Acute bronchiolitis is the most frequent cause of infant hospitalization in the United States. Bronchiolitis typically refers to a viral lower respiratory tract infection during the first two years of life manifesting as a constellation of clinical symptoms including wheezing, cough and respiratory distress. In addition to a tremendous disease burden, bronchiolitis admissions in the United States cost more than $500 million each year.
The primary pathophysiologic processes in bronchiolitis include airway wall and peribronchial inflammation, increased mucous production, sloughing of necrotic epithelial cells, and impaired airway clearance. These processes result in airway obstruction, gas trapping, atelectasis and impaired gas exchange. Standard therapies for bronchiolitis remain supportive, including maintaining hydration and nutrition, ensuring adequate oxygenation, and physical suctioning of the nasal airways to clear secretions. Therapies such as the bronchodilator albuterol, although commonly used in standard practice, have not been proven to impact progression of disease or improve long-term outcomes of bronchiolitis.
Nebulized hypertonic saline (HS) has been shown to increase mucociliary clearance in the airways of individuals with healthy lungs. In addition nebulized HS increases airway clearance for disease processes including asthma, cystic fibrosis and bronchiectasis. A recent Cochrane review examined 4 small studies that suggest that nebulized 3% HS may reduce length of hospital stay and improve clinical severity scores in infants with acute viral bronchiolitis. None of these studies have explored the use of nebulized HS in the emergency department (ED). A recent study examined the use of a single nebulized treatment of epinephrine mixed in 3% HS in 46 infants less than 12 months presenting to the ED with bronchiolitis. This study did not find a difference between epinephrine diluted in normal saline compared to epinephrine diluted in 3% HS. Despite no effect on clinical score, the investigators did note a trend toward decreased rates of hospitalization. Furthermore, since this was the first ED study and the first negative study, the authors concluded that further investigation is necessary to determine if HS has a role in the management of acute bronchiolitis.
The purpose of the current study is to determine whether nebulized 3% HS improves respiratory distress in children 2-23 months presenting to the ED with acute bronchiolitis with persistent respiratory distress after initial therapy with a trial of nebulized albuterol.
Given the tremendous clinical and financial burden of bronchiolitis, any effective therapy, particularly one that is inexpensive, has the potential to result in significant health care savings. If nebulized 3% HS improved clinical scores in the ED, this may provide an inexpensive, safe and effective therapy for children with bronchiolitis in the acute care setting.
