Dialyzing system and method of operating the same

• US 6,733,676 B2
• Filed: 02/19/2002
• Issued: 05/11/2004
• Est. Priority Date: 02/19/2001
• Status: Expired due to Fees

• Current Assignee: Nextier, Nikkiso Company Limited, Nipro Corporation
• Original Assignee: Nextier, Nikkiso Company Limited, Nipro Corporation
• Inventors: Takai, Ichiro
• Primary Examiner(s): Kim, John
• Application Number:
  US10/076,488
• Publication Number:
  US 20020113016A1
• Time in Patent Office: 812 Days
• Field of Search: 210/85, 210/90, 210/97, 210/138, 210/143, 210/321.65, 210/645, 210/646, 210/650, 210/739, 210/741
• US Class Current: 210/650
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/3403 Regulation parameters
• 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 2230/30 Blood pressure A61M2230/04 takes precedence

Abstract

A dialyzing system comprises a dialyzer 10 and an ultrafiltration-regulating unit 24 for regulating inflow and out flow of a dialysate to or from the dialyzer 10 to regulate ultrafiltration. The dialyzing system is adapted to determine a blood pressure from a dialysate pressure detected by a pressure transducer 28 at the time of temporary suspension of the ultrafiltration without use of a special line for measurement of pressure in the blood flow line and free from danger of blood leakage from the blood flow line.

Claims

1. A dialyzing system comprising:

a dialyzer having a dialysate outflow line and a dialysate inflow line;

an ultrafiltration unit connected to the dialyzer by the dialysate outflow line and the dialysate inflow line for regulating a rate of an ultrafiltration process by regulating an outflow rate of a dialysate from the dialyzer so as to become greater than an inflow rate of the dialysate to the dialyzer;

pressure-detecting means arranged in one of the dialysate flow lines to detect a pressure of the dialysate; and

control means for calculating the pressure of a blood flow line connected to the dialyzer based on the pressure of the dialysate detected by the pressure-detecting means and for calculating a pressure gradient in the blood flow line based on a blood flow rate and a flow resistance of the blood flow line,

said control means being adapted to determine the pressure of a blood flow line based on the pressure of the dialysate detected by the pressure-detecting means at a time of a temporary stop of the ultrafiltration process caused by temporarily stopping an operation of the ultrafiltration unit,

wherein the control means monitors and displays the pressure of the blood flow line as a pressure of a specified site of the blood flow line.

2. The dialyzing system according to claim 1, wherein the control means determines the pressure of the blood flow line based on the pressure of the dialysate continuously detected by the pressure-detecting means during the ultrafiltration process and a difference between the pressure of the dialysate at the time of the temporary stop of the ultrafiltration process and a newly stabilized dialysate pressure during in ultrafiltration process at a time of stable ultrafiltration, said stabilized pressure of the dialysate being determined by detection of the pressure of the dialysate after a lapse of a certain time period required for stabilization of the pressure of the dialysate during the ultrafiltration process from a time at which the ultrafiltration process is resumed.

3. The dialyzing system according to claim 1, wherein the control means determines the pressure of the blood flow line predetermined time intervals or at a time when the ultrafiltration rate is changed.

4. The dialyzing system according to claim 1, wherein the control means further comprises monitoring means and display means which directly or indirectly monitor and display the determined pressure of the blood flow line.

5. A method for operating a dialyzing system, comprising the steps of:

temporarily stopping an ultrafiltration operation of an ultrafiltration unit to equalize an inflow of a dialysate into a dialyzer and an outflow of the dialysate from the dialyzer;

detecting the pressure of the dialysate at every temporary stop of the ultrafiltration operation;

calculating the pressure of a blood flow line connected to the dialyzer from the detected pressure of the dialysate;

calculating a pressure gradient in the blood flow line based on a blood flow rate and a flow resistance of the blood flow line; and

monitoring and displaying the pressure of the blood flow line as a pressure of a specified site of the blood flow line.

