[The effect of time on the perception of dyspnea following inhaled long-acting bronchodilator]
Related Experiment Video
Updated: Sep 25, 2026

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method
Published on: February 2, 2024
Paltiel Weiner1, Rasmi Magadle, Marinella Beckerman
1Department of Medicine A, Hillel-Yaffe Medical Center, Hadera, Israel.
Study Objectives:
To assess the effect of time on the change in the perception of dyspnea (POD) following inhalation of long-acting bronchodilator.
Patients And Methods:
Spirometry and the POD were measured in 32 asthmatic patients, with moderate asthma, before and following inhalation of placebo, and salmeterol. The POD was measured while breathing against progressive loads, using a visual analogue scale (VAS).
Results:
The highest FEV1 levels and the lowest POD were measured one hour after salmeterol inhalation. Although the mean FEV1 remained close to its peak value for at least six hours following the inhalation of salmeterol, there was a gradual statistically significant increase in the POD.
Conclusions:
Following inhalation of long-acting bronchodilator (LABD) there is relationship between the increase in the FEV1 and the decrease in POD. With time there is a gradual increase in the perception of dyspnea regardless of the FEV1.
Related Concept Videos
Antiasthma Drugs: β2-Adrenoceptor Agonists
One class of bronchodilators includes β2-adrenoceptor agonists. These agents target the β2-adrenoceptors located on bronchial smooth muscle cells. By stimulating these receptors, β2-agonists induce relaxation in these...
COPD: Management Using Bronchodilators and Corticosteroids
Inhaled Medications
Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features
Pharmacokinetic–Pharmacodynamic Relationship: Duration of Dose-Effect Relationship
Antiasthma Drugs: Methylxanthines
Theophylline is thought to inhibit phosphodiesterase enzymes, increasing intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). This rise in cAMP and cGMP concentrations stimulates cardiac function,...