Natasha Mirza, Andrew N. Goldberg and Melissa A. Simonian

Approach to Swallowing Dysfunction in the Intensive Care Unit Patient

A swallowing assessment should be made on all ICU patients as they recover from critical illness. Problems with swallowing (dysphagia) place patients at high risk for aspiration (defined as penetration of any material below the vocal cords) when they resume oral feeding and drinking. Dysfunction of the normal swallowing mechanism should be suspected in patients after neurologic events or surgical procedures that might affect function of the pharynx or larynx. The same suspicion should apply to all patients who have undergone tracheotomies, who have had prolonged translaryngeal intubation, or both. Similarly, one should assume that patients with endotracheal tubes in place cannot swallow food safely, and attempts at oral feeding should wait until after extubation or conversion to tracheostomy with spontaneous breathing. Consultation with an otolaryngologist, a speech-language pathologist, or both may be indicated for these ICU patients before restarting oral fluids or feeding.

The Swallowing Mechanism

Deglutition is the act of swallowing in which a food or liquid bolus is transported from the mouth through the pharynx and esophagus into the stomach. The anatomic areas involved in swallowing include the oral cavity, pharynx, larynx, and esophagus. Normal deglutition involves a complex series of voluntary and involuntary neuromuscular contractions proceeding from the mouth to the stomach and is commonly divided into three sequential phases (Table 22.1). During the oral phase, intact labial muscles are necessary to ensure an adequate seal that prevents leakage from the oral cavity. This is followed by contractions of the tongue and striated muscles of mastication. The muscles work in a coordinated fashion to mix the food bolus with saliva and propel it from the anterior oral cavity into the oropharynx, where the involuntary swallowing reflex is triggered. The posterior brain controls output for the motor nuclei of cranial nerves V, VII, and XII, and the entire sequence lasts about 1 second.

The pharyngeal phase begins with triggering of the swallow reflex. This reflex comprises a series of coordinated movements crucial to successful swallowing (Table 22.2). In the posterior oropharynx, a complex and precisely coordinated succession of muscular contractions and relaxations occurs. The soft palate elevates to close the nasopharynx, and the suprahyoid muscles pull the larynx up and forward. The epiglottis moves downward to cover the laryngeal opening while striated pharyngeal muscles contract to move the food bolus past the cricopharyngeus muscle (the physiologic upper esophageal sphincter) and into the proximal esophagus. This swallowing reflex also lasts approximately 1 second and involves the motor and sensory tracts from cranial nerves IX and X.

The esophageal phase begins when the upper esophageal sphincter relaxes. This allows the peristaltic wave (which began in the pharynx with triggering of the swallow reflex) to continue in sequential fashion down the esophagus into the stomach. As food is propelled from the pharynx into the esophagus, involuntary contractions of the skeletal muscles of the upper esophagus force the bolus through the mid and distal esophagus. The medulla controls this involuntary swallowing reflex, although voluntary swallowing may be initiated by the cerebral cortex. The lower esophageal sphincter relaxes at the initiation of the swallow, and this relaxation persists until the food bolus is propelled into the stomach. It may take 8 to 20 seconds for the contractions to drive the bolus into the stomach.

Clinical Assessment for Swallowing Dysfunction

Patients who have dysphagia may present with a variety of complaints, but they usually report coughing or choking with or without eating. The presence of a tracheostomy tube often contributes to aspiration and swallowing dysfunction, and a swallowing assessment is often difficult in these circumstances. A swallowing evaluation starts with a review of the patient’s medical and surgical history, hospital course, and respiratory and nutritional status (Figure 22.1). A cognitive screening and complete oral physical examination should then be performed. Patients who are not alert or who are severely cognitively impaired may not be candidates for undergoing further bedside tests to evaluate the risk of aspiration. Oxygen desaturation and copious secretions are also contraindications to these tests.

Patients with oropharyngeal dysphagia present with difficulty in initiating swallowing and may also have associated coughing, choking, or nasal regurgitation. The patient’s speech quality may have a nasal tone. These dysphagias are most often associated with neurologic conditions like a stroke. Visualizing the structural integrity of the oral cavity, the presence or absence of teeth, and the movement and coordination of the tongue, lips, mandible, and palate as well as the status of the mucosa and hydration of the tissues provides the clinician with information regarding the oral phase of the swallow as well as speech intelligibility. Drooling is a sign of poor oral control. Certain medications, especially psychotropic medications, induce xerostomia and thereby prevent adequate mixing and propulsion of the food bolus into the posterior oropharynx. Patients with esophageal dysphagia present with the sensation of food sticking in their throat or chest. However, the patient’s description of the perceived location of the obstruction often does not correlate well with actual pathology, especially if the perceived location is in the cervical area.

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