It accounts for 10% of pediatric visits to the ED, 20% of pediatric admissions, and

20% of deaths in infants. Respiratory distress can potentially lead to respiratory failure (the inability of oxygen ­

ation and ventilation to meet metabolic demands) and

should be recognized and treated promptly.

Several anatomic and physiologic characteristics put

pediatric patients at higher risk for respiratory compro ­

mise. Infants <4 months of age are obligate nose breathers.

Nasopharyngeal obstruction significantly increases the

work of breathing. The location of the narrowest part of

the airway, where a foreign body is likely to lodge, differs in

adults (vocal cords) and children (cricoid cartilage). The

diameter of the pediatric airway is a third that of adults.

Narrowing of the airway leads to a greater relative increase

in resistance to airflow ( 1-mm occlusion decreases crosssectional diameter by 20% in adults vs. 75% in children).

Abdominal musculature is a primary contributor to respiratory effort in children. Abdominal distension and muscle

fatigue can negatively impact ventilation. Pediatric 1 ungs

have a lower functional residual capacity (FRC) with less

reserve potential. PaO 2 decreases more rapidly when ventilation is interrupted.

• Initial treatment may be req uired for sta bil ization

before a complete history and physical examination

can be performed.

• Patient appearance and clinical status always

su persede lab va l ues and imaging.

Respiratory distress may result from either upper air ­

way obstruction, lower airway disorders, or other organ

dysfunction compromising the respiratory system. Upper

airway obstruction is the leading cause of life-threatening

acute respiratory distress. Upper airway obstruction is

defined as blockage of airflow in the larynx or trachea. It is

characterized by stridor, an inspiratory sound caused by air

flow through a partially obstructed upper airway. The age

of the patient can aid in diagnosis.

Common causes of upper airway obstruction in chil ­

dren <6 months include laryngotracheomalacia (chronic,

usually resolves by age 2) and vocal cord paresis or

paralysis. Laryngomalacia and tracheomalacia are con ­

genital conditions that affect the structural integrity of

supporting structures in the upper airway. This leads to

collapse of the affected tissues into the airway during

respiration.

In children >6 months, important causes of upper airway obstruction include viral croup, foreign body aspiration, epiglottitis, bacterial tracheitis, retropharyngeal

abscess, peritonsillar abscess, airway edema from trauma,

thermal or chemical burn, or allergic reaction. Croup

(laryngotracheobronchitis) is the most common cause of

upper airway obstruction and stridor in children aged

3 months to 3 years. It occurs in 5% of children during

their second year of life and is caused by a viral infection

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RESPIRATORY DISTRESS

affecting the subglottic region. The patient presents with a

barking cough, inspiratory stridor, and fever.

Upper airway obstruction from foreign body aspiration

is most common in children aged 1 to 4 years. About

3,000 patients die each year from asphyxia related to foreign body aspiration.

Bacterial infections in the upper airway include epiglottitis and tracheitis. Epiglottitis is less common now since

routine immunization against Haemophilus influenzae type B.

Currently, tracheitis is more likely to be the cause of acute

respiratory failure from airway obstruction than epiglottitis.

Lower airway obstruction has several causes, including

asthma, bronchiolitis, pneumonia, allergic reaction, respiratory distress syndrome, aspiration, and environmental or

traumatic insults. Asthma is the most common chronic

disease in children, affecting 5-10% of the population.

Bronchiolitis is most famously caused by respiratory syncytial virus (RSV), although other pathogens include parainfluenza, influenza, and adenovirus. It is a respiratory

infection that causes inflammation of the bronchioles.

Edema and mucous production lead to obstruction of the

airways with V/Q mismatch and hypoxia. It is most common in infants 2 to 6 months and is associated with

increased likelihood of asthma developing in the future.