Objective: To determine whether high nursing home Aspiration in Nursing Home Residents: A Review
By Teofilo L. Lee-Chiong, Jr., MD, FCCP

Numerous disorders predispose the nursing home resident to aspiration and aspiration pneumonia. In addition to aging itself, many nursing home patients suffer from mental retardation, dementia, and neurologic impairments. Tracheotomized individuals, as well as those receiving enteral tube feedings, are at greater risk for aspiration and its respiratory sequelae. This article focuses on the conditions that predispose nursing home residents to aspiration, the respiratory and psychosocial consequences of aspiration, and the evaluation of dysphagia and aspiration. It concludes with a discussion of the therapy and prevention of chronic and recurrent aspiration. (Annals of Long-Term Care 1998;6[1]:24.)

Aspiration is defined as the displacement of oropharyngeal contents below the true vocal cords and into the larynx. Aspiration and aspiration pneumonia are frequently encountered in nursing home residents. Swallowing abnormalities are present in an estimated 30% to 40% of patients living in nursing homes.1

In the chronic care setting, difficulty with oropharyngeal secretions, aspiration, and the presence of either nasogastric or gastric tubes are significant risk factors for the development of nosocomial pneumonia in the elderly.2 Croghan and associates,2 using videofluoroscopy, detected aspiration in 55% of 40 nursing home patients. Individuals who aspirated during videofluoroscopy had higher rates of rehospitalization and feeding tube placements, and the use of feeding tubes in patients with aspiration problems was associated with a greater incidence of pneumonia and a higher mortality secondary to pneumonia.3

Physiology of Swallowing

Consumption of foods varying in material, temperature, texture, and volume requires the integration of a number of motor, neural, cognitive, and behavioral processes. Normal deglutition or swallowing may be divided into three stages.1 In the initial or oral stage, ingested material is broken down into smaller fragments by chewing, lubricated by salivary secretions, aggregated into a bolus, and transported toward the pharynx.

The second or pharyngeal stage of swallowing begins once the bolus reaches the region of the anterior tonsillar pillars. It involves the cessation of respiration, elevation of the soft palate, contraction of the superior laryngeal constrictor muscle and pharyngeal constrictors, anterior and superior displacement of the larynx, apposition of the vocal cords, relaxation of the cricopharyngeal sphincter, and closure of the laryngeal lumen by the epiglottis. The distal transit of the bolus through the hypopharynx and into the esophagus is thus achieved without laryngeal spillage and nasal regurgitation.

In the final or esophageal stage of swallowing, the bolus is propelled by peristaltic waves through the esophagus. Transient relaxation of the lower esophageal sphincter permits entry of the bolus into the stomach.

Cognitive and behavioral integrity are crucial elements of effective swallowing.4 These psychological aspects of deglutition include:

1. Food recognition. Patients must be able to distinguish food in the meal tray and in their mouth from nonedible objects, such as coins or bottle caps.

2. Emotional and behavioral reaction to food. Unless interest and pleasure accompany feeding, patients will refuse any food that is presented to them.

3. Alertness and stamina. Not only must patients be alert enough to initiate feeding, they must possess the stamina to sustain oral consumption throughout the duration of each meal.

4. Judgment and attentiveness. Judgment is essential in order to curtail potentially dangerous impulses, such as overfilling the mouth with large amounts of food. Patients who are easily distracted may not be able to focus on the meal.

Conditions Predisposing to Aspiration

There are a number of underlying conditions that may enhance the risk of aspiration among nursing home residents (Table I).

Aging

Aging itself may predispose to aspiration.5,6 Elderly individuals commonly display deficiencies in oropharyngeal coordination, reduction in sensory discrimination in the oropharynx, loss of dentition, deficient laryngeal closure, weakening of the muscles of mastication, and diminution in salivary production. In addition, aspiration may occur as a consequence of illnesses common among the elderly, such as dementia, Parkinson's disease, cerebrovascular accidents, and gastroesophageal reflux. Finally, colonization of the mouth and pharynx by pathogens and ineffective cough and gag reflex may render the elderly more prone to the development of pneumonia once aspiration has occurred.2,7

Dementia and Mental Retardation

Many patients with advanced dementia have simply "forgotten" how to swallow.8 Using videofluoroscopic barium swallow, Feinberg and colleagues9 were able to demonstrate major aspiration in 25% and minor aspiration in 50% of institutionalized elderly patients with dementia. A total of 71% of patients displayed oral stage dysfunction, and 43% had impairments related to their pharyngeal stage of swallowing. Nearly half of the residents had multiple-stage swallowing abnormalities.

