Bedside lung ultrasound in the care of the critically ill.

OBJECTIVE: To describe the technique and review the utility of bedside lung ultrasound in acute care.
SUMMARY: Lung ultrasound is a useful point-of-care investigation in acute care, especially in patients with dyspnoea or haemodynamic instability. Although normal lung parenchyma is not accessible to ultrasound, distinctive artefacts arising from parietal and visceral pleura indirectly imply the presence of normal lung. As aeration of lung tissue reduces with disease process, visual assessment of several pathologic entities by ultrasound becomes possible. Ultrasound can be used for qualitative and quantitative assessment as well as to guide intervention. Compared with supine anteroposterior chest x-rays, lung ultrasound is faster and superior at ruling out pneumothorax and diagnosing lung consolidation, pleural effusions or pulmonary oedema. It is a logical and highly valuable extension of echocardiography and can be incorporated into diagnostic algorithms for assessment of dyspnoea, hypotension, chest pain or trauma. It provides rapid information about potentially reversible pathology in cardiac arrest scenarios. Other advantages include bedside availability, repeatability, provision of dynamic diagnostic information, ease of use and the absence of radiation exposure.