after dialysis.
　上記の筋肉量算出方法では、透析の際に容易に取得可能な透析患者の透析前後の血清尿酸濃度から尿酸分布容積を算出し、また透析患者の透析前後の血清尿素濃度から尿素分布容積を算出し、算出した尿素分布容積と尿酸分布容積の差に基づいて筋肉量を算出する。このため、上記の筋肉量算出装置と同様の作用効果を奏することができる。 In the above muscle mass calculation method, the uric acid distribution volume is calculated from the serum uric acid concentrations before and after dialysis in dialysis patients, which can be easily obtained during dialysis, and the urea distribution volume is calculated from the serum urea concentrations before and after dialysis in dialysis patients. Then, the muscle mass is calculated based on the difference between the calculated urea distribution volume and uric acid distribution volume. Therefore, it is possible to achieve the same effect as the muscle mass calculation device described above.
実施例に係る筋肉量算出装置のシステム構成を示す図。The figure which shows the system configuration|structure of the muscle mass calculation apparatus which concerns on an Example. 演算装置が透析患者の筋肉量を算出する処理の一例を示すフローチャート。4 is a flow chart showing an example of processing in which a computing device calculates muscle mass of a dialysis patient; 細胞内区画と細胞外区画に分布する物質を示す模式図。Schematic diagram showing substances distributed in intracellular and extracellular compartments. 尿素分布容積と尿酸分布容積の差と、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて算出した筋肉量と間の相関関係を示す図。Fig. 2 shows the correlation between the difference between the urea distribution volume and the uric acid distribution volume, and the muscle mass calculated by multiplying the creatinine production rate by the value of creatinine equivalence.
　以下に説明する実施例の主要な特徴を列記しておく。なお、以下に記載する技術要素は、それぞれ独立した技術要素であって、単独であるいは各種の組合せによって技術的有用性を発揮するものであり、出願時請求項記載の組合せに限定されるものではない。 The main features of the embodiments described below are listed. It should be noted that the technical elements described below are independent technical elements, and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. do not have.
　本明細書に開示する筋肉量算出装置では、尿素分布容積と尿酸分布容積の差と、筋肉量との間の相関式を記憶する相関式記憶部をさらに備えていてもよい。演算部は、尿素分布容積と尿酸分布容積の差と筋肉量との相関式に基づいて、筋肉量を算出してもよい。 The muscle mass calculation device disclosed in the present specification may further include a correlation formula storage unit that stores a correlation formula between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. The calculation unit may calculate the muscle mass based on the correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass.
　図面を参照して、実施例に係る筋肉量算出装置１０について説明する。筋肉量算出装置１０は、透析患者の筋肉量を算出するために用いられる。図１に示すように、筋肉量算出装置１０は、演算装置１２と、インターフェース装置３０によって構成されている。演算装置１２は、例えば、ＣＰＵ、ＲＯＭ、ＲＡＭ等を備えたコンピュータによって構成することができる。コンピュータがプログラムを実行することで、演算装置１２は、図１に示す算出部２０として機能する。 A muscle mass calculation device 10 according to an embodiment will be described with reference to the drawings. The muscle mass calculator 10 is used to calculate the muscle mass of a dialysis patient. As shown in FIG. 1 , the muscle mass calculation device 10 is composed of an arithmetic device 12 and an interface device 30 . The computing device 12 can be configured by a computer including, for example, a CPU, a ROM, a RAM, and the like. By the computer executing the program, the arithmetic unit 12 functions as the calculation unit 20 shown in FIG.
　また、図１に示すように、演算装置１２は、患者情報記憶部１４と透析情報記憶部１６と相関式記憶部１８備えている。患者情報記憶部１４は、透析患者に関する各種情報を記憶する。患者情報記憶部１４は、インターフェース装置３０を介して入力される透析患者の情報や、算出部２０で算出される透析患者に関する情報を記憶する。インターフェース装置３０を介して入力される透析患者の情報は、例えば、透析患者の透析前後の尿酸濃度、透析前後の尿素濃度、透析前後のクレアチニン濃度等である。算出部２０で算出される透析患者に関する情報は、インターフェース装置３０を介して入力された情報に基づいて算出される尿酸分布容積、尿素分布容積、透析患者の筋肉量である。透析情報記憶部１６は、透析に関する各種情報を記憶する。透析情報記憶部１６は、インターフェース装置３０を介して入力される透析に関する情報や、算出部２０で算出される透析に関する情報を記憶する。算出部２０で算出される透析に関する情報は、例えば、尿素除去量、尿酸除去量等である。 　In addition, as shown in FIG. The patient information storage unit 14 stores various information regarding dialysis patients. The patient information storage unit 14 stores information on dialysis patients input via the interface device 30 and information on dialysis patients calculated by the calculation unit 20 . The dialysis patient's information input via the interface device 30 is, for example, the uric acid concentration before and after dialysis, the urea concentration before and after dialysis, the creatinine concentration before and after dialysis, etc. of the dialysis patient. The information about the dialysis patient calculated by the calculator 20 is the uric acid distribution volume, the urea distribution volume, and the muscle mass of the dialysis patient calculated based on the information input via the interface device 30 . The dialysis information storage unit 16 stores various information related to dialysis. The dialysis information storage unit 16 stores dialysis-related information input via the interface device 30 and dialysis-related information calculated by the calculation unit 20 . The dialysis-related information calculated by the calculator 20 is, for example, the amount of urea removed, the amount of uric acid removed, and the like.
