Respiratory emergencies.

Respiratory emergencies may originate from disease in the airways, thoracic vessels, and pulmonary parenchyma. Airway obstruction may be amenable to bronchoscopic therapies, including laser ablation photodynamic therapy (PDT) and stent placement. Asthma is common, but may be mimicked by endobronchial metastasis. Superior vena cava syndrome (SVCS) is seen most commonly with bronchogenic carcinoma and lymphoma. Emergent treatment need not precede tissue diagnosis in the absence of associated tracheal obstruction. Pulmonary embolism (PE) may now be diagnosed with spiral computed tomography (CT), but ventilation perfusion scintigraphy remains the first-line test. Parenchymal lung disease may result from infections, with neoplastic and iatrogenic etiologies. The incidence of Pneumocystis carinii pneumonia (PCP) is increasing among cancer patients, but it can be prevented by prophylaxis. Attempts to treat adult respiratory distress syndrome (ARDS) through modification of inflammatory mediators have been disappointing, and the prognosis remains poor.