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
• • 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
  • A61M1/1601—Control or regulation
  • A61M1/1603—Regulation parameters
  • A61M1/1605—Physical characteristics of the dialysate fluid
  • A61M1/1607—Physical characteristics of the dialysate fluid before use, i.e. upstream of dialyser
• • 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
  • A61M1/1601—Control or regulation
  • A61M1/1603—Regulation parameters
  • A61M1/1605—Physical characteristics of the dialysate fluid
  • A61M1/1609—Physical characteristics of the dialysate fluid after use, i.e. downstream of dialyser
• • 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
  • A61M1/1601—Control or regulation
  • A61M1/1617—Control or regulation using measurements made during a temporary variation of a characteristic of the fresh dialysis fluid
• • 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
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3317—Electromagnetic, inductive or dielectric measuring means
• • 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
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3324—PH measuring means

Definitions

• the invention relates to a method for determining the dialysance of a dialyzer during an extracorporeal blood treatment and a device for performing the method.
• Hemodialysis is a treatment method to compensate for kidney malfunctions with regard to the removal of urinary substances and the adjustment of the electrolyte concentration in the blood.
• the blood is conducted in an extracorporeal circuit through the blood chamber of a dialyzer, which is separated from a dialysis fluid chamber via a semipermeable membrane.
• the dialysis fluid chamber is flowed through by a dialysis fluid containing the blood electrolytes in a certain concentration.
• the substance concentration (c d ) of the dialysis fluid corresponds to the concentration of a healthy person's blood.
• the patient's blood and the dialysis fluid are generally passed in countercurrent at both sides of the membrane at a predetermined flow rate (Q b and Q d ).
• the urinary substances diffuse through the membrane from the blood chamber into the chamber for dialysis fluid, while electrolytes present in the blood and in the dialysis fluid diffuse from the chamber of higher concentration to the chamber of lower concentration.
• Clearance for a certain substance K is the virtual (calculated) blood volume that is completely freed from a certain substance per minute under defined conditions in the dialyzer.
• Dialysance is another term for determining the performance of a dialyzer, in which the concentration of the eliminated substance in the dialysis fluid is taken into account.
• other parameters are important, such as the values of the aqueous portion of the blood, the blood volume and the blood inlet concentration etc.
• the dialysance or clearance can be determined for a given electrolyte, for example sodium, at an ultrafiltration rate of zero as follows.
• the dialysance D is equal to the ratio between the blood-side mass transport for this electrolyte (Q b x (cbi - cbo)) and the Concentration difference of this electrolyte between the blood and the dialysis fluid at the respective inlet of the dialyzer (cbi - cdi).
• the effective blood flow is the flow of the blood portion in which the substances to be removed are dissolved, ie it refers to the (aqueous) solution volume for this stuff. Depending on the substance, this can be the plasma water flow or the blood water flow, ie the total water content in whole blood.
• Dialysate input concentrations is measured. Assuming that the blood input concentration is constant, the dialysance is determined according to the known method in that the difference between the differences in the dialysis fluid ion concentration on the input side and the output side of the dialyzer at the time of the first and second measurement is determined by this the difference of the dialysis fluid ion concentration at the input side at the time of the first measurement and the second measurement is divided and multiplied by the dialysis fluid flow.
• the relatively long measuring time proves to be disadvantageous, which can be attributed to the fact that after the dialysis fluid has been set to the new input concentration value, a stable equilibrium state must first be established at the dialyzer outlet before the new measured value can be recorded.
• EP 0 272 414 B1 describes a device for determining the change in intravascular blood volume during hemodialysis.
• the dialysance of the dialyzer should also be determined. The measuring method for determining the dialysance is not described in detail, but it is proposed to conduct conductivity measurements on the blood as well as on the dialysis fluid side to determine the dialysance, the integral being formed via the conductivity change on the blood and dialysis fluid side.
• the invention has for its object to provide a method that allows a rapid determination of the dialysance during an extracorporeal blood treatment.
• the invention has for its object to provide an apparatus for performing the method.
• the concentration of a certain substance in the dialysis fluid in the dialysis fluid path upstream of the dialyzer is changed on the basis of a predefined initial value cdil and set again to the initial value.
• a bolus of a hypertonic NaCl solution can be supplied to the dialysis fluid path upstream of the dialyzer who has no influence on the dialysis treatment.
• the concentration of the substance in the dialysis fluid downstream of the dialyzer (dialysis fluid initial concentration cdo) is measured, which changes from a predetermined initial value and returns to the initial value. If the change of
• Dialysis fluid inlet concentration is not known in its time course, the concentration of the substance is also measured upstream of the dialyzer.
• the dialysance is determined by calculating two integrals from which the quotient is formed. It is the quotient of the integral of the difference between the
• Dialysis fluid output concentration cdo and the initial value cdol over time and the integral of the difference between the dialysis fluid inlet concentration cdi and the initial value cdil over time are calculated and the dialysance is determined using the quotient and the predetermined flow rate of the dialysis fluid in the dialysis fluid path.
• the integration can take place within relatively narrow limits, which are based on the width of the concentrate bolus.