　相関式記憶部１８は、尿素分布容積と尿酸分布容積との差と、筋肉量との相関式を記憶している。相関式については、後に詳述する。 The correlation formula storage unit 18 stores a correlation formula between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. The correlation formula will be detailed later.
　筋肉量算出装置１０を用いて、透析患者の筋肉量を算出する方法について説明する。図２に示すように、まず、演算装置１２は、透析患者の筋肉量を算出するために用いる各種情報を取得する（Ｓ１２）。本実施例では、透析患者の筋肉量を算出するために用いる各種情報は、透析患者の透析前後の尿素濃度と、透析患者の透析前後の尿酸濃度と、透析患者の透析による尿素除去量と、透析患者の透析による尿酸除去量である。 A method of calculating the muscle mass of a dialysis patient using the muscle mass calculator 10 will be explained. As shown in FIG. 2, first, the computing device 12 acquires various kinds of information used to calculate the muscle mass of the dialysis patient (S12). In this embodiment, the various information used to calculate the muscle mass of the dialysis patient are the urea concentration of the dialysis patient before and after dialysis, the uric acid concentration of the dialysis patient before and after dialysis, the amount of urea removed by dialysis of the dialysis patient, This is the amount of uric acid removed by dialysis in dialysis patients.
　透析前後の尿酸濃度と尿素濃度は、実測値として取得可能である。例えば、透析前後の尿酸濃度は、以下の手順で取得する。まず、透析前と透析後に透析患者の血液をそれぞれ採取する。そして、採取した透析前の血液を血球と血漿に遠心分離し、分離された血漿中の尿酸濃度を測定する。血漿中の尿酸濃度の測定方法は特に限定しない。作業者は、測定した透析前後の血漿尿酸濃度をインターフェース装置３０に入力する。入力された透析前後の血漿尿酸濃度は、インターフェース装置３０から演算装置１２に出力され、患者情報記憶部１４に記憶される。また、透析による尿酸除去量と尿素除去量は、透析による各種情報から算出可能である。例えば、透析による尿酸除去量は、透析後の透析液排液の尿酸濃度を測定し、測定した尿酸濃度と透析液排液量との積によって尿酸除去量を算出することができる。あるいは、透析によって取得可能な他の情報を用いて算出することもできる。透析によって取得可能な他の情報を用いて尿酸除去量や尿素除去量を算出する方法については、例えば、国際公開第２０１９／１３８９１７号公報等に開示されているため、詳細な説明は省略する。 The uric acid and urea concentrations before and after dialysis can be obtained as actual measurements. For example, uric acid concentrations before and after dialysis are obtained by the following procedure. First, blood is collected from dialysis patients before and after dialysis. Then, the collected blood before dialysis is centrifuged into blood cells and plasma, and the uric acid concentration in the separated plasma is measured. The method for measuring the uric acid concentration in plasma is not particularly limited. The operator inputs the measured plasma uric acid concentrations before and after dialysis into the interface device 30 . The input pre- and post-dialysis plasma uric acid concentrations are output from the interface device 30 to the computing device 12 and stored in the patient information storage unit 14 . Also, the amount of uric acid removed and the amount of urea removed by dialysis can be calculated from various information obtained by dialysis. For example, the amount of uric acid removed by dialysis can be calculated by measuring the concentration of uric acid in the effluent dialysate after dialysis and multiplying the measured uric acid concentration by the amount of effluent dialysate. Alternatively, it can be calculated using other information obtainable by dialysis. A method for calculating the amount of uric acid removed and the amount of urea removed using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. WO 2019/138917, and detailed description thereof will be omitted.
　次に、算出部２０は、ステップＳ１２で取得した各種情報を用いて、尿素分布容積を算出する（Ｓ１４）。以下に、尿素分布容積の算出方法の一例について説明する。尿素分布容積は、尿素除去量を透析前後の尿素濃度差で割ることにより算出することができる。したがって、以下の数１で表す式が成立する。なお、ureaＶは尿素分布容積を示し、ureaＥは尿素除去量を示し、ureaＣｓは透析前の尿素濃度を示し、ureaＣｅは透析後の尿素濃度を示す。 Next, the calculator 20 calculates the urea distribution volume using the various information acquired in step S12 (S14). An example of a method for calculating the urea distribution volume will be described below. The urea distribution volume can be calculated by dividing the amount of urea removed by the urea concentration difference before and after dialysis. Therefore, the formula represented by Equation 1 below is established. In addition, urea V indicates urea distribution volume, urea E indicates urea removal amount, urea Cs indicates urea concentration before dialysis, and urea Ce indicates urea concentration after dialysis.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　算出部２０は、ステップＳ１２で取得した透析前の尿素濃度ureaＣｓと、透析後の尿素濃度ureaＣｅと、尿素除去量ureaＥを上記の数１で表す式に代入することによって、尿素分布容積ureaＶを算出する。 The calculation unit 20 substitutes the pre-dialysis urea concentration urea Cs, the post-dialysis urea concentration urea Ce, and the urea removal amount urea E obtained in step S12 into the above equation (1) to obtain the urea distribution volume Calculate urea V.
