Method for determining adequacy of dialysis based on urea concentration

• US 5,405,315 A
• Filed: 02/15/1994
• Issued: 04/11/1995
• Est. Priority Date: 07/27/1993
• Status: Expired due to Term

• Current Assignee: Soumaya M. Khuri
• Original Assignee: Raja N. Khuri
• Inventors: Khuri, Raja N., Nakhoul, Nazih L.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): NASSER, ROBERT L
• Application Number:
  US08/196,320
• Time in Patent Office: 420 Days
• Field of Search: 604/4-6, 604/17, 604/27-31, 604/49-51, 210/646, 210/647, 210/327.1
• US Class Current: 604/4.01
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1609 after use, i.e. downstream of dialyser
• CPC Class Codes: A61M 1/1619 Sampled collection of used dialysate, i.e. obviating the need for recovery of whole dialysate quantity for post-dialysis analysis
• CPC Class Codes: A61M 1/3609 Physical characteristics of the blood, e.g. haematocrit, urea
• CPC Class Codes: A61M 2202/0498 Urea
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3303 Using a biosensor

Abstract

A method for determining the adequacy of dialysis, using determination of urea concentration in the dialysate effluent with an enzymatic electrode incorporating a urease sensor, and conversion of this information to arterial urea nitrogen utilizing a "flow ratio" correction; and utilizing the arterial blood urea nitrogen derived from readings of an on-line monitoring sensor as an absolute quantity, and the urea reduction ratio as a relative quantity as a new end-point for dialysis adequacy.

Claims

1. A method for determining adequacy of dialysis of a patient, comprising:

(a) providing an enzymatic urease-based sensor;

(b) using said sensor to determine a concentration of urea in dialysate from said dialysis;

(c) utilizing said urea concentration in said dialysate and selected physiological factors associated with the patient and with said dialysis to accurately determine a concentration of urea in arterial blood and to determine dialysis adequacy; and

(d) ceasing dialysis of said patient when said dialysis is adequate as determined in step (c).

2. The method of claim 1 including conducting said steps on an ongoing basis and ceasing dialysis of said patient whenever dialysis of said patient is indicated as adequate.

3. The method for determining adequacy of dialysis of a patient according to claim 1, wherein said selected physiological factors comprise flow rates of venous blood, arterial blood and dialysate fluid.

4. A method for determining adequacy of dialysis of a patient, comprising:

(a) providing an enzymatic urease-based sensor;

(b) using said sensor to determine a concentration of urea in dialysate from said dialysis;

(c) utilizing said urea concentration in said dialysate and selected physiological factors associated with the patient and with said dialysis to accurately determine a concentration of urea in arterial blood and to determine dialysis adequacy;

(d) calculating a urea reduction ratio;

(e) utilizing the dialysis adequacy as an absolute quantity and the urea reduction ratio as a relative quantity as new end-points to determine when to cease dialysis; and

(f) ceasing dialysis of said patient when said dialysis is adequate as determined in step (c) and step (e).

5. A method for determining adequacy of dialysis of a patient, comprising:

(a) providing an enzymatic urease-based sensor electrode;

(b) using said electrode to determine a concentration of urea in dialysate from said dialysis;

(c) utilizing said urea concentration in said dialysate to obtain an arterial urea concentration;

(d) using said arterial urea concentration to obtain a profile of urea reduction;

(e) using said profile to assess dialysis adequacy;

(f) calculating a urea reduction ratio;

(g) utilizing the dialysis adequacy as an absolute quantity and the urea reduction ratio as a relative quantity to determine when to cease dialysis; and

(h) ceasing dialysis of said patient when said dialysis is adequate as determined in steps (e) and (g).