How do patients with either asthma or COPD perceive acute bronchodilation?

Area of Science:

• Respiratory Medicine
• Pulmonology
• Clinical Physiology

Background:

• Assessing patient perception of bronchodilation is crucial for managing asthma and Chronic Obstructive Pulmonary Disease (COPD).
• Subjective measures like the visual analogue scale (VAS) for shortness of breath are commonly used but require validation against objective lung function.
• Understanding the relationship between perceived and actual bronchodilation can improve treatment efficacy and patient-reported outcomes.

Purpose of the Study:

• To evaluate how individuals with asthma and COPD perceive bronchodilation.
• To correlate subjective perception of reduced shortness of breath with objective changes in lung function following bronchodilator administration.
• To characterize the quality of perceptual response in different patient groups.

Main Methods:

• 16 asthma patients and 20 COPD patients inhaled terbutaline (800 micrograms total dose) to induce bronchodilation.
• Subjects rated shortness of breath using a bipolar visual analogue scale (VAS).
• Linear regression analysis assessed the correlation between VAS ratings and lung function changes (e.g., inspiratory vital capacity, forced expiratory volume in one second, specific inspiratory resistance).

Main Results:

• A majority of both asthma (14/16) and COPD (13/20) patients were classified as 'high perceivers' of bronchodilation.
• High perceivers with COPD exhibited greater objective improvements in lung function, particularly inspiratory vital capacity, compared to low perceivers.
• Asthmatics showed the strongest correlation (median r2 = 0.831) between improved shortness of breath and decreased specific inspiratory resistance; COPD low perceivers had unrelated subjective and objective responses.

Conclusions:

• Perceptual characteristics of bronchodilation vary between asthma and COPD patients, with high perceivers generally showing better objective responses.
• The correlation between subjective relief and objective lung function improvement is strongest in asthmatics, particularly when assessed against specific inspiratory resistance.
• In COPD patients, particularly low perceivers, subjective perception may not accurately reflect objective lung function changes, highlighting the need for careful clinical assessment.