From the Guidelines
In chronic obstructive pulmonary disease (COPD), all three types of respiratory work increase, but airway resistance work and elastic work are particularly affected. Airway resistance work increases significantly due to bronchial obstruction from inflammation, mucus hypersecretion, and bronchospasm, making it harder to move air through narrowed airways 1. Elastic work increases because of loss of lung elasticity and hyperinflation, requiring more effort to expand the lungs against altered elastic forces 1. Tissue resistance work also increases to some extent due to structural changes in the lung parenchyma 1. These increased work requirements explain why COPD patients experience dyspnea and fatigue during breathing, particularly during exertion. The progressive nature of COPD means these work requirements continue to increase over time, leading to respiratory muscle fatigue and potentially respiratory failure in advanced disease. Key factors contributing to these changes include:
- Bronchial obstruction
- Loss of lung elasticity
- Hyperinflation
- Structural changes in the lung parenchyma
- Systemic inflammation and muscle dysfunction Pulmonary rehabilitation is a comprehensive intervention that can help reduce dyspnea, increase exercise capacity, and improve quality of life in individuals with COPD 1. Components of pulmonary rehabilitation may include exercise training, education, and behavior change, designed to improve the physical and psychological condition of people with chronic respiratory disease and to promote the long-term adherence to health-enhancing behaviors 1. The benefits of pulmonary rehabilitation have been demonstrated in various studies, including improvements in symptoms, exercise tolerance, and quality of life 1. However, the optimal duration and components of pulmonary rehabilitation programs are still being researched, and more studies are needed to determine the most effective strategies for maintaining benefits over time 1. Overall, the goal of pulmonary rehabilitation is to help individuals with COPD manage their symptoms, improve their functional capacity, and enhance their overall quality of life.
From the Research
Types of Work in COPD
The work of inspiration in COPD can be divided into three fractions:
- Compliance work or elastic work: required to expand the lungs against the lung and chest elastic forces
- Tissue resistance work: required to overcome the viscosity of the lung and chest wall structures
- Airway resistance work: required to overcome airway resistance to movement of air into the lungs
Increase in Work in COPD
In COPD, the following types of work increase:
- Airway resistance work: due to the narrowing of airways and increased resistance to airflow 2, 3
- Tissue resistance work: due to the increased viscosity of the lung and chest wall structures 4
- Compliance work or elastic work: due to the hyperinflation of the lungs and increased elastic forces 5, 6
Key Factors Contributing to Increased Work
Key factors contributing to the increase in work in COPD include: