The most common symptom of COVID-19 in critically ill patients is acute respiratory distress syndrome (ARDS). The majority of patients admitted to the hospital report symptoms of shortness of breath and cough, and many of them end up with invasive or noninvasive respiratory support in the intensive care unit (ICU).
Among patients in the ICU, a frequent complication following intubation (after extubation) is oropharyngeal dysphagia: a type of swallowing disorder that arises due dysfunctions of the oral cavity, pharynx, larynx, or upper esophageal sphincter and is caused by certain health conditions associated with anatomic, respiratory, or neurologic conditions.
It may be characterized by difficulty initiating a swallow, aspiration into the airway, and/or presence of pharyngeal residue.
One of the primary causes of dysphagia in persons with compromised respiratory systems, including those with COVID-19, stems from the incoordination between swallowing and respiration. Respiration and swallowing display an intricate relationship, with both systems sharing neurologic, physiologic, structural, and functional interdependence. The precise timing and coordination between the breathing and swallowing cycles is one of the most important airway defense mechanisms. Most often, swallowing occurs in an expiration-swallow-expiration pattern that helps keep pharyngeal contents away from the larynx and trachea. However, incoordination, such as an increase in inspiration-swallowing or swallowing-inspiration patterns, have been found to exacerbate the symptoms in chronic obstructive pulmonary disease. Incoordination between these systems can lead to aspiration pneumonia, malnutrition, and dehydration and consequently compromise the prognosis of the patient and reduce quality of life. At least 15% to 20% of patients with chronic obstructive pulmonary disease report some form of oropharyngeal dysphagia. This interrelationship between respiration and swallowing makes patients with COVID-19 and ARDS vulnerable to dysphagia.