Symptom Perception during Acute Bronchoconstriction

• Published in: American journal of respiratory and critical care medicine Vol. 162; no. 2; pp. 490 - 496
• Main Authors: KILLIAN, KIERAN J, WATSON, RICHARD, OTIS, JOCELINE, ST. AMAND, TIMOTHY A, O'BYRNE, PAUL M
• Format: Journal Article
• Language: English
• Published: New York, NY Am Thoracic Soc 01-08-2000; American Lung Association
• Subjects: Adult; Biological and medical sciences; Bronchoconstriction - physiology; Bronchoconstrictor Agents; Chest Pain; Chronic obstructive pulmonary disease, asthma; Dyspnea; Female; Humans; Male; Medical sciences; Methacholine Chloride; Pneumology; Respiration; Respiratory Sounds; Sensation; Human; Symptomatology; Bronchoconstriction; Dyspnea; Respiratory disease; Exploration; Perception; Comparative study; Provocation test
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/ajrccm.162.2.9905079

The hypothesis underlying the present study was that some of the variability in symptom intensity seen during acute bronchoconstriction may result from varying intensities of several stimuli yielding several sensations that can be identified by specific descriptive expressions (symptoms). A total of 232 subjects inhaled methacholine in doubling concentrations to a 20% decrease in FEV(1), or 64 mg/ml. The study identified the prevalence of dyspnea, nonspecific discomfort associated with the act of breathing, and 10 specific symptom expressions. Each symptom intensity was rated in Borg scale units. The contribution of the specific symptoms to the intensity of dyspnea is illustrated in the following equation (r = 0. 84): Dyspnea = 0.44 + 0.19 Difficult breathing + 0.41 Chest tightness + 0.20 Breathlessness + 0.14 Labored breathing + 0.11 Chest pain. Dyspnea was more intense with broncho-constriction, baseline pulmonary impairment, weight, and sex (being female). Dyspnea was less intense with age (being older) and as airway responsiveness to methacholine increased (p < 0.05 for all factors). Chest tightness and chest pain were at polar extremes on the discrimination scale, i.e., easily discriminated; chest tightness, difficult and labored breathing were not easily discriminated.