Perception scoring of induced bronchoconstriction as an index of awareness of asthma symptoms.
Perception of asthma symptoms shows a wide interindividual variability. Poor perception of airflow obstruction may lead to undertreatment of asthma. We reviewed the possibility of using a simple test to detect poor perceivers of bronchoconstriction as part of the investigation of asthmat. We studied 150 consecutive subjects referred for assessment of airway responsiveness. All had a histamine PC20 within the asthmatic range (< 16 mg/ml) and a fall in FEV1 of < 20 percent after saline inhalation. On histamine challenge, before each FEV1 measurement, perception of dyspnea was assessed on a modified Borg scale. A perception score of breathlessness at 20 percent fall in FEV1 (PS20) was obtained by interpolation of the two last points on the perception/fall in FEV1 curve. It was concluded that in a hyperreactive population, PS20 (1) showed a normal distribution pattern; (2) was similar in both genders; and (3) increased with age due to high postcontrol saline inhalation scores. Hypoperceivers or hyperperceivers were similar for age, sex, baseline FEV1, and PC20. The PS20 determination may be a useful additional parameter to obtain during provocation tests to assess perception of symptoms associated with bronchoconstriction. Its correlation with clinical outcome remains, however, to be determined.
Boulet
L P
LP
Unité de Recherche, Hôpital Laval Université Laval, Sainte-Foy, Québec, Canada.
Leblanc
P
P
Turcotte
H
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000503:physiopathology* / Q000523:psychology; D016535:Bronchial Hyperreactivity; D001985:Bronchial Provocation Tests; D016084:Bronchoconstriction / Q000187:drug effects; D005260:Female; D005541:Forced Expiratory Volume; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010465:Perception; D012965:Sodium Chloride / Q000008:administration & dosage
D012965:Sodium Chloride; D006632:Histamine