Acute upper airway obstruction is a common pediatric problem caused by a variety of disorders (Table 118-1). The degree of severity of obstruction is variable, depending upon the underlying problem and the size of the airway.
TABLE 118-1 DIFFERENTIAL DIAGNOSIS OF UPPER AIRWAY OBSTRUCTION |Favorite Table|Download (.pdf) TABLE 118-1 DIFFERENTIAL DIAGNOSIS OF UPPER AIRWAY OBSTRUCTION
Foreign body impaction
Foreign body aspiration
Central Nervous System Disorders
Loss of airway protective mechanism
Acute respiratory failure involving the upper airways can be a life-threatening emergency that requires emergent action. Failure to rapidly assess and properly manage acute upper airway obstruction may lead to cardiopulmonary arrest in pediatric patients, who have less pulmonary reserve compared to adults. In this chapter, we will review pediatric upper airway anatomy and discuss the causes, presentation, evaluation, and management of acute upper airway obstruction.
PEDIATRIC AIRWAY CONSIDERATIONS
Compared to adults, pediatric patients have a larger occiput, larger tongue, shorter mandible, and prominent adenoids and tonsils (Fig. 118-1). These differences combine with a relatively smaller airway, lower functional residual capacity, higher peripheral airway resistance, and higher oxygen consumption to put infants and young children at higher risk for decompensation from an upper airway obstruction.
Anatomical differences in pediatric airways.
During inspiration, loose supraglottic tissues collapse inward due to negative inspiratory pressures and then freely enlarge on expiration. This yields characteristic inspiratory stridor in children with supraglottic disorders such as laryngomalacia and supraglottic stenosis. By comparison, the subglottic region is completely encircled by the cricoid cartilage, giving it a fixed size essentially unaffected by airway pressure. Thus, disorders in the subglottic region resulting in decreased lumen size typically produce biphasic stridor, as seen in croup or foreign body aspiration.
Laryngotracheobronchitis, commonly known as croup, is a viral infection resulting in inflammation of the glottis and subglottis. This inflammation or edema produces a characteristic barking cough. Croup is both the most common cause of stridor and infectious cause of upper airway obstruction, affecting up to 5% of all children. The vast majority of cases occur between 6 months and 3 years of age, although croup can afflict older children. Croup has been associated with a number of different viruses, many of which are given in Table 118-2.
TABLE 118-2 INFECTIOUS AGENTS CAUSING CROUP