Usefulness of a low cost digital stethoscope for remote pulmonary auscultation

Introduction: Our aim was to analyze the usefulness of a low-cost stethoscope for remote respiratory auscultation. Methods: Using a device designed for the project, 27 samples of respiratory sounds have been collected. At the same time as the sounds were recorded using a smartphone, a pulmonologist performed real-time auscultation with a conventional stethoscope, marking whether the sound was considered: 1) normal 2) hypophonesis 3) wheezing 4) rhonchus or 5) crackles. Later, the same pulmonologist assessed the anonymized recorded sounds. The sensitivity, specificity, and positive and negative predictive values of digital auscultation compared to conventional auscultation were calculated for each of the characteristics. Two other pulmonologists evaluated the same sounds, and the degree of agreement between them was calculated for each of the items. Results: Of the 27 sounds collected, by conventional auscultation it was described as normal in 6 cases (22.2%), hypophonesis in 2 (7.4%), wheezing in 9 (33.3%), rhonchus in 1 (3.7 %) and crackles in 11 (40.7%). The Se, Sp, PPV and NPV of recorded sound auscultation with respect to the conventional assessment for each sound characteristic can be seen in Table 1. Cohen9s kappa for normality, hypophonesis, wheezing, rhonchus and crackles was 0.691 (95% CI 0.294-1.000), 0.481 (95% CI 0.056-0.910), 0.737 (95% CI 0.395-1.000), 0.314 (95% CI 0.128- 0.756) and 0.900 (95% CI 0.700-1.000), respectively. Conclusions: Remote auscultation using a low-cost digital stethoscope is feasible, and could improve the quality of remote visits in patients with chronic pathologies.