Adults suffering from mental retardation often have numerous neurologic deficits, behavioral maladaptations, and anatomic deformities that can act in concert to severely limit effective and safe deglutition. Their chewing and cup-drinking skills are commonly impaired, and upright feeding may be impossible because of inadequate body-positioning skills.

Neurologic Disorders

Neurologic impairments affecting the cerebral cortex, extrapyramidal tracts, motor neuron, peripheral nerve, neuromuscular junction, and muscle are frequent causes of dysphagia and aspiration among nursing home residents. Veis and Logemann10 observed aspiration using modified barium swallow in one-third of 38 patients following a stroke. In a study conducted by Homer and associates of 47 stroke patients,11 more than one-half of the subjects aspirated during videofluoroscopic modified barium studies. Individuals with advanced age, depressed consciousness, and severe neurologic damage appear to have the highest risk for aspiration. Other causes of cerebral cortical injury--such as trauma, tumors, seizures, toxins, and metabolic derangements--can lead to depression of consciousness and render the victim at increased risk for aspiration.

Dysphagia is encountered in approximately half of patients afflicted with Parkinson's disease.12 Bird et al13 detected swallowing abnormalities on videofluoroscopy in all 16 asymptomatic patients with Parkinson's disease. Dysphagia in Parkinson's disease may be related to oral phase abnormalities, such as inadequate tongue elevation and diminished tongue mobility. Pharyngeal incoordination with ineffective bolus transit through the distal pharynx is also common.12

Tracheostomy and Tube Feedings

Tracheostomy can disrupt laryngeal elevation and closure.14 Long-term tracheostomy may also give rise to laryngeal desensitization, diminution of gag and cough reflexes, and limitation of laryngeal adduction, which can compound preexisting dysphagia. Occasionally, an overinflated tracheostomy cuff can compress the adjacent esophagus, leading to esophageal obstruction and regurgitation of food remnants.

Bonanno15 described dysphagia and aspiration in 3 of 43 tracheotomized patients. Using the Evans blue dye test, Cameron and associates16 were able to recover dye in the tracheostomy aspirate of 69% of tracheotomized patients following dye instillation on the subject's tongue.

Peck and colleagues17 reported that aged and demented nursing home patients on long-term enteral feeding experienced significantly more episodes of aspiration pneumonia compared with those nursing home patients who were not tube fed. In addition, Cogen and Weinryb18 conducted a retrospective review of gastrostomy tubeúfed nursing home patients and observed a 22.9% incidence of aspiration pneumonia.

Finally, Cogen and colleagues,19 after noting aspiration pneumonia in 15.9% of 44 jejunostomy-fed patients residing in a skilled nursing facility, concluded that jejunostomy feedings do not offer effective protection against aspiration pneumonia in patients who had prior histories of swallowing difficulty and aspiration.

Medication-Induced Dysphagia

Deglutition can be disrupted by a variety of medications. Drug-induced dysphagia may arise secondary to esophageal injury, esophageal dysmotility, infectious esophagitis, or xerostomia20 (Table II). Many nursing home residents are prescribed numerous medications, any one of which may, by itself or in combination with other agents, impair normal swallowing.

Aspiration Syndromes

Three major respiratory sequelae result whenever massive aspiration overwhelms the host airway defenses: airway obstruction, chemical pneumonitis, and infectious pneumonia. Aspiration may also give rise to acute respiratory distress syndrome, bronchitis, interstitial pneumonitis, bronchiectasis, fibrosis, and asthmalike symptoms6,21 (Table III). The pulmonary consequences of aspiration are determined chiefly by the frequency of aspiration as well as the character of the aspirate, including its acidity, chemical composition, volume and presence of bile, feeding formulas, and bacteria. Furthermore, chronic aspiration may foster a host of maladaptive psychological responses, such as dependency, helplessness, social withdrawal, and sitophobia (fear of eating). Severe, intractable aspiration may completely curtail oral intake and lead to undernutrition.

