Collection and analysis of a volume of exhaled gas with compensation for the frequency of a breathing parameter

Abstract

Apparatuses are described to accurately determine a gas concentration of a sample of a patient's breath. The apparatuses may include a sample compartment, a breath speed analyzer, a gas analyzer, and a processor. The sample compartment includes an inlet that receives the breath. The breath speed analyzer determines the speed of a portion of the breath. The gas analyzer determines a gas concentration. The processor includes an algorithm that determines a degree of non-homogeneity of the sample based on the speed, and a corrected gas concentration based on the degree of non-homogeneity. In some variations, the gas correction is determined independently of patient cooperation. Apparatuses may be tuned based on the intended population's expected breathing pattern ranges such that the sample compartment is filled with a homogenous end-tidal gas sample regardless of an individual's breathing pattern. These apparatuses are useful, for example, for end-tidal CO analysis. Methods are also described.

1 - 40 . (canceled) 
     
     
         41 . A system for the analysis of exhaled gas comprising:
 a breath rate sensor for measuring a breath rate of a breath sample from a patient;   a sample compartment having a predetermined volume;   a processor operable to execute an algorithm that measures an end-expiratory time of the breath sample to determine the start time and end time for collecting the breath sample and adjusts a flow rate of the breath sample based on the end-expiratory time;   a flow generator that draws the breath sample into the sample compartment according to the adjusted flow rate until the predetermined volume of the sample compartment is completely filled with end-tidal portions of the breath sample.   
     
     
         42 . The system of  claim 41 , further comprising a gas analyzer that measures a concentration of a gas within the sample compartment. 
     
     
         43 . The system of  claim 42 , wherein the gas is carbon monoxide, carbon dioxide, or oxygen. 
     
     
         44 . The system of  claim 41 , wherein the algorithm measures the end-expiratory time using a capnometry signal, a differential capnometry signal, or a pressure signal. 
     
     
         45 . The system of  claim 41 , further comprising a user interface configured to allow a user to input a patient parameter. 
     
     
         46 . The system of  claim 45 , wherein the patient parameter is a patient type. 
     
     
         47 . The system of  claim 46 , wherein the patient type is an adult. 
     
     
         48 . The system of  claim 46 , wherein the patient type is a premature neonate. 
     
     
         49 . The system of  claim 46 , wherein the patient type is a full term infant. 
     
     
         50 . The system of  claim 41 , wherein the flow generator comprises a pump. 
     
     
         51 . A system comprising:
 a breath rate sensor for measuring a breath rate of a breath sample of a patient;   a sample compartment that collects end-tidal portions of the breath sample, the sample compartment having a predetermined volume;   a flow generator having a predetermined flow rate; and   a processor operable to execute an algorithm that determines the number of end-tidal portions for collection based on the measured breath rate, the predetermined flow rate, and the predetermined sample compartment volume.   
     
     
         52 . The system of  claim 51 , further comprising a gas analyzer that measures a concentration of a gas within the sample compartment. 
     
     
         53 . The system of  claim 52 , wherein the sample compartment contains only the end-tidal portion of the breath sample. 
     
     
         54 . The system of  claim 51 , wherein the gas is carbon monoxide, carbon dioxide, or oxygen. 
     
     
         55 . The system of  claim 51 , further comprising a user interface configured to allow a user to input a patient parameter. 
     
     
         56 . The system of  claim 55 , wherein the patient parameter is a patient type. 
     
     
         57 . The system of  claim 56 , wherein the patient type is an adult. 
     
     
         58 . The system of  claim 56 , wherein the patient type is a premature neonate. 
     
     
         59 . The system of  claim 56 , wherein the patient type is a full term infant. 
     
     
         60 . The system of  claim 51 , wherein the flow generator comprises a pump.