　なお、本実施例では、透析前の尿素濃度ureaＣｓと、透析後の尿素濃度ureaＣｅと、尿素除去量ureaＥから尿素分布容積を算出したが、このような構成に限定されない。尿素分布容積は、透析によって取得可能な他の情報を用いて算出してもよい。なお、透析によって取得可能な他の情報を用いて尿素分布容積を算出する方法については、例えば、国際公開第２０１９／１３８９１７号公報等に開示されている。図３に示すように、尿素は、細胞膜４２も毛細血管膜５６も通過するため、体内の水分区画全域（細胞内区画４０と細胞外区画５０を合わせた範囲）に分布する。したがって、尿素分布容積は、総体液量に相当する。このため、例えば、国際公開第２０１９／１３８９１７号公報等に開示されている総体液量の算出方法を用いることによっても、尿素分布容積を算出することができる。 In this example, the urea distribution volume was calculated from the urea concentration urea Cs before dialysis, the urea concentration urea Ce after dialysis, and the urea removal amount urea E, but the configuration is not limited to this. The urea distribution volume may be calculated using other information obtainable by dialysis. A method of calculating the urea distribution volume using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. 2019/138917. As shown in FIG. 3, urea passes through both the cell membrane 42 and the capillary membrane 56, so it is distributed throughout the body's water compartments (the combined range of the intracellular compartment 40 and the extracellular compartment 50). The urea distribution volume therefore corresponds to the total body fluid volume. Therefore, for example, the urea distribution volume can also be calculated by using the method for calculating the total body fluid volume disclosed in International Publication No. 2019/138917.
　次に、算出部２０は、ステップＳ１２で取得した各種情報を用いて、尿酸分布容積を算出する（Ｓ１６）。以下に、尿酸分布容積の算出方法の一例について説明する。尿酸分布容積は、尿酸除去量を透析前後の尿酸濃度差で割ることにより算出することができる。したがって、以下の数２で表す式が成立する。なお、acidＶは尿酸分布容積を示し、acidＥは尿酸除去量を示し、acidＣｓは透析前の尿酸濃度を示し、acidＣｅは透析後の尿酸濃度を示す。 Next, the calculator 20 calculates the uric acid distribution volume using the various information acquired in step S12 (S16). An example of a method for calculating the uric acid distribution volume will be described below. The uric acid distribution volume can be calculated by dividing the uric acid removal amount by the uric acid concentration difference before and after dialysis. Therefore, the following formula (2) is established. Acid V indicates the uric acid distribution volume, acid E indicates the amount of uric acid removed, acid Cs indicates the uric acid concentration before dialysis, and acid Ce indicates the uric acid concentration after dialysis.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　算出部２０は、ステップＳ１２で取得した透析前の尿酸濃度acidＣｓと、透析後の尿酸濃度acidＣｅと、尿酸除去量acidＥを上記の数２で表す式に代入することによって、尿酸分布容積acidＶを算出する。 The calculation unit 20 substitutes the pre-dialysis uric acid concentration acid Cs, the post-dialysis uric acid concentration acid Ce, and the uric acid removal amount acid E obtained in step S12 into the above equation (2) to obtain the uric acid distribution volume Calculate acid V.
　なお、本実施例では、透析前の尿酸濃度acidＣｓと、透析後の尿酸濃度acidＣｅと、尿酸除去量acidＥから尿酸分布容積を算出したが、このような構成に限定されない。尿酸分布容積は、透析によって取得可能な他の情報を用いて算出してもよい。なお、透析によって取得可能な他の情報を用いて尿酸分布容積を算出する方法については、例えば、国際公開第２０１９／１３８９１７号公報等に開示されている。図３に示すように、尿酸は、細胞膜４２を通過しない一方で、毛細血管膜５６を通過するため、体内の水分区画のうち細胞外区画５０にのみ分布し、細胞内区画４０には分布しない。したがって、尿酸分布容積は、細胞外液量に相当する。このため、例えば、国際公開第２０１９／１３８９１７号公報等に開示されている細胞外液量の算出方法を用いることによっても、尿酸分布容積を算出することができる。 In this example, the uric acid distribution volume was calculated from the uric acid concentration acid Cs before dialysis, the uric acid concentration acid Ce after dialysis, and the uric acid removal amount acid E, but the configuration is not limited to this. The uric acid distribution volume may be calculated using other information obtainable by dialysis. A method of calculating the uric acid distribution volume using other information that can be obtained by dialysis is disclosed in, for example, International Publication No. 2019/138917. As shown in FIG. 3, uric acid does not pass through the cell membrane 42 but passes through the capillary membrane 56, so it is distributed only in the extracellular compartment 50 among the water compartments in the body, and is not distributed in the intracellular compartment 40. . Therefore, the uric acid distribution volume corresponds to the extracellular fluid volume. Therefore, for example, the uric acid distribution volume can also be calculated by using the extracellular fluid amount calculation method disclosed in International Publication No. 2019/138917.
