Isocapnic Cold Air Challenge in Patients with COPD: Are There any Predisposing Factors?

Abstract

Cold air hyperventilation is an indirect challenge (cold air challenge, CACh) with high specificity and low sensitivity in defining asthmatic subjects. A small proportion of chronic obstructive pulmonary disease (COPD) patients present with positive CACh. The aim of this prospective study was to investigate the presence of factors related to cold air challenge (CACh) in COPD patients. Factors examined were FEV(1), FEV(1)/FVC, reversibility after bronchodilation, eosinophils in induced sputum, bronchial hyperresponsiveness to methacholine and the spirometric response to tiotropium compared to placebo. We studied 92 consecutive COPD patients in order to retrieve 15 CACh positive + patients. Fifteen COPD patients with negative CACh [CACh(-)], randomly selected from the initial group, were added in order to retrieve a group of 30 patients. Spearman's correlation coefficient was used in order to evaluate possible significant correlations between CACh values and study parameters. Sixteen percent of our subjects presented CACh+. CACh values were repeatable with an intraclass correlation coefficient between the two measurements 0.980 (95% CI 0.940-0.993). The only significant correlation observed was between Delta FEV(1) after CACh [Delta(C)FEV(1)] and trough FEV(1) values post tiotropium inhalation (r(2) = 0.62, p < 0.0001). When we analyzed the response to tiotropium in the 2 separate groups we found that patients with CACh+ presented significantly lower values of trough FEV(1) compared to those with CACh(-). In conclusion, a small proportion of COPD patients present with bronchial hyperresponsiveness to CACh. The only parameter related to CACh + in our study was a smaller bronchodilating effect of tiotropium.

Asthma outcomes: Pulmonary physiology

“…Notably, approximately 15% of patients with COPD have a positive isocapnic hyperventilation challenge. 130 …”

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

“…BHR, usually evaluated by inhalation of methacholine or histamine, has been found to occur in up to 85 % of smokers with COPD [5, 8, 9]. In contrast, BHR elicited by indirect challenge methods, such as isocapnic hyperventilation of cold or dry air (IHDA), was reported to occur much less frequently; only 16 % of smokers were reported to respond to IHDA with increased airway tonus [10, 11]. …”