1. Experimental plan: The infants (0 to 6 month) admitted in pediatric intesive care unit for respiratory distress with bronchiolitis but not requiring mechanical ventilation are randomized in two groups: group "A" is treated with a non-invasive ventilation device(Infantflow) during 6 hours, group "B" is treated conventionally by inhalation of a Air/O2 mixture during 6 hours.