0071643192.pdf

Risk factors include any process that alters the gag/cough reflex.

■ Drug or alcohol intoxication

■ General anesthesia/sedation

■ Use of the esophageal obturator airway

■ Seizures

■ Brain injury and dementia

PATHOPHYSIOLOGY

■ Aspiration of gastric contents →immediate inflammatory response and

chemical pneumonitis.

■ Aspiration of bacterial pathogens →delayed polymicrobial pneumonia.

■ Severity of the insult depends on the volume of the aspirate, presence of

particulate matter, and the pH of the material. High-risk aspirates include

those with volumes>25 mL,particulate food matter,a low pH, and bac-

terial contamination.

SYMPTOMS/EXAM

■ Aspiration event may be immediately followed by coughing or choking in

the awake patient.

■ Tachypnea, shortness of breath

■ Cough productive of bloody or purulent sputum

■ Wheezing, rhonchi, or rales over involved lung fields

DIAGNOSIS

■ Suspect based on clinical history and presentation.

■ CXR:May be completely normal immediately after event; infiltrate will

appear, most frequently in the RLL, within the first 12 hours

TREATMENT

■ Supportive care

■ Indications for antibiotic therapy (piperacillin-tazobactam or clindamycin)

include:

■ Unexplained deterioration

■ Expanding infiltrate

■ New fever >36 hours after aspiration event

■ Avoid: Systemic corticosteroids, which are of no benefit and may be harmful

COMPLICATIONS

■ Respiratory failure and shock

■ Empyema/abscess development

■ Pulmonary fibrosis

■ If the pH of the aspirated material is <2.5, the lungs have suffered a chemi-

cal burn in addition to the ensuing 2° bacterial infection, and the mortal-

ity rate may be as high as 70%.

Lung Abscess

A lung abscess is defined as necrosis of the lung parenchyma by a microbial

infection, most commonly associated with aspiration.

CAUSES

Common organisms include

■ Anaerobes (most common)

■ S. aureus

THORACIC AND RESPIRATORY

DISORDERS