Korean J Asthma Allergy Clin Immunol.  2007 Jun;27(2):111-117.

A Comparative Study between External Resistive Loads to Breathing and Induced Bronchoconstriction on Dyspnea Perception in Asthma

Abstract

BACKGROUND: Since blunted perception of dyspnea may predispose to fatal asthma attacks, dyspnea perception should be measured in severe asthma. Few studies have compared the testing methods.
OBJECTIVE
To investigate whether the degree of dyspnea perception depends on the testing method in asthma. METHOD: The Borg scale-based dyspnea perception scores during breathing through an inspiratory muscle trainer, and during bronchoprovocation tests using histamine or methacholine were measured in asthma patients and normal volunteers. The relationships between Borg scores and atopy markers were determined. RESULT: The delta Borg scores induced by the external resistive loads were significantly lower in subjects with moderate-to-severe airway hyperresponsiveness (AHR) to histamine than in those with negative AHR (P=0.021). Among the patients with AHR to both histamine and methacholine (n= 19), the delta Borg scores/delta lung function ratio induced by histamine was significantly higher than that by methacholine (15.6+/-2.3 vs. 9.5+/-2.1, P<0.05). The load-induced delta Borg scores were significantly related to serum total IgE levels (r=0.541, P<0.05).
CONCLUSION
Dyspnea perception depends on AHR severity. Histamine induces more severe dyspnea than methacholine, and allergy may affect dyspnea perception. Dyspnea perception vary according to the testing methods.

MeSH Terms

Asthma*
Bronchoconstriction*
Dyspnea*
Healthy Volunteers
Histamine
Humans
Hypersensitivity
Immunoglobulin E
Lung
Methacholine Chloride
Respiration*
Histamine
Immunoglobulin E
Methacholine Chloride