Perception of dyspnea during exacerbation and histamine-related bronchoconstriction in patients with asthma

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Abstract

Background:

Numerous studies have been performed concerning the perception of dyspnea during changes in airway caliber provoked in the laboratory setting, but studies of asthma exacerbation are scarce.

Objective:

To investigate whether the perception of dyspnea during histamine-induced bronchoconstriction might be used to identify patients with asthma who sense dyspnea poorly during exacerbation.

Methods:

The perception of dyspnea in 50 patients (45 female, 5 male) with asthma was evaluated at admission with exacerbation and during a stable period. Perceived intensity of dyspnea was estimated using a modified Borg scale. The perception of dyspnea in the stable period 4 to 6 weeks after exacerbation was measured with the histamine challenge test. Perception parameters were defined as the change in Borg score divided by the change in forced expiratory volume in 1 second (FEV1) as a percentage of the baseline FEV1 (δBorg/δFEV1) and as the Borg score at 20% decrease (PS20Histamine) or increase (PS20Exacerbation) in FEV1.

Results:

The perception of dyspnea during asthma exacerbation was unrelated to the perception of dyspnea during histamineinduced bronchoconstriction (for δBorg/δFEV1, β = .08, P = .50; for PS20, β = -.11, P = .40). The κ value for the agreement of poor perceivers at exacerbation and during the stable period was −0.21 (P = .10). However, the intensity of dyspnea caused by histamine-induced bronchoconstriction was lower than that caused by asthma exacerbation (PS20: 1.6 ± 1.1 vs 2.8 ± 2.5, respectively, P = .004; δBorg/δFEV1: 0.08 ± 0.05 vs 0.21 ± 0.28, respectively, P = .001).

Conclusion:

The perception of dyspnea during asthma exacerbation is not correlated with the perception of dyspnea during histamine-induced bronchoconstriction. Therefore, the perception of dyspnea during histamine-induced bronchoconstriction cannot be used to identify the asthmatic patients who perceive dyspnea poorly.

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