CHAPTER 71 ■ RESPIRATORY DISTRESS DEBRA L WEINER, J KATE DEANEHAN INTRODUCTION Respiratory distress is one of the most common chief complaints of children seeking medical care It accounts for nearly 10% of pediatric emergency department visits and 20% of visits of children younger than years Twenty percent of patients admitted to the hospital and 30% of those admitted to intensive care units are admitted for respiratory distress Primary respiratory processes account for approximately 5% of deaths in children younger than 15 years and 20% in infants In addition, respiratory distress contributes substantially to deaths in patients with other primary processes Respiratory arrest is one of the five leading causes of death in pediatric patients Respiratory distress is usually reversible, but failure to treat the condition may result in cardiac arrest with longterm neurologic sequelae or death PATHOPHYSIOLOGY The primary goals of respiration are to meet metabolic demands for O2 and to eliminate CO2 Secondary functions include acid–base buffering, host defense, and hormonal regulation Exchange of O2 and CO2 between the lungs and the blood occurs at the alveolocapillary membrane and depends on adequate and appropriately matched ventilation and perfusion Control of respiration is mediated by central and peripheral neural mechanisms Respiration is an intrinsic brainstem function of the respiratory centers of the medulla It is further influenced by the cerebellum, which alters respiration with postural change; by the hypothalamus, which controls respiration on a moment-to-moment basis; by the limbic system, which modulates respiration in response to emotion; and by the motor cerebral cortex, which controls volitional respiratory activity, including hyper- and hypoventilation and speech Impulses are transmitted from the brain via the vagus and spinal nerves to the larynx, trachea, bronchi, bronchioles, and acini; the glossopharyngeal to the pharynx; the hypoglossal (CN XII) to the tongue; and the spinal accessory (CN XI) to accessory muscles Cervical nerves (C2 to C4), the phrenic nerve (C3 to C5), and the intercostal nerves (T1 to T12), innervate accessory muscles, the respiratory diaphragm, and intercostal muscles, respectively