The perception of dyspnea after bronchoconstriction and bronchodilation in patients with asthma.
BACKGROUND
It is well documented that the perception of dyspnea (POD), subjectively reported by patients, is an important index used to guide treatment. The severity of dyspnea following methacholine-induced bronchoconstriction and added mechanical loads is increasing in popular. No formal attention has been addressed to the reduction in dyspnea following bronchodilators.


OBJECTIVE
To investigate if the magnitude of dyspnea perceived by a subject is independent on the direction (e.g., bronchoconstriction or bronchodilation) of the change in airway resistance.


METHODS
The POD was measured in 26 mild moderate asthmatic patients following bronchodilation, using beta2-agonists, and following bronchoconstriction, induced by methacholine challenge, to almost the same magnitude.


RESULTS
The increase in forced expiratory volume in 1 s (FEV1), 30 min after the inhalation of beta2-agonist (mean +/- SEM 22.3 +/- 0.8%), was associated with a statistically significant decrease (P < 0.005) in the POD. The mean decrease in FEV1 following methacoline challenge, was 23 +/- 0.7% and was followed by a statistically significant increase (P < 0.005) in the POD. The magnitude of the decrease in the POD following albuterol was almost identical to the magnitude of the increase in the POD following methacholine.


CONCLUSIONS
In stable mild-moderate asthmatic patients, the changes in the magnitude of dyspnea, perceived by a subject, is independent on the direction of the change in the FEV1.
Weiner
Paltiel
P
Department of Medicine A, Hillel Yaffe Medical Center, Hadera, Israel. weiner@hillel-yaffe.health.gov.il
Beckerman
Marinella
M
Berar-Yanay
Noa
N
Magadle
Rasmi
R
D058672:Adrenergic beta-2 Receptor Antagonists; D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D016084:Bronchoconstriction / Q000187:drug effects / Q000502:physiology; D016085:Bronchoconstrictor Agents / Q000009:adverse effects*; D001993:Bronchodilator Agents / Q000009:adverse effects*; D004417:Dyspnea / Q000139:chemically induced* / Q000523:psychology; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D010465:Perception
D058672:Adrenergic beta-2 Receptor Antagonists; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D016210:Methacholine Chloride