Work and Effort of Breathing in COPD
An on-line publication this week by Chang and colleagues in the journal Chest describes the experience of breathing difficulty as reported by those who have COPD.
The first author is Andrew Chang, a medical student at the Geisel School of Medicine at Dartmouth. He worked on this research study between his 1st and 2nd years of medical school with three Pulmonary doctors on the staff of Dartmouth-Hitchcock Medical Center. In the study, patients with different respiratory conditions answered “Yes” or “No” for each of 15 different statements that described experiences of breathing discomfort. Then, each person was asked to select the “Best Three” that most closely matched how they felt when short of breath doing daily activities.
Here are the “Best Three” statements chosen by 68 individuals with COPD:
Does your breathing difficulty match up with these statements?
These experiences are considered to be due to the work and effort required by the breathing muscles to breathe in (inspire). Because those with COPD have narrowed breathing tubes (airways), it is often difficult to get all of the air out when exhaling. As a result, air is trapped in the lung leading to hyperinflation of the lungs as shown in the figure.
- I feel out of breath.
- My breathing requires effort.
- I cannot get enough air in.
As a result of the hyperinflation of the lungs, the diaphragm (the main muscle of breathing) has to work harder when it contracts to breathe air in. This added work and effort of the diaphragm is sensed by those who have COPD. This is the major reason why someone with COPD finds that it is hard to breathe or have shortness of breath.
Bronchodilator medications are the cornerstone for treatment of COPD because they open the breathing tubes (airways). This allows more air to be exhaled and thereby reduces hyperinflation – making it easier to breathe. Long-acting bronchodilators that last 12 – 24 hours provide more sustained benefit than the short-acting inhalers (typically last 4 hours).
Hopefully, this information will help you understand why taking your bronchodilator medications regularly is important for your breathing.
On left: Normal size of lungs.
On right: lungs are larger due to inability to exhale completely. This is called HYPERINFLATION.