Aspiration

• Aspiration

  • The inhalation of foreign material into the respiratory tract

  • Most commonly occurs after instrumentation of the upper airways or esophagus (e.g., upper GI endoscopy) or secondary to vomiting and regurgitation of gastric contents

• Aspiration pneumonia: a type of pneumonia that occurs as a result of oropharyngeal secretions and/or gastric contents aspiration

• Aspiration pneumonitis

  • Aspiration of gastric acid that initially causes tracheobronchitis, with rapid progression to chemical pneumonitis

  • May cause ARDS in extreme cases

• Gram-positive and gram-negative aerobic bacteria predominate in community-acquired infections (e.g., S. pneumonia, S. aureus, H. influenza, Enterobacteriaceae).

• Gram-negative bacilli predominate in hospital-acquired infections (e.g., P. aeruginosa, Klebsiella spp.).

• Mixed infections with anaerobic organisms may occur (e.g., Fusobacterium, Peptostreptococcus, Bacteroides).

(predispose individuals to reduced epiglottic gag reflex and dysphagia)

• Altered consciousness: alcohol, sedation, general anesthesia, stroke

• Apoplexy and neurodegenerative conditions

• Gastroesophageal reflux disease, esophageal motility disorders

• Congenital defects (e.g., tracheoesophageal fistula)

• Use of a nasogastric feeding tube

• Immediate symptoms: bronchospasms , dyspnea, wheezing and/or crackles, hypoxemia

• Late symptoms: fever, shortness of breath, cough

• Immediate symptoms: often none

• Late symptoms: fever, shortness of breath, cough with foul-smelling sputum

Clinical diagnosis supported by characteristic laboratory and imaging findings

• Laboratory and microbiological studies: same as for the diagnosis of pneumonia.

• ABG: e.g., ↓ PaO2

• Imaging: The lung region in which the infiltrates are seen depends on the patient's position on aspiration. [38][39]

  • Supine position: superior segment of the right lower lobe (most common site of aspiration)

  • Standing/sitting: posterior basal segment of the right lower lobe

  • Right lateral decubitus position: posterior segment of the right upper lobe or right middle lobe

• Acute aspiration: airway management and respiratory support

• Aspiration pneumonitis: typically requires supportive care only

• Aspiration pneumonia: antibiotic therapy following standard pneumonia treatment regimens

• All patients: supportive care for pneumonia

Complications

• Acute respiratory failure, acute respiratory distress syndrome (ARDS)

• Abscess

Prevention

• Treatment of underlying causes to reduce the risk of aspiration

• Aspiration precautions for patients with risk factors for aspiration

  • Regular oral care

  • Elevation of the head of the bed