• the dialysis fluid inlet or outlet concentration is preferably determined by measuring the conductivity of the dialysis fluid.
• conductivity sensors optical and other sensors for measuring the dialysis fluid inlet or outlet concentration can also be arranged in the dialysis fluid path.
• Figure 1 shows the device for determining the dialysance together with the essential components of a hemodialysis device in a schematic representation
• FIG. 1 shows the dialysis fluid inlet and outlet concentration
• the device for determining the dialysance D of the dialyzer of a dialysis device can form a separate assembly. However, it can also be part of the dialysis device, especially since some components of the device for determining the dialysance are already present in the known dialysis devices.
• the device for determining the dialysance is described below together with the essential components of the dialysis device.
• the dialysis device has a dialyzer 1, which is divided by a semipermeable membrane 2 into a blood chamber 3 and a dialysis fluid chamber 4.
• a blood supply line 5 leads from the patient to the inlet of the blood chamber 3 and a blood discharge line 6 leads back to the patient from the outlet of the blood chamber 3.
• a blood pump 7 which specifies the flow rate of the blood in the extracorporeal circuit is connected to the blood supply line 5.
• the inlet of the dialysis fluid chamber 4 is via a dialysis fluid supply line 8 with a dialysis fluid source 9 and the outlet of the dialysis fluid chamber is connected to a drain 11 via a dialysis fluid discharge line 10.
• a dialysis fluid pump 12 which specifies the flow rate of the dialysis fluid in the dialysis fluid path, is connected into the dialysis fluid discharge line 10.
• the blood pump 7 and the dialysis fluid pump 12 are controlled via control lines 13, 14 by a central control unit 15 of the dialysis device, which has an input unit 16 with which the delivery rates of the pumps can be specified.
• Dialysis fluid discharge line 10 each has a measuring device 17, 18 for determining the substance concentration of the dialysis fluid at the inlet of the dialyzer 1 and the substance concentration of the dialysis fluid at the outlet of the dialyzer.
• the measuring devices 17, 18 for determining the dialysis fluid inlet and outlet concentration cdi, cdo have conductivity sensors arranged upstream and downstream of the dialyzer 1, which preferably measure the temperature-corrected conductivity of the dialysis fluid based on the Na concentration.
• the conductivity sensors are connected to a memory unit 21 via data lines 19, 20.
• the memory unit 21 receives the measured values from the sensors and stores them in chronological order.
• the measured values are fed to a computing and evaluation unit 23 via a data line 22.
• the computing and evaluation unit receives, via the data line 24, the flow rate of the dialysis fluid in the dialysis fluid path predetermined by the dialysis fluid pump 12.
• a display unit 26 is connected to the computing and evaluation unit via a data line 25, on which the dialysance D of the dialyzer 1 and possibly further parameters of the hemodialysis are displayed.
• a device 27 is provided upstream of the dialyzer 1 for changing the dialysis fluid inlet concentration cdi. The device 27 can be used to apply a concentrate bolus to the dialysis fluid flowing into the dialyzer 1, so that the Na concentration of the dialysis fluid in the dialysis fluid path upstream of the dialyzer increases briefly.
• the sequence of the measurement for determining the dialysance D is controlled by a control unit 28, to which the device 27 for changing the Na concentration of the dialysis liquid and the computing and evaluation unit 23 are connected via data lines 29, 30.
• control unit 28 The program sequence for measuring dialysance D defined in control unit 28 is explained in detail below.
• the dialysis fluid which has a predetermined Na concentration, flows through the dialysis fluid chamber 4 of the dialyzer 1 at a flow rate Q d predetermined by the dialysis fluid pump 12.
• the device 27 now increases the dialysis fluid inlet concentration cdi within a short time interval (concentrate bolus), which is detected by means of the conductivity sensor 17 arranged upstream of the dialyzer.
• the dialysis fluid outlet concentration cdo which arises during dialysis is detected by means of the conductivity sensor 18 arranged downstream of the dialyzer.
• FIG. 2 shows the lateral profile of the dialysis fluid inlet and outlet concentration cdi, cdo upstream and downstream of the dialyzer.
• the calculated dialysance D is then displayed on the display unit 26. If the dialysance D is known, further hemodynamic parameters, for example the blood inlet concentration cbi, can be calculated and displayed according to equation (3).
• the denominator (cdi (t) -cdil) dt corresponds to the area labeled A in FIG. 2 under curve I, which indicates the time course of the dialysis fluid inlet concentration cdi.
• the counter j (cdo (t) - cdol) dt corresponds to the area B under the curve II indicating the time course of the dialysis solution starting concentration cdo.
• the integration limits can be determined so that the dialysance D can be determined with sufficient accuracy.
• the integration limits are based on the width of the concentrate bolus.
• empirical scaling factors can also be used for the quotient or separately for individual integrals in order to take systematic deviations into account, for example due to integration limits that are too small.
• formula (5) can be used instead of the formula (4) if an ultrafiltration rate UF 0 and UF ⁇ Q B is used.

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• 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)
• External Artificial Organs (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7873438

Family Applications (1)

Country Status (6)

Cited By (15)

Families Citing this family (5)

Citations (4)

• 1999
  • 1999-07-06 CA CA002336923A patent/CA2336923C/en not_active Expired - Lifetime
  • 1999-07-06 WO PCT/EP1999/004689 patent/WO2000002604A1/de not_active Ceased
  • 1999-07-06 KR KR1020017000247A patent/KR100570322B1/ko not_active Expired - Lifetime
  • 1999-07-06 AU AU51569/99A patent/AU5156999A/en not_active Abandoned
  • 1999-07-06 BR BR9911985-4A patent/BR9911985A/pt not_active IP Right Cessation
  • 1999-07-06 JP JP2000558862A patent/JP4219094B2/ja not_active Expired - Lifetime

Patent Citations (4)

Non-Patent Citations (1)

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