Our study will investigate inhalation therapy of NaCl 3% compared to standard therapy with no inhalation in the treatment of moderate to severe bronchiolitis. The impact on length of hospital stay will be analyzed.

Acute viral bronchiolitis is the most common lower respiratory tract infection in the first year of life and leads to a large number of hospital admissions. The only recommended treatment is supportive. However many different types of drug inhalations have been studied but their efficacy remains controversial.

Our study will compare recommended supportive therapy to supportive therapy combined to hypertonic saline (NaCl 3%) inhalations in the treatment of moderate to severe bronchiolitis. This will be the first study to use a true control group with no inhalation.

Inclusion Criteria:

• children between ages 6 weeks to 24 months
• first episode of wheezing
• diagnosis of moderate to severe bronchiolitis: The patients are ranked as moderately to severely ill according to the Wang clinical severity score

Exclusion Criteria:

• Children with mild bronchiolitis (Wang score < 5)
• Children with pre-existent cardiac disease
• Children with clinically significant chronic respiratory disease
• Immunocompromised children
• Children with a gestational age at birth less than 34 weeks
• Children who received immunoprophylaxis therapy (i.e RSV immune globulin therapy)
• Children who received corticosteroid in any form in the preceding 2 weeks before presentation
• Children who received bronchodilators within 24 hours before presentation
• Children with critical illness at presentation requiring immediate admission to intensive care unit