Hemofiltration system

• US 6,780,322 B1
• Filed: 06/11/2002
• Issued: 08/24/2004
• Est. Priority Date: 04/30/1999
• Status: Expired due to Fees

• Current Assignee: Children's Hospital & Medical Center
• Original Assignee: Children's Hospital & Medical Center
• Inventors: Morales, Efrain O., Hemasilpin, Nat, Bissler, John J., Polycarpou, Marios M.
• Primary Examiner(s): DRODGE, JOSEPH W
• Application Number:
  US10/030,011
• Time in Patent Office: 805 Days
• Field of Search: 210/86, 210/87, 210/96.2, 210/103, 210/137, 210/143, 210/321.65, 210/637, 210/645, 210/646, 210/650, 210/739, 210/740, 210/767, 210/929, 210/96.1, 210/621.65, 604/4.01, 604/5.01, 604/65, 604/67, 604/6.09, 604/6.01, 706/1, 706/3, 706/4, 706/8, 706/47, 706/52, 705/3, 417/36, 417/43
• US Class Current: 210/637
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1603 Regulation parameters
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1611 Weight of the patient
• CPC Class Codes: A61M 1/1615 using measurements made at different flow rates
• CPC Class Codes: A61M 1/1643 with weighing of fresh and used dialysis fluid
• CPC Class Codes: A61M 1/1647 with flow rate measurement of the dialysis fluid, upstream and downstream of the dialyser
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3413 Diafiltration
• CPC Class Codes: A61M 1/342 Adding solutions to the blood, e.g. substitution solutions for preventing coagulation A61M1/3672
• CPC Class Codes: A61M 1/3434 with pre-dilution and post-dilution
• CPC Class Codes: A61M 1/3437 downstream of the filter, e.g. post-dilution with filtrate
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3451 the difference in weight between both ultra-filtrate and substitution reservoir being used as control signal
• CPC Class Codes: A61M 1/3496 Plasmapheresis; Leucopheresis; Lymphopheresis A61M1/3472 takes precedence
• CPC Class Codes: A61M 1/3607 Regulation parameters
• CPC Class Codes: A61M 1/3623 Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3344 : Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/3393 : by weighing the reservoir
• CPC Class Codes: A61M 2205/50 : with microprocessors or computers
• CPC Class Codes: G05B 13/0275 : using fuzzy logic only
• CPC Class Codes: Y10S 210/929 : Hemoultrafiltrate volume measurement or control processes

Abstract

A multipurpose hemofiltration system (10) and method are disclosed for the removal of fluid and/or soluble waste from the blood of a patient. The system (10) continuously monitors the flow rates of drained fluid, blood, and infusate. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted to remove a preselected amount of fluid from the blood in a preselected time period. A supervisory controller (160) can monitor patient parameters, such as heart rate (120) and blood pressure (130), and adjust the pumping rates accordingly. The supervisory controller (160) uses fuzzy logic to make expert decisions, based upon a set of supervisory rules, to control each pumping rate to achieve a desired flow rate and to respond to fault conditions. An adaptive controller (162) corrects temporal variations in the flow rate based upon an adaptive law and a control law.

Claims

1. A hemofiltration system for fluid removal from the blood of a patient, comprising:

a pump capable of pumping a liquid selected from the group consisting of infusate, drained fluid, and blood in the hemofiltration system;

a sensor for measuring the flow rate of fluid in the medical system generated by at least one pump, the flow rate sensor providing flow rate data signals correlated to the fluid flow rate; and

a supervisory controller operably connectable to the at least one pump and operably connected to the flow rate sensor;

at least one monitor for measuring at least one predetermined patient parameter;

said least one patient parameter monitor providing patient parameter data signals correlated to said at least one patient parameter,

wherein the controller is operably connected to said at least one monitor, the controller receiving the flow rate data signals and the patient parameter data signals and analyzing the flow rate data signals and the patient parameter data signals utilizing fuzzy logic having at least one predetermined supervisory rule, and then providing an output signal for the at least one pump to adjust, as necessary on a periodic ongoing basis, the flow rate of liquid generated by the at least one pump for regulating fluid removal from the patient'"'"'s blood.

