Respiratory system: Aspiration

Aspiration

Aspiration: the passage of food, fluid, or other foreign material into the trachea or lungs

Usually, the cough reflex removes material from the upper tract, and passage into the lower tract is prevented by the vocal cords and epiglottis

Complete obstruction of the upper tract inhibits the ability to speak or cough; blockage of the trachea is life-threatening due to inadequate oxygenation

 

The right lower lung is usually the lodging site of aspirated objects

Wherever in the tract the object lodges, it obstructs airflow beyond that point–obstruction of a bronchus à no air delivery and collapse distal to the obstruction (atelectasis)

 

Sharp pointed objects and fatty or irritating solids cause inflammation which causes swelling, edema, and bronchoconstriction à block airflow

Pointed objects may also form a “bridge” upon which other materials collect and cause obstruction

Peanuts and legumes may swell and become more firmly lodged

 

Irritating liquids (vomitus, alcohol, milk) enter many bronchi and cause severe inflammation and á secretion à worsen the obstruction, and impair lung expansion

Fluid aspiration is likely as liquid easily passes the epiglottis and vocal cords to enter the lower tract

 

If the alveoli are affected by inflammation, gas exchange is impaired; severe inflammation with the accompanying build-up of fluids is called aspiration pneumonia, which predisposes to infection

 

Respiratory distress syndrome (the extensive breakdown of alveolar and/or capillary membranes) may develop if inflammation is widespread

 

Toxic solvents may diffuse into the blood and cause systemic damage

 

The risk of fluid aspiration is increased while lying down:

• absence of gravity to assist in proper swallowing
• residual fluid in the mouth or pharynx may drip into the trachea
• more alveoli can be affected

Predisposition to Aspiration and Manifestations

Predisposition:

• Infants: put more objects in their mouths, and move around with them
• Post-operative clients: anesthesia depresses cough and swallows reflex; often supine
• After alcohol consumption: depresses protective reflexes
• Patients with stroke or other neurological damage: depressed cough and swallow reflex
• Lying down: see “fluid aspiration”
• Elderly: often supine, eat and drink while supine; muscle weakness

Manifestations:

• coughing and chocking (incomplete obstruction)
• wheezing ~ liquid aspiration
• dyspnea, tachypnea, tachycardia
• nasal flaring, abnormal chest movements
• hypoxia and cyanosis if severe/prolonged
• respiratory and cardiac arrest if larynx or trachea is totally obstructed