A Study Of The Contribution Of The First And Second Heart Sounds At Frequencies Greater Than 100 Hz To Respiratory Sound Data Recorded At The Trachea

Abstract

One of the problems associated with the quantitative analysis of respiratory sound data has been interference due to the presence of heart sounds. In the past, heart sounds have typically been filtered using cutoff frequencies of less than 75 Hz. This study investigates the possibility of significant heart sound contribution to respiratory sound data recorded at the trachea at frequencies greater than 100 Hz. Segments of breaths from ten subjects with and without heart sounds were analyzed and then compared using a paired difference (or paired population) t test. The data was filtered using a 100 Hz, 8 pole digital filter prior to analysis. The results show that the presence of heart sounds does significantly affect respiratory sound data as described by a set of twenty-five parameters.