　図２に示すように、尿素分布容積と尿酸分布容積が算出されると、算出部２０は、ステップＳ１４で算出された尿素分布容積と、ステップＳ１６で算出された尿酸分布容積と、相関式記憶部１８に記憶される相関式を用いて、筋肉量を算出する（Ｓ２０）。ここで、相関式記憶部１８に記憶される相関式について説明する。 As shown in FIG. 2, when the urea distribution volume and the uric acid distribution volume are calculated, the calculation unit 20 stores the urea distribution volume calculated in step S14, the uric acid distribution volume calculated in step S16, and the correlation formula storage. The muscle mass is calculated using the correlation formula stored in the unit 18 (S20). Here, the correlation formulas stored in the correlation formula storage unit 18 will be described.
　相関式記憶部１８に記憶される相関式は、尿素分布容積と尿酸分布容積の差と、筋肉量との間の相関を示す式である。上述したように、尿素分布容積は総体液量に相当し、尿酸分布容積は細胞外液量に相当する。したがって、尿素分布容積から尿酸分布容積を差し引いた値は、総体液量から細胞外液量を差し引いた値、すなわち、透細胞内液量の値と一致する。細胞内液量は、筋肉量と相関することが知られている。したがって、尿素分布容積と尿酸分布容積の差と、筋肉量との間には、相関があると言える。以下に、相関式の算出方法について説明する。 The correlation formula stored in the correlation formula storage unit 18 is a formula showing the correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. As mentioned above, the urea distribution volume corresponds to the total body fluid volume, and the uric acid distribution volume corresponds to the extracellular fluid volume. Therefore, the value obtained by subtracting the uric acid distribution volume from the urea distribution volume agrees with the value obtained by subtracting the extracellular fluid volume from the total body fluid volume, ie, the permeable intracellular fluid volume. Intracellular fluid volume is known to correlate with muscle mass. Therefore, it can be said that there is a correlation between the difference between the urea distribution volume and the uric acid distribution volume and the muscle mass. A method of calculating the correlation formula will be described below.
　本実施例では、クレアチニン産生速度に着目して、相関式における筋肉量を算出する。体内のクレアチンは、約９８％が筋肉に分布している。クレアチンは、１日あたり約２％がクレアチニンに非可逆的に非酵素的に変換される。したがって、１日にクレアチンがクレアチニンに変換される量（すなわち、クレアチニン産生速度）は、体内のクレアチンの量に比例する。すなわち、クレアチニン産生速度は、体内の筋肉量に比例する。このように、１日に産生されるクレアチニン量（クレアチニン産生速度）と筋肉量の比率は、creatinine equivalenceと称されており、例えば、Picouらにより、クレアチニン産生速度の単位をｍｇ/日、筋肉量の単位をｋｇとした時、creatinine equivalenceは、０．０１８６であると報告されている。すなわち、ｍｇ/日単位のクレアチニン産生速度にcreatinine equivalenceの値（０．０１８６）を掛け合わせると、ｋｇ単位の筋肉量が算出される。したがって、クレアチニン産生速度を取得できれば、筋肉量を算出することができる。 In this example, focusing on the creatinine production rate, the muscle mass in the correlation formula is calculated. About 98% of creatine in the body is distributed in muscle. Creatine is irreversibly non-enzymatically converted to creatinine at approximately 2% per day. Therefore, the amount of creatine converted to creatinine per day (ie, creatinine production rate) is proportional to the amount of creatine in the body. That is, the rate of creatinine production is proportional to the muscle mass in the body. Thus, the ratio between the amount of creatinine produced per day (creatinine production rate) and muscle mass is called creatinine equivalence. For example, Picou et al. The creatinine equivalence is reported to be 0.0186 when the unit of weight is kg. That is, multiplying the creatinine production rate in mg/day by the creatinine equivalence value (0.0186) yields muscle mass in kg. Therefore, if the creatinine production rate can be obtained, the muscle mass can be calculated.
　クレアチニン産生速度を算出する方法について説明する。本実施例では、クレアチニンのキネティックモデルを解析してクレアチニン産生速度を算出する。例えば、１週間に３回透析を行う透析患者では、週３回の透析によって除去されたクレアチニン除去量の合計が、１週間で産生されたクレアチニンの総量と一致する。そこで、週３回の透析によるクレアチニン除去量の合計から１日当たりのクレアチニン産生量（すなわち、クレアチニン産生速度）を算出する。 Explain how to calculate the creatinine production rate. In this example, a kinetic model of creatinine is analyzed to calculate the creatinine production rate. For example, in a dialysis patient who undergoes dialysis three times a week, the total amount of creatinine removed by dialysis three times a week corresponds to the total amount of creatinine produced in one week. Therefore, the amount of creatinine produced per day (that is, the creatinine production rate) is calculated from the total amount of creatinine removed by dialysis three times a week.
