Lung ultrasound (LUS) is a point-of-care ultrasound technique that assesses the pleural interface and lung parenchyma for pneumothorax, pulmonary edema, pneumonia, and pleural effusion. Though lung tissue itself cannot be directly imaged with ultrasound, characteristic artifact patterns at the pleural line provide highly accurate diagnostic information.
The presence of lung sliding (pleural movement with respiration) effectively rules out pneumothorax at the examined site. B-lines — comet-tail artifacts arising from the pleural line — indicate interstitial fluid and are graded for severity of pulmonary congestion. Consolidation appears as tissue-like echogenicity with dynamic air bronchograms. Pleural effusion is visible as an anechoic space above the diaphragm. The BLUE protocol and FALLS protocol systematize LUS for undifferentiated dyspnea and shock.
Lung ultrasound competency is incorporated into critical care, emergency, and anesthesia training as well as advanced diagnostic sonography programs. Sonographers in ICUs and emergency departments apply LUS as an adjunct to full chest assessment. The technique’s high sensitivity for pneumothorax and pulmonary edema — superior to supine chest X-ray — makes it one of the most impactful POCUS applications in clinical medicine.