Pediatric emergency medicine trisk 2761 2761

Oxygen dissociation (e.g.,
methemoglobinemia, carbon monoxide,
or cyanide poisoning)
Hypothermia, hyperthermia
Sepsis
Obstructive sleep apnea syndrome
Acute chest syndrome in patients with
sickle cell anemia
Causes of acute respiratory failure can also be categorized with consideration
of location in the respiratory system ( Table 99.1 ). In addition to primary
pulmonary disease, many disorders outside the respiratory tract can lead to
respiratory failure.
Primary pulmonary conditions must be considered. Parenchymal lung disease
can lead to acute respiratory failure, particularly in younger children, and those
with underlying cardiopulmonary disease (e.g., bronchopulmonary dysplasia
[BPD] or congenital heart disease). In such cases, the additional respiratory
embarrassment from acute pulmonary infection can push these patients into
respiratory failure.
Any condition that causes further narrowing or collapse of the intrinsically
small pediatric airway can have a profound effect on air flow. Edema from
infectious, allergic, or caustic etiologies; foreign material in the airway; or
obstruction by enlarged or compressing anatomic structures can restrict airflow.
These may occur in isolation or in combination.
Asthma is the most common etiology for lower airway disease, but infections
such as bronchiolitis or viral pneumonia are also common. Foreign-body
aspiration can present acutely with airway obstruction, or may be a delayed
diagnosis following the development of secondary postobstructive atelectasis,
edema, or pneumonia.
Chest wall deformities and mechanical impairments prevent full expansion of
the chest, leading to decreased vital capacity, decreased minute ventilation, and
resultant hypercapnia. Inefficient respiratory efforts can cause subsequent

hypoxia. Oftentimes, these patients maintain near-normal respiratory function
until additional physiologic compromise occurs, often from illness as minor as an
upper respiratory infection.
Disruption of nonpulmonary respiratory physiology often results from either
reversible or irreversible causes of central nervous system (CNS) disease. CNS
disease may result in depressed respiratory drive, or inability to maintain