Sensor calibration and blood volume determination

• US 6,718,190 B2
• Filed: 12/09/2002
• Issued: 04/06/2004
• Est. Priority Date: 10/14/1997
• Status: Expired due to Term

• Current Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Original Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Inventors: Starostin, Dimitry M., Krivitski, Nikolai M.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/314,817
• Publication Number:
  US 20030130570A1
• Time in Patent Office: 484 Days
• Field of Search: 600/310, 600/320, 600/322, 600/481, 600/504, 604/4.01, 604/5.01, 604/6.08, 356/39, 356/432, 356/441, 356/442
• US Class Current: 600/322
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0275 using tracers, e.g. dye dilution
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

A method and device for the continuous real-time monitoring of relative blood volume change, based on registration of blood hemoglobin concentration, during long periods of time, such as dialysis session. A method and device for cardiac output measurement during dialysis, surgeries, intensive care procedure is provided. Calibration of a sensor in response to a change in a measureable blood property is determined from a coefficient corresponding to a change in the measured blood property.

Claims

1. A method for measuring a blood volume change, the method comprising:

(a) connecting an arterial tubing portion of a dialysis system to withdraw blood from a patient and connecting a venous tubing portion of the dialysis system to deliver filtered blood to the patient;

(b) operably coupling an optical sensor to the venous tubing portion of the dialysis system;

(c) changing an ultrafiltration rate of the dialysis system;

(d) determining at least one photometric property of blood at the venous tubing portion of dialysis system;

(e) determining a calibration coefficient of at least the optical sensor; and

(f) determining a blood volume change corresponding to the calibration coefficient.

2. The method of claim 1, wherein changing the ultrafiltration rate includes changing the ultrafiltration rate by a known amount.

3. The method of claim 1, wherein changing the ultrafiltration rate includes temporarily stopping the ultrafiltration.

4. The method of claim 1, wherein determining the at least one photometric property of blood includes determining a property corresponding to a protein in the blood.

5. The method of claim 1, wherein determining the at least one photometric property of blood includes determining a property corresponding to a protein concentration in the blood.

6. The method of claim 1, wherein determining the at least one photometric property of blood includes determining a property corresponding to a hematocrit of the blood.

7. The method of claim 1, wherein determining the at least one photometric property of blood includes determining a property corresponding to red blood cells in the blood.

8. The method of claim 1, wherein determining the at least one photometric property of blood includes determining a property corresponding to an optical density of the blood.