Method and apparatus for kidney dialysis

• US 5,487,827 A
• Filed: 05/13/1994
• Issued: 01/30/1996
• Est. Priority Date: 04/19/1991
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: Althin Medical, Inc.
• Inventors: Hogard, Michael E., Peterson, Bruce A.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US08/242,312
• Time in Patent Office: 627 Days
• Field of Search: 210/85, 210/87, 210/96.2, 210/646, 210/929, 210/97, 210/143, 210/321.6, 604/4-6, 604/30, 73/204.25, 417/1, 417/9, 417/32, 417/43
• US Class Current: 210/87
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1607 before use, i.e. upstream of dialyser
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/165 with a dialyser bypass on the dialysis fluid line
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/1664 with temperature control
• CPC Class Codes: A61M 1/1666 by dissolving solids
• CPC Class Codes: A61M 1/168 Sterilisation or cleaning before or after use
• CPC Class Codes: A61M 1/1684 Checking the module characteristics before reuse
• CPC Class Codes: A61M 1/1686 by heat
• CPC Class Codes: A61M 1/1688 with recirculation of the sterilising fluid
• CPC Class Codes: A61M 1/169 using chemical substances
• CPC Class Codes: A61M 1/1692 Detection of blood traces in dialysate
• CPC Class Codes: A61M 1/1694 with recirculating dialysing liquid
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 2039/1005 Detection of disconnection
• CPC Class Codes: A61M 2205/3313 used specific wavelengths
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3324 PH measuring means
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 : with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: G06F 3/0482 : Interaction with lists of selectable items, e.g. menus
• CPC Class Codes: G06F 3/04847 : Interaction techniques to control parameter settings, e.g. interaction with sliders or dials
• CPC Class Codes: G16H 20/40 : relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: Y10S 210/929 : Hemoultrafiltrate volume measurement or control processes

Abstract

A number of improvements relating to methods and apparatuses for kidney dialysis are disclosed. These include checking of dialysate bypass status using flow measurement; using a flow sensor to confirm the absence of ultrafiltration during bypass; automatic testing of ultrafiltration function by removal of a discrete volume from a portion of the dialysate flow path coupled with a pressure test of that part of the flow path; using a touch screen user interface; bar graph profile programming of ultrafiltration, sodium, and bicarbonate parameters; using a RAM card to upload treatment instructions to, and to download treatment data from, the machine; automatic setting of proportioning mode (acetate or bicarbonate) based on connections of concentrate lines; predicting dialysate conductivity values based on brand and formulation of concentrates; minimizing no-flow dead time between dialysate pulses; initiating operation in a timed mode from a machine power-off condition; preserving machine mode during machine power-fail condition; calibration scheduling and reminding; automatic level adjusting; and blood leak flow rate detecting.

Claims

1. A kidney dialysis machine comprising:

a dialyzer with a dialysate compartment, a blood compartment separated from the dialysate compartment by a dialysis membrane, a dialysate input, a dialysate output, a blood input, and a blood output;

means for preparing dialysate and means for circulating the dialysate through a dialysate circuit, the dialysate circuit including the dialysate compartment, the dialysate input and the dialysate output of the dialyzer;

means for effecting extracorporeal circulation of blood from a dialysis patient through a blood circuit, the blood circuit including the blood compartment, the blood input, and the blood output of the dialyzer;

shunting means for directing flow of dialysate away from the dialysate compartment;

sensing means for sensing that no dialysate is flowing to the dialysate compartment whenever said shunting means is directing dialysate flow away from the dialysate compartment; and

means responsive to said sensing means for turning off said means for circulating dialysate through the dialysate circuit whenever said shunting means should be directing dialysate flow away from the dialysate compartment but said sensing means detects dialysate flow to the dialysate compartment.

2. A kidney dialysis machine as recited in claim 1 wherein said sensing means also is operable for sensing that no net passage of liquid from the blood compartment to the dialysate compartment occurs whenever said shunting means is directing dialysate away from the dialysate compartment.

3. A kidney dialysis machine as recited in claim 1 wherein said shunting means comprises a bypass valve hydraulically coupled to the dialysate circuit, the bypass valve being adapted to actuate, upon receiving a signal indicating an alarm condition requiring bypass of the dialysate from the dialysate compartment, the directing of dialysate away from the dialysate compartment.

4. A kidney dialysis machine as recited in claim 1 wherein said sensing means comprises a flow sensor situated in the dialysate circuit.

5. A kidney dialysis machine as recited in claim 4 wherein the flow sensor comprises first and second thermistors in thermal contact with the dialysate in the dialysate circuit.

6. A kidney dialysis machine as recited in claim 5 wherein the first thermistor is energized by a constant electrical current, and the second thermistor is energized by an electrical current that is less than the electrical current energizing the first thermistor, thereby causing the first and second thermistors to exhibit a differential electrical resistance whenever liquid is flowing past the first and second thermistors but not when liquid is not flowing past the first and second thermistors.

