Pulmonary diagnostics.

Term infants with respiratory distress may have extremely varied etiologies of their illnesses. These range from anatomical malformations to infectious or inflammatory conditions to genetic, metabolic, or neurological abnormalities. This article reviews the present array of diagnostic studies available to the clinician, including the physical examination, imaging (radiography, computed tomography, magnetic resonance imaging, ultrasound, and nuclear scanning techniques), lung mechanics and function testing, evaluation of gas exchange (blood gases, pulse oximetry, transcutaneous monitoring, and end-tidal carbon monoxide measurements), and anatomical studies (bronchoscopy and lung biopsy). These tests and procedures are reviewed and a stepwise approach recommended.