SENSOR FUSION AND PROBABILISTIC PARAMETER ESTIMATION METHOD AND APPARATUS

• US 20120022350A1
• Filed: 07/12/2011
• Published: 01/26/2012
• Est. Priority Date: 07/21/2010
• Status: Active Grant

• Current Assignee: Vital Metrix Inc.
• Original Assignee: Streamline Automation LLC
• Inventors: Teixeira, Rodrigo
• Granted Patent: US 8,494,829 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

A probabilistic digital signal processor using data from multiple instruments is described. Initial probability distribution functions are input to a dynamic state-space model, which operates on state and/or model probability distribution functions to generate a prior probability distribution function, which is input to a probabilistic updater. The probabilistic updater integrates sensor data from multiple instruments with the prior to generate a posterior probability distribution function passed (1) to a probabilistic sampler, which estimates one or more parameters using the posterior, which is output or re-sampled in an iterative algorithm or (2) iteratively to the dynamic state-space model. For example, the probabilistic processor operates on fused data using a physical model, where the data originates from a mechanical system or a medical meter or instrument, such as an electrocardiogram or pulse oximeter to generate new parameter information and/or enhanced parameter information.

Claims

1. An apparatus configured for processing sensor data representative of a body, comprising:

an analyzer, comprising;

a physical model representative of function of a body constituent, said physical model coded into a digital signal processor embedded in said analyzer, said digital signal processor configured to;

generate a prior probability distribution function using said physical model; and

repetitively fuse input data originating from at least two types of medical instruments with the prior probability distribution function to generate a posterior probability distribution function,

said processor configured to process the posterior probability distribution function to generate an output of at least one of;

a monitored parameter value representative of the body; and

an estimated parameter value representative of the body.

2. The apparatus of claim 1, wherein said two types of medical instruments comprise:

a pulse oximeter; and

an electrocardiogram device.

3. The apparatus of claim 1, wherein a portion of said input data originating from said pulse oximeter comprises a first value of at least one of:

first raw data;

a current;

a voltage;

a spectral value; and

a blood oxygen saturation.

4. The apparatus of claim 3, wherein a portion of said input data originating from said electrocardiogram device comprises a second value of at least one of:

second raw data;

processed sensor data; and

an output.

5. The apparatus of claim 4, wherein said output comprises a measure other than said first value and said second value.

6. The apparatus of claim 1, wherein at least one of said two types of medical instruments comprises:

an instrument configured to monitor a hemodynamic process.

7. The apparatus of claim 1, wherein at least one of said two types of medical instruments comprises:

an instrument configured to monitor an electrodynamic process related to a heart.

8. The apparatus of claim 1, wherein a first medical instrument of said medical instruments comprises a spectral intensity sensor configured to measure at least one wavelength of light, wherein a second medical instrument of said medical instruments comprises an electrical sensor configured to measure electrical signals originating from the body.

9. The apparatus of claim 1, further comprising an environment sensor configured to generate environment data representative of a local environment state outside of the body, said digital signal processor further configured to fuse the environment data with said input data originating from said medical instruments.

10. A method for processing sensor data representative of a body, comprising the steps of:

using a physical model, representative of function of a body constituent, coded into a digital signal processor of an analyzer;

generating a prior probability distribution function using said physical model;

repetitively fusing input data originating from at least a first medical instrument and a second medical instrument with the prior probability distribution function to generate a posterior probability distribution function; and

processing the posterior probability distribution function with said processor to generate at least one of;

a monitored parameter value representative of the body; and

an estimated parameter value representative of the body.

11. The method of claim 10, further comprising the steps of:

determining a noise artifact event through analysis of the input data from said first instrument; and

using said noise artifact event to filter the input data from said second instrument.

12. The method of claim 10, wherein said estimated parameter value comprises:

a metric to a parameter not output by either said first instrument or said second instrument.

13. The method of claim 12, wherein said metric comprises a permittivity.

14. The method of claim 10, wherein the input data from said first instrument comprises hemodynamic data outside of a heart of the body.

15. The method of claim 14, wherein the input data from said second instrument comprises electrodynamic data representative of an electrodynamic signal originating in the heart of the body.

16. The method of claim 15, further comprising the step of:

using both the hemodynamic data and the electrodynamic signal to generate an estimate of the autonomic nervous system tone.

17. The method of claim 11, further comprising the step of:

combining the input signal from said first instrument and said second instrument, said step of combining resulting in at least one of;

a generated measure of heart rate; and

a heart rate variability measure,

wherein the input data from said first instrument comprises a hemodynamic measure.

18. A system configured for processing sensor data representative of a body, comprising:

an analyzer, comprising;

a physical model representative of function of a body constituent, said physical model coded into a digital signal processor electrically couple to a medical device, said digital signal processor configured to;

process input data comprising both;

(1) a first signal measuring an electrical signal originating in the body, and

(2) a second non-environmental signal measuring a state of the body, said second signal not comprising the electrical signal originating in the body;

repetitively fuse the input data with a prior probability distribution function to generate a posterior probability distribution function; and

process the posterior probability distribution function to generate at least one of;

a monitored parameter value; and

an estimated parameter value.

19. The apparatus of claim 18, wherein the second signal comprises a measure of a hemodynamic state of the body.

20. The apparatus of claim 18, wherein said physical model comprises at least one equation related to blood flow rate in the body.