Airway Obstruction

Foreign bodies lodged in the extrathoracic airway can manifest as stridor and aphonia. Wheezing may be encountered if more distal impaction of the intrathoracic airways occurs. Occult aspiration may present simply with unexplained fever, sputum production, hemoptysis, or pleuritic chest pain.

Although a chest radiograph alone is often sufficient to diagnose radiopaque foreign bodies, bronchoscopy may be necessary when aspirated materials are radiolucent. Massive aspiration of fluid or particulate matter can produce respiratory distress with death secondary to asphyxia. Heimlich maneuvers accompanied by forceful coughing should be attempted to dislodge the bolus. Often, transtracheal cannulation, cricothyrotomy, or endotracheal incubation are needed to secure the airways.

Aspirated peanuts, dental fragments, coins, meat particles, or vegetable pieces may produce secondary bacterial infection unless promptly removed with bronchoscopy. Small-volume aspiration of inert liquids rarely demands specific therapy other than oxygenation and fluid management.

Chemical Pneumonitis

One of the initial descriptions of chemical pneumonitis was reported by Mendelson22 in 1949 involving aspiration of gastric acid. Since then, chemical pneumonitis has been observed following aspiration of bile, exogenous acids, mineral oils, alcohols, and hydrocarbons.23

Early symptoms consist of severe dyspnea, wheezing, and cough. Profound hypoxemia, pulmonary congestion, cyanosis, and shock suggest widespread chemical injury. Sputum may become hemorrhagic and purulent. A change in the color or volume of sputum, worsening cough, or increasing congestion can herald the emergence of secondary bacterial pneumonia, a complication for up to 25% of patients suffering from acid aspiration.24 The risk of superimposed infections can be greatly reduced by prompt retrieval of aspirated material via bronchoscopy or suctioning. Prophylactic antibiotics and corticosteroids have not proven beneficial in mitigating the damage from chemical aspiration.

As with airway obstruction, oxygenation as well as fluid and electrolyte balance should be optimized. Large-volume aspiration involving two or more lobes, early apnea or shock, marked acidity of the aspirate, and superimposed infection confer a worse prognosis.24,25

Bacterial Pneumonia

Pleuropulmonary infections (pneumonitis, necrotizing pneumonia, lung abscess, bronchiectasis, and empyema) constitute the third major pulmonary sequelae of aspiration. Pathogens may either contaminate oropharyngeal secretions or gastric contents as they pass through the pharynx during swallowing or superinfect previously damaged lung parenchyma in the aftermath of airway obstruction or chemical pneumonitis.

The type of invading pathogen depends primarily on the prevailing oropharyngeal flora. Oral secretions normally contain 107 to 108 anaerobes per ml.26 Concentrations of anaerobic bacteria can reach 1012per g in the gingival crevices.27 Bacterial density is markedly increased in the presence of gingivitis, periodontal diseases, and nasogastric intubation.21,28 Thus, community-acquired aspiration pneumonia commonly involves anaerobes including Bacteroides splanchnicus, Prophyromonas splanchnicus, Fusobacterium splanchnicus, Prevotella, and Peptostreptococcus, and aerobes such as Streptococcus viridans.28On the other hand, the predominant organisms in nosocomial aspiration pneumonia are Staphylococcus aureus; gram-negative organisms such as Klebsielia, Enterobacter, Escherichia coli, Proteus, Pseudomonas, and Serratia; and anaerobes.29 Oral neocolonization by these highly pathogenic strains is enhanced by alcoholism, achlorhydria, chronic malnutrition, immunosuppression, lengthy hospitalization, generalized debility, chronic illness, use of broad-spectrum antibiotic agents, and administration of antacids or H2 blockers.6,21,28

Bacterial pneumonia can develop acutely with fever, rigors, and sputum production or may progress insidiously and present merely with malaise, weight loss, and low-grade fever. Foul-smelling sputum and hemoptysis suggest the presence of anaerobic bacteria. Parenchymal infection, if unchecked, can be transformed into necrotizing pneumonia, lung abscess, or empyema.

