Comparison of lung auscultation between smartphone and digital stethoscope in patients with asthma: a feasibility study

Abstract

Lung auscultation using smartphones9 built-in microphone is a promising technology to monitor respiratory conditions outside medical facilities. We aimed to compare lung sounds acquired by smartphones with the ones acquired by a digital stethoscope according to their quality and ability to capture adventitious sounds. A cross-sectional study was conducted with 17 adults with self-reported asthma (13 females, 35±12y). Lung auscultation was performed by clinicians in 7 different locations (trachea; right and left anterior, upper posterior and lower posterior chest), first with a digital stethoscope and then with the patient’s smartphone. Recordings from smartphones (n=119) and the stethoscope (n=119) were independently classified according to their quality and presence of adventitious sounds by two annotators. A third annotator solved the disagreements. The quality of the recordings was higher with the digital stethoscope than with smartphones (84% vs. 59%, p<.001). Adventitious sounds were present in 3% of the recordings acquired with smartphones and in 9% of those acquired with the digital stethoscope (p=.109). Agreement regarding presence of adventitious sounds between smartphones and stethoscope was slight (86%, k=.14 (95%CI -.14-.41). Results showed a better agreement between the two annotators for recordings quality (88%, k=.70(95%CI. 60-.81)) than for the presence of adventitious sounds (79%, k=.22(95%CI. 05-.38)). Smartphone auscultation seems a viable approach to record lung sounds and to capture adventitious sounds, although its performance is yet to be comparable to digital auscultation. Further research is required to improve this technology.