2. The control system of claim 1, wherein said at least one patient parameter monitor is selected from the group consisting of a blood pressure monitor providing blood pressure data signals, a heart rate monitor providing heart rate data signals, and combinations thereof.

3. The control system of claim 2, wherein the medical system is an ultrafiltration system and the at least one predetermined supervisory rule is selected from the group consisting of:

a) If heart rate is high and blood pressure is normal or low, then decrease ultrafiltration and wait a first predetermined time,

b) If blood pressure is low and heart rate is normal or high, then decrease ultrafiltration and wait a second predetermined time,

c) If blood pressure is low and heart rate is low, then provide the user a choice between a decrease or increase of the ultrafiltration rate and wait a third predetermined time,

d) If blood pressure is high and heart rate is high for a fourth predetermined time, then provide the user with a choice between a decrease or increase of the ultrafiltration rate,

e) If blood pressure is high and heart rate is low for a fifth predetermined time, then increase ultrafiltration,

f) The lowest possible value of ultrafiltration is a predetermined minimum rate per hour and the highest possible value of the ultrafiltration rate is a predetermined percentage above that of a predetermined maximum ultrafiltration rate,

g) If an increase in ultrafiltration occurs such that the filtered fraction is greater than a predetermined filtered fraction, then increase the blood pump flow such that the filtered fraction equals the predetermined filtered fraction.

4. The control system of claim 2, wherein the sensor is selected from the group consisting of a flowmeter and a weight scale.

5. The control system of claim 1, further comprising a second sensor for measuring the flow rate of fluid generated by a second pump, the second flow rate sensor providing second flow rate data signals correlated to the fluid flow rate, wherein the supervisory controller is further operably connectable to the second pump and operably connected to the second flow rate sensor, the controller receiving the second flow rate data signals and analyzing the signals utilizing fuzzy logic based on at least one predetermined supervisory rule and the controller then providing an output signal for the second pump to adjust, as necessary on a periodic ongoing basis, the flow rate of fluid generated by the second pump.

6. The control system of claim 5, further comprising a third sensor for measuring the flow rate of fluid in the medical system generated by a third pump, the third flow rate sensor providing third flow rate data signals correlated to the fluid flow rate, wherein the supervisory controller is further operably connectable to the third pump and operably connected to the third flow rate sensor, the controller receiving the third flow rate data signals and analyzing the signals utilizing fuzzy logic based on at least one predetermined supervisory rule and the controller then providing an output signal for the third pump to adjust, as necessary on a periodic ongoing basis, the flow rate of fluid generated by the third pump.

7. The control system of claim 6, further comprising:

a fourth sensor for measuring the flow rate of fluid in the medical system generated by a fourth pump, the fourth flow rate sensor providing fourth flow rate data signals correlated to the fluid flow rate, wherein the supervisory controller is further operably connectable to the fourth pump and operably connected to the fourth flow rate sensor, the controller receiving the fourth flow rate data signals and analyzing the signals utilizing fuzzy logic based on at least one predetermined supervisory rule and the controller then providing an output signal to the fourth pump to adjust, as necessary on a periodic ongoing basis, the flow rate of fluid generated by the fourth pump.

8. The control system of claim 1, further comprising an adaptive controller operably connectable to the pump and to said flow rate sensor, the adaptive controller receiving said flow rate data signals, using an adaptive law to generate a set of controller parameters for correcting time-dependent deviations of the flow rate of the respective fluid from a predetermined blood flow rate, and using a control law to generate an output signal from the set of controller parameters for adjusting the pumping rate of fluid generated by the pump to achieve the predetermined blood flow rate, said adaptive controller then providing the output signal for the pump on a periodic ongoing basis.

9. A hemofiltration system for fluid removal from the blood of a patient, comprising:

a pump capable of pumping a liquid selected from the group consisting of infusate, drained fluid, and blood in the hemofiltration system;

a flow rate sensor for measuring the flow rate of the liquid generated by the at least one pump, the flow rate sensor providing flow rate data signals correlated to the liquid flow rate; and

an adaptive controller operably connectable to the at least one pump and operably connected to the flow rate sensor, the controller receiving the flow rate data signals and generating an output signal for adjusting the pumping rate of the liquid generated by the at least one pump, the controller providing the output signal for the at least one pump on a periodic ongoing basis, the controller using an adaptive law to generate a set of controller parameters for correcting time-dependent deviations of the flow rate from a predetermined flow rate, and using a control law to generate the output signal from the set of controller parameters for adjusting the pumping rate of the liquid generated by the at least one pump to achieve the predetermined flow rate for regulating fluid removal from the patient'"'"'s blood.