Anaerobic lung infections are best treated with penicillin, clindamycin, or metronidazole in combination with penicillin.27 Antibiotic regimens for aerobic organisms with proven efficacy for nosocomial aspiration pneumonia include penicillinase-resistant penicillins or cephalosporins for Staphylococcus aureus, vancomycin for methicillin-resistant Staphylococcus aureus, and ceftazidime for gram-negative bacteria.30 Combinations of a betalactam and a beta-lactamase inhibitor, imipenem, chloramphenicol, cefoxitin, and ceftizoxime are also useful for individuals with mixed aerobicúanaerobic nosocomial pneumonia.27 Antimicrobial therapy should preferably be initiated using parenteral agents that may subsequently be replaced by oral medications once clinical or radiographic improvement is noted. Approximately 10% of persons with lung abscess fail to respond to medical management and require surgical drainage.31

Prognosis of anaerobic lung infections treated early is generally favorable. In contrast, nosocomial pneumonia with mixed bacterial flora, advanced age, neutropenia, underlying malignancy, prior antibiotic use, and tobacco and alcohol abuse is associated with worse outcomes.32

Diagnosis

Investigation of patients presenting with aspiration should include an evaluation of dysphagia as well as its potential sequela, aspiration.

Evaluation of Dysphagia

The duration, progression, and periodicity of dysphagia should be determined for each patient. Inquiries into the presence of choking during meals, excessive drooling, hoarseness, nasal regurgitation, throat discomfort, or heartburn must be made. Physical examination should focus on lip and tongue mobility, voice quality, forcefulness of coughing and throat clearing, and the presence of the gag reflex.

Observing patients during their meals may uncover specific food types responsible for dysphagia. Their oral cavity must be examined postprandially, searching for retention of food particles.

Radiologic investigation of dysphagia should be tailored to meet individual needs. Static films of the pharynx and esophagus may be obtained if tumors or other structural lesions are suspected. Dynamic examination of swallowing using videofluoroscopic modified barium swallow is currently the accepted standard for evaluating dysphagia.1 With this technique, the complex motions of the tongue, soft palate, epiglottis, pharynx, and larynx can be filmed and analyzed frame by frame.

Evaluation of Aspiration

The possibility of aspiration and aspiration pneumonia should be entertained in any individual presenting with a prior history of aspiration, known predisposition to aspiration, pneumonia involving dependent bronchopulmonary segments (especially if associated with cavitation), abscess formation and putrid-smelling sputum, unexplained hoarseness, and nocturnal respiratory symptoms.

Demonstration in specimens recovered by bronchoscopy or endotracheal suction of amylase, glucose, lipid-laden macrophages, gastric material, bile, feeding formulas, or methylene-blue-stained squamous epithelial cells following dye ingestion confirms the presence of aspiration. It can also be diagnosed by measuring intrapulmonary uptake on radionuclide scanning after a 99mTc sulfurcolloid meal.21

Guided by gravity, aspirated material tends to localize in dependent areas of the lung.26,28 Thus, chest films may demonstrate infiltrates in the superior segments of the lower lobes or posterior segments of the upper lobes if aspiration occurred during recumbency. In an upright individual, the dependent segments are the basal portions of the lower lobes.

Therapy

Disorders that may predispose patients to dysphagia and aspiration should be identified and treated. Optimal medical management of Parkinson's disease, myasthenia gravis, and Guillain-Barré syndrome can significantly minimize dysphagia. Medications and foods known to decrease lower esophageal sphincter pressure, thereby promoting gastroesophageal reflux, should be avoided. Severe cases of gastroesophageal reflux may improve with pharmacologic intervention using antacids, H2 blockers, sucralfate, omeprazole, metoclopramide, betanechol, or cisapride.33

Route of nutrition, diet volume, and food consistency may need to be modified depending on the frequency and severity of aspiration. Nutrition can be provided by oral, enteric tube, or parenteral feeding, either alone, in combination, or sequentially. The patient's nutritional status, cognitive and behavioral skills, state of consciousness, mobility, immunocompetence, and the preferences of the patient and his or her family must be considered in selecting among the various routes of nutrition.

