Bronchial or Laryngeal Obstruction Induced by Exercise?

Abstract

A child suspected of exercise-induced laryngeal obstruction and asthma is examined by laryngoscopy and respiratory resistance (Rrs) after exercise challenge. Immediately at exercise cessation, the visualized adduction of the larynx in inspiration is reflected in a paroxystic increase in Rrs. While normal breathing has apparently resumed later on during recovery from exercise, the pattern of Rrs in inspiration is observed to reoccur following a deep breath or swallowing. The procedure may thus help diagnosing the site of exercise-induced obstruction when laryngoscopy is not available and identify re-inducers of laryngeal dysfunction.

Self‐reported exercise‐induced dyspnea and airways obstruction assessed by oscillometry and spirometry in adolescents

“…Despite the reported high FOT sensitivity to changes in the upper airways, 34 we did not identify specific oscillatory patterns in EILO subjects. A previous study 15 reported an R 5,insp higher than R 5,exp in an EILO patients. Previous studies reported the same pattern also during vocal cord dysfunction (VCD) 35,36 .…”

“…To date, only one case study has addressed the possibility to identify EILO by FOT. 15 In this study, we investigated in an adolescent population: (i) the relationship between reported EID, EIB (FEV 1 fall ≥10%), and the post-exercise challenge changes in FOT parameters; and (ii) the overlap between abnormal FOT response and EIB in relation to inflammatory characteristics and EID; and (iii) baseline and exerciseinduced changes in FOT parameters in relation to EILO.…”

“…The forced oscillation technique (FOT), also called oscillometry, allows monitoring of the resistance (Rrs) and reactance (Xrs) of the respiratory system during tidal breathing and is sensitive to changes in the upper and lower airways 8,9 . As FOT can detect airway obstruction with minimal patient co‐operation, it might be used instead of, or together with, spirometry and CLE test to evaluate post‐exercise changes 10–15 . Furthermore, as the relation between exertional symptoms, EIB, and EILO is not strong, 2,16 changes in lung mechanics during quiet breathing may correlate better and could explain additional symptoms.…”

“…The FEV 1 and FOT responses to exercise only partially overlap in adults, 10,12,14 and no data are available in children or adolescents. To date, only one case study has addressed the possibility to identify EILO by FOT 15 …”

Clinical significance and applications of oscillometry

“…Model analysis has indicated the potential of oscillometry for assessing vocal cord dysfunction (VCD) [171,172]. It is recommended to carefully examine intratidal changes in Z rs for large positive swings during inspiration [173], especially when tidal inspiratory flow limitation may be suspected [174], and to identify markedly positive differences between inspiratory and expiratory R rs [175]. Owing to expiratory glottal narrowing, these differences are usually negative in control subjects or stable asthmatics and may be enhanced further in acute bronchoconstriction [175][176][177].…”