Background

Recently, the analysis of tidal breathing flow-volume loop (TBFVL) and multiple breath washout (MBW) allow the study of respiratory function even in uncooperative infants.

Aims

-To evaluate the role of TBFVL and MBW in infant with suspected airway obstruction

- To evaluate the differences between the patients with inspiratory stridor and the patients with expiratory stridor

- To evaluate the correlation between the respiratory function tests and endoscopy.

Methods

We enrolled 34 patients younger than 6 months of age with a clinical diagnosis of stridor inspiratory or expiratory, and 15 controls healthy. For each patient, we performed TBFVL and MBW respiratory function tests. When clinically indicated, patients underwent endoscopy.

Results

At T0 patients with stridor had inspiratory time (p=0.004) and expiratory time (p= 0.002) increased than healthy controls.

At T0 we found two different abnormal morphological patterns in the TBFVL depending on the type of stridor (Figure 1).

At T0 patient with expiratory stridor had inspiratory volume (p=0.003) and expiratory volume (p=0.004) reduced and a reduced Lung clearence index (p= 0.004) and incresead residual functional capacity (p= 0.003) than patient with inspiratory stridor.

We showed a good concordance between respiratory function test and endoscopy.

Conclusion

Respiratory function tests could be a valid tool in the management of patients with suspected airway obstruction, reducing the use of invasive procedures and contributing to a better use of economic resources of the health system.