Bronchial Responsiveness to Dry Air Hyperventilation in Smokers May Predict Decline in Airway Status Using Indirect Methods

Abstract

BackgroundDisabling respiratory symptoms and rapid decline of lung function may occur in susceptible tobacco smokers. Bronchial hyperresponsiveness (BHR) elicited by direct challenge methods predicts worse lung function outcomes. The aim of this study was to evaluate whether BHR to isocapnic hyperventilation of dry air (IHDA) was associated with rapid deterioration in airway status and respiratory symptoms.MethodsOne hundred twenty-eight smokers and 26 age- and sex-matched healthy individuals with no history of smoking were investigated. All subjects completed a questionnaire. Spirometry and impulse oscillometry (IOS) measurements were recorded before and after 4 min of IHDA. The tests were repeated after 3 years in 102 smokers and 11 controls.ResultsEighty-five smokers (66 %) responded to the challenge with a ≥2.4-Hz increase in resonant frequency (Fres), the cutoff limit defining BHR, as recorded by IOS. They had higher Fres at baseline compared to nonresponding smokers [12.8 ± 3.2 vs. 11.5 ± 3.4 Hz (p < 0.05)] and lower FEV1 [83 ± 13 vs. 89 ± 13 % predicted (p < 0.05)]. Multivariable logistic regression analysis indicated that wheezing (odds ratio = 3.7, p < 0.01) and coughing (odds ratio = 8.1, p < 0.05) were significantly associated with hyperresponsiveness. An increase in Fres was recorded after 3 years in responding smokers but not in nonresponders or controls. The difference remained when subjects with COPD were excluded.ConclusionsThe proportion of hyperresponsive smokers was unexpectedly high and there was a close association between wheezing and coughing and BHR. Only BHR could discriminate smokers with rapid deterioration of airway status from others.

Impact of anxiety and depression on respiratory symptoms

“…Bronchial responsiveness was the most important determinant for wheezing and breathlessness. A close association between wheezing and bronchial responsiveness has been shown in other studies [35]. In the present study, FEV1 was a significant determinant for four out of seven respiratory symptoms (wheezing, breathlessness, wheezing when not having cold and attack of breathlessness after activity) and atopy was associated with respiratory symptoms except for breathlessness at rest.…”

Clinical Application of Forced Oscillation Technique (FOT) in Early Detection of Airway Changes in Smokers

“…Although there are a few original articles evaluating the usefulness of FOT in detecting early smoking-related changes in lungs, it is extremely difficult to draw any conclusions from these studies (Summary Table 1). There is no agreement on the findings of these studies regarding the sensitivity and reliability of different parameters to detect small airway abnormalities in smokers, further the studies did not use comparable oscillation techniques [19,20,[31][32][33][34][35][36][37][38][39]. Accordingly, it is timely to highlight these discrepancies and review the current status of FOT applicability for detecting early smoking associated changes in lungs.…”