Pediatric emergency medicine trisk 4065 4065
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displacement of the point of maximal impulse; shift or alteration in the heart
tones; or new murmurs, gallops, or friction rubs.
Evaluation
The most important study when evaluating any patient with a thoracic emergency
is a high-quality chest radiograph. The radiographs of the chest in the
posteroanterior (PA) and lateral views should be performed in an upright position
(unless contraindicated by the patient’s condition). The width of the mediastinum
and the degree of mediastinal shift are much better seen in the upright chest
radiograph. Moreover, abnormalities in the lung, pleural cavity, and diaphragm
are also best appreciated in this view. When a pulmonary effusion exists, lateral
decubitus anteroposterior views of the chest or an ultrasound can be obtained to
determine whether the effusion layers freely or is loculated.
In interpreting the chest radiograph, the clinician should distinguish between a
diffuse pulmonary problem and a focal lesion. Hyperaeration of one portion of
the lung suggests air trapping in the involved lobe. Hyperaeration of the entire
lung field on one side is usually the result of compensatory enlargement of the
lung because of atelectasis and loss of lung volume on the opposite side.
Depending on the condition, laboratory studies and advanced imaging modalities
may be indicated.
AIRWAY COMPROMISE
Airway compromise can occur anywhere in the respiratory tract from the nose to
the alveolus. Obstructive emergencies relating to the oropharynx, larynx, and
proximal trachea are discussed in Chapters 106 ENT Trauma and 118 ENT
Emergencies . Compromise of the more distal tracheobronchial tree may be
caused by lesions in the lumen, in the wall, or external to the bronchus. Intrinsic
bronchial obstructions may result from narrowing of the lumen by a tumor (e.g.,
carcinoid tumor), foreign body, or a mucous plug. Obstruction from lesions in the
wall of the bronchus includes collapse from tracheomalacia and stenosis after
tracheostomy. Extrinsic lesions (e.g., bronchogenic cyst or inflamed lymph
nodes) become symptomatic when the compression impinges on a bronchus.
Table 124.1 lists intraluminal, mural, and extrinsic conditions that produce airway
obstruction.
The anatomic level of the obstruction correlates with its effects: An obstruction
of the distal tracheobronchial tree may lead to segmental lung overdistention or
segmental infection. An obstruction of the proximal trachea affects both lungs,
with a much greater likelihood of catastrophe for the patient. Similarly, greater
degrees of obstruction, as a rule, lead to greater effects on gas exchange and
