Pediatric emergency medicine trisk 1396 1396
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Musculoskeletal deformity or disease involving the support structures of the chest
may severely restrict lung expansion, limiting normal ventilatory efforts or
attempts at compensatory ventilation for respiratory dysfunction and other
systemic disturbances.
Intrathoracic conditions that may produce respiratory distress include air leak
and space-occupying lesions, including fluid collections and masses. Air leak
may be traumatic or spontaneous. Pneumothorax occurs when air enters the
pleural space either by chest wall penetration (open pneumothorax) or by rupture
of lung through the visceral pleura (closed pneumothorax) and causes collapse of
the lung. With tension pneumothorax, air is able to enter the pleural space but not
egress. Pneumothorax often presents with nonspecific signs of respiratory
distress, as well as ipsilateral chest wall hyperexpansion, decreased or absent
breath sounds, and hyperresonance to percussion. Rarely, a patient will have
bilateral pneumothoraces, in which case, the examination may be symmetric.
With tension pneumothorax, there is also jugular venous distension (JVD) and
deviation of the trachea and mediastinum away from the air leak. Tension
pneumothorax decreases venous return and thus cardiac output. It is therefore life
threatening and must be relieved immediately by needle thoracostomy. Pleural
effusion is another space-occupying lesion which may be caused by infection,
inflammation, ischemia, trauma, malignancy, major organ failure, drug
hypersensitivity, or venous or lymphatic obstruction. Physical examination
findings include decreased breath sounds and a pleural rub. Flail chest, caused by
multiple rib fractures and resulting in inefficient expansion of the thorax, is rare
in children given the deformability of their immature bones. Absence of rib
fractures does not preclude air leak, hemothorax, and/or pulmonary contusion.
Mass lesions include congenital or traumatic diaphragmatic hernia, esophageal
anomalies, benign or neoplastic masses, and vascular malformations (see Chapter
96 Neonatal Emergencies ). Pectus that restricts lung expansion may also
compromise ventilation.
Cardiovascular
Congenital and acquired heart disease may result in respiratory distress from
decreased cardiac output, reduced O2 saturation, and/or congestive heart failure
(CHF). Compromised cardiac output, most commonly caused by congenital
structural heart defects, cardiac arrhythmias, myocarditis, or pericarditis with
effusion may result in insufficient tissue O2 delivery to meet metabolic demands.
Pericardial tamponade causes decreased cardiac output as a result of
compromised cardiac filling. Classic physical examination findings of arterial
