Non-interfering physiological sensor system

• US 8,504,130 B2
• Filed: 08/18/2009
• Issued: 08/06/2013
• Est. Priority Date: 10/07/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Gonopolskiy, Oleg, Widman, Ronald A., Anderson, Arik
• Primary Examiner(s): Winakur, Eric
• Assistant Examiner(s): Liu, Chu Chuan (JJ)
• Application Number:
  US12/543,362
• Publication Number:
  US 20100087718A1
• Time in Patent Office: 1,449 Days
• Field of Search: 600/310, 600/322, 600/323, 600/330, 600/336, 600/340, 600/344, 600/473, 600/476, 356/41, 702/19
• US Class Current: 600/336
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7228 Signal modulation applied to the input signal sent to patient or subject; demodulation to recover the physiological signal modulation H03C

Abstract

A system includes a light source, a photodetector in optical communication with the light source, and a processor in communication with said photodetector and configured to output a signal representing oxygen saturation independent of an interfering signal from an interfering source. The system may further include an analog-to-digital converter in communication with the processor that is configured to digitize a signal from the photodetector by oversampling and output oversampling data to the processor. The processor may include an averaging filter that averages the oversampling data received from said analog-to-digital converter prior to decimation to generate an oversampling number.

Claims

1. A system comprising:

a light source;

at least one photodetector in optical communication with said light source; and

a processor in communication with said photodetector and configured to output a signal independent of an interfering signal caused by an interfering sensor; and

an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and output oversampling data to said processor;

wherein said processor includes an averaging filter in communication with said analog-to-digital converter and configured to average the oversampling data received from said analog-to-digital converter prior to decimation based on an oversampling number associated with a sampling frequency of the analog-to-digital converter and a frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of the filter at one or more frequencies associated with the interfering signal.

2. A system as set forth in claim 1, wherein said averaging filter includes a notch before decimation, wherein said notch has a frequency that corresponds to a frequency of the interfering signal.

3. A system as set forth in claim 1, wherein said processor is configured to apply a weighted linear combination to the oversampling data.

4. A system as set forth in claim 3, wherein the weighted linear combination includes at least one of a weight and an oversampling number that are varied randomly.

5. A system as set forth in claim 1, wherein said photodetectors are configured to receive the interfering signal and wherein said processor is configured to measure a frequency of the interfering signal.

6. A system as set forth in claim 1, wherein at least one of said photodetectors is configured to detect the interfering signal from the interfering sensor.

7. A tissue oximeter sensor comprising:

a light source;

a photodetector in optical communication with said light source; and

a processor in communication with said photodetector and configured to output a signal representing oxygen saturation independent of an interfering signal caused by an interfering source, wherein the processor is configured to;

select an oversampling number based on a sampling frequency and a frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of a filter at one or more frequencies associated with the interfering signal, and

reduce the interfering signal in accordance with the oversampling number.

8. A sensor as set forth in claim 7, an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor.

9. A sensor as set forth in claim 8, wherein said processor includes an averaging filter in communication with said analog-to-digital converter and configured to average oversampling data received from said analog-to-digital converter.

10. A sensor as set forth in claim 9, wherein said processor is configured to apply a weighted linear combination to the oversampling data.

11. A sensor as set forth in claim 10, wherein the weighted linear combination includes at least one of a weight and the oversampling number.

12. A sensor as set forth in claim 11, wherein the weight corresponds to a frequency of the interfering signal.

13. A sensor as set forth in claim 7, wherein said light source and said photodiode are disposed on a sensor pad.

14. A sensor as set forth in claim 7, wherein said light source is disposed on a first sensor pad and said photodetector is disposed on a second sensor pad.

15. A sensor as set forth in claim 7, wherein said photodetector is configured to detect a frequency of the interfering signal.

16. A system comprising:

a tissue oximeter sensor having a light source in optical communication with a photodetector and a processor in communication with said photodetector;

an interfering sensor configured to output an interfering signal having a frequency;

wherein said tissue oximeter is configured to output a signal independent of the interfering signal output by said interfering sensor by;

selecting an oversampling number based on a sampling frequency and the frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of a filter at one or more frequencies associated with the interfering signal, and

reducing the interfering signal in accordance with the oversampling number.

17. A system as set forth in claim 16, wherein said tissue oximeter sensor includes an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor.

18. A system as set forth in claim 17, wherein said processor includes an averaging filter in communication with said analog-to-digital converter and configured to average oversampling data received from said analog-to-digital converter.