Table 4 Possible suggested causes for false-positive and negative results of bedside ultrasonography for the diagnosis of traumatic chest injuries

Pneumothorax

False positive

Achalasia

Pleural adhesions

Phrenic nerve palsy

Pulmonary fibrosis

Pulmonary atelectasis

Cardiopulmonary arrest

Congestive heart failure

Right main bronchus intubation

Subcutaneous chest emphysema

Acute respiratory distress syndrome

Significant concomitant lung contusion

Bullous emphysema/pulmonary blebs

Chronic obstructive pulmonary disease

High positive end expiratory pressure-ventilated patients

False negative

Lung remained in contact with the chest wall despite PTX

Operator, machine or transducer conditions

Cardiac movement with left lung sliding

Subcutaneous chest emphysema

Occult small pneumothorax

Hemothorax

False positive

Pleural effusion differential diagnoses

False negative

Minimal amount hemothorax

Subcutaneous emphysema

Lung contusion

False positive

Pulmonary fibrosis

Cardiogenic pulmonary edema

Acute respiratory distress syndrome

False negative

Subcutaneous emphysema

Inaccessible to ultrasound (retrosternal, paravertebral, etc.)