Diet selection must likewise be individualized. Foods with strong flavors may facilitate swallowing. Solids and semisolids are often easier to swallow than liquids and food items that readily break apart. Videofluoroscopy can aid immensely in the initial selection of optimal food consistency. Thereafter, diet can be altered based on the patient's weight, anthropometric data, and blood chemistry profiles.

Patients should be closely supervised during meals. Individuals with deficits in the oral stage of swallowing may benefit from oral prosthesis such as obturators and guide bars, which redirect food fragments to more functional areas of the mouth that are involved with deglutition. In addition, they may be provided with feeding utensils that allow better food reception into the mouth, such as specially contoured spoons, forks, and cups.

Swallowing skills can usually be improved with rehabilitation. Speech therapy focusing on acquisition of new chewing, cup-drinking, and body-positioning patterns may be invaluable in patients with disabling dysphagia. It is imperative that the patient's partner and family members be taught the Heimlich maneuver as well as the use of suction devices. Removal of any oral residue after meals, either manually or by suctioning, cannot be overemphasized.

Patients who continue to aspirate despite extensive speech therapy may require alternative routes of nutrition. If nasoenteric feedings become necessary, small bore tubes should be chosen, because large-caliber catheters can impede the closure of the lower esophageal sphincter.23 Gastric volumes must be monitored to avoid overdistention of the stomach.

Finally, surgical interventions may be necessary if aspiration persists despite optimal medical measures.34,35 Surgical management of dysphagia includes vocal cord augmentation for unilateral vocal cord weakness, anti-aspiration stents for immediate and short-term stabilization of patients with reversible causes of aspiration, laryngotracheal diversion and separation techniques for patients with chronic aspiration problems with potential for recovery, and laryngectomy for individuals suffering from permanent and life-threatening aspiration.

Conclusion

Aspiration and aspiration pneumonia are common problems in the long-term care setting. Elderly residents and patients suffering from dementia, mental retardation, or neurologic impairments are at greater risk for aspiration. Chronic aspiration, in turn, may lead to a number of respiratory and psychosocial sequelae, such as airway obstruction, chemical pneumonitis, infectious pneumonia, sitophobia, social withdrawal, dependency, and malnutrition. When treating patients with chronic aspiration difficulties, the physician must address the individual's nutritional status, cognitive skills, behavior patterns, immunocompetence, and his or her preferences. Numerous therapeutic options are available to the clinician caring for patients with recurrent aspiration. In addition to diet selection, swallowing rehabilitation may benefit persons with disabling dysphagia. Enteral feedings and surgery may be necessary in patients who continue to aspirate despite optimal medical management.

The medical director is responsible for the timely identification, prevention, and treatment of aspiration pneumonia among nursing home residents. It is essential that the medical director promote awareness of this common and potentially disabling condition among members of the medical and nursing staff. He or she should monitor patients for any respiratory or psychological sequelae. Aided by the nursing and dietary staff and speech therapists, the medical director should conduct a search for remediable causes of dysphagia and aspiration and should implement a program of speech rehabilitation, designed both to minimize maladaptive feeding behavior and to foster safer means of deglutition.

Acknowledgment

The author wishes to thank Grace Zamudio, Donna Croteau, and Karen Berube for their assistance in preparing this article.

About the Author

Dr. Lee-Chiong is the Medical Director of Coos County Nursing Home in Berlin, New Hampshire. Address for correspondence: Teofilo L. Lee-Chiong, Jr., MD, FCCP, Medical Director, Coos County Nursing Home, 364 Cates Hill Road, Berlin, NH 03570-0416.

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Annals of Long-Term Care - ISSN: 1524-7929 - Volume 6 - Issue 01 - January 1998