10. The control system of claims 9, wherein the adaptive law further includes parameter projections to limit the output signal to a range between a predetermined minimum output signal and a predetermined maximum output signal.

11. The control system of claim 9, wherein the sensor is selected from the group consisting of a flowmeter and a weight scale.

12. The control system of claim 11, wherein the sensor is a weight scale providing weight data signals and the flow rate data signals comprise the rate change in the weight data signals.

13. A method of controlling a pump in a hemofiltration system, comprising:

measuring the flow rate of a liquid selected from the group consisting of infusate, drained fluid, and blood generated by the pump to obtain flow rate data signals correlated to the fluid flow rate;

measuring at least one patient parameter to obtain patient parameter data signals correlated to said at least one patient parameter;

analyzing the flow rate data signals and the patient parameter data signals utilizing fuzzy logic having at least one predetermined supervisory rule; and

providing an output signal to the pump to adjust, as necessary on a periodic ongoing basis, the flow rate of liquid generated by the pump for regulating fluid removal from the patient'"'"'s blood.

14. A method of controlling a pump in an ultrafiltration system, comprising:

measuring a flow rate of a liquid selected from the group consisting of infusate, drained fluid, and blood in the hemofiltration system generated by the pump to obtain flow rate data signals correlated to the liquid flow rate;

generating a set of controller parameters from the flow rate signals for correcting time-dependent deviations of the flow rate from the predetermined flow rate;

generating an output signal using a control law from the set of controller parameters, the output signal capable of adjusting the pumping rate of liquid generated by the pump to achieve a predetermine flow rate; and

providing the output signal to the pump on a periodic ongoing basis to correct the deviations of the flow rate from the predetermined flow rate for regulating fluid removal from the patient'"'"'s blood.

15. Hemofiltration method for removal of fluid from the blood of a patient, comprising:

pumping blood from a patient through a hemofilter and back to the patient;

monitoring the blood outflow from the blood pump and generating blood flow rate data signals;

maintaining a supply of infusate in a first reservoir;

monitoring the weight of infusate in the first reservoir and generating infusate flow rate data signals, pumping the infusate to the hemofilter;

pumping drained fluid from the hemofilter into a second reservoir;

monitoring the weight of drained fluid in the second reservoir and generating drained fluid flow rate data signals;

monitoring at least one predetermined patient parameter, such as patient heart rate and/or blood pressure, and generating parameter data signals correlated thereto; and

controlling the pumping rate of the blood, the drained fluid, and the infusate with a programmed computer, the computer being responsive to the flow rate data signals, the computer;

receiving the flow rate data and parameter data signals;

analyzing the received signals with fuzzy logic having at least one predetermined supervisory rule; and

generating an output signal to each pump based upon the analysis of the received flow rate data and parameter data signals to adjust, as necessary on a periodic ongoing basis, the flow rate of fluid generated by each pump, for regulating fluid removal from the patient'"'"'s blood.

16. Hemofiltration method for removal of fluid from the blood of a patient, comprising

pumping blood from a patient through a hemofilter and back to the patient;

sensing the performance of the blood pump and generating a first set of controller parameters from a fist adaptive law;

monitoring the blood outflow from the blood pump and generating blood flow rate data signals;

maintaining a supply of infusate in a first reservoir;

monitoring the weight of infusate in the first reservoir and generating infusate flow rate data signals;

pumping the infusate to the hemofilter;

sensing the performance of the infusate pump generating a second set of controller parameters from a second adaptive law;

pumping drained fluid from the hemofilter into a second reservoir;

monitoring the weight of drained fluid in the second reservoir and generating drained fluid flow rate data signals;

sensing the performance of the drained fluid pump and generating a third set of controller parameters from a third adaptive law;

controlling the pumping rate of the blood, the drained fluid, and the infusate with a programmed computer to correspond to a set of predetermined pumping rates, the computer being responsive to the flow rate data signals and the controller parameters,

using a control law to generate an output signal from the flow rate data signals and the controller parameters for correcting time-dependent deviations of the flow rate from the set of predetermined pumping rates; and

providing the output signal to at least one pump on a periodic ongoing basis, for regulating fluid removal from the patient'"'"'s blood.

