Human beings essentially have two jobs to do when we swallow.
First, we have to move food and liquid through the mouth and the pharynx, past the airway, and into the esophagus and stomach. Second, we have to simultaneously protect the airway.
Airway protection has a number of built-in redundancies:
- The tongue gets the bolus moving
- The epiglottis inverts to direct the bolus away from the airway and provide some protection over the glottis
- The vocal folds adduct
- The larynx elevates so that the arytenoids contact the underside of the epiglottis
- The laryngeal valve closes
But one of the most important things we do to protect our airway is we stop breathing. This period of “respiratory pause” is important to airway protection. And timing, of course, is critical here—we have to stop breathing before the bolus can enter the airway, and we have to maintain that respiratory pause until the swallow is complete.1, 2, 3
What Happens When Breathing Is Compromised?
Dysphagia clinicians are often asked to evaluate patients with underlying respiratory compromise as occurs with chronic obstructive pulmonary disease (COPD), recent extubation, pneumonia, and, most recently, COVID-19.
What should we be looking for?
Low Tolerance for Respiratory Pause
Respiratory pause during swallowing is important for airway protection—but what if your patient’s breathing is compromised by lung disease or respiratory failure?
That period of breathing cessation, so necessary to airway protection, becomes very difficult to tolerate. Even a brief pause in respiration, repeated for each swallow, has the potential to increase work of breathing and respiratory rate while decreasing oxygen saturation levels.
Shorter Periods of Respiratory Pause
Whenever there is physiological conflict in the body, breathing always wins. As patients become short of breath and the work of breathing increases, we often see the duration of the respiratory pause decrease, with early return to breathing during the swallow.4, 5
While this may compromise swallow safety, particularly if the food and liquid are still moving through the pharynx when breathing resumes, we have to remember that breathing always wins.
Impaired Breathing-Swallow Coordination
We also know that when the respiratory system is compromised, respiratory-swallow patterning changes.
In those of us with healthy lungs, our swallow is typically bracketed by exhalation. We exhale a little, swallow, then continue our exhalation. This post-swallow exhalation helps clear the airway of any potential residue and facilitates laryngeal elevation and closure.
In patients with underlying respiratory compromise, repeated periods of breathing cessation result in air hunger, and we’re more likely to see a post-swallow inhalatory pattern. Combine that air hunger, post-swallow inhalation, and an inefficient swallow, and any residue in the pharynx could be inhaled into the airway.6, 7, 8
What Can SLPs Do?
Watch the Breathing
Pay careful attention to breathing when assessing and treating patients with respiratory failure, COVID-19, pneumonia, COPD, Parkinson’s disease, or any diagnosis that could potentially compromise respiration. Additionally, watch for increases in work of breathing or respiratory rate, which could indicate impaired breathing-swallow coordination.
Consider the Fatigue Factor
Two or three swallows may not have a significant impact on breathing-swallow coordination, but what happens over the course of an entire meal? Swallowing places considerable demands on the respiratory system, and coordination and timing often deteriorate as that system fatigues. Your patient may have considerably more difficulty near the end of the meal than at the beginning—or more difficulty with dinner than breakfast.
We don’t have too many “one size fits all” interventions in the rehabilitation world, but if we did have one, it would probably be “go slow.” Small bites and sips, pauses between swallows, and a slower rate of intake overall can help to regulate breathing and decrease the demands on the respiratory system.
If your client can’t breathe very well—no matter the cause—swallowing is going to be difficult, too. When breathing changes, so does swallowing… and if you can’t breathe, you can’t swallow.
- Hopkins-Rossabi, T., Curtis, P., Temenak, M., Miller, C., & Martin-Harris, B. (2019). Respiratory phase and lung volume patterns during swallowing in healthy adults: a systematic review and meta-analysis. Journal of Speech, Language, and Hearing Research, 62(4), 868–882.
- Hiss, S. G., Treole, K., & Stuart, A. (2001). Effects of age, gender, bolus volume, and trial on swallowing apnea duration and swallow/respiratory phase relationships of normal adults. Dysphagia, 16(2), 128–35.
- Preiksaitis, H. G., Mayrand, S., Robins, K., & Diamant, N. E. (1992). Coordination of respiration and swallowing: effect of bolus volume in normal adults. American Journal of Physiology, 263(3 Pt 2), R624–30.
- Boden, K., Hardemark Cedborg, A. I., Eriksson, L. I., Witt Hedström, H., Keylenstierna, R., Sundman, E., & Ekberg, O. (2009). Swallowing and respiratory pattern in young healthy individuals recorded with high temporal resolution. Neurogastroenterology and Motility, 21(11), 1163–e101.
- Yagi, N., Oku, Y., Nagami, S., Yamagata, Y., Kayashita, J., Ishikawa, A., & Domen, K., et al. (2017). Inappropriate timing of swallow in the respiratory cycle causes breathing-swallowing discoordination. Frontiers in Physiology, 22(8), 676.
- Mohan, R. & Mohapatra, B. (2020). Shedding light on dysphagia associated with COVID-19: The what and why. OTO Open, April 2020.
- Nagami, S., Oku, Y., Yagi, N., Sato, S., Uozumi, R., Morita, S., & Yamagat, Y., et al. (2017). Breathing-swallowing discoordination is associated with frequent exacerbations of COPD. BMJ Open Respiratory Research, 4, e000202.
- Gross, R. D., Atwood Jr., C. W., Ross, S. B., Olszewski, J. W., & Eichhorn, K. A. (2009). The coordination of breathing and swallowing in chronic obstructive pulmonary disease. American Journal of Respiratory and Critical Care Medicine, 179(7), 559–65.