Basic principles and current applications of lung ultrasonography in the intensive care unit

Until recently, the sonographic visualization of pulmonary and pleural diseases was considered a poorly accessible method, due to the inability of sound to penetrate air-filled lung. Despite its limitations, lung ultrasonography is becoming an important diagnostic tool in a growing number of pathological situations such as pneumonia, atelectasis, interstitial-alveolar syndrome, pulmonary embolism, pneumothorax and pleural effusion. The low sensitivity of CXR and the difficulties of performing CT make this technique invaluable for bedside use in the intensive care unit. Lung ultrasonography is an easily repeatable and radiation-free technique, and therefore, an attractive imaging tool for use on a daily basis, especially in the management of critically ill patients.