ABSTRACT
Ultrasound (US) is considered an extension of a clinician’s physical examination and may even replace the common stethoscope.1 Point-of-care ultrasound (POCUS) is being used in many medical specialties, with published guidelines for POCUS training.2-6 Many residency programs have also made POCUS training mandatory in their curriculum.7,8
Physic principles dictate that air is an enemy to any US examination. Indeed, air acts as a mirror to completely reflect US beams. It seems logical to think the lung would not be the right candidate for POCUS. However, lungs are not only made of air, but from various combinations of lung parenchyma and physiologic or pathologic fluids. The passage of US beams through normal or pathologic lung creates artifacts. Lung US relies on the interpretation of these artifacts in combination with the clinical setting to make a diagnosis. By following a simple algorithm, it is easy to diagnose the most common thoracic and lung pathologies such as pleural eusion, pulmonary edema, acute respiratory distress syndrome (ARDS), pneumonia, and pneumothorax. Lung US is also useful to exclude esophageal and mainstem bronchial intubation. It can also diagnose diaphragmatic paralysis.
