Method and apparatus for monitoring the efficacy of fluid resuscitation

• US 7,195,595 B2
• Filed: 05/23/2005
• Issued: 03/27/2007
• Est. Priority Date: 05/21/2004
• Status: Expired due to Fees

• Current Assignee: Nova Technology Corporation (Baker Hughes Company)
• Original Assignee: Nova Technology Corporation (Baker Hughes Company)
• Inventors: Campbell, Michael J. E., Ling, Geoffrey
• Primary Examiner(s): Nasser; Robert L.
• Application Number:
  US10/908,681
• Publication Number:
  US 20060116587A1
• Time in Patent Office: 673 Days
• Field of Search: None
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content

Abstract

Relative Mean Arterial Pressure values are obtained non-invasively using a probe to obtain moisture measurements at a selected site on a subject. A control collects data samples. A converter produces a relative value of Mean Arterial Pressure (MAP) in response to the collected data (DPM) in accordance with a correlation defined by:
MAP=(DPM−DPM(0))/K(I).

Claims

1. A method for providing a relative value of mean arterial pressure of a subject comprising the steps of:

A. measuring tissue moisture at a selected area of perfused tissue of the subject,

B. acquiring data samples of the measured moisture content at the selected area, and

C. converting the collected data to a value of mean arterial pressure.

2. A method as recited in claim 1 wherein said measurement includes making successive impedance measurements at the selected area.

3. A method as recited in claim 1 wherein said measurement includes making successive impedance measurements at a plurality of areas of perfused tissue.

4. A method as recited in claim 1 wherein said converting includes generating the relative value of mean arterial pressure, MAP, according to MAP={DPM−

DPM(0)}/K(I) where DPM represents the average of the impedance measurements, where DPM(0) is the value of DPM for MAP=0 and K(I) is a constant.

5. A method as recited in claim 4 wherein different values of K(I) are stored for different analyses.

6. A method as recited in claim 4 wherein said measurement includes making successive impedance measurements at the selected area.

7. A method as recited in claim 4 wherein said measurement includes making successive impedance measurements at a plurality of areas of perfused tissue.

8. A method as recited in claim 7 wherein different values of K(I) are stored for different analyses.

9. Apparatus for providing a relative value of mean arterial pressure of a subject comprising:

A. means for measuring tissue moisture at a selected are of perfused tissue of the subject,

B. means for acquiring data samples of the measured moisture content at the selected area, and

C. means for converting the collected data to the relative value of mean arterial pressure.

10. Apparatus as recited in claim 9 wherein said measurement means comprises a dermal phase meter for generating successive impedance measurements at the selected area.

11. Apparatus as recited in claim 9 wherein said measurement means comprises a dermal phase meter for generating successive impedance measurements at a plurality of areas of perfused tissue.

12. Apparatus as recited in claim 9 wherein said converting means includes means for generating the relative value of mean arterial pressure, MAP, according to MAP={DPM−

DPM(0)}/K(I) where DPM represents the average of the impedance measurements, where DPM(0) is the value of DPM for MAP=0 and K(I) is a constant.

13. Apparatus as recited in claim 12 including means for storing different values of K(I) for different analyses.

14. Apparatus as recited in claim 12 wherein said measurement means includes dermal phase meter means for making successive impedance measurements at the selected area.

15. Apparatus as recited in claim 12 wherein said measurement means includes dermal phase meter means for making successive impedance measurements at a plurality of areas of perfused tissue.

16. Apparatus as recited in claim 15 including means for storing different values of K(I) for different analyses.