PNEUMONIA : A CASE-CONTROL STUDY. DIAGNOSTIC PERFORMANCE OF AN UNSUPERVISED DIGITAL STETHOSCOPE FOR COMMUNITY ACQUIRED CHILDHOOD PNEUMONIA : A CASE-CONTROL STUDY. Benissa MR*, Starkov P**, Sola J**, Verjus C**, Manzano S*, Hugon F*, Gervaix A* *University Hospital of Geneva, Paediatric Emergency Department (HUG) **Centre Suisse d’Electronique et de Microtechnique (CSEM) INTRODUCTION : Pneumonia is the leading cause of child mortality under five years of age worldwide, killing 920 136 children in 2015. World Health Organization (WHO) developed a case management algorithm for the diagnosis of pneumonia. Primary aim: characterize child lung auscultation sounds by a digital stethoscope in acute lower respiratory infection and to develop an integrated algorithm to precise if it could be differentiated from normal auscultation. We also compared automated lung sounds analysis with current WHO algorithm for pneumonia. MATERIAL AND METHODS: A digital stethoscope ( Littman 3200®) was evaluated in a feasibility prospective case-control study at the paediatric emergency department of the Geneva University Hospital from January 2016 to December 2017. Lung auscultation was recorded ( cf. Figure 1). Distinction between bacterial and viral pneumonia was done with biological blood sample, microbiology tests, and Chest X Ray (CXR). Two experts in respiratory medicine segmented inspiratory from expiratory time and labelled each segmentation. Chest sounds were transformed into Mel-spectrograms, and patches were created for the machine learning process. A pipeline containing a Convolutional Neural Network (NN) and a Hidden Markov Model (HMM) was used for inspiratory and expiratory event prediction. Inter-observer reliability was assessed by using Fleiss’Kappa. Diagnostic performance was assessed by Receiver Operating Characteristic (ROC) curves in a complete cases analysis. Local Ethics Committee approved this protocol. Inclusion criteria: Clinical diagnostic of a chest infection (fever > 38 °C, dyspnea, tachypnea, respiratory distress, cough. Age < 60 months. Signed consent. RESULTS : We recruited 60 cases, analyzed 48 patients and 22 controls (cf. Figure 2). Mean age was 31 months, with 32 males and 16 female cases ( cf. Table 1). Mean time procedure was 5.2 minutes [4.1-6.3]. We diagnosed 21 bacterial pneumonia, 5 viral pneumonia, and 22 obstructive bronchitis. For bacterial and viral pneumonia, inter-observer reliability was good, with a Fleiss’ Kappa of 0.89 [0.77-0.92], CI 95%. This method significantly differentiates bacterial pneumonia from other auscultation patterns, with an Area Under Curve of 0.89 [0.79-0.99], significantly higher than the WHO algorithm (cf. Figure 3a). It significantly differentiates viral pneumonia and obstructive bronchiolitis from other auscultation patterns, with an Area Under Curve of 0.83 [0.71-0.96] (cf. Figure 3b). CONCLUSION: Digital stethoscope provides a good diagnostic performance compared to WHO algorithm. This method is objective and can be more readily standardized than subjective auscultation. It could become an unsupervised diagnostic tool for childhood pneumonia diagnostic in low-resource settings by healthcare workers. Corresponding author: Dr Benissa Mohamed-Rida, MD MSc MPH PhD Student Institute of Global Health, University of Geneva Email: mohamed-rida.benissa@hcuge.ch