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Initial therapy for acute aspiration depends on prompt recognition that aspiration has occurred and involves treatment of acute hypoxemia and bronchospasm. Nasogastric tube feeding should be discontinued. The upper airway should be suctioned if tube feeding, foreign material, or secretions are still present in the oropharynx. Suctioning should be properly performed to avoid inducing gagging and emesis. Supplemental oxygen by mask or nasal cannula should be administered while initial assessment is being performed. Use of an air entrainment mask (commonly called a Venturi mask) is recommended to ensure a consistent, high inspired-oxygen concentration. Intubation and positive pressure mechanical ventilatory support may be required in severe cases. Lung injury after aspiration is immediate, and the role of bronchoscopy is limited to removal of large particulate matter or a foreign body when present.
Many episodes of nosocomial aspiration represent chemical pneumonitis and do not require antibiotic therapy. Prophylactic treatment with antibiotics does not prevent subsequent infectious pneumonia, may select for resistant organisms, and is not recommended. However, because many patients who aspirate are debilitated or immunocompromised and are at increased risk for infectious pneumonia, physicians often choose to begin treatment with broad-spectrum antibiotics in this setting.
Most patients with aspiration pneumonia are treated empirically, at least initially. Recommendations for antibiotic regimens are based mainly on patient risk factors, coverage of likely pathogens, the setting in which the aspiration event occurred (community versus hospital or long-term care facility), and expert opinion. Few controlled clinical trials comparing treatment regimens for aspiration pneumonia have been performed. No current evidence for the use of a particular agent or regimen is strong enough to supercede a rational approach based on the physician's knowledge of the patient's medical history, local pathogens, and antimicrobial resistance patterns. Adjunctive corticosteroids have no proven value in the treatment of aspiration pneumonia and may be deleterious.
Recommended antibiotic regimens for community-acquired aspiration pneumonia include clindamycin (Cleocin), beta-lactam and beta-lactamase inhibitor combinations such as ampicillin sodium and sulbactam sodium (Unasyn), or penicillin plus metronidazole (Flagyl). Despite good in vitro activity against most anaerobes, monotherapy with metronidazole has been associated with a high clinical failure rate and should not be used to treat aspiration pneumonia. The newer fluoroquinolones (eg, levofloxacin [Levaquin], gatifloxacin [Tequin], moxifloxacin hydrochloride [Avelox]) have reasonable anaerobic activity and achieve high concentrations in lung tissue and endobronchial secretions. Trimethoprim-sulfamethoxazole (Bactrim, Cotrim, Septra), aztreonam (Azactam), and aminoglycosides have little or no activity against anaerobes.
Antimicrobial coverage for gram-negative enteric bacilli and staphylococci must be considered in nosocomial aspiration pneumonia. The risk of aggressive pathogens, such as Pseudomonas aeruginosa and Acinetobacter species, is highest in patients in intensive care units and those in whom pneumonia develops after hospitalization for 5 or more days. Patients with coma, head trauma, diabetes mellitus, or end-stage renal disease and those known to be colonized by S aureus are at high risk for staphylococcal pneumonia.
Patients with hospital-acquired aspiration pneumonia may be treated with cefepime hydrochloride (Maxipime) or ceftazidime plus clindamycin or metronidazole; a beta-lactam and beta-lactamase inhibitor combination such as ampicillin and sulbactam, piperacillin sodium and tazobactam sodium (Zosyn), or ticarcillin and clavulanate potassium (Timentin); or a newer fluoroquinolone. For patients who are allergic to penicillin, a newer fluoroquinolone or a combination of clindamycin plus aztreonam may be considered. Antistaphylococcal coverage should be added for patients known to have nasopharyngeal colonization with staphylococci and patients with other active staphylococcal infections. Review of a sputum Gram stain, if available, for the presence of gram-positive cocci in clusters is helpful. Vancomycin (Vancocin, Vancoled) should be used initially for antistaphylococcal coverage in hospitals where methicillin-resistant S aureus is a concern. The American Thoracic Society guidelines on treatment of hospital-acquired pneumonia in adults provide useful guidance for physicians in selecting appropriate initial antibiotic regimens.
When the decision is made to treat with antibiotics from the outset, the patient's clinical course should be monitored. Prompt clinical response over the next 1 to 2 days, including rapid clearing of pulmonary infiltrates, suggests chemical pneumonitis rather than bacterial pneumonia, and antibiotic therapy should be stopped. Culture results available after 2 to 3 days should be reviewed and used to narrow antimicrobial coverage.
In one study, resolution of fever in patients treated for aspiration pneumonia was comparable to that in patients with pneumococcal pneumonia. Defervescence occurred in one half of the patients with aspiration pneumonia within 2 days of initiation of antibiotic therapy, and 80% became afebrile within 5 days. Prolonged fever is more common in patients with lung abscess or with infections due to aggressive pathogens, such as P aeruginosa.
No controlled studies have addressed the duration of antibiotic therapy for aspiration pneumonia. Treatment for 7 to 10 days appears reasonable for patients who respond promptly. Therapy should be extended for a minimum of 14 to 21 days if highly resistant pathogens, such as P aeruginosa or Acinetobacter species, are isolated. Patients with cavitary pneumonia or lung abscess require long-term treatment for 4 to 8 weeks or more.
Complications of aspiration pneumonia include lung abscess, empyema, and bronchopleural fistula. Most lung abscesses respond to prolonged antibiotic treatment. Adequate pleural drainage is essential in all patients with empyema.
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