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

Table 1 Appearance of different clinical settings

Clinical setting	Artifacts
Normal lung	Some air
Pneumothorax	Full of air
Interstitial syndrome	Air and minimal fluid
Pleural effusion	Full of fluid
Lung consolidation	Fluid and air (more fluid, tissue-like)

Table 2 Bedside Lung Ultrasound in Emergency protocol, profiles

Profile	Characteristic items	Diagnosis
A’ profile	Lack of lung sliding, and presence of lung point	Pneumothorax
B profile	Anterior lung sliding, with presence of lung comet tails	Acute pulmonary edema
B’ profile	Lung comet tails, with abolished anterior lung sliding	Pneumonia
A/B profile	Anterior predominant B lines on one side, and predominant A lines on the other	Pneumonia
C profile	Anterior alveolar consolidations	Pneumonia
A profile	Anterior lung sliding with A lines, and the presence of DVT	Pulmonary embolism
A-V-PLAPS-profile	Anterior lung sliding with A lines, PLAPS, absence of DVT	Pneumonia
Nude profile	Anterior lung sliding with A lines, absence of DVT or PLAPS	Severe asthma or exacerbated COPD

DVT: Depth venous thrombosis; PLAPS: Posterior and/or lateral alveolar and/or pleural syndrome; COPD: Chronic obstructive pulmonary disease.

Table 3 Thoracic ultrasound advantages

Thoracic ultrasound advantages
Rapid diagnosis
No limitation with setting, patient position, or clinical conditions
Differential diagnosis (e.g., chest pain, pulmonary edema, exacerbation of chronic obstructive pulmonary disease, subpulmonary effusion, subphrenic fluid accumulation, and tumors)
Diagnose presence and nature of pleural effusions
Guide invasive procedures (e.g., thoracentesis, chest tube placement, and biopsy)
Diagnose diaphragm paralysis
Diagnose localized pleural tumors or pleural thickening, assess invasion of the pleura and chest wall
Diagnose pneumothorax, drainage, or verify lung expansion
Few limitations in ventilated patients

Table 4 Acute respiratory disorders

Pleural effusion	Pleural effusion is an echo-free zone (dark zone) that causes lung consolidation and floating in the pleural effusion
	TUS allows the nature of the fluid to be distinguished:
	Transudate: Anechoic and echo-free pattern
	Exudate: Echogenic, with small moving dots (e.g., leukocytes, erythrocytes, fibrin, and protein particles), fibrous strings, and mobile or immobile septations with encapsulated liquid
	TUS allows for the quantification of pleural effusion volume
	Ultrasound may guide thoracentesis and biopsy of the parietal pleura
Pneumothorax	The interposition of gas between the visceral and parietal pleural layers, lack of lung sliding, and B-lines; only horizontal A-lines can be seen. Stratosphere sign is the characteristic pattern of the lack of lung sliding evaluated by M-mode. The lung point is the precise area of the chest wall where visceral and parietal pleura regain contact with each other, as well as where the regular reappearance of lung sliding replaces the pneumothorax pattern
Diaphragmatic function	A diaphragm study can be made by placing the probe below the costal margin and using M-mode to display the motion of the anatomical structures; normal inspiratory diaphragmatic movement is caudal, while normal expiratory trace is cranial. In M-mode, diaphragmatic excursion, speed of diaphragmatic contraction, inspiratory time, and duration of the cycle can be measured

TUS: Thoracic ultrasound.

Table 5 Comparative table of different acute respiratory disorders

	A-lines	B-lines	Lung sliding	Pulse	Particular characteristics
Normal	Present	Rare	Present	Present
Pneumothorax	Present	Never	Absent	Absent	Lung point
Pleural effusion	Absent	Absent	Absent	Absent	Presence of B-lines in cases of concomitant interstitial syndrome or pneumonia
Interstitial syndrome	Absent	Multiple	Present	Present	B-lines crowded and confluent (white lung)