Oral Health and Aspiration Pneumonia
According to Logemann, "swallowing refers to the entire act of deglutition from placement of food in the mouth through the oral, pharyngeal, and esophageal stages until the material enters the stomach through the gastroesophageal junction."1 Dysphagia is defined as "difficulty moving food from the mouth to the stomach."1 Dysphagia can result in serious consequences including malnutrition, dehydration, aspiration pneumonia, and death. Approximately 1 in 25 adults will present with dysphagia each year.2
The risk of developing dysphagia-related complications such as pulmonary aspiration is increased in the geriatric population.3-6 The Agency for Health Care Policy and Research (now the Agency for Healthcare Research and Quality) has reported that approximately one-third of patients presenting with dysphagia will develop aspiration pneumonia, and approximately 60,000 individuals will die from such complications each year.7
Pneumonia is caused by an inflammation of the air sacs (alveoli) of the lungs. In older adults, most pneumonia cases are caused by aspiration, termed aspiration pneumonia, which is a function-base category of pneumonia.8 Aspiration is defined as the misdirection of oropharyngeal or gastric contents into the trachea below the level of the vocal folds. Aspiration can lead to pneumonitis, abscesses, obstruction, and pneumonia.9 Aspiration pneumonia occurs when foreign material originating from the oral cavity (consisting of food debris, saliva, biofilm, or a combination of these) enters the bronchial tree and lung alveoli.10
Aspiration pneumonia is common among older adults due to poor oral hygiene, medication side effects, and medical comorbidities leading to increased risk of dysphagia. Aspiration pneumonia causes high mortality in nursing homes, where it is the second most common infection, with a prevalence between 30% and 69.6%.11-16 It's also been reported that 30% of older patients with dysphagia develop aspiration pneumonia.17
The physiology of swallowing naturally changes with increasing age. For instance, as the elasticity of connective tissues and muscle mass begin to diminish, a reduction of strength and range of motion results in deficits in the efficiency and effectiveness of the biomechanics of swallowing.18 As age advances, the speed and ease of swallowing decreases as more time is required for oral preparation of food into a bolus, which leads to decreased timeliness of swallow function.19
These anatomical and physiological changes may accumulate over time, resulting in an increase of postswallow residue during eating as well as penetration of swallowed material within the upper airway. Furthermore, advancing age contributes to a decrease in taste, smell, and oral moisture, which can further affect swallow physiology.18 The combination of these changes in the biomechanics of swallow function makes dysphagia a key contributor to pneumonia and malnutrition in the geriatric community.
In a study conducted by Chen and colleagues, 15% of individuals who were 65 years or older and residing in an independent living facility conveyed difficulties swallowing. Of those, a majority suffered significant quality of life impairments in one or more area of the MD Anderson Dysphagia Inventory. Approximately 23% of the participants believed dysphagia to be subsequent to natural aging, and approximately 37% disagreed. Results indicated that the prevalence of dysphagia is considerably high in the population of the geriatric community. Given these findings, it's imperative for the geriatric community to be appropriately educated about dysphagia in the community.20
In a 2017 study, Huang, Chiou, and Liu found that approximately 50% of individuals residing in nursing homes experience some degree of dysphagia. They reported that the residents who present with dysphagia typically have secondary complications associated with loss of mobility and/or sensation and weakness or paralysis on a specific side of their limbs and/or mouths. These deficits can make it difficult for them to know whether they've pocketed food in the mouth and not swallowed. They also diminish the residents' ability to participate independently in daily living activities such as brushing their teeth. Lack of appropriate oral care by an older adult or a caregiver can lead to a buildup of bacteria within the oropharyngeal cavity, which may further increase the risk of aspiration pneumonia.21
Oral Care and Aspiration Pneumonia
Koichiro reported that the oral cavities of patients who develop aspiration pneumonia have similar characteristic mucous membranes, soft tissue, teeth, and oral function including the following23:
• Residue in oral mucous epithelium and oral dryness: Due to suppressed oral function, the secretion of mucosal resting saliva increases and mixes with the residue in the oral epithelium to form a sticky paste that adheres to the oral cavity. Impaired self-cleaning function of the oral cavity leads to reduced regeneration of the oral mucous membrane, resulting in mucus remaining on the palate and lingual coating. This bacterial flora coating the palate or lingual surface contains bacteria not typically present in the healthy mouth that raises the risk of aspiration pneumonia. The main microorganism causing aspiration pneumonia is thought to be gram-negative anaerobic bacteria that live in secreta (phlegm), epithelial residue, crusts, and saliva.
• Morphological damage to oral hard tissue (teeth): Inadequate oral care can result in multiple and simultaneous cases of dental caries and potential rotting of the tooth crown. Food residue tends to attach to decayed teeth, creating a bacterial plaque and contributing to the development of bacterial flora that cannot be removed easily. Significant halitosis is a sign that decaying matter is present in the oral cavity, and the presence of such matter leads to a grave risk of aspiration pneumonia.
