Fig. 1.

Procedure for detecting pleural effusion with ultrasound. To detect the presence or absence of pleural effusion with ultrasound, the patient is evaluated in the seated position (A) and the supine position (B). With the patient in the seated position (A), the researcher slides the longitudinally oriented transducer inferiorly from the lung apices. With the patient in the supine position (B), the researcher obtains a coronal view of the lung base. A pleural effusion is detected if the researcher identifies both a positive spine sign and free fluid