Evaluation of expiratory gas mass device as a measure of lung function test in healthy Iraqi subjects


Several types of devices are used to perform spirometric tests based on the measurement of lung volumes and their subdivisions. Lung volumes, hence, are represented by the volume of expired air. There was a controversy about the difference between body and ambient temperatures which may extremely affect gas volume. The aim of this cross sectional study is to construct and evaluate a simple device called expiratory gas mass device as a reliable, reproducible, accurate and convenient tool to substitute Vitalograph spirometer as a measure of lung function in healthy Iraqi subjects. Forced expiratory maneuver is done by(300) healthy Iraqi subject aged (20-50)years old 146 male and 154 female through the standardized spirometer and then through the newly constructed gas mass device. The accuracy (systematic error) and reproducibility (random error) were tested for the constructed gas mass device . The results revealed that there were no significant differences in values of FVC and AGM measured by standard Vitalograph spirometer and gas mass device respectively between male and female .Regression lines indicated that there were strong positive correlations between gas mass (GM) and FVC in male and female. It is concluded that gas mass device is simple, portable and easily handled device. It is also reproducible and accurate device for the measurement of GM in normal subjects.