Rapid and accurate diagnosis and treatment are crucial and problematic for patients admitted to an intensive care unit. The incorrect physical examination was extensively reported when the intensive care unit was admitted. Various methods of diagnostic imaging were developed, but most lacked sensitivity, availability and portability. When a short echocardiographic study is added to extend the physical examination, the diagnostic accuracy can be increased. Ultrasound (US) has grown rapidly and has been widely accepted. In a recent study up to 36 per cent of patients admitted to a non-cardiac intensive care unit had one or more occult heart defects. Intensive patients with thoracic and abdominal pathologies often require the ultrasound examination for prompt diagnosis and treatment, and prevent deterioration or death of the patient's disease. In this review article, we discussed the role of the United States in the intensive care unit and we concluded that the critical care community has a number of application points for ultrasound in the intensive care unit. The literature advances rapidly every year. Thoracic applications, such as lung, cardiac and diaphragm ultrasound, and brain ultrasound and procedural direction are the main topics of focus. The trend of the new studies is to demonstrate the diagnostic exactness of new ultrasound treatment methods and their impact on the daily practise of critical care.