Breath selection for analysis

Abstract

Methods and systems are described to obtain and analyze a gas sample from a desired section of the breath of a person, while accounting for erratic, episodic or otherwise challenging breathing patterns that may otherwise make the capturing of a gas sample from the desired section of breath difficult. These techniques may provide more reliable, accurate and adequate samples of gas such as end-tidal gas, and ultimately an accurate analysis of the sample captured.

1 - 18 . (canceled) 
     
     
         19 . An apparatus for breath selection comprising:
 a sensor that measures a plurality of breathing parameters of a series of exhaled breaths, wherein a plurality of predetermined criteria are based on the plurality of breathing parameters;   a processor that applies a breath selection algorithm to the series of exhaled breaths and identifies a first valid exhaled breath when the first exhaled breath meets at least two or more of the plurality of predetermined criteria, the at least two or more predetermined criteria comprising a peak amplitude and a time-based value, and wherein the breath selection algorithm further identifies a second valid exhaled breath when the second valid exhaled breath meets a percent comparison of the two or more predetermined criteria;   a breath sampling system that captures the second valid exhaled breath; and   a gas analyzer that measures an analyte in the second valid exhaled breath.   
     
     
         20 . The apparatus of  claim 19 , wherein the analyte comprises carbon monoxide. 
     
     
         21 . The apparatus of  claim 19 , wherein the time-based value is selected from the group consisting of a time duration below the peak amplitude value, a time duration below a baseline value, an inspiratory time, a breath period time, an expiratory time, and end-tidal time, a CO 2  value over time, and an O 2  value over time. 
     
     
         22 . The apparatus of  claim 19 , wherein the breath selection algorithm further comprises identifying a second valid exhaled breath based on a breath period between the first and second valid exhaled breaths. 
     
     
         23 . The apparatus of  claim 22 , wherein the breath period is based on a breath rate. 
     
     
         24 . The apparatus of  claim 19 , wherein the sensor comprises a carbon monoxide sensor, a pressure sensor, or an infrared (IR) sensor. 
     
     
         25 . A method for selecting a valid exhaled breath for analysis comprising:
 identifying a first valid exhaled breath based on the first valid exhaled breath meeting at least two or more predetermined criteria, the at least two or more predetermined criteria comprising a peak amplitude and a time-based value;   identifying a second valid exhaled breath based on a percent comparison of the at least two or more predetermined criteria;   capturing the second valid exhaled breath using a breath sampling system; and   measuring an analyte in the second valid exhaled breath.   
     
     
         26 . The method of  claim 25 , wherein the analyte comprises carbon monoxide. 
     
     
         27 . The method of  claim 25 , wherein the time-based value is selected from the group consisting of a time duration below the peak amplitude value, a time duration below a baseline value, an inspiratory time, a breath period time, an expiratory time, and end-tidal time, a CO 2  value over time, and an O 2  value over time. 
     
     
         28 . The method of  claim 25 , wherein identifying the second valid exhaled breath is further based on a breath period between the first and second valid exhaled breaths. 
     
     
         29 . The method of  claim 28 , wherein the breath period is based on a breath rate. 
     
     
         30 . An apparatus for breath selection comprising:
 a sensor that measures parameters of a first exhaled breath, a second exhaled breath, and a third exhaled breath;   a first processor that determines if a first measurement of the first exhaled breath meets a first predetermined criteria;   a second processor that determines if a second measurement of the second exhaled breath meets a second predetermined criteria, wherein the second measurement is made when the first measurement is determined to meet the first predetermined criteria;   a third processor that determines if a third measurement of the third exhaled breath meets a third predetermined criteria, wherein the third measurement is made when the second measurement is determined to meet the second predetermined criteria; and   a breath sampling system that stores the third exhaled breath when the third processor determines the third measured parameter meets the third predetermined criteria.   
     
     
         31 . The apparatus of  claim 30 , wherein the third predetermined criteria is based upon a trend associated with a plurality of breaths.