6. The method for operating a dialyzing system according to claim 5, further comprising the steps of:

determining the pressure of the blood flow line by continuously detecting the pressure of the dialysate during the ultrafiltration operation and a difference between the pressure of the dialysate at the time of a temporary stop of the ultrafiltration operation and a newly stabilized dialysate pressure during the ultrafiltration operation at a time of stable ultrafiltration; and

determining said stabilized pressure of the dialysate by detecting the pressure of the dialysate after a lapse of a certain time period required for stabilizing the pressure of the dialysate during the ultrafiltration operation from a time at which the ultrafiltration operation is resumed.

7. The method of operating a dialyzing system according to claim 5, further comprising the step of:

determining the pressure of the blood flow line at predetermined time intervals or at a time when a rate of an ultrafiltration operation is changed.

8. A dialyzing system comprising:

a dialyzer having a dialysate outflow line and a dialysate inflow line;

an ultrafiltration unit connected to the dialyzer by the dialysate outflow line and the dialysate inflow line for regulating a rate of an ultrafiltration process by regulating an outflow rate of a dialysate from the dialyzer to a rate greater than an inflow rate of the dialysate to the dialyzer;

pressure-detecting means arranged in one of the dialysate flow lines to detect a pressure of the dialysate; and

control means for regulating and controlling said ultrafiltration unit to temporarily stop or resume the ultrafiltration process and for determining a pressure of a blood flow line connected to the dialyzer on the basis of the pressure of the dialysate detected by the pressure-detecting means, said control means comprising;

timer means for alternately generating signals to temporarily stop and to resume the a ultrafiltration process;

calculating means for determining a pressure of a blood flow line based on the pressure of the dialysate detected by said pressure-detecting means at a time of a temporary stop of the ultrafiltration process caused by the temporary ultrafiltration-stop signal from the timer means; and

means for monitoring and displaying the determined pressure of the blood flow line.

9. The dialyzing system according to claim 8, wherein the control means determines the pressure of the blood flow line, based on the pressure of the dialysate continuously detected by said pressure-detecting means during a ultrafiltration process and a difference between the pressure of the dialysate at the time of the temporary stop of the ultrafiltration process and a newly stabilize dialysate pressure during ultrafiltration at a time of stable ultrafiltration process, said stabilized dialysate pressure being determined by detection of the dialysate pressure after a lapse of a certain time period required for stabilization of the ultrafiltration process from a time at which the water removal is resumed.

10. The dialyzing system according to claim 8, wherein said calculating means determine the pressure of the blood flow line at predetermined time intervals or at time when the ultrafiltration rate is changed.

11. The dialyzing system according to claim 8, wherein the control means further comprises monitoring means and display means which directly or indirectly monitor and display the determined pressure of the blood flow line.

12. The dialyzing system according to claim 8, wherein the calculating means calculate the pressure of the blood flow line based on the detected pressure of the dialysate and a pressure gradient in the blood flow line, said pressure gradient being determined based on a blood flow rate and a flow resistance of the blood flow line, and wherein the control means monitors and display the calculated pressure of the blood flow line as a pressure of a specified site of a blood flow line.

13. The dialyzing system according to claim 8, wherein said control means allows aid ultrafiltration unit to regulate the outflow rate of the dialysate to a rate equal to the inflow rate of the dialysate to temporarily stop the ultrafiltration when it receives said temporary stop signal sent from said timer means, but allows said ultrafiltration unit to increase the outflow rate of the dialysate from the dialyzer to a rate greater than the inflow rate of a fresh dialysate to the dialyzer to develop ultrafiltration in the dialyzer when it receives a signal for resumption of ultrafiltration sent from said timer means.

14. The dialyzing system according to claim 8, wherein the control system further includes a ultrafiltration rate-setting device for setting an ultrafiltration rate, and wherein said control means, when received a signal sent from said ultrafiltration rate-setting device, outputs a signal for temporary stop of ultrafiltration before changing the ultrafiltration rate to determine the dialysate pressure just before the stop of ultrafiltration.