17. Continuous hemofiltration system for removal of fluid from the blood of a patient, comprising:

a hemofilter;

a first pump for pumping blood from a patient through said hemofilter and back to the patient;

a flowmeter downstream of said first pump to measure the blood outflow rate from the blood pump, said flowmeter generating blood flow rate data signals correlated to the blood outflow rate;

a first reservoir for maintaining a supply of infusate;

a second pump for pumping the infusate firm said first reservoir to said hemofilter;

a second reservoir for receiving drained fluid from said hemofilter;

a third pump for pumping the drained fluid from said hemofilter to said second reservoir; and

an adaptive controller operably connected to said first pump and to said blood flowmeter, said adaptive controller receiving said blood flow rate data signals, using an adaptive law to generate a set of controller parameters for correcting time-dependent deviations of the blood outflow rate from a target blood outflow rate, and using a control law to generate an output signal from the set of controller parameters for adjusting the pumping rate of fluid generated by the first pump to achieve the target blood flow rate, said adaptive controller then providing the output signal to the first pump on a periodic ongoing basis for regulating fluid removal from the patient'"'"'s blood.

18. The continuous hemofiltration system of claim 17, further comprising:

at least one monitor for measuring at least one predetermined patient parameter, said least one patient parameter monitor providing patient parameter data signals correlated to said at least one patient parameter;

a first scale to measure the weight of infusate in said first reservoir, said first scale generating infusate flow rate data signals correlated to the infusate weight;

a second scale to measure the weight of drained fluid in said second reservoir, said second scale generating drained fluid flow rate data signals correlated to the drained fluid weight; and

a supervisory controller operably connected to said pumps, to said flowmeter, to said scales, and to said at least one patient parameter monitor, said controller receiving said flow rate data signals and said patient parameter data signals and analyzing said signals utilizing fuzzy logic having at least one predetermined supervisory rule, said controller then providing an output signal to said pumps to adjust, as necessary on a periodic ongoing basis, the flow re of fluid generated by each at least one pump for regulating fluid removal from the patient'"'"'s blood.

19. Continuous hemofiltration system for removal of fluid from the blood of a patient, comprising:

a hemofilter;

a first pump for pumping blood from a patient through said hemofilter and back to the patient;

a flowmeter downstream of said first pump to measure the blood outflow rate from the blood pump, said flowmeter generating blood flow rate data signals correlated to the blood outflow rate;

a first reservoir for maintaining a supply of infusate;

a first scale to measure the weight of infusate in said first reservoir, said first scale generating infusate flow rate data signals correlated to the infusate weight;

a second pump for pumping the infusate from said first reservoir to said hemofilter;

a second reservoir for receiving drained fluid from said hemofilter;

a second scale to measure the weight of drained fluid in said second reservoir, said second scale generating drained fluid flow rate data signals correlated to the drained fluid weight;

a third pump for pumping the drained fluid from said hemofilter to said second reservoir;

at least one monitor for measuring at least one patient parameter, said least one patient parameter monitor providing patient parameter data signals correlated to said at least one patient parameter; and

a supervisory controller operably connected to said first, second and third pumps, to said flowmeter, to said first and second scales, and to said at least one patient parameter monitor, said controller receiving the blood flow rate data signals, the infusate flow rate data signals, the drained fluid flow rate data signals, and the patient parameter data signals, said supervisory controller analyzing said signals utilizing fuzzy logic having at least one predetermined supervisory rule, and said supervisory controller then providing an output signal to one or more of said first, second and third pumps to adjust, as necessary on a periodic ongoing basis, the flow rate of fluid generated by the one or more of said first, second and third pumps for regulating fluid removal from the patient'"'"'s blood.