Patients with moderate to severe chronic obstructive pulmonary disease (COPD) exhibit a disordered breathing-swallowing pattern that may account for their higher risk of aspiration pneumonia, according to new research from the University of Pittsburgh.
In the first issue for April of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine, Roxann Diez Gross, Ph.D., and colleagues report that patients with moderate to severe COPD exhibit alterations between breathing and swallowing patterns even when they are not experiencing exacerbations.
While it was previously known that COPD patients exhibited decoupling of the breathing-swallowing pattern of saliva during exacerbations, until now there were no formal studies detailing to what extent, if any, disruptions in breathing and swallowing coordination occurred in COPD patients outside of exacerbations during normal eating.
The researchers examined the relationship between swallowing and timing of breathing in 25 patients with moderate to severe COPD and compared them with 25 healthy subjects. Each subject was asked to consume nine wafer cookies and ten teaspoons of pudding to determine whether there were differences in the handling of solid versus semi-solid food.
The researchers found that in patients with COPD, a pattern emerged that was strikingly different from that of healthy controls.
"In healthy subjects, the usual pattern is to time swallows to occur during early to mid exhalation. Healthy individuals also nearly exclusively follow each swallow with exhalation. This pattern assures that there is sufficient air pressure below the vocal folds during a swallow and prevents inhalation of food residue after swallowing," said Dr. Gross. "In contrast, in COPD patients, we saw that several aspects of their swallowing and breathing timing were disrupted such that swallows were occurring during inhalation or where followed by inhalation. COPD patients also swallowed more often at the end of exhalation at lower lung volumes."