Pleural effusion. Use of the semi-supine position for radiographic detection.

Chest radiographs of 100 routinely examined patients were evaluated to study the effectiveness of the oblique semi-supine position when attempting to identify pleural effusion. Comparisons were made to images obtained with the patient in the lateral decubitus position. Radiography was performed without noticeable discomfort for 62 patients in the lateral decubitus position and for 97 patients in the oblique semi-supine position. The visualization of free pleural fluid was not affected by the different body positions, but demonstration of encapsulated fluid was superior in views obtained with the patient in the oblique semi-supine posture. For most individuals with suspected pleural effusion, the oblique semi-supine position is preferable to the lateral decubitus position.