RESPIRATORY PHASE DETERMINATION APPARATUS, RESPIRATORY PHASE DETERMINATION METHOD AND RESPIRATORY PHASE DETERMINATION PROGRAM

• US 20140243697A1
• Filed: 04/30/2014
• Published: 08/28/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: YAMADA, Maki, ENDO, Mitsuru, HORII, Noriaki
• Granted Patent: US 9,597,011 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

Disclosed is a respiratory phase determination apparatus enabling a respiratory phase determination robust to personal differences in respiration among subjects and fluctuations in respiration of subjects in person without any need for calibration. The apparatus includes a first period feature value extraction section that extracts a first period feature value representing a feature of a first breath sound in a respiratory period, a second period feature value extraction section that extracts a second period feature value representing a feature of a second breath sound in the respiratory period, a feature value relativization/combining section that relativizes the first and the second period feature values and calculates a combined feature value, and a respiratory phase determination section that compares combined feature values of two neighboring respiratory periods and determines whether the two respiratory periods are each an inspiratory phase or expiratory phase based on the comparison result and a predetermined datum.

Claims

1. A respiratory phase determination apparatus comprising:

a respiratory period estimation section that estimates a respiratory period based on at least one of a first breath sound acquired from a first position of a body of a subject and a second breath sound acquired in synchronization with the first breath sound from a second position of the body of the subject;

a first period feature value extraction section that extracts a first period feature value representing a feature of the first breath sound in the respiratory period;

a second period feature value extraction section that extracts a second period feature value representing a feature of the second breath sound in the respiratory period;

a feature value relativization/combining section that relativizes the first period feature value and the second period feature value and calculates a combined feature value; and

a respiratory phase determination section that compares the combined feature value in the respiratory period with a combined feature value in a respiratory period near the respiratory period and determines whether each of the two respiratory periods is an inspiratory phase or expiratory phase based on a comparison result and a predetermined datum.

2. The respiratory phase determination apparatus according to claim 1, wherein the first breath sound and the second breath sound are breath sounds acquired at different positions where an inspiratory phase and expiratory phase have a reverse magnitude relation.

3. The respiratory phase determination apparatus according to claim 1, wherein the respiratory phase determination section adopts a determination result with which inspiratory phases and expiratory phases appear alternately in a series of respiratory periods or adopts a determination result which has a greater difference from the datum, when two determination results for one respiratory period are obtained as a result of the determination, and are in conflict with each other.

4. The respiratory phase determination apparatus according to claim 1, further comprising:

a first sensor that is attached at the first position to acquire a first biological sound including the first breath sound;

a second sensor that is attached at the second position to acquire a second biological sound including the second breath sound;

a first breath sound extraction section that extracts the first breath sound from the first biological sound; and

a second breath sound extraction section that extracts the second breath sound from the second biological sound.

5. The respiratory phase determination apparatus according to claim 1, further comprising a result output section that outputs a determination result from the respiratory phase determination section using a predetermined method.

6. The respiratory phase determination apparatus according to claim 1, wherein:

the first breath sound is a tracheal breath sound or bronchial breath sound; and

the second breath sound is a vesicular breath sound.

7. A respiratory phase determination method comprising:

estimating a respiratory period based on at least one of a first breath sound acquired from a first position of a body of a subject and a second breath sound acquired in synchronization with the first breath sound from a second position of the body of the subject;

extracting a first period feature value representing a feature of the first breath sound in the respiratory period;

extracting a second period feature value representing a feature of the second breath sound in the respiratory period;

relativizing the first period feature value and the second period feature value and calculating a combined feature value; and

comparing the combined feature value in the respiratory period with a combined feature value in a respiratory period near the respiratory period and determining whether each of the two respiratory periods is an inspiratory phase or expiratory phase based on a comparison result and a predetermined datum.

8. A respiratory phase determination program that causes a computer to execute processing comprising:

estimating a respiratory period based on at least one of a first breath sound acquired from a first position of a body of a subject and a second breath sound acquired in synchronization with the first breath sound from a second position of the body of the subject;

extracting a first period feature value representing a feature of the first breath sound in the respiratory period;

extracting a second period feature value representing a feature of the second breath sound in the respiratory period;

relativizing the first period feature value and the second period feature value and calculating a combined feature value; and

comparing the combined feature value in the respiratory period with a combined feature value in a respiratory period near the respiratory period and determining whether each of the two respiratory periods is an inspiratory phase or expiratory phase based on a comparison result and a predetermined datum.