　まず、１回の透析によるクレアチニン除去量を算出する方法について説明する。１回の透析によるクレアチニン除去量は、透析前に体内の存在していたクレアチニン量から透析後に体内に存在しているクレアチニン量を差し引いた値と等しい。透析前に体内の存在していたクレアチニン量は、クレアチニン分布容積と透析前の血清クレアチニン濃度の積と等しく、透析後に体内に存在しているクレアチニン量は、クレアチニン分布容積と透析後の血清クレアチニン濃度の積と等しい。したがって、以下の数３で表す式が成立する。なお、Ｒは１回の透析によるクレアチニン除去量を示し、Ｖはクレアチニン分布容積を示し、Ｃｐｒｅは透析前の血清クレアチニン濃度を示し、Ｃｐｏｓｔは透析後の血清クレアチニン濃度を示す。 First, the method for calculating the amount of creatinine removed by one dialysis will be explained. The amount of creatinine removed by one dialysis is equal to the amount of creatinine present in the body before dialysis minus the amount of creatinine present in the body after dialysis. The amount of creatinine present in the body before dialysis is equal to the product of the creatinine distribution volume and the serum creatinine concentration before dialysis, and the amount of creatinine present in the body after dialysis is the creatinine distribution volume and the serum creatinine concentration after dialysis equal to the product of Therefore, the following formula (3) holds. R indicates the amount of creatinine removed by one dialysis, V indicates the creatinine distribution volume, Cpre indicates the serum creatinine concentration before dialysis, and Cpost indicates the serum creatinine concentration after dialysis.
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　クレアチニン分布容積は、通常、体重の約４９％であることが統計的に知られている。したがって、クレアチニン分布容積は、透析後の体重に０．４９を掛け合わせることによって推定することができる。以上から、透析前の血清クレアチニン濃度と、透析後の血清クレアチニン濃度と、透析後の体重から、１回の透析によるクレアチニン除去量を算出することができる。そして、週３回のクレアチニン除去量をそれぞれ算出し、算出されたクレアチニン除去量を合計すると、１週間のクレアチニン除去量が算出される。これを７で割ることで、１日当たりのクレアチニン除去量、すなわち、クレアチニン産生速度を算出できる。 It is statistically known that the creatinine distribution volume is usually about 49% of body weight. Therefore, the creatinine volume of distribution can be estimated by multiplying the post-dialysis body weight by 0.49. From the above, the amount of creatinine removed by one dialysis can be calculated from the serum creatinine concentration before dialysis, the serum creatinine concentration after dialysis, and the body weight after dialysis. Then, the amount of creatinine removed three times a week is calculated, and the calculated amounts of creatinine removed are totaled to calculate the amount of creatinine removed for one week. By dividing this by 7, the amount of creatinine removed per day, that is, the creatinine production rate can be calculated.
　上述したように、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせると、筋肉量を算出できる。しかし、クレアチニン産生速度は、筋肉量以外の多くの因子の影響も受ける。例えば、クレアチニン産生速度を示す尿中へのクレアチニンの排泄量は、通常でも４～８％の変動があり、激しい運動によって５～１０％増加し、さらに、野菜だけの食事から肉や魚を中心とする食事に切り替えると、１０～３０％増加する。したがって、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて算出した筋肉量は日々、大きく変動する。 As mentioned above, muscle mass can be calculated by multiplying the creatinine production rate by the creatinine equivalence value. However, creatinine production rate is also affected by many factors other than muscle mass. For example, the amount of creatinine excreted into the urine, which indicates the rate of creatinine production, fluctuates by 4-8% even under normal circumstances, and increases by 5-10% with vigorous exercise. increased by 10-30% when switched to Therefore, the muscle mass calculated by multiplying the creatinine production rate by the creatinine equivalence value fluctuates greatly from day to day.
　一方、身体の細胞な中で肥大し、あるいは委縮し得るのは筋肉細胞だけである。これは細胞内液と筋肉量とは比例関係にあることを示唆している。ところで、尿素分布容積は体内の全水分量に一致し、尿酸分布容積は細胞外液量と一致することが知られている。そこで、尿素分布容積から尿酸分布容積を差し引いた値は、細胞内液量と一致すると考えられる。これは、尿素分布容積から尿酸分布容積を差し引いた値は、筋肉量と相関することを示唆している。 On the other hand, muscle cells are the only cells in the body that can expand or shrink. This suggests that there is a proportional relationship between intracellular fluid and muscle mass. By the way, it is known that the urea distribution volume corresponds to the total water content in the body, and the uric acid distribution volume corresponds to the extracellular fluid content. Therefore, the value obtained by subtracting the uric acid distribution volume from the urea distribution volume is considered to match the intracellular fluid volume. This suggests that the value obtained by subtracting the uric acid distribution volume from the urea distribution volume correlates with muscle mass.
　本発明者らの調べたところでは、尿素分布容積から尿酸分布容積を差し引いた値（ｘ）、とクレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて算出した筋肉量（ｙ）との間は、図４に示すように相関関係があった。具体的には、本発明者らは、７４名の患者について、尿素分布容積と尿酸分布容積を算出し、次に、尿素分布容積と尿酸分布容積の差を算出した。また、７４名の患者について、クレアチニン産生速度を算出し、次に、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて筋肉量を算出した。図４に示すように、尿素分布容積と尿酸分布容積の差と、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて算出した筋肉量との間には、以下の数４で表す回帰式で示される関係が認められた。なお、Ｄは尿素分布容積と尿酸分布容積の差（Ｌ）を示し、ＳＭＭはクレアチニン産生速度（ｍｇ/日）にcreatinine equivalenceの値（０．０１８６）を掛け合わせて算出した筋肉量（ｋｇ）を示す。 