**8. Conclusions**

This chapter initially provided a brief overview of dysphagia, coordination of breathing and swallowing, and COPD. This was followed by a historical review that described the research through the decades on swallowing in COPD. In addition to these previous studies, new results were presented. This analysis provides evidence that (1) the apnea interval increases with the swallowed volume in COPD; (2) COPD patients had higher swallowing apnea time compared to controls in larger volumes; (3) the occurrence of inspiratory patterns after swallowing increases in COPD, which may facilitate the occurrence of aspiration in these patients, and (4) the prototype that was described in section 6 is suitable for clinical studies.

Routine clinical evaluation of swallowing disorders in COPD has yet to gain full acceptance, but the evidence of the importance of these analyses is growing fast. The results of the present study, together with the results described in the historical review, provide additional evidence that patients with COPD might present modifications in deglutition and a specialized evalu‐ ation is necessary for safe deglutition, especially in case of acute exacerbation.

### **Acknowledgements**

20 mL). These findings disagree with those described in the study by Gross [38], which observed no difference in apnea time between the COPD and control group. These authors note, however, that in the swallows of COPD patients in which apnea occurred in inspiration time, the apnea interval was longer. Physiologically, the presence of longer periods of apnea in COPD could indicate a compensatory mechanism for airway protection against aspiration

The control group presented an increased number of swallows in the standard-expiration apnea-expiration (EE) pattern in all studied volumes (Figure 8). This is in close agreement with previous studies [9, 20, 22, 50]. This finding supports the theory that swallowing during the expiratory phase represents less risk of aspiration and therefore may be considered a protective mechanism of the airways. Swallowing during the inspiratory phase may facilitate the entry of food and saliva into the airways during and after swallowing [22]. Other patterns were also observed in this group. In order of increasing frequency: inspiration-apnea-expiration (IE), expiration-apnea-inspiration (EI), and inspiration-apnea-inspiration (II). This result is consis‐ tent with that reported by Martin-Harris [22]. The pattern II presented the smallest frequency

COPD patients more frequently showed the EE and EI patterns (Figure 8). Similar findings were reported in the study conducted by Cjevic [2]. The pattern II occurred less frequently compared with other patterns. Comparing the swallowing of COPD patients with control subjects, it can be observed that the pattern EI (Figure 8C) occurs more frequently in COPD patients compared to control subjects. This phenomenon was observed in all studied volumes. Considering the pattern II (Figure 8D), we observe that this also occurs more frequently in COPD, particularly in exams using 20 mL. In agreement with the present work, the study by Gross [38] describes that patients with COPD had pre and post inspiration swallowing apnea more often than the control subjects. These results are consistent with the observation that the

This chapter initially provided a brief overview of dysphagia, coordination of breathing and swallowing, and COPD. This was followed by a historical review that described the research through the decades on swallowing in COPD. In addition to these previous studies, new results were presented. This analysis provides evidence that (1) the apnea interval increases with the swallowed volume in COPD; (2) COPD patients had higher swallowing apnea time compared to controls in larger volumes; (3) the occurrence of inspiratory patterns after swallowing increases in COPD, which may facilitate the occurrence of aspiration in these patients, and (4)

Routine clinical evaluation of swallowing disorders in COPD has yet to gain full acceptance, but the evidence of the importance of these analyses is growing fast. The results of the present study, together with the results described in the historical review, provide additional evidence that patients with COPD might present modifications in deglutition and a specialized evalu‐

in all volumes, which agrees with previous results [9, 20, 22].

inspiration after swallowing facilitates aspiration of food and saliva.

the prototype that was described in section 6 is suitable for clinical studies.

ation is necessary for safe deglutition, especially in case of acute exacerbation.

of food residuals.

222 Seminars in Dysphagia

**8. Conclusions**

The authors would like to thank the Brazilian Council of Research and Development (CNPq), the Rio de Janeiro State Foundation for Research (FAPERJ), and the Rio de Janeiro State University – PROCIÊNCIA Program for research grants.
