High-flow Nasal Oxygen Therapy in Hospitalized Infant With Moderate-to-severe Bronchiolitis

Inclusion Criteria: * first episode of hospitalised bronchiolitis (as defined by American Academy of Pediatrics clinical criterions ) * aged 7 days- 6 months * transcutaneous SpO2 in room air \< 95% * modified Wood's Clinical Asthma Score (m-WCAS) ≥ 2 et ≤ 5 * agreement of at least one of the parents or legal tutor for his child to participate in biomedical research * affiliation to social security (beneficiary or entitled), except beneficiary of State medical help Exclusion Criteria: * Urgent need for mechanical ventilation support either by nCPAP ou endotracheal route * Severe form defined by modified Wood's Clinical Asthma Score (mWCAS) exceeding 5 or 6, requiring non invasive ventilation (n CPAP) * Uncorrected cyanotic heart disease, innate immune deficiency, cranio-facial malformation, congenital stridor, tracheotomy * Inclusion in other observational study.