According to the investigation by the present inventors, between the value (x) obtained by subtracting the uric acid distribution volume from the urea distribution volume and the muscle mass (y) calculated by multiplying the creatinine production rate by the creatinine equivalence value, There was a correlation as shown in FIG. Specifically, the inventors calculated the urea distribution volume and the uric acid distribution volume for 74 patients, and then calculated the difference between the urea distribution volume and the uric acid distribution volume. Also, for 74 patients, the creatinine production rate was calculated, and then the muscle mass was calculated by multiplying the creatinine production rate by the value of creatinine equivalence. As shown in FIG. 4, the difference between the urea distribution volume and the uric acid distribution volume, and the muscle mass calculated by multiplying the creatinine production rate by the value of creatinine equivalence, is expressed by the following regression equation 4. relationship was recognized. D indicates the difference (L) between the urea distribution volume and the uric acid distribution volume, and SMM is the muscle mass (kg) calculated by multiplying the creatinine production rate (mg/day) by the creatinine equivalence value (0.0186). indicate.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
図４において、クレアチニン産生速度にcreatinine equivalenceの値を掛け合わせて算出した筋肉量は、回帰直線の上下にズレ（残差）の合計が最小となるように分布している。ところで、算出されたクレアチニン産生速度には、食事において摂取した肉や魚に含まれていたクレアチニンや運動の際に筋肉から漏れ出したクレアチニンが含まれている。したがって、このズレは、クレアチニン産生速度の測定誤差だけでなく、食事や運動によるクレアチニン産生速度の変動および自然のクレアチニン産生速度の変動によるものでもある。以上より、回帰直線上の値は、食事における蛋白質摂取量のバラつきや運動量のバラつきが平均化された値であると考えられる。すなわち、この回帰直線を用いて、尿素分布容積と尿酸分布容積の差から筋肉量を算出する場合には、食事や運動による誤差が含まれない筋肉量が算出される。 In FIG. 4, the muscle mass calculated by multiplying the creatinine production rate by the creatinine equivalence value is distributed above and below the regression line so that the total deviation (residual error) is minimized. By the way, the calculated creatinine production rate includes creatinine contained in meat and fish ingested in meals and creatinine leaked from muscles during exercise. Therefore, this deviation is due not only to measurement errors in the creatinine production rate, but also to fluctuations in the creatinine production rate due to diet and exercise, and fluctuations in the natural creatinine production rate. From the above, it is considered that the values on the regression line are values obtained by averaging variations in dietary protein intake and exercise amounts. That is, when using this regression line to calculate the muscle mass from the difference between the urea distribution volume and the uric acid distribution volume, the muscle mass is calculated without errors due to diet and exercise.
　ステップＳ１８において、算出部２０は、相関式記憶部１８に記憶される相関式に、ステップＳ１４で算出された尿素分布容積からステップＳ１６で算出された尿酸分布容積を差し引いた値を代入する。これにより、筋肉量を精度よく算出することができる。 In step S18, the calculation unit 20 substitutes the value obtained by subtracting the uric acid distribution volume calculated in step S16 from the urea distribution volume calculated in step S14 into the correlation expression stored in the correlation expression storage unit 18. Thereby, the muscle mass can be calculated with high accuracy.
なお、本実施例では、Picouらが報告したcreatinine equivalenceの値を用いて相関式を作成した。しかし、creatinine equivalenceの値は、これに限定しない。他の研究者が報告したcreatinine equivalenceの値を用いて相関式を作成してもよい。 In this example, a correlation formula was created using the value of creatinine equivalence reported by Picou et al. However, the value of creative equivalence is not limited to this. A correlation may be created using creatinine equivalence values reported by other researchers.
　なお、本実施例では、演算装置１２は、上記の相関式を求める分析機能を有していてもよい。演算装置１２がこのような分析機能を有することによって、尿素分布容積と尿酸分布容積の間の差Ｄと筋肉量との間の相関関係について誤差が小さくなり、尿素分布容積と尿酸分布容積の間の差Ｄから筋肉量を算出する精度を向上させることができる。 It should be noted that, in this embodiment, the computing device 12 may have an analysis function for obtaining the above correlation formula. Since the arithmetic unit 12 has such an analysis function, the error in the correlation between the difference D between the urea distribution volume and the uric acid distribution volume and the muscle mass is reduced, and the difference between the urea distribution volume and the uric acid distribution volume is reduced. The accuracy of calculating the muscle mass from the difference D can be improved.
　以上、本明細書に開示の技術の具体例を詳細に説明したが、これらは例示にすぎず、請求の範囲を限定するものではない。請求の範囲に記載の技術には、以上に例示した具体例を様々に変形、変更したものが含まれる。また、本明細書または図面に説明した技術要素は、単独であるいは各種の組合せによって技術的有用性を発揮するものであり、出願時請求項記載の組合せに限定されるものではない。また、本明細書または図面に例示した技術は複数目的を同時に達成するものであり、そのうちの一つの目的を達成すること自体で技術的有用性を持つものである。 Specific examples of the technology disclosed in this specification have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings achieve multiple purposes at the same time, and achieving one of them has technical utility in itself.

