Relation of the perception of airway obstruction to the severity of asthma

Abstract

Background-Patients with a poor perception of their symptoms of asthma seem to have an increased risk of an asthma attack. The influence of factors such as airway calibre, bronchial hyperresponsiveness, age and sex on the "perceptiveness" of a patient are poorly understood. It is of clinical importance to identify patients who are likely to have a poor perception of their symptoms. We have studied the perception of bronchoconstriction by asthmatic patients during a histamine provocation test and analysed the influence of bronchial obstruction, hyperresponsiveness, sex, and age. We were particularly interested to establish whether there was any diVerence in perception between subjects with a greater or lesser severity of asthma (expressed as bronchial obstruction, hyperresponsiveness). with a low degree of "perceptiveness" for bronchoconstriction. This suggests that patients with a more severe degree of asthma either show adaptation of "perceptiveness" for airway obstruction or that low perceptiveness leads to more severe asthma. (Thorax 1999;54:15-19) Methods-One

Effect of asthma severity on symptom perception in childhood asthma

“…Apter et al (1) reported that patients with lower forced expiratory flow between 25% and 75% of the vital capacity (FEF ) tended to be less accurate perceivers. Chetta et al (24) found that poor perception was associated with asthma severity and Bijl-Hofland et al (25) reported that low baseline forced expiratory volume in 1 s (FEV 1 ) and high hyperresponsiveness were associated with a low perceptiveness of bronchoconstriction. In contrast, Pfeiffer et al (14) concluded that good and poor perceivers did not differ in terms of the severity or duration of asthma and Fritz et al (11) reported that children s perceptual accuracy of symptoms was not related to severity.…”

Baixo grau de percepção da dispneia após teste de broncoprovocação induzida por metacolina em pacientes com asma

“…(11)(12)(13) Others, however, have found no such association. (3) However, 21 (39.5%) did not perceive any changes in the degree of dyspnea even after a 20% fall in FEV 1 (Figure 3). …”

“…However, when the patients were stratified by FEV 1 , the authors observed, by means of multiple regression analysis, that low baseline FEV 1 was associated with poorer perception of dyspnea. (3) Another…”

“…It has been demonstrated that a poor perception of bronchoconstriction is associated with bronchial hyperresponsiveness, suggesting that patients develop a mechanism of tolerance, a theory also supported by another group of authors. (3,14) The use of inhaled corticosteroids as maintenance medication has been related to the perception of bronchoconstriction. Our study found no such association, possibly due to the fact that only a small number of patients used inhaled corticosteroids, alone or in combination with a long-acting bronchodilator.…”

“…Studies have found that the proportion of such patients ranges from 15% to 60%. (1)(2)(3) A study conducted in the state of Bahia, Brazil, found that 51% of the patients with moderate to severe asthma had a poor perception of dyspnea. (4) Limited patient ability to identify the degree of airway obstruction is a risk factor for asthmarelated mortality.…”