Aspiration Pneumonia in Older Adults
Aspiration pneumonia refers to an infection of the lung parenchyma in an individual that has inhaled a bolus of endogenous flora that overwhelms the natural defenses of the respiratory system. While there are not universally agreed upon criteria, the diagnosis can be made in patients with the appropriate risk factors and clinical scenario, in addition to a radiographic or an ultrasonographic image of pneumonia in the typical dependent lung segment. Treatment options for aspiration pneumonia vary based on the site of acquisition (community-acquired aspiration pneumonia [CAAP] versus healthcare-associated aspiration pneumonia [HCAAP]), the risk for multidrug-resistant (MDR) organisms, and severity of illness. Hospitalized CAAP patients without severe illness and with no risk for MDR organisms or Pseudomonas aeruginosa (PA) can be treated with standard inpatient community-acquired pneumonia therapy covering anaerobes. Patients with CAAP and either of the following—risk factors for MDR pathogens, septic shock, need for an intensive care unit (ICU) admission, or mechanical ventilation—can be considered for broader coverage against anaerobes, methicillin-resistant Staphylococcus aureus (MRSA), and PA. Severe aspiration pneumonia that originates in a long-term care facility or HCAAP with one or more risk factors for MDR organisms should be considered for similar treatment. HCAAP with one or more risk factors for MDR organisms or PA, plus septic shock, need for ICU admission or mechanical ventilation should receive double coverage for PA in addition to coverage for MRSA and anaerobes. Multiple gaps in current understanding and management of aspiration pneumonia require future research, with a particular focus on antibiotic stewardship.
© 2019 Society of Hospital Medicine
Prevention
Although the healthcare system has practices in place to prevent aspiration pneumonia, the evidence supporting them are either inconclusive or not of ideal methodological design. Two systematic reviews failed to show statistically significant decreases in rates of aspiration pneumonia or mortality using the standard of care positioning strategies or thickened fluids in patients with chronic dysphagia.37,38 One study showed a decreased incidence of all pneumonia in dysphasic patients with dementia or Parkinson disease when a chin-down posture (with thin liquids) or thickened fluids in a head-neutral position was used. The study, however, has significant limitations, including a lack of a “no treatment” group for comparison, which did not allow investigators to conclude that the decreased incidence was from their interventions.39
There are preventive strategies that show a decreased risk of aspiration pneumonia. Poor oral hygiene seems to be a modifiable risk factor to establish better control of oral flora and decrease aspiration pneumonia. A systematic review of five studies, evaluating the effects of oral healthcare on the incidence of aspiration pneumonia in frail older people, found that tooth brushing after each meal along with cleaning dentures once a day and professional oral healthcare once a week decreases febrile days, pneumonia, and dying from pneumonia.40A two-year historical cohort study using aromatherapy with black pepper oil, followed by application of capsaicin troches, and finally menthol gel, as the first meal, leads to a decreased incidence of pneumonia and febrile days in older adults with dysphagia.41 Well-designed validation studies may establish these practices as the new standard of care for preventing pneumonia in patients with dysphagia.
Feeding Tubes
Multiple studies show that in older adults with advanced dementia there is no survival benefit from percutaneous endoscopic gastrostomy (PEG) tube placement42-44 and more recent systematic reviews also conclude that there is currently no evidence to support the use of PEG tubes in this specific population.45,46 In February 2013, as part of the American Board of Internal Medicine Foundation Choosing Wisely® campaign, the American Geriatrics Society advised providers not to recommend percutaneous feeding tubes in patients with advanced dementia, rather, “offer assisted oral feeding.”47 It is worth noting, however, that none of the studies reviewed were of ideal methodological design, so opinions may change with future studies.
A more recent study compared liquid feeds versus semisolid feeds in patients with PEG tubes. The study shows a 22.2% incidence of aspiration pneumonia in the liquid feed group, which is comparable to prior studies, but the incidence of aspiration pneumonia is only 2.2% in the semisolid feed group (P < .005).48 A benefit of this size warrants future studies for validation.
CONCLUSION
Aspiration pneumonia leads to increased mortality when compared with CAP and HCAP.2 Until future studies validate or refute the current understanding surrounding its management, the following should provide some guidance: aspiration pneumonia should be suspected in any individual with risk factors of aspiration who presents with typical or atypical symptoms of pneumonia. Confirmation of the diagnosis requires an image representative of pneumonia in the typical dependent lung segment on chest X-ray, lung ultrasound, or noncontrast CT scan of the chest. Treatment of aspiration pneumonia should take into account the site of acquisition, severity of illness, and risk for MDR organisms as the causative organisms may include Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and gram-negative rods, in addition to the traditional organisms classically thought to cause aspiration pneumonia-anaerobes.