7. A kidney dialysis machine as recited in claim 1 further comprising alarm means responsive to said sensing means so as to trigger an alarm response whenever said sensing means senses dialysate flow through the dialysate compartment during a time when said shunting means should be directing flow of dialysate away from the dialysate compartment.

8. A kidney dialysis machine as recited in claim 1 further comprising alarm means responsive to said sensing means so as to trigger an alarm response whenever said sensing means senses a net passage of liquid from the blood compartment to the dialysate compartments that occurs during a time when said shunting means should be directing flow of dialysate away from the dialysate compartment.

9. An apparatus for delivering dialysate comprising a dialysate circuit including a dialyzer, the apparatus further comprising:

(a) a pump hydraulically connected to a dialysate supply, the pump being operative to urge flow of dialysate from the dialysate supply through the dialysate circuit and dialyzer;

(b) a bypass valve disposed in the dialysate circuit upstream of the dialyzer, the bypass valve being operative to stop dialysate, flowing through the dialysate circuit, from flowing to the dialyzer during an unsafe dialysis condition; and

(c) a flow sensor means disposed in the dialysate circuit between the bypass valve and the dialyzer, the flow sensor means being operative to (1) sense the presence or absence of dialysate flow to the dialyzer, and (2) turn off the pump during an unsafe dialysis condition in which the flow sensor means detects dialysate flow to the dialyzer and the bypass valve should be stopping flow of dialysate to the dialyzer.

10. An apparatus according to claim 9, wherein the flow sensor means comprises first and second thermistors in thermal contact with dialysate in the dialysate circuit.

11. An apparatus according to claim 10, wherein the first thermistor is energized by a constant electrical current, and the second thermistor is energized by an electrical current that is less than the electrical current energizing the first thermistor, thereby causing the first and second thermistors to exhibit a differential electrical resistance whenever dialysate is flowing past the first and second thermistors but not when dialysate is not flowing past the first and second thermistors.

12. An apparatus for delivering dialysate comprising a dialysate circuit including a dialyzer, the apparatus further comprising:

(a) a pump hydraulically connected to a dialysate supply, the pump being operative to urge flow of dialysate from the dialysate supply through the dialysate circuit and dialyzer;

(b) a bypass valve disposed in the dialysate circuit upstream of the dialyzer, the bypass valve being operative to stop dialysate, flowing through the dialysate circuit, from flowing to the dialyzer during an unsafe dialysis condition; and

(c) first and second thermistors each in thermal contact with dialysate in the dialysate circuit between the bypass valve and the dialyzer, the first thermistor being energized by a constant electrical current, and the second thermistor being energized by an electrical current that is less than the electrical current energizing the first thermistor, thereby causing the first and second thermistors to exhibit a differential electrical resistance whenever dialysate is flowing past the first and second thermistors but not when dialysate is not flowing past the first and second thermistors, thereby enabling the first and second thermistors to (1) sense the presence or absence of dialysate flow to the dialyzer, and (2) turn off the pump during an unsafe dialysis condition in which the bypass valve should be stopping flow of dialysate to the dialyzer.

13. An apparatus for delivering dialysate comprising a dialysate circuit including a dialyzer having a dialysate compartment and a blood compartment, the apparatus further comprising:

(a) a pump hydraulically connected to a dialysate supply, the pump being operative to urge flow of dialysate from the dialysate supply through the dialysate circuit and the dialysate compartment of the dialyzer;

(b) a bypass valve disposed in the dialysate circuit upstream of the dialyzer, the bypass valve being operative to stop dialysate, flowing through the dialysate circuit, from flowing to the dialysate compartment of the dialyzer during an unsafe dialysis condition; and

(c) a flow sensor means disposed in the dialysate circuit between the bypass valve and the dialyzer, the flow sensor means being operative to (1) sense the presence or absence of dialysate flow to the dialysate compartment of the dialyzer, and (2) turn off the pump during an unsafe dialysis condition in which the flow sensor means detects dialysate flow to the dialysate compartment and the bypass valve should be stopping flow of dialysate to the dialysate compartment.

14. An apparatus according to claim 13 wherein the flow sensor means is further operative to (1) sense the presence or absence of flow of liquid from the blood compartment to the dialysate compartment, and (2) stop flow of blood to the blood compartment during said unsafe dialysis condition.

15. An apparatus for delivering dialysate comprising a dialysate circuit including a dialyzer having a dialysate compartment and a blood compartment, the apparatus further comprising:

(a) a pump hydraulically connected to a dialysate supply, the pump being operative to urge flow of dialysate from the dialysate supply through the dialysate circuit and dialyzer;

(b) a bypass valve disposed in the dialysate circuit upstream of the dialyzer, the bypass valve being operative to stop dialysate, flowing through the dialysate circuit, from flowing to the dialyzer during an unsafe dialysis condition; and

(c) a flow sensor means disposed in the dialysate circuit between the bypass valve and the dialyzer, the flow sensor means being operative to (1) sense the presence or absence of flow of liquid from the blood compartment to the dialysate compartment, and (2) stop flow of blood to the blood compartment during said unsafe dialysis condition.