System and method for controlling the flow of exhaled breath during analysis

Abstract

A system and method for controlling the flow rate of a gaseous sample in an exhaled breath analysis system is disclosed. Two embodiments are described in this patent: a single pump embodiment and a dual pump embodiment. In each of these embodiments, a pump or pumps are used to control the flow rate of the breath sample as it moves through the analysis system. Also, the system includes means to conduct side stream, stopped flow analysis.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to systems and methods for the analysis of exhaled breath. [0003] 2. General Background [0004] Analysis of a subject's exhaled breath is a promising clinical tool, with potential application in the diagnosis and management of many conditions. For instance, changes in nitric oxide (NO) concentration in exhaled breath can indicate a change in the level of inflammation in the airway of a patient with asthma, indicating an increase in the likelihood of an asthmatic attack. Excessive carbon monoxide (CO) can indicate hemolytic jaundice, and high levels of hydrogen can indicate carbohydrate malabsorption. [0005] It is difficult to build an exhaled breath analyzer because fluctuations in temperature, humidity, breath flow etc. complicate and interfere with the analysis. These difficulties are especially acute when the device is designed to measure trace gases, such as NO, since the sensitivity requir...

AI Technical Summary

Benefits of technology

[0010] The present invention has a number of different embodiments, but the common element is the use of a pump or pumps to affect and control the flow rate of the exhaled breath. Two specific embodiments are described, but the scope of the present patent should be determined by its claims, and should not be limited to these two particular embodiments.

Problems solved by technology

It is difficult to build an exhaled breath analyzer because fluctuations in temperature, humidity, breath flow etc. complicate and interfere with the analysis.

These difficulties are especially acute when the device is designed to measure trace gases, such as NO, since the sensitivity required for such analyzers also makes the devices much more sensitive to changes in testing conditions.

But these previous systems are far from ideal.

The “patient control” method is crude and imprecise, and depends on the patient's ability to adjust flow rate.

It is also difficult to use with children.

Likewise, the Moilanen system is somewhat complex and requires a relatively high number of components, since it depends on a relatively complicated feedback control for operation.

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