BODY-WORN MONITOR FOR MEASURING RESPIRATORY RATE

• US 20110257489A1
• Filed: 04/19/2010
• Published: 10/20/2011
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated (Foxconn Technology Co., Ltd.)
• Original Assignee: Sotera Wireless Incorporated (Foxconn Technology Co., Ltd.)
• Inventors: BANET, Matt, DHILLON, Marshal, McCOMBIE, Devin
• Granted Patent: US 8,888,700 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

The invention provides a system for measuring respiratory rate (RR) from a patient. The system includes an impedance pneumography (IP) sensor, connected to at least two electrodes, and a processing system that receives and processes signals from the electrodes to measure an IP signal. A motion sensor (e.g. an accelerometer) measures at least one motion signal (e.g. an ACC waveform) describing movement of a portion of the patient'"'"'s body to which it is attached. The processing system receives the IP and motion signals, and processes them to determine, respectfully, frequency-domain IP and motion spectra. Both spectra are then collectively processed to remove motion components from the IP spectrum and determine RR. For example, during the processing, an algorithm determines motion frequency components from the frequency-domain motion spectrum, and then using a digital filter removes these, or parameters calculated therefrom, from the IP spectrum.

Claims

1. A system for measuring respiratory rate from a patient, comprising:

an impedance pneumography sensor connected to at least two electrodes, the impedance pneumography sensor comprising a processing circuit configured to process signals from the at least two electrodes to measure an impedance pneumography signal from the patient;

a motion sensor connected to the patient and configured to measure at least one motion signal corresponding to motion of a portion of the patient'"'"'s body to which it is attached; and

a processing system configured to receive the impedance pneumography signal and process it to determine a frequency-domain impedance pneumography spectrum, and to receive the motion signal and process it to determine a frequency-domain motion spectrum, the processing system further configured to collectively process both the impedance pneumography spectrum and motion spectrum to remove motion components from the impedance pneumography spectrum and then determine respiratory rate.

5. The system of claim 1, further comprising a sensor module that comprises both the impedance pneumography sensor and the motion sensor.

6. The system of claim 5, wherein the sensor module is configured to be worn on the patient'"'"'s torso.

7. The system of claim 6, wherein the sensor module comprises at least one analog-to-digital converter configured to digitize the impedance pneumography signal.

8. The system of claim 7, wherein the sensor module comprises at least one analog-to-digital converter configured to digitize the motion signal.

11. The system of claim 8, wherein the sensor module comprises the processing system.

12. The system of claim 8, further comprising a wireless transceiver.

13. The system of claim 12, wherein the processing system is remote from the patient, and the wireless transceiver is configured to wirelessly transmit digitized versions of the impedance pneumography signal and motion signal to the processing system.

14. The system of claim 13, wherein the processing system is further configured to wireless transmit a value describing respiratory rate to a second processor worn on the patient'"'"'s body.

15. The system of claim 14, wherein the second processor is configured to display the value describing respiratory rate on the patient'"'"'s body.

16. The system of claim 1, wherein the motion sensor is an accelerometer.

17. The system of claim 16, wherein the accelerometer is configured to generate a unique motion waveform for each axis of a coordinate system.

18. The system of claim 17, wherein the processing system is further configured to process each unique motion waveform to determine a posture corresponding to the patient.

19. The system of claim 5, wherein the sensor module further comprises a temperature sensor.

20. The system of claim 5, wherein the sensor module further comprises a sensor for measuring an electrocardiogram.

21. The system of claim 5, wherein the sensor module comprises a housing, the housing comprising a connector that connects directly to an electrode worn on the patient'"'"'s torso.

2. A system for measuring respiratory rate from a patient, comprising:

an impedance pneumography sensor connected to at least two electrodes, the impedance pneumography sensor comprising a processing circuit configured to process signals from the at least two electrodes to measure an impedance pneumography signal from the patient;

a motion sensor connected to the patient and configured to measure at least one motion signal corresponding to motion of a portion of the patient'"'"'s body to which it is attached; and

a processing system, worn on the patient'"'"'s body and connected to the impedance pneumography sensor and the motion sensor, the processing system configured to;

i) receive the impedance pneumography signal from the impedance pneumography sensor and process it to determine a frequency-domain impedance pneumography spectrum;

ii) receive the motion signal from the motion sensor and process it to determine a frequency-domain motion spectrum;

iii) determine motion frequency components from the frequency-domain motion spectrum;

iv) remove frequency components from the impedance pneumography spectrum corresponding to the motion frequency components to generate a processed frequency-domain impedance pneumography spectrum; and

v) analyze the processed frequency-domain impedance pneumography spectrum to determine respiratory rate.

3. A system for determining respiratory rate values for a patient, comprising:

a first sensor, configured to worn on the patient'"'"'s torso, comprising an impedance pneumography sensor;

a second sensor, configured to be worn on the patient'"'"'s torso, comprising an accelerometer;

a processing system, configured to be worn on the patient'"'"'s body and operably connect to both the first and second sensors, the processing system configured to determine a respiratory rate value by calculating a frequency-domain transform of signals from both the first and second sensors, and then removing motion components determined from the frequency-domain transform of one signal from the frequency-domain transform of the other signal.

4. A system for determining respiratory rate values for a patient, comprising:

a first sensor, configured to worn on the patient'"'"'s torso, comprising an impedance pneumography sensor;

a second sensor, configured to be worn on the patient'"'"'s torso, comprising an accelerometer;

a processing system, configured to be worn on the patient'"'"'s wrist and operably connect to the first and second sensors, the processing system configured to determine a respiratory rate value by collectively processing frequency-domain spectra of signals from both the first and second sensors.

9. The system of claim 9, further comprising a serial transceiver configured to transmit digitized versions of the impedance pneumography signal and motion signal to the processing system.

10. The system of claim 10, wherein the processing system is configured to be worn on the patient'"'"'s wrist.