Swallowing Disorders

Neuromuscular disorder or mechanical obstruction can cause difficulty in swallowing (dysphagia).

Dysphagia can be classified into distinct types: Oropharyngeal dysphagia due to malfunction of the tongue, pharynx, larynx and/or upper esophageal sphincter and esophageal dysphagia due to malfunction of the esophagus.

Dysphagia is often a symptom of a systemic disease (impaired consciousness, sarcopenia, dyspnea).

Effects of dysphagia can go undetected until more serious medical complications—such as respiratory disorders, sepsis, and/or profound weakness and cachexia—are identified.

According to AHRQ, approximately 300,000–600,000 people each year are affected by dysphagia and around 51,000 of these cases stem from neurologic disorders other than stroke.

Aspiration pneumonia is one of the leading causes of death among the elderly.

Not all pts with swallowing disorders will develop an aspiration pneumonia but the majority are at risk for dehydration and malnourishment.

Subclinical dysphagia often becomes symptomatic periop with increased volume of airway secretions; effects of sedatives, opioids, and neuromuscular blocking agents; and inflammation.

Increased risk of aspiration when consciousness is impaired (decreased sensorium, impaired breathing-swallowing coordination).

Impaired breathing-swallowing interplay in pts with dyspnea and impaired mental status.

Full stomach/impaired gastric emptying.

Mask ventilation: Gastric inflation may increase the risk of life-threatening regurgitation and pulm aspiration.

Underlying malnourishment/frailty/sarcopenia: Poor periop outcome.

Risk of extubation failure: Deconditioned pt (weakness, anemia, renal failure).

Aspiration in pts with severe muscle weakness.

Dysphagia is defined as any difficulty that can affect the swallowing mechanism or safe transference of food, liquid, and secretions anywhere through and along the digestive tract.

Only 40– 60% of institutionalized elderly have overt signs and symptoms of oropharyngeal dysphagia.

About 50% of hospitalized pts with recurrent respiratory failure leading to reintubation have swallowing disorders and silent aspiration.

Oropharyngeal dysphagia in the hospitalized elderly is an indicator of poor prognosis for pts with pneumonia; however, this is dependent on their functional capacity prehospitalization and any functional decline that occurs during hospitalization.

Pts with overt signs or symptoms of aspiration often have poor functional status, a higher prevalence of neurologic comorbidities, and greater exposure to paralytics or sedative drugs that might affect level of consciousness, swallow efficiency, and coordination.

Adequate screening methods to identify pts at risk for aspiration help to prevent adverse outcomes (aspiration, inadequate hydration, poor nutrition).

Muscle weakness is an independent predictor of aspiration in critically ill pts.

Complete evaluation of swallowing disorders to diagnose and treat dysphagia and determine aspiration risk requires a multidisciplinary team and is not limited to bedside clinical evaluation. It might include a combination of instrumental tests such as FEES, VSS, and/or BaS.

Hospitals that implement a swallowing screening do have a lower rate of aspiration pneumonia, reduced rate of readmission, decreased length of stay, increased staff and patient satisfaction, and reduced admission cost.

An aspiration risk screening tool can be used in pts who are considered to be at risk for swallowing disorders.

Evaluation:

• Clinical bedside evaluation: Aims to determine risk and presence and severity of swallowing disorder and aspiration risk. It includes reviewing history and identifying risk factors for swallowing disorders, observing pt’s level of arousal and alertness, oral sensory motor evaluation, observation for any signs or motor speech or voice abnormalities, observation of food and liquid administration, and saliva management.

• FEES: Allows structural laryngeal evaluation and functional evaluation of swallowing efficiency and safety. Assessment of aspiration before, during, and after swallowing. During the moment of swallow is the view is obliterated, so microaspiration might go undetected.

• Video swallowing study: Considered the gold standard. Allows functional evaluation of swallowing efficiency and safety from oral cavity to stomach. Uses barium in different consistencies. Not only detects prandial aspiration but also determines the cause, and all efforts are made to eliminate aspiration and improve efficiency of swallowing during examination. Requires hemodynamic stability and travel off the floor and involves radiation exposure.

• BaS: Evaluates esophageal function and clearance. Might detect aspiration but does not eliminate and or seek to understand causes of aspiration aside from esophageal retroflow or reflux. Larger volumes of barium are ingested, and pts may be prone during procedure if they are unable to stand up. Pts at risk for prandial aspiration are not considered safe to participate on a BaS.

• Swallow screening: Pass/fail procedure to determine overt risk of aspiration, safety to feed, and likelihood of need for further swallow assessment. There are many tools available but few have been validated. The Massachusetts General Hospital Swallow Screening test is a two-step exam:

  • Part 1: The pt is essentially assessed for readiness. The screener looks at wakefulness, breathing, posture, and cleanliness of the mouth. If any of these items are missing, the patient fails, is kept NPO, and rescreening is performed as appropriate.

  • Part 2: This includes the five elements most sensitive to determining risk of aspiration. Four of the elements have a 1-point value (tongue movement, volitional cough, vocal quality, and pharyngeal sensation). Note that pharyngeal sensation must be intact on both sides to receive a score of 1. The ability to swallow water without a cough, throat clear, wet or congested quality of voice, or shortness of breath is assigned 2 points because this is the best indicator of aspiration risk.

  • A score of 5 or 6 is needed to pass. A score of 4 or less results in a fail. If at any time during the screening there is concern for aspiration, the pt fails based on clinical judgment.

  • This screening instrument requires appropriate training to assure valid and reliable assessment. It was created to detect aspiration and has been validated on neurologic population. For more information and training, go to https://www2.massgeneral.org/stopstroke/swallowScreen .

  • Pts with known history of dysphagia or medical diagnosis that frequently causes swallowing disorders (stroke, head and neck cancer, neuromuscular disorder) who have signs or symptoms of dysphagia (coughing/choking) or aspiration (recurrent pneumonias, recurrent fever of unknown cause) should be referred to a bedside clinical swallow evaluation to determine need of further instrumental evaluation.

Leading causes of dysphagia include stroke, neurodegenerative diseases, brain tumors, and traumatic head or cervical spine injuries.

Other common mechanisms of dysphagia include local cancer of head, neck, and esophagus; respiratory diseases (acute hypoxia and/or hypercarbia); congenital structural defects (cleft palate, tracheoesophageal fistula, laryngeal cleft, esophageal atresia); frailty; sarcopenia; and poor nutritional status.

Airway devices: Large tracheal cannulas and nasogastric tubes, cervical collars.