Abstract: Objective To investigate the effects of atomization inhalation of hyperosmotic saline combined with phlegm-reducing drugs on the clinical effects and adverse reactions of severe bronchiolitis. 
Methods A total of 80 children with severe bronchiolitis were selected and divided into sinple group and combination group according to envelope method, with 40 cases in each group. The sinple group was treated with intravenous infusion of the expectorant ambroxol, while the combination group was treated with atomization inhalation of hypertonic saline on the basis of the sinple group. Clinical efficacy, time of symptom elimination, inflammatory cells, blood gas indexes and the incidence of adverse reactions were compared between two groups. 
Results The total effective rate of combination group was higher than that of single group(P＜0.05). The disappearance time of shortness of breath, wheeze, cough and asthma in combination group were all lower than those in single group(P＜0.05). After treatment, the cell count, neutrophils, eosinophils and lymphocytes in two groups were lower than those before treatment, and the cell count, neutrophils, eosinophils and lymphocytes in the combination group were lower than those in the single group(P＜0.05). Arterial partial pressure of oxygen(PaO2) and blood oxygen saturation(SpO2) in both groups were higher than those before treatment, and PaCO2 was lower than that before treatment. PaO2 and SpO2 in combination group were higher, while PaCO2 in group 2 was lower, as compared with those in the single group(P＜0.05). There was no significant difference in the incidence of adverse reactions between two groups(P＞0.05). 
Conclusion Atomization inhalation of hypertonic saline combined with ambroxol hydrochloride is more effective in the treatment of children with severe bronchiolitis, which can improve cough and asthma symptoms, reduce the level of neutrophils, and improve oxygen content, with good safety.

Key words: bronchiolitis, saline solution, hypertonic, ambroxol