Incremental value of thoracic ultrasound in intensive care units: Indications, uses, and applications

Abstract

Emergency physicians are required to care for unstable patients with life-threatening conditions, and thus must make decisions that are both quick and precise about unclear clinical situations. There is increasing consensus in favor of using ultrasound as a real-time bedside clinical tool for clinicians in emergency settings alongside the irreplaceable use of historical and physical examinations. B-mode sonography is an old technology that was first proposed for medical applications more than 50 years ago. Its application in the diagnosis of thoracic diseases has always been considered limited, due to the presence of air in the lung and the presence of the bones of the thoracic cage, which prevent the progression of the ultrasound beam. However, the close relationship between air and water in the lungs causes a variety of artifacts on ultrasounds. At the bedside, thoracic ultrasound is based primarily on the analysis of these artifacts, with the aim of improving accuracy and safety in the diagnosis and therapy of the various varieties of pulmonary pathologic diseases which are predominantly "water-rich" or "air-rich". The indications, contraindications, advantages, disadvantages, and techniques of thoracic ultrasound and its related procedures are analyzed in the present review.

Keywords: Echocardiography; Heart failure; Intensive care unit; Pleural effusion; Pneumothorax; Thoracic ultrasound.

Figure 1

Longitudinal approach with longitudinal probe; allow to see upper and lower ribs visible (a), along with their shadow’s cone, and pleural line (arrow).

Figure 2

Bat sign with convex probe. Consistsmake of two adjacent ribs with the pleural line between [upper and lower ribs are the “wings” of the “bat”(a), whileand, the pleural line that is the “back body” of the “bat” (arrow)]. Under Below the pleural line it is also possible to see two A-lines.

Figure 3

M-mode and seashore sign assist with, helps to the documentation of lung sliding on a picture.

Figure 4

A-lines. A: A-lines whit with convex probe; B: A-lines whit with sector probe. Arrow shows the pleural line, (a) shows A-lines.

Figure 5

B-lines. (a) shows B-lines.

Figure 6

Pleural effusion. Pleural effusion is an echo-free [dark zone (a)], which and determinates the compression of the lung that appears consolidated, and floating in the pleural effusion (arrow).

Figure 7

Loculated pleural effusion, which appears as a dark zone (a) and contains immobile septations (arrow) with encapsulated liquid.

Figure 8

Stratosphere sign. Pointing M-mode into the zone characterized by the abolition lack of lung sliding it shows a characteristic pattern, namely the stratosphere sign (as opposed to the normal seashore sign) (by image courtesy of Dr. Ilario De Sio).

Figure 9

Lung point (arrow). Is the precise area of the chest wall, where the regular reappearance of the lung sliding replaces the pneumothorax pattern and it corresponds to the point where the visceral and parietal pleura regain contact with each other (by image courtesy of Dr. Lucia Morelli).

Figure 10

M-mode, diaphragmatic excursion (see the text) (by image courtesy of Dr. Lucia Morelli).