Pulmonary function testing with tidal breath analyze technique is useful in predicting persistant small airway damage in infants with acute bronchiolitis.

Background: Due to technical difficulties, lung function in infants is less studied. This prospective cross-sectional study investigated breathing parameters by using tidal breath analysis (TBA) technique in hospitalized infants with the first-time acute bronchiolitis (AB).

Methods: This study enrolled 111 infants aged 1 month-2 years: 61 with AB and 50 healthy controls. Lung function was assessed using TBA technique on the first day of hospitalization and repeated at the 7th and 30th days after the treatment.

Results: The parameters of tPTEF, tPTEF:tE, VT/kg, and tI/tE ratio were still significantly lower at the 30th day of the disease. tPTEF:tE ratio was inversely correlated with hospitalization duration and severity of disease and strongly correlated with VPTEF:VE (r = .876, P < .001) in infants with AB.

Conclusion: Due to restoration of pulmonary function dynamics in the lower respiratory tract was a long-lasting process, TBA is a useful and easy method for pulmonary function among infants and may help clinicians to predict persistent small airway damage.