Variability study of plethysmographic measurements and single loop decomposition analysis of pulmonary signals

Detailed assessment of pulmonary mechanics parameters provides a valuable diagnostic tool. For this study a full body plethysmograph was used to collect specific airway resistance (sRaw), intrathoracic gas volume (TGV), and the total lung capacity (TLCpleth). To that end a combined pulmonary function test (PFT) maneuver was performed to collect sRaw, TGV, and slow vital capacity (SVC) and other long volume measures of a sample of male test subjects of varying ages. Most of the research on the subject of the measure of plethysmographic parameters concludes that it is an effort independent test; however, the results of this study found higher pulmonary efforts during plethysmograph collection can possibly induce error in the results. Varying pulmonary efforts are maybe a consequence of unfamiliarity of the test subject with the required maneuvers such as increased breathing frequency and the sudden occluded flow during the measure. Clinical technicians performing pulmonary function tests such as this should be knowledgeable of the optimum effort needed for accurate measure for the PFT system. Additionally two different applications were used for pulmonary data collection, Breeze PFT software and its companion Wave Form Analyzer Tester (WFATester) maintenance application. Single loop decomposition techniques were used in developed scripts to show use of these two methods providing the clinical engineer a validity of the primary method used by the PFT clinician for the plethysmographic measure.