Physiological assessment system

• US 20060009687A1
• Filed: 03/30/2005
• Published: 01/12/2006
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Goldstein, Mitchell, De Felice, Claudio, Latini, Giuseppe
• Granted Patent: US 7,292,883 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

A physiological assessment system comprises a sensor and first and second processors. The sensor is adapted to generate a signal responsive to a living organism. The first processor is configured to derive a measured parameter from the sensor signal. The second processor is configured to analyze nonlinear dynamics of the measured parameter so as to provide a physiological assessment of the living organism.

Claims

1. A physiological assessment system comprising:

a sensor adapted to generate a signal responsive to a living organism;

a first processor configured to derive a measured parameter from said signal; and

a second processor configured to analyze nonlinear dynamics of said measured parameter so as to provide a physiological assessment of said living organism.

2. The physiological assessment system according to claim 1 wherein:

said sensor is adapted to transmit optical radiation of at least two wavelengths into a tissue site and generate a detector signal responsive to said optical radiation after absorption by pulsatile blood flow within said tissue site;

said first processor is a pulse oximeter; and

said measured parameter is a perfusion index.

3. The physiological assessment system according to claim 2 wherein:

said second processor calculates a statistic responsive to the variability of said perfusion index; and

said physiological assessment corresponds to illness severity

4. The physiological assessment system according to claim 3 wherein said statistic is determined by chaos data analysis.

5. The physiological assessment system according to claim 4 wherein said compared to a predetermined normality range.

6. The physiological assessment system according to claim 5 wherein:

said pulse oximeter derives a second measured parameter, and

said second processor calculates a second statistic responsive to the variability of said second measured parameter.

7. The physiological assessment system according to claim 6 wherein said second measured parameter is pulse rate.

8. A physiological assessment system comprising:

a pulse oximeter adapted to measure a perfusion index;

an analyzer configured to provide at least one statistic responsive to variability of said perfusion index; and

an interpreter configured to indicate illness severity based upon said at least one statistic.

9. The physiological assessment system according to claim 8 further comprising a data storage for compiling time series data for said perfusion index.

10. The physiological assessment system according to claim 9 further comprising a visual indication of at least one of perfusion index variability and illness severity.

11. The physiological assessment system according to claim 9 further comprising an aural indication of at least one of perfusion index variability and illness severity.

12. The physiological assessment system according to claim 10 wherein said analyzer is a chaos data analyzer.

13. The physiological assessment system according to claim 12 further comprising:

a predetermined range input to said interpreter,

said interpreter capable of comparing said at least one statistic to said range so as to indicate illness severity.

14. A physiological assessment method comprising the steps of:

deriving time series data for at least one physiological parameter;

calculating a nonlinear dynamics measure based upon said time series data;

evaluating said nonlinear dynamics measure with respect to a predetermined criterion; and

providing a physiological assessment based upon said evaluation.

15. The physiological assessment method according to claim 14 wherein said deriving step comprises the substep of measuring perfusion index with a pulse oximeter.

16. The physiological assessment method according to claim 15 wherein said calculating step comprises the substep of obtaining a variability measure for said perfusion index.

17. A physiological assessment method according to claim 16 wherein said evaluating step comprises the substep of comparing said variability measure to a predetermined cutoff value.

18. A physiological assessment method according to claim 17 wherein said providing step comprises the substep of outputting an illness severity indication.

19. The physiological assessment method according to claim 18 wherein:

said deriving step comprises the further substep of measuring pulse rate; and

said calculating step comprises the substep of obtaining a variability measure for the combination of said perfusion index and said pulse rate.

20. The physiological assessment method according to claim 19 wherein said evaluating step comprises the substep of performing a chaos data analysis on said time series data.