Claims (4)

  1. 　透析患者の透析前後の血清尿素濃度を取得する尿素濃度取得部と、
    　透析患者の透析前後の血清尿酸濃度を取得する尿酸濃度取得部と、
    　取得した透析前後の血清尿素濃度から算出される尿素分布容積と取得した透析前後の血清尿酸濃度から算出される尿酸分布容積の差に基づいて筋肉量を算出する演算部と、を備えている、筋肉量算出装置。     a urea concentration acquisition unit that acquires the serum urea concentration of a dialysis patient before and after dialysis;
    a uric acid concentration acquisition unit that acquires the serum uric acid concentration of a dialysis patient before and after dialysis;
    a calculation unit that calculates muscle mass based on the difference between the urea distribution volume calculated from the obtained serum urea concentrations before and after dialysis and the uric acid distribution volume calculated from the obtained serum uric acid concentrations before and after dialysis, Muscle mass calculator.
  2. 　前記尿素分布容積と前記尿酸分布容積の前記差と、筋肉量との間の相関式を記憶する相関式記憶部をさらに備えており、
    　前記演算部は、前記相関式記憶部に記憶される前記相関式に基づいて筋肉量を算出する、請求項１に記載の筋肉量算出装置。     further comprising a correlation formula storage unit that stores a correlation formula between the difference between the urea distribution volume and the uric acid distribution volume and muscle mass,
    The muscle mass calculation device according to claim 1, wherein the calculation unit calculates the muscle mass based on the correlation expression stored in the correlation expression storage unit.
  3. 　前記相関式は、前記尿素分布容積と前記尿酸分布容積の前記差と、クレアチニン産生速度とcreatinine equivalenceとの積との間の関係を示す、請求項２に記載の筋肉量算出装置。 3. The muscle mass calculation device according to claim 2, wherein the correlation formula indicates the relationship between the difference between the urea distribution volume and the uric acid distribution volume, and the product of the creatinine production rate and creatinine equivalence.
  4. 　透析患者の透析前後の血清尿素濃度を取得する尿素濃度取得工程と、
    　透析患者の透析前後の血清尿酸濃度を取得する尿酸濃度取得工程と、
    　取得した透析前後の血清尿素濃度から算出される尿素分布容積と取得した透析前後の血清尿酸濃度から算出される尿酸分布容積の差に基づいて筋肉量を算出する算出工程と、を備えている、筋肉量算出方法。     A urea concentration acquisition step of acquiring the serum urea concentration of a dialysis patient before and after dialysis;
    a uric acid concentration obtaining step of obtaining the serum uric acid concentration of a dialysis patient before and after dialysis;
    a calculating step of calculating muscle mass based on the difference between the urea distribution volume calculated from the obtained serum urea concentrations before and after dialysis and the uric acid distribution volume calculated from the obtained serum uric acid concentrations before and after dialysis; Muscle mass calculation method.
PCT/JP2022/004955 2021-02-12 2022-02-08 Device for calculating muscle mass and method for calculating muscle mass WO2022172926A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2022580637A JPWO2022172926A1 (en) 2021-02-12 2022-02-08

