Patients will be recruited from the pediatric and adult clinical departments of the Geneva University Hospitals.

Inclusion Criteria:

• Age > 1 year old.
• Healthy patients on the day of auscultation OR
• Patients with lower respiratory tract diseases (e.g., bronchitis, pneumonia, etc.). OR
• Patients with low (i.e., <92%) pulse oximetry values (e.g., cyanotic heart defect such as tetralogy of Fallot, transposition of great vessels, etc.). AND / OR
• Patients with fever >38.0°C.
• And for all: Information and written consent of the patient or a legal representative.

Exclusion Criteria:

• Refusal of consent.
• Clinical signs of severity: acute hypoxia, hypercapnia, acute respiratory failure, acute circulatory failure.
• Immune disorder, primary ciliary dyskinesia, antecedent of neonatal bronchopulmonary dysplasia.
• Contraindications and limitations of the MD as described in the instructions for use.
• Contraindications to the class of medical devices being studied, e.g. known hypersensitivity or allergy to the device material.
• Clinically significant concomitant disease states.
• Inability to follow the study procedures, e.g. due to language problems, psychological disorders, dementia, etc.
• Participation in another study with an investigational drug or other medical device within 30 days prior to and during the present study.