Data analysis
Descriptive statistics were performed and reported in terms of absolute frequencies or percentages for qualitative data and expressed as mean with standard deviation in parenthesis or in terms of medians, with lower and upper quartiles in brackets, for quantitative data. Comparisons between BAL data in tracheomalacia children and reference values were performed using Mann U Whitney. Data were analysed using “Statistica release eight” (StatSoft Corp., Tulsa, OK), and a difference of P value less than 0.5 was considered as statistically significant