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-021201 2021-02-12
JP2021021201 2021-02-12

Publications (1)

Publication Number Publication Date
WO2022172926A1 true WO2022172926A1 (en) 2022-08-18

Family

ID=82837552

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/004955 WO2022172926A1 (en) 2021-02-12 2022-02-08 Device for calculating muscle mass and method for calculating muscle mass

Country Status (2)

Country Link
JP (1) JPWO2022172926A1 (en)
WO (1) WO2022172926A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11218536A (en) * 1998-01-30 1999-08-10 Toru Niisato Method for computing production speed of creatinine by using hemodialytic data
WO2019138917A1 (en) * 2018-01-10 2019-07-18 ニプロ株式会社 Apparatus for calculating amount of extracellular fluid and method for calculating amount of extracellular fluid
JP2020174739A (en) * 2019-04-15 2020-10-29 ニプロ株式会社 Extracellular fluid amount standardization apparatus, extracellular fluid amount evaluation apparatus equipped with the same, and computer program for standardizing extracellular fluid amount

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11218536A (en) * 1998-01-30 1999-08-10 Toru Niisato Method for computing production speed of creatinine by using hemodialytic data
WO2019138917A1 (en) * 2018-01-10 2019-07-18 ニプロ株式会社 Apparatus for calculating amount of extracellular fluid and method for calculating amount of extracellular fluid
JP2020174739A (en) * 2019-04-15 2020-10-29 ニプロ株式会社 Extracellular fluid amount standardization apparatus, extracellular fluid amount evaluation apparatus equipped with the same, and computer program for standardizing extracellular fluid amount

Also Published As

Publication number Publication date
JPWO2022172926A1 (en) 2022-08-18

Similar Documents

Publication Publication Date Title
Raimann et al. Comparison of fluid volume estimates in chronic hemodialysis patients by bioimpedance, direct isotopic, and dilution methods
CA2562875C (en) A method and a device for determining the hydration and/or nutrition status of a patient
US7072710B2 (en) Method and a device for determining the dry weight of a patient with kidney failure
EP2874540B1 (en) Calibration of a body parameter for monitoring dialysis
Kowalchuk et al. Role of lungs and inactive muscle in acid-base control after maximal exercise
US20050039763A1 (en) Determining the hydration status of a patient
Johansson et al. Body composition in patients treated with peritoneal dialysis.
Marroni et al. Phase angle bioelectrical impedance analysis (BIA) as a biomarker tool for liver disease
JP7218660B2 (en) Extracellular fluid volume standardization device, extracellular fluid volume evaluation device provided with the same, and computer program for standardizing extracellular fluid volume
WO2022172926A1 (en) Device for calculating muscle mass and method for calculating muscle mass
EP3738624B1 (en) Apparatus for calculating amount of extracellular fluid and method for calculating amount of extracellular fluid
Dolgos et al. The importance of body composition and dry weight assessments in patients with chronic kidney disease
US11363963B2 (en) Method and device for determining the hydration, fitness and nutrition status of a human body
Garred et al. Equations for the calculation of the protein catabolic rate from predialysis and postdialysis urea concentrations and residual renal clearance in stable hemodialysis patients
JP2022160220A (en) Extracellular fluid amount standardization device, extracellular fluid amount evaluation device comprising the same, and computer program for standardizing extracellular fluid amount
CN110111871B (en) Dry weight assessment method and system based on dynamic model
JPWO2020040208A1 (en) Extracellular fluid volume calculation device and extracellular fluid volume calculation method
CN107533070A (en) For the method and apparatus for the filtration rate for determining patient
Gurtner et al. Gas-to-blood PCO2 differences during severe hypercapnia
Iacone et al. Estimation of glomerular filtration rate from skeletal muscle mass. A new equation independent from age, weight, gender, and ethnicity
Mupere et al. Implementation of a field study of body composition among infants and young children in sub-Saharan Africa
Licht et al. Measurement of transmembrane potential in the study of systemic disease
TW202242413A (en) Method for evaluating mitochondrial function in organ and tissue other than kidney of subject
Riskiana et al. ASSOCIATION OF CHANGES MAGNESIUM AND CHLORIDE LEVELS TO MUSCLE STRENGTH FOR PRE AND POST REGULAR HEMODIALYSIS PATIENTS
Dzaharudin et al. Model comparison of estimated glomerular filtration rate for acute kidney injury in intensive care unit

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22752749

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2022580637

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22752749

Country of ref document: EP

Kind code of ref document: A1