• Impaired oral function: Impairments in the oral phase of swallowing may be secondary to poor mastication, which prevents the formation of a bolus, and food adheres to the surface of the teeth in its original shape; lack of awareness/sensation of food in the oral cavity; and inadequate clearance of the bolus from the oral cavity, leading to oral residue. These types of functional impairments of the oral phase can cause poor oral hygiene and, consequently, increase the risk of aspiration.
Oral care management decreases the incidence of aspiration pneumonia in the elderly population. To adequately reduce the risk of aspiration pneumonia, a patient must receive sufficient oral care, including proper cleaning. At minimum, oral care should include mechanical cleaning of the lingual surface and palate to successfully remove pathogenic bacteria. The oral cavity responds promptly to proper care, becoming moist and healthy in color, and the improved oral cavity can influence the whole body.23
Koichiro outlined aspects of oral care management, which include retaining moisture in the oral cavity and cleaning the lingual surfaces and palate.23 Retaining moisture in the oral cavity is essential to oral health and function. Moisturizing agents such as gels, creams, and liquids have been suggested. Gauze, cotton, sponge brushes, or special brushes specifically designed for mucous membranes should be used to meticulously and reliably enhance the effects of moisture retention and cleaning. The lingual surface and palate frequently accumulate microorganisms. Mechanically cleaning them can help reduce the risk of aspiration pneumonia.
A delay in initiation of the pharyngeal swallow can lead to preswallow spillage of material into the hypopharynx and the trachea before or at the onset of the pharyngeal swallow. A weak swallow frequently leads to excess residue and incomplete clearance of the bolus. This residue can remain in the hypopharynx after the swallow and may enter the airway when breathing resumes. These physiologic changes are most significant with a food bolus, suggesting that aspiration of food material is more harmful than aspiration of liquid material and more likely to result in aspiration pneumonia. Aspiration of secretions and excess oral secretions are both significantly associated with aspiration pneumonia.22
Older patients are prone to poor oral health due to increased presence of periodontal and dental disease as well as lack of adequate oral care. As dental health diminishes, there's an increase in the bacterial load in the oral cavity, and aspiration of bacteria-laden oropharyngeal material into the lungs further increases the risk of developing aspiration pneumonia. Additionally, patients who are more debilitated with multiple underlying diseases, use of multiple medications, and poor functional status are at a higher risk of aspiration pneumonia.
Variables such as being dependent for feeding and oral care are also significantly related to development of aspiration pneumonia.23 Aspiration of oropharyngeal secretions, specifically saliva, may explain the origin of anaerobic bacteria that can be cultured from aspiration pneumonia.22,23
While dysphagia is a risk factor for the development of aspiration pneumonia, dysphagia alone is not sufficient to cause pneumonia. This suggests that dysphagia and aspiration may not be critical risk factors in a person who is medically stable; has a clean, healthy oral cavity; and/or is independent for activities of daily living, especially feeding. If these conditions are not present, aspiration pneumonia may develop.
The role of dysphagia and aspiration in the development of aspiration pneumonia can be better understood by considering the interaction between bacterial colonization and patient resistance to the process. Thus, it's suggested that the development of aspiration pneumonia occurs when aspiration of pathogenic material into the lung occurs and patient resistance to infection is compromised.22
Oral care is a key intervention for reducing the risk of infection, adverse health outcomes, and fatality associated with aspiration pneumonia. Oral care interventions have been shown to decrease the incidence of pneumonia in the elderly population and improve quality of life.26-28 Although professional oral care may not be possible, an oral care routine should be established and enforced for all elderly patients.
Adherence to a prescribed oral care protocol has been shown to be a simple, cost-effective method that significantly improves oral health scores within one week for patients with oropharyngeal dysphagia. Incorporating a validated oral health assessment into the oropharyngeal dysphagia screening process may increase the efficacy of identifying patients at risk of developing aspiration pneumonia. Additionally, including an oral health assessment in the speech-language pathologist's clinical assessment of oropharyngeal dysphagia should be considered. Appropriate referrals for dental treatment and incorporation of an oral care regimen should be included into each patient's rehabilitation plan.29
— Jennifer M. Pusins, CScD, CCC-SLP, BCS-S, IBCLC, is an assistant professor and clinical supervisor at Nova Southeastern University. She's a board-certified specialist in swallowing and swallowing disorders, and her area of clinical expertise is in the assessment and management of dysphagia across the life span. She's presented at the state, national, and international levels on various topics related to dysphagia.
— Carly Ferguson, BS, is a graduate student at Nova Southeastern University in the Master of Science in Speech-Language Pathology program. She has a specific interest in dysphagia and has worked with patients with dysphagia during her clinical practicums.
— Ashley V. Persaud, BA, SLP-A, is a speech-language pathologist assistant in the Miami-Dade County school district and a student in the Master of Science in Speech-Language Pathology program at Nova Southeastern University. She received her BA in liberal studies and triple minored in psychology, sociology, and business administration at the University of Houston. She received her graduate certificate in communication sciences and disorders from Florida International University.
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