Rationale: During deglutition, a strongly preferred exhale-swallow-exhale pattern has been shown in healthy adults. Disruption of this pattern can provoke prandial aspiration. Impaired coordination of breathing and swallowing has been measured in patients with chronic obstructive pulmonary disease (COPD) during the exacerbated state, but no reports describe the coordination of breathing and swallowing in stable patients with COPD during oral intake.
Objectives: To test the hypothesis that persons with moderate to severe COPD would show disordered coordination of breathing and swallowing during oral intake when compared with a matched, healthy control group.
Methods: This study used a prospective, repeated measures design using 25 subjects with COPD and 25 control subjects. Respiratory inductance plethysmography and nasal thermistry were used simultaneously to track respiratory signals. Submental surface EMG was used to mark the presence of each swallow within the respiratory cycle. Data were recorded while participants randomly and spontaneously swallowed solids and semi-solids.
Measurements and main results: Logistic regression showed that participants with COPD swallowed solid food during inhalation more frequently than normal subjects (P = 0.002) and had a significantly higher rate of inhaling after swallowing semi-solid material (P < 0.001). Subjects with COPD also swallowed pudding at low Vt significantly more often than they did the cookie (P = 0.006). Conversely, the control subjects swallowed cookie at low Vt significantly more often than pudding (P = 0.034). Significant differences in deglutitive apnea durations were also found.
Conclusions: Patients with COPD exhibit disrupted coordination of the respiratory cycle with deglutition. Disrupted breathing-swallowing coordination could increase the risk of aspiration in patients with advanced COPD and may contribute to exacerbations.