Respiratory mechanics and peripheral airway inflammation and dysfunction in asthma
Article first published online: 22 APR 2013
© 2013 Blackwell Publishing Ltd
Clinical & Experimental Allergy
Volume 43, Issue 5, pages 521–526, May 2013
How to Cite
Clinical & Experimental Allergy, 2013 (43)521–526., , , , , , , , , .
- Issue published online: 22 APR 2013
- Article first published online: 22 APR 2013
- Accepted manuscript online: 10 JAN 2013 04:11AM EST
- Manuscript Accepted: 3 JAN 2013
- Manuscript Revised: 20 DEC 2012
- Manuscript Received: 31 MAY 2012
- alveolar nitric oxide;
- forced oscillation technique;
- ventilation inhomogeneity
Clinical application of the forced oscillation technique (FOT) has progressed with the spread of commercially available FOT devices. The correlation between respiratory impedance and spirometry has been reported; however, the association with airway inflammation and pulmonary function, in the lung periphery in particular, is unclear.
To assess whether respiratory impedance is associated with peripheral airway inflammation and dysfunction in asthma.
Subjects included 78 patients with overall controlled asthma. We measured whole-breath or within-breath respiratory system resistance (Rrs) and reactance (Xrs) using a commercially available multi-frequency FOT device (MostGraph-01), and assessed the correlation with the fraction of exhaled nitric oxide (FeNO), alveolar nitric oxide concentration (CANO), maximal NO flux in the conductive airways (J'awNO), and the N2 phase III slope of single breath N2 washout (delta N2).
The differences between inspiratory and expiratory phases of Xrs at 5 Hz (X5), resonant frequency (Fres), and a low-frequency reactance area (ALX) were significantly correlated with CANO; however, there was no correlation between respiratory impedance and FeNO or J'awNO. The delta N2 values were significantly correlated with whole-breath, inspiratory, and expiratory Rrs and Xrs, except for R20.
Conclusions and Clinical Relevance
We conclude that respiratory impedance reflects peripheral airway inflammation and ventilation inhomogeneity.