Respiratory waveform analyzer
First Claim
1. An expiratory waveform analyzer, operable to analyze an expiratory waveform, which is generated based on a concentration of a component in expiratory gas of a subject measured over a plurality of time intervals, the expiratory waveform analyzer comprising:
- an expiratory gas concentration generator which generates a concentration signal indicating values of the concentration of the component based on an output signal from a sensor that measures the concentration of the component;
a flatness calculator which calculates differences between the values of the concentration of the component indicated by the concentration signal over the plurality of time intervals of the expiratory waveform based on the concentration signal, and which calculates a flatness of the expiratory waveform based on the calculated differences;
a reliability calculator which calculates a reliability of the expiratory waveform based on the flatness and the values of the concentration of the component indicated by the concentration signal; and
a respiratory rate detecting portion which determines whether the expiratory waveform is reliable for inclusion in calculation of a respiratory rate of the subject based on the reliability of the expiratory waveform, and calculates the respiratory rate of the subject using the expiratory waveform in response to determining that the expiratory waveform is reliable and calculates the respiratory rate of the subject without inclusion of the expiratory waveform in response to determining that the expiratory waveform is not reliable.
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Accused Products
Abstract
A respiratory waveform analyzer, operable to analyze a respiratory waveform, which is generated based on a temporal change of a concentration of a component in respiratory gas of a subject, includes: a respiratory gas concentration generator which generates a concentration signal based on an output signal from a sensor that is placed to measure the concentration of the component; a flatness calculator which calculates a flatness indicative of flat degree of the respiratory waveform based on a temporal change of the concentration signal; and a reliability calculator which calculates a reliability of the respiratory waveform based on the flatness and the concentration signal.
10 Citations
15 Claims
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1. An expiratory waveform analyzer, operable to analyze an expiratory waveform, which is generated based on a concentration of a component in expiratory gas of a subject measured over a plurality of time intervals, the expiratory waveform analyzer comprising:
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an expiratory gas concentration generator which generates a concentration signal indicating values of the concentration of the component based on an output signal from a sensor that measures the concentration of the component; a flatness calculator which calculates differences between the values of the concentration of the component indicated by the concentration signal over the plurality of time intervals of the expiratory waveform based on the concentration signal, and which calculates a flatness of the expiratory waveform based on the calculated differences; a reliability calculator which calculates a reliability of the expiratory waveform based on the flatness and the values of the concentration of the component indicated by the concentration signal; and a respiratory rate detecting portion which determines whether the expiratory waveform is reliable for inclusion in calculation of a respiratory rate of the subject based on the reliability of the expiratory waveform, and calculates the respiratory rate of the subject using the expiratory waveform in response to determining that the expiratory waveform is reliable and calculates the respiratory rate of the subject without inclusion of the expiratory waveform in response to determining that the expiratory waveform is not reliable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An expiratory waveform analyzer comprising:
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a sensor that detects over a duration of time a concentration of a gas component of a subject at each of a plurality of time intervals in the duration of time; an expiratory gas concentration generator that generates an expiratory waveform over the duration of time based on the concentration of the gas component at each of the plurality of time intervals; a flatness calculating portion that calculates differences between the concentration of the gas component at each consecutive pair of the plurality of time intervals in the duration of time, and that calculates a flatness scaling factor for each of the plurality of time intervals based on the calculated differences; a reliability calculating portion that scales the concentration of the gas component at each of the plurality of time intervals by the flatness scaling factor for the respective each of the plurality of time intervals, the scaled concentration of the gas component at each of the plurality of time intervals being a reliability of the concentration of the gas component at each of the plurality of time intervals; an effective concentration detecting portion that determines a reliability of the expiratory waveform based on the reliabilities of the concentration of the gas component at each of the plurality of time intervals, compares the reliability of the expiratory waveform to a waveform reliability threshold, and determines whether the expiratory waveform is a reliable expiratory waveform based on a result of the comparing; and an expiratory rate detecting portion that calculates an expiratory rate of the patient based on the expiratory waveform in response to the effective concentration detecting portion determining that the expiratory waveform is the reliable expiratory waveform, wherein the expiratory rate detecting portion calculates the expiratory rate of the patient by ignoring the expiratory waveform in response to the effective concentration detecting portion determining that the expiratory waveform is not the reliable expiratory waveform.
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Specification