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pulmonary aspiration; foreign body aspiration

Inspiratory suction into the airways of fluid or foreign body, such as saliva or vomitus. Etiology: 1) aspiration of gastric contents 2) aspiration of saliva or ingested substances 3) aspiration of foreign body Risk factors: 1) impaired consciousness 2) impaired pharyngeal or laryngeal function (see swallowing) a) myopathy b) neuropathy c) immediately postextubation 3) increased intragastric pressure or volume a) nausea/vomiting b) ileus c) tube feeding* [3] 4) esophageal disorders that predispose to reflux *tube feeding does not reduce risk of aspiration; it increases risk [3] Epidemiology: - most healthy people aspirate without any important clinical consequences [3] Pathology: 1) aspiration of inert liquids or foreign bodies a) airway obstruction b) acute respiratory distress c) hypoxemia 2) aspiration pneumonitis a) low pH (< 2.5) of aspirated gastric contents b) large volume of aspirate 3) aspiration pneumonia a) occurs in 40% of patients who aspirate b) most commonly 2-5 days after aspiration event c) mixed aerobic/anaerobic organisms Clinical manifestations: - sudden onset dyspnea, monophonic wheeze, history of stroke, normal chest X-ray suggests foreign body aspiration Special laboratory: - fiberoptic bronchoscopy if aspiration of foreign body suspected* - swallowing evaluation of uncertain benefit [3] - bedside water-swallow testing - single sips of <= 20 mL: sensitivity, 63%-71%; specificity, 90% - consecutive sips (100 mL without stopping): sensitivity, 91%; specificity, 53% - progressively increasing swallowing volume: sensitivity, 86%; specificity, 65% [4] * sudden onset dyspnea, monophonic wheeze, history of stroke, normal chest X-ray Radiology: - chest X-ray - aspiration of inert liquids or foreign bodies a) pulmonary infiltrates b) atelectasis c) lobar collapse - chest CT (image of chicken vertebrae) [5] Differential diagnosis: - universal choking sign may be observed if airway obstruction is in the upper airway Management: 1) aspiration of inert liquids or foreign bodies -> bronchoscopy (early) 2) aspiration pneumonitis (see aspiration pneumonitis) -> withold antibiotics until evidence of bacterial superinfection except in association with: 1] intestinal obstruction 2] gingivitis or periodontitis (severe) 3] immunocompromised host 3) aspiration pneumonia (see aspiration pneumonia) -> mixed aerobic/anaerobic organisms - clindamycin or penicillin G - coverage for hospitalized patients should include: - Staphylococcus aureus - gram negative bacteria 4) general a) nothing by mouth NPO b) nasogastric tube c) swallowing study if indicated

Related

aspiration pneumonia aspiration pneumonitis (Mendelson's syndrome) esophagus foreign body gastroesophageal reflux disease (GERD) larynx pharynx swallowing (deglutition) trachea

Specific

meconium aspiration

General

lung disease aspiration sign/symptom

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 252-53
  2. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 993-4
  3. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  4. Brodsky MB, Suiter DM, Gonzalez-Fernandez M Screening Accuracy for Aspiration Using Bedside Water Swallow Tests: A Systematic Review and Meta-Analysis. Chest. 2016 Jul;150(1):148-63. PMID: 27102184
  5. Seah HM, Mautone M Aspiration of a Chicken Bone. Images in Clinical Medicine N Engl J Med 2018; 378:e25. May 3, 2018 PMID: 29719185 https://www.nejm.org/doi/full/10.1056/NEJMicm1713423